DE102018132033A1 - Method and system for detecting at least one hazardous substance - Google Patents

Abstract

A method for the detection of at least one hazardous substance, in particular an explosive, on a sample, in particular in a spatial detection area, in which method a first optical spectrum of the sample is recorded during a first spectrum recording time window with a first optical spectroscopy method and with a second optical spectroscopy method a second optical spectrum of the sample is recorded during a second spectrum recording time window, the first and second optical spectroscopy methods differing, the first optical spectrum and the second optical spectrum being compared with provided reference spectra of the at least one hazardous substance in order to determine whether the at least one If there is or is not a hazardous substance on the sample so that it can be used in particular for security checks for all persons and objects to be checked, it is proposed that the first spectrum acquisition time window and the second spectrum acquisition time window at least partially overlap in time, in particular completely. An improved system for detecting at least one hazardous substance on a sample is also proposed.

Description

The present invention relates to a method for detecting at least one hazardous substance, in particular an explosive, on a sample, in particular in a spatial detection area, in which method a first optical spectrum of the sample is recorded during a first spectrum recording time window using a first optical spectroscopy method, and with a second optical spectroscopy method, a second optical spectrum of the sample is recorded during a second spectrum recording time window, the first and second optical spectroscopy methods differing, the first optical spectrum and the second optical spectrum being compared with provided reference spectra of the at least one hazardous substance to determine whether the at least one hazardous substance is present on the sample or not.

The invention further relates to a system for detecting at least one hazardous substance, in particular an explosive, on a sample, in particular in a spatial detection area, which system includes a first optical spectroscopy device for recording a first optical spectrum of the sample during a first spectrum recording time window and a second optical spectroscopy device for recording a second optical spectrum of the sample during a second spectrum recording time window, the first and the second optical spectroscopy device differing, the system comprising an evaluation device for comparing the first optical spectrum and the second optical spectrum with provided reference spectra of the at least one hazardous substance and to determine whether the at least one hazardous substance is present on the sample or not.

In particular when carrying out security checks, for example at border crossings or at airports, different devices are used, in particular security scanners, X-ray devices and metal detectors with which dangerous objects can be detected. However, it is not possible with these devices to directly recognize or identify hazardous substances, such as explosives or explosives in particular. So far, direct detection of such hazardous substances has only been shown in large quantities of pure substance under laboratory conditions. Therefore, during the security checks, sample swabs from suspicious surfaces are still only taken on a random basis in order to check a person and in particular their luggage for contamination and contact with a hazardous substance. So far, this sample has been analyzed in an additional control step.

It is known to characterize chemical substances by means of optical spectroscopy. Raman spectroscopy and infrared spectroscopy are used here in particular. In infrared spectroscopy, the wavelength of the light that excites the sample is tuned and the absorption of the sample is determined as a function of the excitation wavelength. Absorption bands arise in particular at wavelengths which correspond to a molecular oscillation or rotation of the molecule. Raman spectroscopy examines the inelastic scattering of light on molecules. The sample is exposed to light of a very short wavelength. The wavelength of backscattered light is shifted towards longer wavelengths due to the interaction with molecules of the sample. The intensity of the backscattered light is measured with a wavelength-dependent detector. A shift in the wavelength corresponds to a specific vibration of the molecule.

A problem with the detection of hazardous substances is, in particular, that the known methods are very time-consuming, so that detection in real time has so far been practically impossible. The use of systems of the type described at the beginning in security checks is therefore not possible in practice, since the measurement times required take too long to check in particular every person and every piece of luggage for hazardous substances.

It is therefore an object of the present invention to improve a method and a system of the type described at the outset in such a way that it can be used in particular in security checks for all persons and objects to be checked.

This object is achieved according to the invention in a method of the type described in the introduction in that the first spectrum acquisition time window and the second spectrum acquisition time window overlap at least partially in time. In particular, the two spectrum acquisition time windows completely overlap.

The solution proposed according to the invention makes it possible, in particular, to use two spectroscopy methods simultaneously or at least partially simultaneously in order to check a sample, for example a piece of clothing or a piece of luggage, for hazardous substances. By using two different spectroscopy methods, more extensive measurement data can be recorded with which the sample, especially hazardous substances on it, can be characterized reliably and quickly. For example, two different optical spectra can be recorded simultaneously, which can then be compared with corresponding reference spectra of different hazardous substances. If there is a match, there is evidence with very high reliability that one or more hazardous substances are attached to the sample. In the evaluation, it is in particular not absolutely necessary, but it is possible to record the two spectra separately and to compare them with separate spectra of different spectroscopy methods. Rather, it is also possible to process the acquired measurement data of both spectroscopy methods together in a single data record and to compare them with a corresponding reference data record of the reference data records of one or more hazardous substances. This procedure enables efficient and fast data processing, in particular a quick comparison of the acquired measurement data with known reference data. In particular, the first spectrum recording time window can be identical to the second spectrum recording time window. Furthermore, the one spectrum acquisition time window can be completely covered by the other spectrum acquisition time window. It is also advantageous if the spectroscopy methods differ in such a way that there can be no interactions in the measurements. This is possible in particular if the measurements take place in different spectral ranges, for example on the one hand in the infrared spectral range and on the other hand in the ultraviolet spectral range.

It is advantageous if the first and second optical spectra of the sample are recorded when the sample is arranged in a spatially predetermined detection area. In this way it can be ensured that an examination of the sample is only actually carried out if it is in the predetermined detection range. For example, the detection area during the security check at an airport can be a spatially delimited area predetermined by a security gate. In particular, this can be when walking through or standing in a metal detector or else an area specified by a body scanner.

It is advantageous if the first optical spectroscopy method is infrared spectroscopy and if an infrared spectrum is recorded from the sample as the first spectrum. In particular, the spectroscopic method can be MIR reflection spectroscopy. In this method, the wavelength of an MIR laser is continuously tuned, in particular changed after a certain number of pulses emitted by the laser. An absorption of the MIR laser radiation by the sample is measured in backscatter geometry, so that an absorption spectrum of a surface of the sample is obtained after a complete measurement cycle.

It is advantageous if first pulsed electromagnetic radiation is applied to the sample in order to record the first optical spectrum and if an intensity of first scattered radiation scattered back from the sample is detected. A large number of individual measurements can be carried out in this way. For example, each pulse of electromagnetic radiation can be used to interact with the sample and the first scattered radiation that is scattered back by the sample can be detected. In particular, an absorption spectrum of the sample can be recorded in a simple manner.

It is favorable if a wavelength of the first pulsed electromagnetic radiation is tuned during the first spectrum recording time window and if the intensity of the first scattered radiation is detected as a function of the wavelength of the first pulsed electromagnetic radiation. For example, the wavelength of the first pulsed electromagnetic radiation can be changed after a certain number of pulses. The more individual measurements are carried out at the same wavelength, the better the signal-to-noise ratio of the measurement.

The first pulsed electromagnetic radiation is preferably generated with a first radiation source. In particular, the first radiation source can be a first laser, more particularly an IR laser. A laser can provide the required intensity of the first pulsed electromagnetic radiation, which is required to record meaningful optical spectra.

Furthermore, it is advantageous if the first pulsed electromagnetic radiation is scanned over the sample. In particular, it can be scanned one-dimensionally or two-dimensionally over the sample. This has the particular advantage that the sample can be examined over a large area, and depending on the total measurement time available and taking into account a deflection or scanning speed, a large number of individual measurements can be carried out not only in identical but in different spatial areas of the sample .

According to a further preferred variant of the method, it can be provided that the second optical spectroscopy method is Raman spectroscopy and that a Raman spectrum is recorded from the sample as the second spectrum becomes. In particular, Raman spectroscopy can be UV Raman spectroscopy. With this spectroscopic method, the sample is exposed to ultraviolet radiation.

It is advantageous if second pulsed electromagnetic radiation is applied to the sample in order to record the second optical spectrum and if an intensity of second scattered radiation scattered back from the sample is detected in a spectrally resolved manner. Due to the interaction of the second pulsed electromagnetic radiation with the sample, second scattered radiation is scattered back, which in Raman spectroscopy shows characteristic Stokes lines and anti-Stokes lines adjacent to the frequency of the pulsed electromagnetic radiation with wavelength-dependent detection. Distances of the respective detected lines from one another or from the wavelength of the second pulsed electromagnetic radiation correspond to oscillation frequencies of the backscattering molecules. A shift towards longer wavelengths occurs when a molecule absorbs energy from the radiation field. The energy difference corresponds to the energy of a vibrational state of the molecule. Both in IR spectroscopy and in Raman spectroscopy, vibrational bands of molecules that are characteristic of them are detected. In particular, the position and the intensity of the respective signals in the spectra can be used to infer characteristic vibrations of certain molecules.

For Raman spectroscopy in particular, it is advantageous if the wavelength of the second pulsed electromagnetic radiation is kept constant during the second spectrum recording time window. Thus, during the second spectrum acquisition time window, a number of individual measurements corresponding to the number of radiation pulses can be carried out, the signals of which can be added up to form an overall spectrum.

The second pulsed electromagnetic radiation is advantageously generated with a second radiation source. In particular, this can be a second laser, for example a UV laser. Lasers have the particular advantage that high intensities of the electromagnetic radiation can be provided. This is particularly advantageous in Raman spectroscopy, since this is the only way to obtain a detectable measurement signal.

In order in particular to be able to examine and characterize the sample over a large area, it is advantageous if the second pulsed electromagnetic radiation is scanned over the sample. In particular, it can be scanned one-dimensionally or two-dimensionally over the sample.

Furthermore, it is advantageous if the first pulsed electromagnetic radiation is generated at a first repetition rate and that the second pulsed electromagnetic radiation is generated at a second repetition rate, and if the first repetition rate and the second repetition rate are identical or different. With identical repetition rates, synchronous measurements in particular can be carried out. This means that pulses of the first and second electromagnetic radiation are simultaneously sent to the sample, which then interact with it. Scattered radiation backscattered from the sample is then detected. If the repetition rates are different, so-called crosstalk effects can be minimized in a simple manner. Furthermore, the best possible signal-to-noise ratio for the measured spectra can be achieved in a maximum of a short time. Asynchronous means in particular that pulses of the first and second electromagnetic radiation do not strike the sample at the same time, but at different times or only partially overlapping in time.

Furthermore, it is expedient if the sample is subjected to the first pulsed electromagnetic radiation and the second pulsed electromagnetic radiation in synchronism and if the first scattered radiation and second scattered radiation scattered back from the sample are detected synchronously. The sample can thus be characterized in a very short time using two different optical spectroscopy methods. Additional, redundant or complementary information about the sample to be characterized can thus be obtained, which help to shorten an overall measurement time.

Alternatively, it may be advantageous if the first pulsed electromagnetic radiation and the second pulsed electromagnetic radiation are applied to the sample asynchronously and if the first scattered radiation and second scattered radiation backscattered by the sample are detected asynchronously. In this way, crosstalk effects in particular can be eliminated and, moreover, two different optical spectra of the sample can be recorded in the shortest possible time with the best possible signal-to-noise ratio.

