CN113466186A

CN113466186A - Detection device and method for scintillator afterglow

Info

Publication number: CN113466186A
Application number: CN202010243019.4A
Authority: CN
Inventors: 王燕春; 何会绍; 邹湘; 朱维彬; 张清军; 李元景
Original assignee: Nuctech Co Ltd
Current assignee: Nuctech Co Ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-01

Abstract

The present disclosure provides a detection apparatus and method for scintillator afterglow. The detection device includes: the LED chip light source is used for emitting ultraviolet light after being turned on and not emitting the ultraviolet light after being turned off, wherein the ultraviolet light irradiates on the scintillator so that the scintillator emits light signals; the photoelectric detector is used for receiving the optical signal sent by the scintillator and converting the optical signal into an electric signal; the signal processor is used for carrying out signal processing on the electric signals so as to obtain the scintillation light intensity of the scintillator; and the information processing device is used for receiving the intensity of the scintillation light from the signal processor, fitting to obtain a curve of the intensity of the scintillation light changing along with time, and obtaining the afterglow characteristic parameters of the scintillator according to the curve. This disclosure has realized the convenient detection of scintillator afterglow.

Description

Detection device and method for scintillator afterglow

Technical Field

The disclosure relates to the field of scintillator detection, and in particular to a device and a method for detecting afterglow of a scintillator.

Background

For an activator-doped luminescent material, the host crystal can absorb incident high-energy photons, and the absorbed photon energy can be received by the activator ion or absorbed by the crystal lattice and then transferred to the activator ion, and one or more electrons of the activator ion are promoted to a higher excited state. These electrons, when returned to their lower excited state, emit photons of correspondingly lower energy. The high-energy photons absorbed by the scintillator are typically X-rays or gamma rays, etc. Typically, the scintillator is used to emit photons having energies in the visible range.

The known scintillator attenuates the light emitted by the scintillator in two steps when the excitation radiation is terminated. The first step is to decay rapidly from a full light output to a lower value. This process is called attenuation. The decay gradient at this value has essentially transitioned to a lower decay rate. The second step continues to decay at this lower decay rate. This decay of low intensity is generally a longer decay, where the decaying luminescence is called afterglow glow. Usually defined as its lower than full intensity value of 2%. The initial rapid decay time is called the decay time (decay time) and is typically from the moment the excitation radiation is terminated until the light output drops to 1/e of its full intensity value.

The overall decay time of the scintillator has a significant impact on the performance of modern radiation imaging detectors. The sampling time of the radiation imaging detector is usually several milliseconds at present, and the sampling interval of a CT (Computed Tomography) device with higher scanning speed is required to be within 1 millisecond. The decay time of the current mainstream scintillator can reach within microseconds, so the influence of the decay time on the performance of the detector is small. Different scintillating materials, or the same system of scintillating materials but with different trace impurities or different processing techniques, may result in scintillating materials with distinct afterglow characteristics. The effect of afterglow on modern radiation imaging devices is very significant. In the field of radiation imaging, it is generally desirable that the afterglow be as small as possible. Therefore, in the aspects of research and development of scintillation materials, scintillator quality control, design of scintillator detectors and the like, detection of scintillator afterglow is an important link.

Disclosure of Invention

The technical problem that this disclosure solved is: the utility model provides a detection device for scintillator afterglow to realize the convenient detection of scintillator afterglow.

According to an aspect of the embodiments of the present disclosure, there is provided a detection apparatus for scintillator afterglow, including: the LED chip light source is used for emitting ultraviolet light after being turned on and not emitting the ultraviolet light after being turned off, wherein the ultraviolet light irradiates on the scintillator so that the scintillator emits light signals; the photoelectric detector is used for receiving the optical signal sent by the scintillator and converting the optical signal into an electric signal; the signal processor is used for carrying out signal processing on the electric signal so as to obtain the scintillation light intensity of the scintillator; and the information processing equipment is used for receiving the scintillation light intensity from the signal processor, fitting to obtain a curve of the scintillation light intensity along with time change, and obtaining afterglow characteristic parameters of the scintillator according to the curve.

In some embodiments, the ultraviolet light has a wavelength in the range of 200nm to 350 nm.