It is expedient if a distance of the sample from the first radiation source and / or from the second radiation source is determined by a transit time measurement of the pulses of the first pulsed electromagnetic radiation and / or the second pulsed electromagnetic radiation. In particular, it can be checked whether the signals actually correlate to the preset distance between the radiation sources and the sample. It is also possible to use this additionally determined information in order to further increase the sensitivity and thus the reliability of the method increase. In particular, taking into account the determined transit time, measurement time windows can be defined automatically, the temporal width of which corresponds in particular to a width of the pulse of electromagnetic radiation. The signals can then actually be determined via these measurement time windows, so that a DC value can be output as a signal for each of these measurement time windows. Furthermore, a background measurement time window in which only a background signal is expected is also automatically determined for each of the two spectroscopic methods. A background-free measurement signal then results from the difference between the signals in the measurement time windows on the one hand and the background measurement time windows on the other. In particular, interference, for example caused by sunlight or room lighting, can be effectively suppressed.

It is expedient if the first spectrum recording time window is divided into a plurality of first measuring intervals, if a pulse of the first electromagnetic radiation with a first pulse width is generated in every first measuring interval, and if the first scattered radiation is detected in a first measuring time window of the first measuring interval. This procedure has the particular advantage that a large number of individual measurements can be carried out in each spectrum recording time window for each of the two optical spectroscopy methods. In particular, a signal-to-noise ratio can be significantly improved. Furthermore, by precisely specifying a time delay of the first measurement time window with respect to each pulse of electromagnetic radiation, it can be ensured that only backscattered radiation from the sample is detected, but not the pulsed electromagnetic radiation that is generated by the first radiation source.

In order to avoid interference in particular, it is advantageous if the first measurement time window has a duration that corresponds to the first pulse width. In particular, this enables measurement signals to be averaged over time in the first measurement time window, for example with a field programmable gate array (FPGA).

The sensitivity of the spectroscopic examination can be increased, in particular, by the pulse width corresponding to a maximum of 10% of the first measurement interval. This corresponds to a low duty cycle of a maximum of 10%. In this way, a distance to the sample can be determined, in particular, over a transit time of the respective pulse of electromagnetic radiation. Furthermore, measurement time windows and background measurement time windows can be specified in a targeted manner as described.

It is advantageous if, in every first measurement interval after each first measurement time window, first background radiation is detected in a first background measurement time window. By forming the difference between the signals in every first measurement time window and in every first background measurement time window, a background-free measurement signal can be obtained by which interference can be effectively suppressed.

It is advantageous if the first background window has a duration that corresponds to the first pulse width. In particular, if the first measurement time window also has a time duration that corresponds to the first pulse width, any background radiation can thus be eliminated in a simple manner by forming a difference by means of a difference measurement.

To determine a background-free measurement signal, it is expedient if a difference is formed between the detected first scattered radiation and the detected first background radiation in order to determine the first optical spectrum.

According to a further preferred variant of the method according to the invention, it can be provided that the second spectrum recording time window is divided into a plurality of second measuring intervals, that a pulse of the second electromagnetic radiation with a second pulse width is generated in every second measuring interval and that the second scattered radiation is in a second measuring time window of the second measurement interval is detected. In particular, the second scattered radiation can be detected independently of the pulse of the second electromagnetic radiation, so that interference from the pulse on the measurement signal can be avoided.

The second measurement time window preferably has a time duration which corresponds to the second pulse width. In this way it can in particular be achieved that the second scattered radiation, which is obtained due to the interaction of the pulse of the second electromagnetic radiation with the sample, can be completely detected.

The second pulse width advantageously corresponds to a maximum of 10% of the second measurement interval. As already described above, such a sensitivity of the method can be increased by a duty cycle of a maximum of 10%.

Furthermore, it is advantageous if, in every second measurement interval after every second measurement time window, a second background radiation is detected in a second background measurement time window. Here too, as described, there can be a difference between the Measurement signal in the second measurement time window and the measurement signal in the second background measurement time window are formed in order to eliminate the background radiation and thus any interference.

It is advantageous if the second background measurement window has a duration that corresponds to the first pulse width. In particular, if the second measurement time window also has a duration that corresponds to the second pulse width, measurement signals can be averaged over both the second measurement time window and the second background time window. Furthermore, a background-free measurement signal can be obtained in a simple manner by forming the difference.

It is expedient if, in order to determine the second optical spectrum, a difference is formed between the detected second scattered radiation and the detected second background radiation. In this way, interference such as, in particular, sunlight or room lighting can be reliably eliminated.

The method can be carried out in a particularly simple manner if the first pulse width and the second pulse width are specified identically. In particular in the case of a synchronous measurement with synchronously generated pulses of the first and second electromagnetic radiation, a sample can be characterized with high accuracy in the shortest possible time.

The object stated at the outset is further achieved according to the invention in a system of the type described in the introduction in that the first spectrum recording time window and the second spectrum recording time window overlap at least partially in time. In particular, the spectrum acquisition time windows can completely overlap.

As already explained in detail above, two different optical spectra can be recorded significantly faster at the same time or in comparison to a serial measurement. This makes it possible, in particular, to use such a system, for example for personal checks, for example for passenger checks at airports. The sample can be characterized in a completely contactless manner and from a predetermined distance in the manner described. In particular, the proposed system can improve reliability in characterizing the sample as to whether there are any hazardous substances attached to it. In particular, an intensity of the electromagnetic radiation provided by the spectroscopy devices can be kept below a predetermined limit value in order to avoid a health hazard. In particular, such a system can be used at the same time if, for example, a passenger is examined for dangerous objects using a security scanner. With the system, for example, it can be checked in parallel and without contact in the lower leg area. The sample then forms, for example, the passenger's shoes or trousers. In addition, the system can be designed such that a measurement cannot be perceived by the person being examined, which is particularly possible if spectroscopy is carried out in optical spectral ranges that lie outside the visible spectral range, for example in the infrared spectral range and in the ultraviolet spectral range.

It is expedient if the system comprises a spatially predetermined detection area, in which the sample for recording the first and second optical spectra is arranged. For example, the detection area for a person can be specified by marking on a floor. The detection area can also be defined by a three-dimensionally limited space, as is the case with a body scanner, for example.

The first optical spectroscopy device preferably comprises or is an infrared spectrometer. In particular, it can be designed in the form of a MIR reflection spectrometer. Absorption spectra in the infrared, for example in the middle infrared, spectral range can be recorded directly with an infrared spectrometer. A weakening of the excitation radiation by the sample is measured depending on the wave. Infrared radiation is particularly absorbed when molecules are excited to vibrate or rotate.

It is advantageous if the first spectroscopy device comprises a first radiation source for generating first pulsed electromagnetic radiation and a first detector for measuring an intensity of first scattered radiation scattered back from the sample. In particular, the first scattered radiation can be measured in a correlated manner, which is reflected back by the first pulsed electromagnetic radiation due to the interaction with the sample.

The first radiation source is preferably designed to tune a wavelength of the first pulsed electromagnetic radiation during the first spectrum recording time window. The first optical spectroscopy device can be used to record an absorption of the sample depending on the wavelength. Absorption maxima always result for the sample at those wavelengths at which vibrations or rotations of the molecules are excited. Each Such vibrations and rotations are characteristic of molecules because of their structure. An infrared spectrum of a molecule represents a “fingerprint” of the molecule.

In order to be able to provide a sufficient radiation intensity for the recording of infrared spectra, it is advantageous if the first radiation source is designed in the form of a first laser. In particular, it can be designed in the form of an IR laser. For example, the laser can be designed in the form of a tunable, pulsed quantum cascade laser with a tuning range from 6 μm to 11.5 μm. Such a laser can be used to achieve tuning speeds of up to 5000 cm ^-1 / s or even higher, in particular in a wavelength scan mode.

In order, in particular, not to be able to examine only a small area of the sample, it is advantageous if the system comprises a first scanning device for scanning the first pulsed electromagnetic radiation over the sample. In particular, the scanning device can be designed for one-dimensional or two-dimensional scanning. Line scans over the sample or area scans over the sample can thus be carried out. In this way, the likelihood of detection of hazardous substances if they are actually present on the sample can be significantly improved.

It is advantageous if the second optical spectroscopy device is or comprises a Raman spectrometer. In particular, it can be a UV Raman spectrometer. The Raman spectrometer can be used to determine the interaction of monochromatic radiation with a molecule which changes its polarizability when it rotates or oscillates. In addition to the irradiated frequency caused by the Rayleigh scattering, other signals are observed in the spectrum of the light scattered on the sample. Frequency differences from the incident light correspond to the energies of rotation, vibration, phonon or spin flip processes that are characteristic of the respective substance. Conclusions about the investigated substance can be drawn from the spectrum obtained, similar to an infrared spectrum. The lines appearing in a Raman spectrum are also referred to as Stokes lines and anti-Stokes lines.

It is expedient if the second spectroscopy device comprises a second radiation source for generating second pulsed electromagnetic radiation and a second detector for measuring the intensity of a second scattered radiation scattered back from the sample. With suitable detectors, different wavelengths can be detected simultaneously. For example, a corresponding photodiode array can be used. By pulsed exposure of the sample to electromagnetic radiation, a large number of individual measurements can then be carried out as described above, the signals of the individual measurements being added up in order to obtain the corresponding lines in the Raman spectrum sufficient to obtain the quality and intensity required for the presence certain molecules, in particular the hazardous substances to be detected, to be clearly determined.

For Raman spectroscopy in particular, it is advantageous if the second radiation source is designed to generate the second pulsed electromagnetic radiation with a constant wavelength.

So that in particular a sufficient intensity is available for carrying out Raman spectroscopic examinations, it is advantageous if the second radiation source is designed in the form of a second laser. In particular, it can be a UV laser. Ultraviolet radiation is not visible to humans, so the system can be used without a person controlled by this system becoming aware of the examination.

The system preferably comprises a second scanning device for scanning the second pulsed electromagnetic radiation over the sample. In particular, the sample can be scanned one-dimensionally or two-dimensionally. If the system comprises two scanning devices, these can in particular be designed such that they deflect the first pulsed electromagnetic radiation and the second pulsed electromagnetic radiation over the sample in such a way that they always scan different areas of the sample. In particular, undesirable interactions can be avoided in this way.

According to a further preferred embodiment of the invention, it can be provided that the first radiation source is designed to generate the first pulsed electromagnetic radiation with a first repetition rate and that the second radiation source is designed to generate the second pulsed electromagnetic radiation with a second repetition rate and that the first Repetition rate and the second repetition rate are identical or different. In particular with identical repetition rates, the optical spectra can be recorded completely synchronously with the two spectroscopy devices. In particular, the pulses of electromagnetic radiation can be simultaneously and with the same Apply the pulse duration or pulse width to the sample. Different repetition rates enable asynchronous measurements in particular. Pulses of electromagnetic radiation hit the sample for the different spectroscopy devices at different times. In particular, pulse lengths or pulse widths of the electromagnetic radiation can also be selected differently. In particular, crosstalk effects can be easily eliminated.

The system preferably comprises a distance determination device for determining a distance of the sample from the first radiation source and / or from the second radiation source. The distance determination device can in particular be designed to carry out a transit time measurement for the laser pulses. In particular, taking into account such distance information, which can be calculated from the running time of a laser pulse, a first and / or second measurement time window can be automatically specified at a time interval corresponding to the distance of the sample from the pulse of electromagnetic radiation. In particular, a measurement time window can also be specified in which scattered radiation, also referred to as retroreflection, can be measured from the sample, which was caused in each case by the pulsed electromagnetic radiation.

For the use of the system, it is favorable if it has an operating device for entering data. For example, data and settings required for operating the system can be made by a user.

The system advantageously comprises a control device for controlling the first and / or second optical spectroscopy device. With such a control device, the interaction of both spectroscopy devices can be optimized in particular. In particular, it can thus be ensured that the spectrum acquisition time windows overlap sufficiently, in particular completely overlap, in order to require the shortest possible time for an examination of the sample as a whole.

The system preferably comprises a storage device for storing reference spectra of hazardous substances and for storing the measured first and second optical spectra. Reference spectra are in particular also reference data that are provided by combining different optical spectra. It is then not necessary to compare two measured spectra with two reference spectra, but only a single comparison is required if the measured data are also combined with the two spectroscopy devices by suitable processing. In this way, an evaluation time can be shortened significantly.

The system preferably comprises an output device for outputting information as to whether or not the at least one hazardous substance is present on the sample. The output device can in particular output signals and information optically and / or acoustically. Contaminated samples can thus be selected in a simple manner and, if the result is positive, can also be additionally examined.

Furthermore, the use of one of the systems described above for carrying out one of the methods described above is proposed. Hazardous substances can then be detected simply, quickly and reliably in the manner described.

1. 1. Verfahren zum Detektieren von mindestens einem Gefahrstoff, insbesondere eines Explosivstoffs, an einer Probe (26), insbesondere in einem räumlichen Detektionsbereich (18), bei welchem Verfahren mit einem ersten optischen Spektroskopieverfahren ein erstes optisches Spektrum der Probe (26) während eines ersten Spektrumaufnahmezeitfensters (106) aufgenommen wird und mit einem zweiten optischen Spektroskopieverfahren ein zweites optisches Spektrum der Probe (26) während eines zweiten Spektrumaufnahmezeitfensters (108) aufgenommen wird, wobei sich das erste und das zweite optische Spektroskopieverfahren unterscheiden, wobei das erste optische Spektrum und das zweite optische Spektrum mit bereitgestellten Referenzspektren des mindestens einen Gefahrstoffs verglichen werden zum Bestimmen, ob der mindestens eine Gefahrstoff an der Probe (26) vorhanden ist oder nicht, dadurch gekennzeichnet, dass das erste Spektrumaufnahmezeitfenster (106) und das zweite Spektrumaufnahmezeitfenster (108) zeitlich mindestens teilweise überlappen, insbesondere vollständig.
2. 2. Verfahren nach Satz 1, dadurch gekennzeichnet, dass die ersten und zweiten optischen Spektren der Probe (26) dann aufgenommen werden, wenn die Probe (26) in einem räumlich vorgegebenen Detektionsbereich (18) angeordnet ist.
3. 3. Verfahren nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass das erste optische Spektroskopieverfahren Infrarotspektroskopie ist, insbesondere MIR-Reflexionsspektroskopie, und dass von der Probe (26) als erstes Spektrum ein Infrarotspektrum aufgenommen wird.
4. 4. Verfahren nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass zum Aufnehmen des ersten optischen Spektrums die Probe (26) mit erster gepulster elektromagnetischer Strahlung (50) beaufschlagt wird und dass eine Intensität von der Probe (26) zurückgestreuter erster Streustrahlung (58) detektiert wird.
5. 5. Verfahren nach Satz 4, dadurch gekennzeichnet, dass eine Wellenlänge der ersten gepulsten elektromagnetischen Strahlung (50) während des ersten Spektrumaufnahmezeitfensters (106) durchgestimmt wird und dass die Intensität der ersten Streustrahlung (58) in Abhängigkeit der Wellenlänge der ersten gepulsten elektromagnetischen Strahlung (50) detektiert wird.
6. 6. Verfahren nach Satz 4 oder 5, dadurch gekennzeichnet, dass die erste gepulste elektromagnetische Strahlung (50) mit einer ersten Strahlungsquelle (48), insbesondere in Form eines ersten Lasers (52), weiter insbesondere in Form eines IR-Lasers (54), erzeugt wird.
7. 7. Verfahren nach einem der Sätze 4 bis 6, dadurch gekennzeichnet, dass die erste gepulste elektromagnetische Strahlung (50) über die Probe (26) gescannt wird, insbesondere ein- oder zweidimensional.
8. 8. Verfahren nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass das zweite optische Spektroskopieverfahren Ramanspektroskopie ist, insbesondere UV-Raman-Spektroskopie, und dass von der Probe (26) als zweites Spektrum ein Raman-Spektrum aufgenommen wird.
9. 9. Verfahren nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass zum Aufnehmen des zweiten optischen Spektrums die Probe mit zweiter gepulster elektromagnetischer Strahlung (76) beaufschlagt wird und dass eine Intensität von der Probe (26) zurückgestreuter zweiter Streustrahlung (86) spektral aufgelöst detektiert wird.
10. 10. Verfahren nach Satz 9, dadurch gekennzeichnet, dass eine Wellenlänge der zweiten gepulsten elektromagnetischen Strahlung (76) während des zweiten Spektrumaufnahmezeitfensters (108) konstant gehalten wird.
11. 11. Verfahren nach Satz 9 oder 10, dadurch gekennzeichnet, dass die zweite gepulste elektromagnetische Strahlung (76) mit einer zweiten Strahlungsquelle (74), insbesondere in Form eines zweiten Lasers (78), weiter insbesondere in Form eines UV-Lasers (80), erzeugt wird.
12. 12. Verfahren nach einem der Sätze 9 bis 11, dadurch gekennzeichnet, dass die zweite gepulste elektromagnetische Strahlung (76) über die Probe (26) gescannt wird, insbesondere ein- oder zweidimensional.
13. 13. Verfahren nach einem der Sätze 9 bis 12, dadurch gekennzeichnet, dass die erste gepulste elektromagnetische Strahlung (50) mit einer ersten Repetitionsrate erzeugt wird und dass die zweite gepulste elektromagnetische Strahlung (76) mit einer zweiten Repetitionsrate erzeugt wird, und dass die erste Repetitionsrate und die zweite Repetitionsrate identisch oder unterschiedlich sind.
14. 14. Verfahren nach einem der Sätze 9 bis 13, dadurch gekennzeichnet, dass die Probe (26) mit der ersten gepulsten elektromagnetischen Strahlung (50) und der zweiten gepulsten elektromagnetischen Strahlung (76) synchron beaufschlagt wird und dass die von der Probe (26) rückgestreute erste Streustrahlung (60) und zweite Streustrahlung (86) synchron detektiert wird.
15. 15. Verfahren nach einem der Sätze 9 bis 14, dadurch gekennzeichnet, dass die Probe (26) mit der ersten gepulsten elektromagnetischen Strahlung (50) und der zweiten gepulsten elektromagnetischen Strahlung (76) asynchron beaufschlagt wird und dass die von der Probe (26) rückgestreute erste Streustrahlung (60) und zweite Streustrahlung (86) asynchron detektiert wird.
16. 16. Verfahren nach einem der Sätze 9 bis 15, dadurch gekennzeichnet, dass ein Abstand (58, 84) der Probe (26) von der ersten Strahlungsquelle (48) und/oder von der zweiten Strahlungsquelle (74) durch eine Laufzeitmessung der Pulse (110, 112) der ersten gepulsten elektromagnetischen Strahlung (50) und/oder der zweiten gepulsten elektromagnetischen Strahlung (76) bestimmt wird.
17. 17. Verfahren nach einem der Sätze 7 bis 16, dadurch gekennzeichnet, dass das erste Spektrumaufnahmezeitfenster (106) in eine Mehrzahl erster Messintervalle (M_n ) unterteilt wird und dass in jedem erstem Messintervall (M_n ) ein Puls (110) der ersten elektromagnetischen Strahlung (50) mit einer ersten Pulsbreite erzeugt wird, dass die erste Streustrahlung (60) in einem ersten Messzeitfenster (116) des ersten Messintervalls (M_n ) detektiert wird.
18. 18. Verfahren nach Satz 17, dadurch gekennzeichnet, dass das erste Messzeitfenster (116) eine Länge aufweist, welche der ersten Pulsbreite entspricht.
19. 19. Verfahren nach Satz 17 oder 18, dadurch gekennzeichnet, dass die erste Pulsbreite maximal 10% des ersten Messintervalls (M_n ) entspricht.
20. 20. Verfahren nach einem der Sätze 17 bis 19, dadurch gekennzeichnet, dass in jedem ersten Messintervall (M_n ) nach jedem ersten Messzeitfenster (116) in einem ersten Hintergrundmesszeitfenster (120) erste Hintergrundstrahlung detektiert wird.
21. 21. Verfahren nach Satz 20, dadurch gekennzeichnet, dass das erste Hintergrundmesszeitfenster (120) eine Länge aufweist, welche der ersten Pulsbreite entspricht.
22. 22. Verfahren nach Satz 20 oder 21, dadurch gekennzeichnet, dass zum Bestimmen des ersten optischen Spektrums eine Differenz zwischen der detektierten ersten Streustrahlung (60) und der detektierten ersten Hintergrundstrahlung gebildet wird.
23. 23. Verfahren nach einem der Sätze 9 bis 22, dadurch gekennzeichnet, dass das zweite Spektrumaufnahmezeitfenster (108) in eine Mehrzahl zweiter Messintervalle (R_m ) unterteilt wird und dass in jedem zweiten Messintervall (R_m ) ein Puls (112) der zweiten elektromagnetischen Strahlung (76) mit einer zweiten Pulsbreite erzeugt wird, dass die zweite Streustrahlung (86) in einem zweiten Messzeitfenster (118) des zweiten Messintervalls (R_m ) detektiert wird.
24. 24. Verfahren nach Satz 23, dadurch gekennzeichnet, dass das zweite Messzeitfenster (118) eine Länge aufweist, welche der zweiten Pulsbreite entspricht.
25. 25. Verfahren nach Satz 23 oder 24, dadurch gekennzeichnet, dass die zweite Pulsbreite maximal 10% des zweiten Messintervalls (R_m ) entspricht.
26. 26. Verfahren nach einem der Sätze 23 bis 25, dadurch gekennzeichnet, dass in jedem zweiten Messintervall (R_m ) nach jedem zweiten Messzeitfenster (118) in einem zweiten Hintergrundmesszeitfenster (122) zweite Hintergrundstrahlung detektiert wird.
27. 27. Verfahren nach Satz 26, dadurch gekennzeichnet, dass das zweite Hintergrundmesszeitfenster (122) eine Zeitdauer aufweist, welche der ersten Pulsbreite entspricht.
28. 28. Verfahren nach Satz 26 oder 27, dadurch gekennzeichnet, dass zum Bestimmen des zweiten optischen Spektrums eine Differenz zwischen der detektierten zweiten Streustrahlung und (86) der detektierten zweiten Hintergrundstrahlung gebildet wird.
29. 29. Verfahren nach einem der Sätze 23 bis 28, dadurch gekennzeichnet, dass die erste Pulsbreite und die zweite Pulsbreite identisch vorgegeben werden.
30. 30. System (10) zum Detektieren von mindestens einem Gefahrstoff, insbesondere eines Explosivstoffs, an einer Probe, insbesondere in einem räumlichen Detektionsbereich (18), welches System (10) eine erste optische Spektroskopieeinrichtung (28) zum Aufnehmen eines ersten optischen Spektrums der Probe (18) während eines ersten Spektrumaufnahmezeitfensters (106) und eine zweite optische Spektroskopieeinrichtung (30) zum Aufnehmen eines zweiten optischen Spektrums der Probe (18) während eines zweiten Spektrumaufnahmezeitfensters (108) umfasst, wobei sich die erste und die zweite optische Spektroskopieeinrichtung (28, 30) unterscheiden, wobei das System (10) eine Auswerteeinrichtung (42) umfasst zum Vergleichen des ersten optischen Spektrums und des zweiten optischen Spektrums mit bereitgestellten Referenzspektren des mindestens einen Gefahrstoffs und zum Bestimmen, ob der mindestens eine Gefahrstoff an der Probe (26) vorhanden ist oder nicht, dadurch gekennzeichnet, dass das erste Spektrumaufnahmezeitfenster (106) und das zweite Spektrumaufnahmezeitfenster (108) zeitlich mindestens teilweise überlappen, insbesondere vollständig.
31. 31. System nach Satz 30, dadurch gekennzeichnet, dass das System einen räumlich vorgegebenen Detektionsbereich (18) umfasst, in dem die Probe (26) zum Aufnehmen der ersten und zweiten optischen Spektren angeordnet ist.
32. 32. System nach Satz 30 oder 31, dadurch gekennzeichnet, dass die erste optische Spektroskopieeinrichtung (28) ein Infrarotspektrometer (44) ist oder umfasst, insbesondere ein MIR-Reflexionsspektrometer (46).
33. 33. System nach einem der Sätze 30 bis 32, dadurch gekennzeichnet, dass die erste Spektroskopieeinrichtung (28) eine erste Strahlungsquelle (48) zum Erzeugen erster gepulster elektromagnetischer Strahlung (50) umfasst und einen ersten Detektor (64) zum Messen einer Intensität von der Probe (26) zurückgestreuter erster Streustrahlung (60).
34. 34. System nach Satz 33, dadurch gekennzeichnet, dass die erste Strahlungsquelle (48) ausgebildet ist zum Durchstimmen einer Wellenlänge der ersten gepulsten elektromagnetischen Strahlung (50) während des ersten Spektrumaufnahmezeitfensters (106).
35. 35. System nach Satz 33 oder 34, dadurch gekennzeichnet, dass die erste Strahlungsquelle (48) in Form eines ersten Lasers (52) ausgebildet ist, insbesondere in Form eines IR-Lasers (54).
36. 36. System nach einem der Sätze 33 bis 35, dadurch gekennzeichnet, dass das System (10) eine erste Scaneinrichtung (38) umfasst zum Scannen der ersten gepulsten elektromagnetischen Strahlung (50) über die Probe (26), insbesondere ein- oder zweidimensional.
37. 37. System nach einem der Sätze 30 bis 36, dadurch gekennzeichnet, dass die zweite optische Spektroskopieeinrichtung (30) ein Ramanspektrometer (70) ist oder umfasst, insbesondere UV-Raman-Spektrometer (72).
38. 38. System nach einem der Sätze 30 bis 37, dadurch gekennzeichnet, dass die zweite Spektroskopieeinrichtung (30) eine zweite Strahlungsquelle (74) zum Erzeugen zweiter gepulster elektromagnetischer Strahlung (76) umfasst und einen zweiten Detektor (90) zum wellenlängenabhängigen Messen einer Intensität von der Probe (26) zurückgestreuter zweiter Streustrahlung (86).
39. 39. System nach Satz 38, dadurch gekennzeichnet, dass die zweite Strahlungsquelle (74) ausgebildet ist zum Erzeugen der zweiten gepulsten elektromagnetischen Strahlung (76) mit konstanter Wellenlänge.
40. 40. System nach Satz 38 oder 39, dadurch gekennzeichnet, dass die zweite Strahlungsquelle (74) in Form eines zweiten Lasers (78) ausgebildet ist, insbesondere in Form eines UV-Lasers (80).
41. 41. System nach einem der Sätze 38 bis 40, dadurch gekennzeichnet, dass das System (10) eine zweite Scaneinrichtung (40) umfasst zum Scannen der zweiten gepulsten elektromagnetischen Strahlung (76) über die Probe (26), insbesondere ein- oder zweidimensional.
42. 42. System nach einem der Sätze 38 bis 41, dadurch gekennzeichnet, dass die erste Strahlungsquelle (48) ausgebildet ist zum Erzeugen der ersten gepulsten elektromagnetischen Strahlung (50) mit einer ersten Repetitionsrate und dass die zweite Strahlungsquelle (74) ausgebildet ist zum Erzeugen der zweiten gepulsten elektromagnetischen Strahlung (76) mit einer zweiten Repetitionsrate und dass die erste Repetitionsrate und die zweite Repetitionsrate identisch oder unterschiedlich sind.
43. 43. System nach einem der Sätze 38 bis 42, dadurch gekennzeichnet, dass das System (10) eine Abstandsbestimmungseinrichtung (58, 84) umfasst zum Bestimmen eines Abstands der Probe (26) von der ersten Strahlungsquelle (48) und/oder von der zweiten Strahlungsquelle (74).
44. 44. System nach Satz 30 bis 43, dadurch gekennzeichnet, dass das System (10) eine Bedieneinrichtung (22) umfasst zum Eingeben von Daten.
45. 45. System nach einem der Sätze 30 bis 44, dadurch gekennzeichnet, dass System (10) eine Steuerungseinrichtung (32) umfasst zum Steuern der ersten und/oder zweiten optischen Spektroskopieeinrichtung (28, 30).
46. 46. Vorrichtung nach einem der Sätze 30 bis 45, dadurch gekennzeichnet, dass das System (10) eine Speichereinrichtung (26) umfasst zum Speichern von Referenzspektren von Gefahrstoffen und zum Speichern der gemessenen ersten und zweiten optischen Spektren.
47. 47. System nach einem der Sätze 30 bis 46, dadurch gekennzeichnet, dass das System (10) eine Ausgabeeinrichtung (34) umfasst zum Ausgeben einer Information, ob der mindestens eine Gefahrstoff an der Probe (26) vorhanden ist oder nicht.
48. 48. Verwendung eines Systems (10) nach einem der Sätze 30 bis 47 zur Durchführung eines Verfahrens nach einem der Sätze 1 bis 29.