In some embodiments, the detection device further comprises: the chip controller is electrically connected with the LED chip light source and is used for controlling the LED chip light source to be turned on or turned off; and the time of the turn-off process when the chip controller controls the LED chip light source to be turned off is 10 microseconds to 100 microseconds.

In some embodiments, the chip controller is further configured to adjust the light emitting power of the LED chip light source to adjust the intensity of the ultraviolet light emitted by the LED chip light source.

In some embodiments, the detection device comprises: and the collimator is in contact with the light emergent surface of the LED chip light source and is used for collimating ultraviolet light emitted by the LED chip light source to obtain collimated ultraviolet light and irradiating the collimated ultraviolet light on the scintillator.

In some embodiments, the LED chip light source, the photodetector, the scintillator, and the collimator are disposed within a dark box.

In some embodiments, the detection device further comprises: the object stage is used for bearing the scintillator; the LED chip light source, the collimator, the photoelectric detector and the scintillator are positioned on the same side of the objective table.

In some embodiments, the photodetector comprises a window of a material that is opaque to ultraviolet light.

In some embodiments, the material of the window comprises borosilicate glass.

In some embodiments, the LED chip light source and the photodetector are respectively located on both sides of the scintillator, and the scintillator and the photodetector are coupled by an optical coupler.

In some embodiments, the detection device further comprises: and the detector power supply is electrically connected with the photoelectric detector and used for supplying power to the photoelectric detector.

In some embodiments, the photodetector comprises: photomultiplier tubes, silicon photomultiplier tubes, or multi-pixel photon counters.

In some embodiments, the electrical signal is an analog electrical signal; the signal processor includes: the signal amplification unit is used for receiving the analog electric signal from the photoelectric detector and amplifying the analog electric signal to obtain an amplified analog electric signal; and the signal acquisition unit is electrically connected with the signal amplification unit and used for acquiring the amplified analog electric signal according to a preset sampling frequency, converting the amplified analog electric signal into a digital electric signal to obtain the scintillation light intensity and outputting the scintillation light intensity to the information processing equipment.

In some embodiments, the sampling frequency is greater than 1 KHz.

In some embodiments, the base material of the LED chip light source comprises: at least one of GaAs, GaAsP, GaAlAs, GaP, and AlGaN.

According to another aspect of the embodiments of the present disclosure, there is provided a method for detecting afterglow of a scintillator using the detection apparatus as described above, comprising: turning on the LED chip light source to enable the LED chip light source to emit ultraviolet light, wherein the ultraviolet light irradiates on a scintillator to enable the scintillator to emit light signals, and the LED chip light source is turned off after the LED chip light source is turned on for a preset time; receiving an optical signal emitted by the scintillator by using a photoelectric detector, and converting the optical signal into an electric signal; performing signal processing on the electric signal by using a signal processor to obtain the scintillation light intensity of the scintillator; and receiving the scintillation light intensity from the signal processor by using information processing equipment, fitting to obtain a curve of the scintillation light intensity along with time change, and obtaining afterglow characteristic parameters of the scintillator according to the curve.

In some embodiments, before turning on the LED chip light source, the method further comprises: acquiring an excitation spectrum of the scintillator; and selecting an LED chip light source corresponding to the peak wavelength of the excitation spectrum according to the excitation spectrum of the scintillator.

The detection device comprises an LED chip light source, a photoelectric detector, a signal processor and information processing equipment. The LED chip light source emits ultraviolet light after being turned on and does not emit ultraviolet light after being turned off. The ultraviolet light impinges on the scintillator to cause the scintillator to emit a light signal. The photodetector receives the optical signal from the scintillator and converts the optical signal into an electrical signal. The signal processor performs signal processing on the electric signal to obtain the scintillation light intensity of the scintillator. The information processing device receives the intensity of the scintillation light from the signal processor, fits a curve of the intensity of the scintillation light changing with time, and obtains afterglow characteristic parameters of the scintillator according to the curve. The detection device realizes convenient detection of the afterglow of the scintillator.