The above description thus includes in particular the embodiments of methods and systems for detecting at least one hazardous substance defined below in the form of numbered sentences:

1. 1. Method for detecting at least one hazardous substance, in particular an explosive, on a sample ( 26 ), especially in a spatial detection area ( 18th ), with which method with a first optical spectroscopy method a first optical spectrum of the sample ( 26 ) during a first spectrum acquisition time window ( 106 ) is recorded and with a second optical spectroscopy method a second optical spectrum of the sample ( 26 ) during a second spectrum acquisition time window ( 108 ) is recorded, with the first and the second optical spectroscopy method differing, the first optical spectrum and the second optical spectrum being compared with provided reference spectra of the at least one hazardous substance in order to determine whether the at least one hazardous substance is present on the sample ( 26 ) is present or not, characterized in that the first spectrum acquisition time window ( 106 ) and the second spectrum recording time window ( 108 ) overlap at least partially in time, in particular completely.
2. 2. Procedure according to sentence 1 , characterized in that the first and second optical spectra of the sample ( 26 ) are recorded when the sample ( 26 ) in a spatially predetermined detection area ( 18th ) is arranged.
3. 3. The method according to one of the preceding sentences, characterized in that the first optical spectroscopy method is infrared spectroscopy, in particular MIR- Reflection spectroscopy, and that from the sample ( 26 ) an infrared spectrum is recorded as the first spectrum.
4. 4. The method as claimed in one of the preceding sentences, characterized in that, for recording the first optical spectrum, the sample ( 26 ) with the first pulsed electromagnetic radiation ( 50 ) and that an intensity of the sample ( 26 ) scattered first scattered radiation ( 58 ) is detected.
5. 5. Procedure according to sentence 4th , characterized in that a wavelength of the first pulsed electromagnetic radiation ( 50 ) during the first spectrum acquisition time window ( 106 ) is tuned and that the intensity of the first scattered radiation ( 58 ) depending on the wavelength of the first pulsed electromagnetic radiation ( 50 ) is detected.
6. 6. Procedure according to sentence 4th or 5 , characterized in that the first pulsed electromagnetic radiation ( 50 ) with a first radiation source ( 48 ), especially in the form of a first laser ( 52 ), especially in the form of an IR laser ( 54 ), is produced.
7. 7. Procedure according to one of the sentences 4th to 6 , characterized in that the first pulsed electromagnetic radiation ( 50 ) about the sample ( 26 ) is scanned, especially one or two dimensions.
8. 8. The method according to one of the preceding sentences, characterized in that the second optical spectroscopy method is Raman spectroscopy, in particular UV Raman spectroscopy, and that of the sample ( 26 ) a Raman spectrum is recorded as the second spectrum.
9. 9. The method according to any one of the preceding sentences, characterized in that for recording the second optical spectrum, the sample with second pulsed electromagnetic radiation ( 76 ) and that an intensity of the sample ( 26 ) scattered second scattered radiation ( 86 ) is detected spectrally resolved.
10. 10. Procedure according to sentence 9 , characterized in that a wavelength of the second pulsed electromagnetic radiation ( 76 ) during the second spectrum acquisition time window ( 108 ) is kept constant.
11. 11. Procedure according to sentence 9 or 10th , characterized in that the second pulsed electromagnetic radiation ( 76 ) with a second radiation source ( 74 ), especially in the form of a second laser ( 78 ), especially in the form of a UV laser ( 80 ), is produced.
12. 12. Procedure according to one of the sentences 9 to 11 , characterized in that the second pulsed electromagnetic radiation ( 76 ) about the sample ( 26 ) is scanned, especially one or two dimensions.
13. 13. Procedure according to one of the sentences 9 to 12 , characterized in that the first pulsed electromagnetic radiation ( 50 ) is generated with a first repetition rate and that the second pulsed electromagnetic radiation ( 76 ) is generated with a second repetition rate, and that the first repetition rate and the second repetition rate are identical or different.
14. 14. Procedure according to one of the sentences 9 to 13 , characterized in that the sample ( 26 ) with the first pulsed electromagnetic radiation ( 50 ) and the second pulsed electromagnetic radiation ( 76 ) is applied synchronously and that the sample ( 26 ) backscattered first scattered radiation ( 60 ) and second scattered radiation ( 86 ) is detected synchronously.
15. 15. Procedure according to one of the sentences 9 to 14 , characterized in that the sample ( 26 ) with the first pulsed electromagnetic radiation ( 50 ) and the second pulsed electromagnetic radiation ( 76 ) is applied asynchronously and that the sample ( 26 ) backscattered first scattered radiation ( 60 ) and second scattered radiation ( 86 ) is detected asynchronously.
16. 16. Procedure according to one of the sentences 9 to 15 , characterized in that a distance ( 58 , 84 ) the sample ( 26 ) from the first radiation source ( 48 ) and / or from the second radiation source ( 74 ) by measuring the transit time of the pulses ( 110 , 112 ) of the first pulsed electromagnetic radiation ( 50 ) and / or the second pulsed electromagnetic radiation ( 76 ) is determined.
17. 17. Procedure according to one of the sentences 7 to 16 , characterized in that the first spectrum acquisition time window ( 106 ) in a plurality of first measuring intervals ( M _n ) is divided and that in every first measurement interval ( M _n ) a pulse ( 110 ) of the first electromagnetic radiation ( 50 ) is generated with a first pulse width that the first scattered radiation ( 60 ) in a first measurement time window ( 116 ) of the first measurement interval ( M _n ) is detected.
18. 18. Procedure according to sentence 17th , characterized in that the first measurement time window ( 116 ) has a length that corresponds to the first pulse width.
19. 19. Procedure according to sentence 17th or 18th , characterized in that the first pulse width is a maximum of 10% of the first measurement interval ( M _n ) corresponds.
20. 20. Procedure according to one of the sentences 17th to 19th , characterized in that in every first measurement interval ( M _n ) after every first measurement time window ( 116 ) in a first background measurement time window ( 120 ) first background radiation is detected.
21. 21. Proceeding according to sentence 20th , characterized in that the first background measurement time window ( 120 ) has a length that corresponds to the first pulse width.
22. 22. Procedure according to sentence 20th or 21st , characterized in that, to determine the first optical spectrum, a difference between the detected first scattered radiation ( 60 ) and the detected first background radiation is formed.
23. 23. Procedure according to one of the sentences 9 to 22 , characterized in that the second spectrum recording time window ( 108 ) in a plurality of second measuring intervals ( R _m ) and that every second measurement interval ( R _m ) a pulse ( 112 ) of the second electromagnetic radiation ( 76 ) is generated with a second pulse width that the second scattered radiation ( 86 ) in a second measurement time window ( 118 ) of the second measurement interval ( R _m ) is detected.
24. 24. Procedure according to sentence 23 , characterized in that the second measurement time window ( 118 ) has a length that corresponds to the second pulse width.
25. 25. Procedure according to sentence 23 or 24th , characterized in that the second pulse width is a maximum of 10% of the second measurement interval ( R _m ) corresponds.
26. 26. Procedure according to one of the sentences 23 to 25th , characterized in that in every second measuring interval ( R _m ) after every second measurement time window ( 118 ) in a second background measurement window ( 122 ) second background radiation is detected.
27. 27. Procedure according to sentence 26 , characterized in that the second background measurement window ( 122 ) has a duration that corresponds to the first pulse width.
28. 28. Procedure according to sentence 26 or 27th , characterized in that a difference between the detected second scattered radiation and (86) the detected second background radiation is formed to determine the second optical spectrum.
29. 29. Procedure according to one of the sentences 23 to 28 , characterized in that the first pulse width and the second pulse width are specified identically.
30. 30. system ( 10th ) for detecting at least one hazardous substance, in particular an explosive, on a sample, in particular in a spatial detection area ( 18th ), Which system ( 10th ) a first optical spectroscopy device ( 28 ) for recording a first optical spectrum of the sample ( 18th ) during a first spectrum acquisition time window ( 106 ) and a second optical spectroscopy device ( 30th ) for recording a second optical spectrum of the sample ( 18th ) during a second spectrum acquisition time window ( 108 ), the first and the second optical spectroscopy device ( 28 , 30th ) differentiate, whereby the system ( 10th ) an evaluation device ( 42 ) for comparing the first optical spectrum and the second optical spectrum with provided reference spectra of the at least one hazardous substance and for determining whether the at least one hazardous substance is present on the sample ( 26 ) is present or not, characterized in that the first spectrum acquisition time window ( 106 ) and the second spectrum recording time window ( 108 ) overlap at least partially in time, in particular completely.
31. 31. System according to sentence 30th , characterized in that the system has a spatially predetermined detection area ( 18th ) in which the sample ( 26 ) is arranged to record the first and second optical spectra.
32. 32. System by sentence 30th or 31 , characterized in that the first optical spectroscopy device ( 28 ) an infrared spectrometer ( 44 ) is or includes, in particular a MIR reflection spectrometer ( 46 ).
33. 33. System according to one of the sentences 30th to 32 , characterized in that the first spectroscopy device ( 28 ) a first radiation source ( 48 ) to generate first pulsed electromagnetic radiation ( 50 ) and a first detector ( 64 ) to measure an intensity from the sample ( 26 ) scattered first scattered radiation ( 60 ).
34. 34. System by sentence 33 , characterized in that the first radiation source ( 48 ) is designed to tune a wavelength of the first pulsed electromagnetic radiation ( 50 ) during the first spectrum acquisition time window ( 106 ).
35. 35. System by sentence 33 or 34 , characterized in that the first radiation source ( 48 ) in the form of a first laser ( 52 ) is designed, in particular in the form of an IR laser ( 54 ).
36. 36. System according to one of the sentences 33 to 35 , characterized in that the system ( 10th ) a first scanning device ( 38 ) for scanning the first pulsed electromagnetic radiation ( 50 ) about the sample ( 26 ), especially one or two dimensions.
37. 37. System according to one of the sentences 30th to 36 , characterized in that the second optical spectroscopy device ( 30th ) a Raman spectrometer ( 70 ) is or includes, in particular UV Raman spectrometers ( 72 ).
38. 38. System according to one of the sentences 30th to 37 , characterized in that the second spectroscopy device ( 30th ) a second radiation source ( 74 ) for generating second pulsed electromagnetic radiation ( 76 ) and a second detector ( 90 ) for wavelength-dependent measurement of an intensity from the sample ( 26 ) scattered second scattered radiation ( 86 ).
39. 39. System by sentence 38 , characterized in that the second radiation source ( 74 ) is designed to generate the second pulsed electromagnetic radiation ( 76 ) with constant wavelength.
40. 40. System according to sentence 38 or 39 , characterized in that the second radiation source ( 74 ) in the form of a second laser ( 78 ) is designed, in particular in the form of a UV laser ( 80 ).
41. 41. System according to one of the sentences 38 to 40 , characterized in that the system ( 10th ) a second scanning device ( 40 ) for scanning the second pulsed electromagnetic radiation ( 76 ) about the sample ( 26 ), especially one or two dimensions.
42. 42. System according to one of the sentences 38 to 41 , characterized in that the first radiation source ( 48 ) is designed to generate the first pulsed electromagnetic radiation ( 50 ) with a first repetition rate and that the second radiation source ( 74 ) is designed to generate the second pulsed electromagnetic radiation ( 76 ) with a second repetition rate and that the first repetition rate and the second repetition rate are identical or different.
43. 43. System according to one of the sentences 38 to 42 , characterized in that the system ( 10th ) a distance determination device ( 58 , 84 ) includes to determine a distance of the sample ( 26 ) from the first radiation source ( 48 ) and / or from the second radiation source ( 74 ).
44. 44. System by sentence 30th to 43 , characterized in that the system ( 10th ) an operating device ( 22 ) for entering data.
45. 45. System according to one of the sentences 30th to 44 , characterized in that system ( 10th ) a control device ( 32 ) for controlling the first and / or second optical spectroscopy device ( 28 , 30th ).
46. 46. Device according to one of the sentences 30th to 45 , characterized in that the system ( 10th ) a storage device ( 26 ) for storing reference spectra of hazardous substances and for storing the measured first and second optical spectra.
47. 47. System according to one of the sentences 30th to 46 , characterized in that the system ( 10th ) an output device ( 34 ) includes to output information whether the at least one hazardous substance on the sample ( 26 ) is present or not.
48. 48. Using a system ( 10th ) after one of the sentences 30th to 47 to carry out a procedure according to one of the sentences 1 to 29 .

• 1: eine schematische Darstellung eines ersten Ausführungsbeispiels eines Systems zum Detektieren von Gefahrstoffen;
• 2: eine schematische Darstellung eines weiteren Ausführungsbeispiels eines Systems zur Detektion von Gefahrstoffen;
• 3: eine weitere perspektivische Ansicht der Anordnung aus 2;
• 4: eine schematische Prinzipskizze eines weiteren Ausführungsbeispiels eines Systems zum Detektieren von Gefahrstoffen;
• 5: eine schematische Darstellung eines weiteren Ausführungsbeispiels eines Systems zum Detektieren von Gefahrstoffen;
• 6: eine schematische Darstellung von sich überlappenden Spektrumaufnahmezeitfenstern für zwei unterschiedliche Spektroskopieverfahren;
• 7: eine schematische Darstellung ähnlich 6 mit Erläuterung der Aufteilung der Spektrumaufnahmezeitfenster in eine Mehrzahl von Messintervalle;
• 8: eine schematische Darstellung zweier teilweise überlappender Spektru ma ufna h mezeitfenster;
• 9: eine schematische Darstellung zweier vollständig überlappender Spektru ma ufnah mezeitfenster;
• 10: eine schematische Darstellung zweier Spektrumaufnahmezeitfenster, wobei das eine das andere zeitlich vollumfänglich umfasst;
• 11: eine schematische Darstellung einer wellenlängenabhängigen Anregung einer Probe zur Messung einer spektralen Signatur derselben mittels MIR-Reflexionsspektroskopie;
• 12: eine schematische Darstellung einer Anregung einer Probe bei der UV-Ramanspektroskopie mit konstanter Wellenlänge des Anregungslasers;
• 13: eine schematische Darstellung dreier Messintervalle bei einer synchronen Messung zweier optischer Spektren;
• 14: eine schematische Darstellung eines asynchronen zeitlichen Abtastens einer Probe zur Messung zweier optischer Spektren;
• 15: eine schematische Darstellung der Vorgehensweise bei der Messung eines Ramanspektrums;
• 16: eine schematische Darstellung der Vorgehensweise bei der Messung eines Infrarotspektrums;
• 17: eine schematische Darstellung eines weiteren Ausführungsbeispiels eines Systems zum Detektieren von Gefahrstoffen beim Abscannen der Probe im Detektionsbereich;
• 18: eine schematische Darstellung optischer Komponenten eines Systems zum Detektieren von Gefahrstoffen;
• 19: eine schematische Darstellung eines weiteren Ausführungsbeispiels eines Systems zum Detektieren von Gefahrstoffen;
• 20: eine schematische Darstellung eines Ablaufs einer Untersuchung einer Probe;
• 21: eine schematische Darstellung des Ablaufs der Datenerfassung unter Verwendung vorprozessierter Messdaten zur Ermittlung auffälliger Substanzen;
• 22: eine fotografische Wiedergabe einer Stoffprobe, auf welcher Ammoniumnitrat innerhalb einer markierten Fläche aufgebracht wurde; und
• 23: eine beispielhafte Darstellung eines Differenzspektrums, welches ermittelt wurde aus Ramanmessungen innerhalb und außerhalb der markierten Fläche.

The following description of preferred embodiments of the invention serves in conjunction with the drawings for a more detailed explanation. Show it:

• 1 : a schematic representation of a first embodiment of a system for detecting hazardous substances;
• 2nd : a schematic representation of a further embodiment of a system for the detection of hazardous substances;
• 3rd : Another perspective view of the arrangement 2nd ;
• 4th : a schematic schematic diagram of a further embodiment of a system for detecting hazardous substances;
• 5 : a schematic representation of a further embodiment of a system for detecting hazardous substances;
• 6 : a schematic representation of overlapping spectrum acquisition time windows for two different spectroscopy methods;
• 7 : a schematic representation similar 6 with explanation of the division of the spectrum acquisition time window into a plurality of measurement intervals;
• 8th : a schematic representation of two partially overlapping spectrum acquisition time windows;
• 9 : a schematic representation of two completely overlapping spectrum recording time windows;
• 10th : a schematic representation of two spectrum acquisition time windows, one of which fully encompasses the other;
• 11 : a schematic representation of a wavelength-dependent excitation of a sample for measuring a spectral signature of the same by means of MIR reflection spectroscopy;
• 12 : a schematic representation of an excitation of a sample in UV Raman spectroscopy with a constant wavelength of the excitation laser;
• 13 : a schematic representation of three measurement intervals in a synchronous measurement of two optical spectra;
• 14 : a schematic representation of an asynchronous time sampling of a sample for measuring two optical spectra;
• 15 : a schematic representation of the procedure for measuring a Raman spectrum;
• 16 : a schematic representation of the procedure for measuring an infrared spectrum;
• 17th : A schematic representation of a further embodiment of a system for detecting hazardous substances when scanning the sample in the detection area;
• 18th : a schematic representation of optical components of a system for detecting hazardous substances;
• 19th : a schematic representation of a further embodiment of a system for detecting hazardous substances;
• 20th : a schematic representation of a sequence of an examination of a sample;
• 21st : a schematic representation of the sequence of data acquisition using preprocessed measurement data for the determination of abnormal substances;
• 22 : a photographic reproduction of a fabric sample on which ammonium nitrate has been applied within a marked area; and
• 23 : an exemplary representation of a difference spectrum, which was determined from Raman measurements inside and outside the marked area.

In 1 is schematically a first embodiment of a system 10th shown for the detection of one or more hazardous substances. It includes a housing 12 , in which two spectroscopy devices are arranged, which have a first pulsed laser radiation field 14 and a second pulsed laser radiation field 16 in a detection area 18th radiate. In the detection area 18th for example, a person 20th position so that the radiation fields 14 and 16 hit their feet and lower legs.

One from the system 10th included control device 22 in the form of a touch panel, which forms a user interface, enables an operator of the system, not shown 10th Make entries and read measurement results. For this purpose, the control device 22 in particular comprise a display device.

The two laser radiation fields 14 and 16 are overlapping simultaneously or temporally on the detection area 18th emitted. For example, the person 20th if it is examined as a passenger with a security scanner for dangerous objects at an airport or the like, in parallel with the system 10th be touchlessly controlled in their lower leg area. In particular is an integration of the system 10th possible in a security scanner.

In the 2nd and 3rd is schematically another application example for a system 10th shown for the detection of one or more hazardous substances. The person 20th is located in a security scanner 24th with which it is examined for dangerous objects. With the security scanner 24th it can either be a metal detector or a body scanner. Simultaneously with the examination for dangerous objects, the person can 20th with the system in the area of the lower legs and shoes contactless and eye-safe for hazardous substance residues, such as explosive residues in particular.

The system 10th enables an individual examination of people 20th . This enables a clear assignment of an examination result to the person examined in each case 20th .

The system 10th enables it in combination with the security scanner 24th carry out different examinations in a single control step, namely whether the respective person 20th carries dangerous objects on the body and is contaminated with hazardous substances. In this way, a significant amount of time can be saved when checking people. This is a great advantage especially when handling passengers at airports, since the additional verification of the person 20th , whether it is contaminated with hazardous substances or not does not require an additional test step.

The area of the shoes as well as the lower leg area of the person 20th define a sample 26 that with the system 10th is examined.

A simplified block diagram of an embodiment of a system 10th for the detection of one or more hazardous substances is exemplified in 4th shown.

The system 10th comprises a first spectroscopy device 28 and a second spectroscopy device 30th . These are effective for control purposes with a control device 32 connected.

The control device 32 is also with the control device 22 connected for control purposes, also with an output device 34 , with which information can be output, whether on the sample 26 one or more hazardous substances are present, as well as with a storage device 36 , which is designed for storing reference data or reference spectra of hazardous substances and for storing measured optical spectra.

The system 10th further comprises a first scanning device 38 and a second scanning device 40 , each one of the spectroscopy facilities 28 and 30th assigned. They serve the laser radiation fields 14 and 16 in a predetermined manner, for example one-dimensionally or two-dimensionally, over the detection area 18th to scan.

The two spectroscopy facilities 28 and 30th are trained differently.

The control device 32 can in particular an evaluation device 42 include to compare measured species with reference data to determine whether or not one or more hazardous substances are present on the sample based on the comparison.

5 shows an example of a block diagram of another embodiment of a system 10th a little more detailed.

The first spectroscopy facility 28 is in the form of an infrared spectrometer 44 , namely in the form of a MIR reflection spectrometer 46 educated. It comprises a first radiation source 48 for generating first pulsed electromagnetic radiation 50 . The first source of radiation 48 is in the form of a first laser 52 trained, namely in the form of an IR laser 54 . The first source of radiation 48 is also designed to tune a wavelength of the radiation 50 in a given time window.

The one from the first radiation source 48 generated radiation 50 comes with a beam adjustment device 56 , which comprises one or more optical elements, on the first scanning device 38 redirected. This then directs the radiation 50 put to the test 26 from.

A wavelength of radiation 50 lies in a range from 3 µm to about 50 µm in the so-called middle infrared spectral range.

The first spectroscopy facility 28 is a defined distance 58 relative to the detection area 18th positioned.

From the rehearsal 26 retroreflected first scattered radiation 60 is via a receiving optics 62 to a first detector 64 pictured. With the detector 64 becomes an intensity of the first scattered radiation 60 measured over time. Because the excitation of the sample 26 with the radiation 50 takes place depending on the wavelength, results from the temporal resolution of a detection signal at the first detector 64 a wavelength-dependent MIR reflection spectrum.

Via a data connection 66 is the first detector 64 with a first data acquisition device 68 connected.

The second spectroscopy facility 30th is in the form of a Raman spectrometer 70 , namely a UV Raman spectrometer 72 , educated.

The second spectroscopy facility 30th comprises a second radiation source 74 for generating second pulsed electromagnetic radiation 76 . The second source of radiation 74 is designed to generate the second pulsed electromagnetic radiation 76 with constant wavelength. This is the second source of radiation 74 in the form of a second laser 78 trained, namely in the form of a UV laser 80 . This is designed to generate the second radiation 76 in the deep ultraviolet spectral range, in particular with a wavelength in a range from about 200 nm to about 400 nm.

That from the second radiation source 74 generated second radiation 76 meets a second beam adjustment device 82 and is transferred from this to the second scanning device 40 directed. From there the second pulsed electromagnetic radiation hits 76 also on the detection area 18th and is about the sample 26 scanned.

The second spectroscopy facility 30th is from the detection area 18th spaced apart. A distance 84 lies just like the distance 58 in a range of about 1 m to about 5 m. The distances are preferably 58 and 84 about 2 m.

The one from the sample 26 due to the exposure to the second pulsed electromagnetic radiation 76 backscattered second scattered radiation 86 is with a second receiving optics 88 to a second detector 90 pictured. The second detector 90 is designed for high-resolution, wavelength-dependent measurement of an intensity of the second scattered radiation 86 .

The second detector 90 is over a data connection 92 with a second data acquisition device 94 connected.

The control device 32 is effective for control with both the radiation sources 48 and 74 as well as with the data acquisition devices 68 and 94 connected. Via the control effective with the control device 32 connected operating device 22 an operator can use the system 10th serve overall. For example, an operator can take a measurement to examine the sample 26 with the control device 22 start and end if necessary.

The one with the data acquisition devices 68 and 94 recorded data signals from the detectors 64 and 90 are about data connections 96 and 98 to a transformation facility 100 forwarded. There the measurement data are obtained with the first spectroscopy device 28 and the second spectroscopy device 30th determined measurement data, on the one hand the MIR measurement and on the other hand the Raman measurement, combined for further data evaluation. Thus, two separate spectra are not recorded and compared with corresponding reference MIR spectra and reference Raman spectra, which would alternatively also be possible without further ado, but rather combined into a single data set. In this way, the complementary properties of both spectroscopy devices 28 and 30th be exploited.

This data transformed in this way is transferred via a further data connection 102 to the evaluation device 42 forwarded. This processes them with the transformation device 100 merged measurement data further by using suitable algorithms and compares the data record thus provided with data records from a database, the corresponding data records, that is to say spectral information which was determined using MIR measurements and Raman measurements, with the transformed data. The evaluation device 42 transmits the result of the evaluation to the output device 34 . This can be integral with the operating device 22 or also be formed separately from this.

The output device 34 gives an operator of the system 10th whether there is one or more hazardous substances on the sample 26 were detected. The output can, for example, take place optically through differently colored signal areas or else acoustically. Furthermore, the test result for the determined hazardous substances can optionally also be displayed in full text with the output device 34 be issued.

The scanning devices 38 and 40 scan the sample 26 at the same time or at least with a temporal overlap, as will be explained in more detail below. Through the scanning devices 38 and 40 can be achieved in particular that the sample 26 can be examined extensively.

The sequence of an examination of the sample 26 is schematically in 6 shown. An operator starts by input on the operating device 22 at the time t _p the investigation. The control device 32 activates the first spectroscopy device 28 at the time t _p and at the time t ₁ the second spectroscopy device 30th . The control device 32 ends the operation of the first spectroscopy device 28 at the time t ₂ and the operation of the second spectroscopy device 30th at the time t _E .

With the first spectroscopy device 28 is thus in a first spectrum acquisition time window 106 an MIR reflection spectrum was recorded. The first spectrum acquisition time window 106 extends between the times t _p and t ₂ .

With the second spectroscopy device 30th is in a second spectrum acquisition time window 108 a Raman spectrum was recorded. The second spectrum acquisition time window 108 extends between the times t ₁ and t _E .

The spectrum acquisition time window 106 and 108 overlap as schematically in 6 partially represented in time, namely between the times t ₁ and t ₂ for the time period Δt, which is the difference between the times t ₂ and t ₁ corresponds, i.e. Δt = t ₂ - t ₁ .

Due to the overlap of the spectrum acquisition time window 106 and 108 for the time period Δt is shorter in comparison to measurements carried out in series, that is to say in succession, with the first spectroscopy device 28 and the second spectroscopy device 30th a total measurement time or a total test time of the sample 26 . With the described procedure, Raman and infrared spectra can be recorded and simultaneously be evaluated so that a more specific and reliable detection of any on the sample 26 adhering hazardous substances is possible.

7 shows schematically the subdivision of the two with the spectroscopy devices 28 and 30th performed measurements. With the first spectroscopy device 28 becomes the first spectrum acquisition time window 106 in n first measuring intervals M _n divided up. The second spectrum acquisition time window becomes corresponding 108 identical measurement intervals in m R _m divided. As described in more detail below, every measurement interval M _n and R _m a pulse of the respective radiation or 76 on the sample 26 blasted and in each of the measurement intervals mentioned M _n and R _m one of the first and second scattered radiation 60 and 86 assigned measurement signal.

As in 7 Shown schematically below, is in every measurement interval M _n the wavelength λ of the first radiation source 48 continuously tuned.

The in the respective measuring intervals M _n and R _m recorded data are added up and as described with the data acquisition devices 24th and 68 recorded and sent to the transformation facility 100 forwarded.

The 8th to 10th schematically show possible overlaps between the spectrum acquisition time windows 106 and 108 .

In 8th is schematically simplified again the situation 6 shown. Here the spectrum acquisition time windows overlap 106 and 108 for the time period Δt between the times t ₁ and t ₂ .

9 shows the case where there is a complete temporal overlap of the spectrum acquisition time window 106 and 108 given is. Both spectrum acquisition time windows 106 and 108 start at the time t _p and end in time t _E . In other words, the times fall t _p and t ₁ on the one hand and t _E and t ₂ on the other hand together.

10th shows an example of a case in which the spectrum acquisition time window 106 and 108 are of different lengths. In the example shown, the spectrum acquisition time window is 108 shorter than the spectrum acquisition time window 106 . In this case, as in the case of 9 illustrated case, the times t _p and t _E through the spectrum acquisition time window 106 Are defined. The spectrum acquisition time window 108 lies completely within the spectrum acquisition time window 106 . A temporal overlap in the period Δt thus corresponds to the time difference between the times t ₂ and t ₁ that the end or the beginning of the spectrum recording time window 108 define. Of course, the case in 10th is shown schematically, also be the other way round, i.e. the spectrum acquisition time window 106 can be shorter than the spectrum acquisition time window 108 and lie completely in the latter.

11 shows schematically the procedure for MIR reflection spectroscopy. As already mentioned, this is the wavelength of the first radiation source 48 tuned. The wavelength can be tuned in particular between successive pulses from the first radiation source 48 be generated. In principle, tuning the wavelength during a pulse would also be conceivable. The backscattered first scattered radiation 60 is using the spectral broadband detector 90 detected.

The procedure for UV Raman spectroscopy is different. As in 12 shown schematically, the wavelength of the second radiation source remains in this case 74 over the entire second spectrum acquisition time window 108 constant. The second scattered radiation 86 is using the detector 64 detected spectrally resolved.

With the described exemplary embodiments of systems 10th In particular, two different measurement techniques can be carried out.

13 shows schematically the procedure for a synchronous measurement. At the beginning of each of the two measuring intervals R ₁ and M ₁ , which completely overlap in time, becomes a first pulse 110 respectively 112 the first radiation 50 or the second radiation 76 generated. At an interval 114 which is twice the light travel time for the distances 58 and 84 corresponds to both the first scattered radiation 60 as well as the second scattered radiation 86 each in a measurement time window 116 respectively 118 detected. The measurement time window 116 and 118 correspond to the pulse durations of the pulses 110 and 112 .

Somewhat separated from the measurement window 118 is in a background measurement window 120 a background signal of the sample 26 measured. That in the measurement window 116 The measured signal can then in particular be around the measurement signal in the background measurement time window 120 be corrected in order to effectively suppress interference caused by sunlight or room lighting, for example.

In the manner described, a synchronous measurement takes place in all measurement intervals M _n and R _m proceeded. This procedure enables the determined Raman data to be averaged in order to improve a signal-to-noise ratio.

The procedure for an asynchronous measurement is shown schematically in 14 shown. This is where the pulses are triggered 110 and 112 not asynchronous, but asynchronous. Furthermore, the measuring intervals M _n and R _m different lengths. So it is measured with different repetition rates. The first source of radiation 48 is with a repetition rate f _ME and the second radiation source 74 is with a repetition rate f _R operated. 14 shows schematically the case where the repetition rate f _ME is greater than the repetition rate f _R .

Due to the asynchronous triggering of the pulses 110 and 112 in particular cross-talk effects can be eliminated. Furthermore, due to the different repetition rates, the best possible signal-to-noise ratio can be achieved in a very short time for measuring the spectra. Furthermore, optimal adjustments of widths of the pulses can be made 110 and 112 at gate times of the detectors 64 and 90 can be adjusted to achieve maximum sensitivity and at the same time to quickly tune the wavelength of the first radiation source 48 to enable.

The 15 and 16 show the procedure for asynchronous measurement in a slightly modified representation. 15 shows a section of the spectrum acquisition time window 108 and a measurement interval R ₁ . In 16 is a schematic section of the spectrum acquisition time window 116 and a section of the measurement interval M ₂ shown. In the measuring interval M ₂ is after every pulse 110 the wavelength of the first radiation source 48 changed, for example continuously tuned to longer wavelengths. This tuning of the wavelength of the first radiation source 48 takes place in every measuring interval M _n .

17th shows an example of a possible procedure for scanning the detection area 18th . A first scan line 124 the first radiation 50 over the detection area 18th is also shown schematically as a second scan line 126 the second radiation 76 over the detection area 18th . In this way, very reliable data acquisition can take place, since within the entire measurement time, that is, between the times t _p and t _E , the entire detection area with one of the two radiations 50 or 76 was scanned.

The scanning devices 38 and 40 preferably work in the opposite direction to ensure fast signal acquisition and high reliability even when the sample is moving 26 , in particular a person 20th , to guarantee, because within half the total measuring time the complete detection range is already 18th was scanned using one of the two different spectroscopic methods. The described scanning can also achieve an improved deduction of background effects and also an increase in sensitivity by comparing areas with and without contamination of hazardous substances. In addition, by scanning the sample 76 localization of possible local contamination sites can be safely achieved.

In 18th is schematically another embodiment of a system 10th shown. In particular, the two spectroscopy devices can 38 and 40 in one housing 12 which is a length 128 of about 80 cm, a width 130 of about 40 cm and a height 132 of about 50 cm.

In 18th are elements of the system 10th with the same reference numerals as in the exemplary embodiments, in particular the 4th and 5 .

In 19th is another embodiment of a system 10th shown schematically. Identical components and assemblies are provided with identical reference numerals as in the exemplary embodiments in FIG 4th and 5 .

A touchscreen display takes over the function of the operating device as an example 22 and the output device 34 and enables an operator to enter user data and output the measurement results. Alternatively, a keyboard and a display that is arranged or configured spatially separate therefrom can also be used. A representation of the measurement results is adapted according to a specification by the operator. For example, test results can be represented qualitatively, for example by the indication "dangerous substance present", or quantitatively, by means of a corresponding classification.

The control device 32 is realized by a computer. It forms an interface between the operator and hardware of the system 10th . A field programmable gate array (FPGA) and drivers of the lasers are created using special software 52 and 78 , external water cooling of the UV laser 80 as well as the detector 90 controlled, in particular to switch these components on and off.

The FPGA 134 becomes the synchronization of the spectroscopy facilities 28 and 30th utilized. This involves parallel processing of the FPGA 134 exploited the laser via an electronic pulse 52 and 78 trigger and corresponding pulses 110 and 112 send out.

For the first spectroscopy device 28 becomes the FPGA 134 used simultaneously to detect voltages of the detector 64 with a large bandwidth / sample rate and high bit resolution via an AD converter 136 capture. This signal is in parallel in the FPGA 134 through an implemented boxcar averaging algorithm 138 processed and back to the control device 32 sent.

Furthermore, further, slow digital outputs of the FPGA 134 used to peripheral components of the system 10th digitally controlled, for example water cooling 142 for the first radiation source 48 as well as the first detector 64 or a status LED to indicate a status of the peripheral components.

The second laser 78 is designed in the form of a pulsed nanosecond laser that emits in the deep UV spectral range.

The second beam adjustment device 82 can in particular optionally include a telescope for beam expansion in order to determine the laser intensity of the radiation 76 according to the optical radiation protection regulation so that it is outside the system 10th lies in the eye-safe area.

The second scanning device 40 is designed in the form of a high-speed galvo mirror for fast beam guidance, for example the sample 26 , especially a shoe area of the person 20th , can be scanned with a one-dimensional line scan.

The receiving optics 88 comprises a mirror and lens arrangement for collecting the backscattered second scattered radiation 86 . These are, in particular, the Stokes-shifted photons. The second receiving optics 88 is equipped with specially designed anti-reflective coatings for UV wavelengths.

To suppress the wavelength of the second laser 78 and other possible sources of interference is between the second receiving optics 88 and the second detector 90 an optical filter 146 arranged. This is formed by a combination of notch and longpass filters, optionally also a bandpass filter, so that only the backscattered Raman signal of the second scattered radiation 86 is detected.

The first laser 52 is in the form of a tunable, pulsed quantum cascade laser with a tuning range from 6 µm to 11.5 µm. In the wavelength scan mode, tuning speeds of up to 5000 cm ^-1 / s can be achieved.

A pulsed operation of the first laser 52 by the FPGA 134 triggered with a duty cycle of 10% enables the use of a boxcar averaging measurement scheme so that background signals from sources of interference can be effectively suppressed. The water cooling 142 serves to thermally stabilize the first laser 52 .

The first beam adjustment device 56 also includes a telescope arrangement with a combination of germanium lenses with a special anti-reflective coating or a combination of gold mirrors.

The first scanning device 38 also includes high-speed galvo mirrors for fast beam guidance, thus the thrust area of the person to be checked 20th can be scanned with a one-dimensional line scan. Here, gold mirrors are used for beam guidance.

The first receiving optics include a 3 "off-axis parabolic mirror with gold coating. Alternatively, a 3" germanium lens with anti-reflective coating can be used. To optimize the signal strength, the size of the receiving optics can be adjusted if necessary.

Between the first receiving optics 62 and the first detector 64 is in this embodiment of the system 10th an optical filter 148 in the form of a MIR bandpass filter to suppress interference sources in the sensitivity range of the first detector 64 arranged. The optical filter 148 blocks the wavelengths outside the tuning range of the first laser 48 .

The first detector 64 is in this embodiment of the system 10th in the form of a MIR point detector with an integrated four-stage TEC and preamplifier. The first detector is used for heat dissipation and to achieve maximum detectability 64 from water cooling 142 chilled. Electrical voltages of the first detector 64 be with the AD converter 136 captured and with the FPGA 134 processed further.

20th schematically shows a block diagram for the sequence of an examination of a sample 26 or a person 20th . After a user input, the examination of the sample is started. The detection area 18th , also known as Region of Interest (ROI), is defined. The scanning devices 38 and 40 are reset to their respective starting positions. The FPGA 134 sends trigger pulses to the individual devices to start the measurements. In this way, the measurements of the two spectroscopy devices 28 and 30th electronically synchronized. Here you can either a synchronous or an asynchronous measurement can be carried out as described above.

The Raman spectrum and the MIR reflection absorption spectrum are temporally at different positions of the sample 26 added. In order to take a two-dimensional image, the radiation fields 14 and 16 over the detection area 18th screened.

In 21st an acquisition of the measurement data is shown in detail as an example.

As the first detector 64 an MCT detector is used for data acquisition, the signal of which is digitized via an AD converter (ADC) for further processing. In parallel with a second MCT detector is the time of occurrence of the positive edge of the pulse 110 measured directly at the laser output, which is used for the described transit time determination to determine the distance 58 as well as for the further synchronization. In addition, the power of each pulse is determined via a look-up table in order to eliminate laser fluctuations through the balance detection scheme used. The measurement window is displayed according to the duration of the laser pulses 116 from which measurement data are extracted and averaged. The data is then adapted for further data processing.

With Raman spectroscopy, several channels are recorded simultaneously, for example 1064 channels, so that the complete Raman spectrum is recorded for each measurement. In addition, there is a dark spectrum in the background measurement time windows 120 and 122 recorded in order to minimize external environmental influences such as temperature and humidity on the spectra.

Due to the high spectral tuning speed of the IR laser used 54 can with a corresponding repetition rate f _ME the entire detection range within a period of approximately one second 18th be recorded with sufficient accuracy.

In 22 a photo of a fabric sample is shown, on which the smallest amounts of ammonium nitrate (NH ₄ O ₃ ) were applied within the marked area. It is a substance that is used in particular for the production of explosives.

Although no residue on the surface of the sample 26 are visible to the naked eye, contamination of the sample can be detected within a few seconds using the described method. 23 shows here the measurement of a Raman spectrum as a difference measurement between areas inside and outside the marked area. The spectrum shows a characteristic vibration band of the ammonium nitrate at 1040 cm ^-1 .

The described exemplary embodiments of systems 10th to detect one or more hazardous substances are particularly suitable for use in airport security checks. Such systems can also 10th can also be used in other areas, for example in security checks at major events such as festivals and sporting events.

The systems described in particular enable fully automated identification of people 20th who had contact with explosive hazardous substances. The examinations can be documented in a traceable and automated manner. A detection of the detection area 18th can be done mechanically by means of a camera and a corresponding scanning with the radiation 50 and 76 can be specified automatically. The systems also make it possible 10th to also look for anomalies in the detected signals in order to discover unknown, novel substances.

Furthermore, the protection of the privacy of the examined persons 20th guaranteed because no photos are taken, but only physical information is evaluated.

The systems described 10th are easy to use. They require a clear field of vision and allow an open and transparent test situation. In addition, the combined use of two different optical spectroscopy methods enables an extremely short total measuring time. The system 10th can be designed in particular as a compact, low-weight device for flexible use, especially mobile.

Technically, the systems make it possible 10th high resolution and bandwidth as well as dynamics and thus a high detection performance of any hazardous substances. The risk of false alarms can be minimized in this way. In addition, reliable and quiet continuous operation is possible.

The systems 10th enable the search for conspicuous substances in the detection area 18th . This is independent of the specific nature of the sample 26 in the detection area, i.e. regardless of the substance on which the hazardous substances to be detected are located.

The proposed method is also insensitive to temperature fluctuations. The systems 10th can also be integrated into local networks.

A fire load of the systems 10th is low. Furthermore, their use is harmless since they can be operated safely. Future adjustments are possible via software updates.

Reference symbol list

10th

system

12

casing

14

first laser radiation field

16

second laser radiation field

18th

Detection range

20th

person

22

Control device

24th

Security scanner

26

sample

28

first spectroscopy device

30th

second spectroscopy device

32

Control device

34

Dispenser

36

Storage device

38

first scanning device

40

second scanning device

42

Evaluation device

44

Infrared spectrometer

46

MIR reflection spectrometer

48

first radiation source

50

first radiation

52

first laser

54

IR laser

56

first beam adjustment device

58

distance

60

first scattered radiation

62

first receiving optics

64

first detector

66

Data Connection

68

first data acquisition device

70

Raman spectrometer

72

UV Raman spectrometer

74

second radiation source

76

second radiation

78

second laser

80

UV laser

82

second beam adjustment device

84

distance

86

second scattered radiation

88

second receiving optics

90

second detector

92

Data Connection

94

second data acquisition device

96

Data Connection

98

Data Connection

100

Transformation device

102

Data Connection

104

Data Connection

106

first spectrum acquisition time window

108

second spectrum acquisition time window

110

Pulse

112

Pulse

114

distance

116

Measurement time window

118

Measurement time window

120

Background measurement window

122

Background measurement window

124

first scan line

126

second scan line

128

length

130

width

132

height

134

FPGA

136

AD converter

138

Boxcar averaging algorithm

140

Digital output

142

Water cooling

144

Status LED

146

optical filter

148

optical filter

Claims (20)

Method for detecting at least one hazardous substance, in particular an explosive, on a sample (26), in particular in a spatial detection area (18), in which method with a first optical Spectroscopy method a first optical spectrum of the sample (26) is recorded during a first spectrum recording time window (106) and with a second optical spectroscopy method a second optical spectrum of the sample (26) is recorded during a second spectrum recording time window (108), the first and the Distinguish second optical spectroscopy methods, the first optical spectrum and the second optical spectrum being compared with provided reference spectra of the at least one hazardous substance in order to determine whether the at least one hazardous substance is present on the sample (26) or not, characterized in that the first spectrum recording time window (106) and the second spectrum acquisition time window (108) overlap at least partially in time, in particular completely. Procedure according to Claim 1 , characterized in that a) the first and second optical spectra of the sample (26) are recorded when the sample (26) is arranged in a spatially predetermined detection area (18), and / or b) the first optical spectroscopy method is infrared spectroscopy , in particular MIR reflection spectroscopy, and that the sample (26) records an infrared spectrum as the first spectrum. Method according to one of the preceding claims, characterized in that to record the first optical spectrum, the sample (26) is subjected to first pulsed electromagnetic radiation (50) and that an intensity of the first scattered radiation (58) scattered back from the sample (26) is detected . Procedure according to Claim 3 , characterized in that a) a wavelength of the first pulsed electromagnetic radiation (50) is tuned during the first spectrum recording time window (106) and that the intensity of the first scattered radiation (58) is detected as a function of the wavelength of the first pulsed electromagnetic radiation (50) and / or b) the first pulsed electromagnetic radiation (50) is generated with a first radiation source (48), in particular in the form of a first laser (52), more particularly in the form of an IR laser (54), and / or c) the first pulsed electromagnetic radiation (50) is scanned over the sample (26), in particular in one or two dimensions. Method according to one of the preceding claims, characterized in that the second optical spectroscopy method is Raman spectroscopy, in particular UV Raman spectroscopy, and that a Raman spectrum is recorded by the sample (26) as the second spectrum. Method according to one of the preceding claims, characterized in that, in order to record the second optical spectrum, second pulsed electromagnetic radiation (76) is applied to the sample and that an intensity of second scattered radiation (86) scattered back from the sample (26) is detected in a spectrally resolved manner. Procedure according to Claim 6 , characterized in that a) a wavelength of the second pulsed electromagnetic radiation (76) is kept constant during the second spectrum recording time window (108) and / or b) the second pulsed electromagnetic radiation (76) with a second radiation source (74), in particular in Form of a second laser (78), further in particular in the form of a UV laser (80), and / or c) the second pulsed electromagnetic radiation (76) is scanned over the sample (26), in particular one or two dimensions, and / or d) the first pulsed electromagnetic radiation (50) is generated at a first repetition rate and that the second pulsed electromagnetic radiation (76) is generated at a second repetition rate and that the first repetition rate and the second repetition rate are identical or different and / or e) the sample (26) with the first pulsed electromagnetic radiation (50) and the second pulsed electromagnetic radiation (76) is applied synchronously and that the first scattered radiation (60) and second scattered radiation (86) backscattered by the sample (26) are detected synchronously and / or f) the sample (26) with the first pulsed electromagnetic radiation (50 ) and the second pulsed electromagnetic radiation (76) is applied asynchronously and that the first scattered radiation (60) and second scattered radiation (86) backscattered by the sample (26) is detected asynchronously and / or g) a distance (58, 84) of the Sample (26) from the first radiation source (48) and / or from the second radiation source (74) by measuring the transit time of the pulses (110, 112) of the first pulsed electromagnetic radiation (50) and / or the second pulsed electromagnetic radiation (76) is determined. Procedure according to one of the Claims 4 to 7 , characterized in that the first Spectrum recording time window (106) is divided into a plurality of first measuring intervals (M _n ) and that in every first measuring interval (M _n ) a pulse (110) of the first electromagnetic radiation (50) is generated with a first pulse width that the first scattered radiation (60 ) is detected in a first measurement time window (116) of the first measurement interval (M _n ), wherein in particular a) the first measurement time window (116) has a length which corresponds to the first pulse width, and / or b) the first pulse width is at most 10% of the corresponds to the first measurement interval (M _n ) and / or c) first background radiation is detected in every first measurement interval (M _n ) after each first measurement time window (116) in a first background measurement time window (120), the first background measurement time window (120) in particular having a length , which corresponds to the first pulse width, and / or to determine the first optical spectrum a difference between the detected first scattered radiation (60) and the detected first background radiation is formed. Procedure according to one of the Claims 6 to 8th , characterized in that the second spectrum recording time window (108) is subdivided into a plurality of second measuring intervals (R _m ) and in that a pulse (112) of the second electromagnetic radiation (76) with a second pulse width is generated in every second measuring interval (R _m ) that the second scattered radiation (86) is detected in a second measurement time window (118) of the second measurement interval (R _m ). Procedure according to Claim 9 , characterized in that a) the second measurement time window (118) has a length which corresponds to the second pulse width, and / or b) the second pulse width corresponds to a maximum of 10% of the second measurement interval (R _m ) and / or c) in every second Measuring interval (R _m ) is detected after every second measuring time window (118) in a second background measuring time window (122) second background radiation, wherein in particular c1) the second background measuring time window (122) has a time duration which corresponds to the first pulse width, and / or c2) for Determining the second optical spectrum, a difference is formed between the detected second scattered radiation and (86) the detected second background radiation, and / or d) the first pulse width and the second pulse width are specified identically. System (10) for detecting at least one hazardous substance, in particular an explosive, on a sample, in particular in a spatial detection area (18), which system (10) has a first optical spectroscopy device (28) for recording a first optical spectrum of the sample (18 ) during a first spectrum recording time window (106) and a second optical spectroscopy device (30) for recording a second optical spectrum of the sample (18) during a second spectrum recording time window (108), the first and the second optical spectroscopy device (28, 30) distinguish, the system (10) comprising an evaluation device (42) for comparing the first optical spectrum and the second optical spectrum with provided reference spectra of the at least one hazardous substance and for determining whether the at least one hazardous substance is present on the sample (26) or not, characterized in that the first spectrum on acquisition time window (106) and the second spectrum acquisition time window (108) overlap at least partially in time, in particular completely. System according to Claim 11 , characterized in that a) the system comprises a spatially predetermined detection area (18) in which the sample (26) for recording the first and second optical spectra is arranged, and / or b) the first optical spectroscopy device (28) is an infrared spectrometer (44) is or comprises, in particular a MIR reflection spectrometer (46). System according to Claim 11 or 12 characterized in that the first spectroscopy device (28) comprises a first radiation source (48) for generating first pulsed electromagnetic radiation (50) and a first detector (64) for measuring an intensity of first scattered radiation (60) scattered back from the sample (26). , in particular the first radiation source (48) being designed to tune a wavelength of the first pulsed electromagnetic radiation (50) during the first spectrum recording time window (106). System according to Claim 13 , characterized in that a) the first radiation source (48) is in the form of a first laser (52), in particular in the form of an IR laser (54), and / or b) the system (10) is a first scanning device (38 ) includes for scanning the first pulsed electromagnetic radiation (50) over the sample (26), in particular one or two dimensions. System according to one of the Claims 11 to 14 , characterized in that the second optical spectroscopy device (30) is or comprises a Raman spectrometer (70), in particular UV Raman spectrometer (72). System according to one of the Claims 11 to 15 characterized in that the second spectroscopy device (30) comprises a second radiation source (74) for generating second pulsed electromagnetic radiation (76) and a second detector (90) for measuring a wavelength-dependent second scattered radiation (86) scattered back from the sample (26) ). System according to Claim 16 , characterized in that the second radiation source (74) a) is designed to generate the second pulsed electromagnetic radiation (76) with constant wavelength and / or b) is designed in the form of a second laser (78), in particular in the form of a UV Lasers (80). System according to Claim 16 or 17th , characterized in that a) the system (10) comprises a second scanning device (40) for scanning the second pulsed electromagnetic radiation (76) via the sample (26), in particular in one or two dimensions and / or b) the first radiation source ( 48) is designed to generate the first pulsed electromagnetic radiation (50) with a first repetition rate and that the second radiation source (74) is designed to generate the second pulsed electromagnetic radiation (76) with a second repetition rate and that the first repetition rate and the second Repetition rate are identical or different and / or c) the system (10) comprises a distance determining device (58, 84) for determining a distance of the sample (26) from the first radiation source (48) and / or from the second radiation source (74). System according to Claim 11 to 18th , characterized in that the system (10) comprises a) an operating device (22) for entering data and / or b) a control device (32) for controlling the first and / or second optical spectroscopy device (28, 30) and / or c) a storage device (26) for storing reference spectra of hazardous substances and for storing the measured first and second optical spectra and / or d) an output device (34) for outputting information as to whether the at least one hazardous substance on the sample ( 26) is present or not. Use of a system (10) according to one of the Claims 11 to 19th to carry out a method according to one of the Claims 1 to 10th .

Images