Other features of the present disclosure and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

The present disclosure may be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating a detection apparatus for scintillator afterglow according to some embodiments of the present disclosure;

FIG. 2 is a block diagram illustrating a detection apparatus for scintillator afterglow according to further embodiments of the present disclosure;

FIG. 3 is a block diagram illustrating a signal processor according to some embodiments of the present disclosure;

FIG. 4 is a block diagram illustrating a detection apparatus for scintillator afterglow according to further embodiments of the present disclosure;

pr scintillator fig. 5 is a graph showing the excitation spectrum of a GOS: Pr scintillator according to some embodiments of the present disclosure;

FIG. 6 is a flow chart illustrating a method of detecting scintillator afterglow according to some embodiments of the present disclosure.

It should be understood that the dimensions of the various parts shown in the figures are not drawn to scale. Further, the same or similar reference numerals denote the same or similar components.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be intervening devices between the specific device and the first device or the second device. When a particular device is described as being coupled to other devices, that particular device may be directly coupled to the other devices without intervening devices or may be directly coupled to the other devices with intervening devices.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

The principle of scintillator afterglow measurement is as follows: after the radiation irradiated on the scintillator is stopped rapidly, the scintillation luminescence signal is continuously acquired for a certain period of time at a certain sampling interval (for example, several milliseconds), so that a corresponding spectrogram is obtained. One of the keys to this measurement process is how quickly stopping the irradiation of the radiation is achieved.

At present, the main afterglow detection methods at home and abroad mainly comprise the following steps:

for example, scintillator afterglow can be measured using a fast stop radiation method implemented at the source end of the radiation. The electron accelerator used by the method is expensive, large in size and difficult to popularize and use. In addition, most of the rays used by the method are pulse-type, the duty ratio is small, and the effective irradiation time to the scintillator is short. The afterglow of the scintillator has a certain cumulative effect, so that the afterglow characteristic of the scintillator is difficult to effectively reflect by the pulsed radiation source. And the isotope source always has a gamma (gamma) ray beam, so that the radiation is not easy to be quickly stopped.

The X-ray tube has small volume and convenient use, the energy range is from dozens of kilovolts to hundreds of kilovolts, but the X-ray tube is an X-ray source which continuously outputs ray beams generally, and the X-ray tube has certain advantages if used as a ray source for afterglow detection. However, when the conventional X-ray tube is used as a radiation source for afterglow detection, the X-ray tube still emits X-rays, i.e., residual X-rays, after the power of the X-ray tube is cut off, and the residual X-rays have adverse effects on the afterglow detection. Both the residual X-ray intensity and the average X-ray photon energy decrease with time, decaying approximately exponentially with time.

The intensity of the residual X-rays differs for different models of X-ray tubes. For example, the intensity of the residual X-rays of a typical X-ray tube after 10ms (milliseconds) of power off can reach 40% of the X-ray intensity when the X-ray tube is powered on, and the average energy of X-photons is attenuated to about 50% of the X-ray tube power on (the average energy varies greatly from manufacturer to manufacturer and from model to model).

Researchers have implemented special methods to achieve fast stopping radiation of X-ray tubes, such as fast rotation of targets, deflection of electron beams off targets, etc., but X-ray tubes used to implement these techniques are expensive.

For example, X-ray fast blocking methods can be used to measure scintillator afterglow. Rapid X-ray blocking is typically achieved with shutters or heavy material barriers. Since blocking X-rays requires a heavy metal material, which moves at high speed and blocks the X-rays, the required movement facilities are complicated and difficult, and thus a shut-off speed of about 10 milliseconds or more is generally achieved.

The embodiment of the disclosure provides a detection device for scintillator afterglow, thereby realizing convenient detection of the scintillator afterglow.

FIG. 1 is a block diagram illustrating a detection apparatus for scintillator afterglow according to some embodiments of the present disclosure. As shown in fig. 1, the detection device includes an LED (Light Emitting Diode) chip Light source 101, a photodetector 102, a signal processor 103, and an information processing apparatus 104.

The LED chip light source 101 is configured to emit ultraviolet light 121 after being turned on and not emit ultraviolet light after being turned off. The ultraviolet light 121 impinges on the scintillator 110 to cause the scintillator to emit a light signal 122. The light signal 122 is a flashing light.

For example, the ultraviolet light may be deep ultraviolet light. For example, the ultraviolet light may have a wavelength ranging from 200nm to 350 nm.

In some embodiments, the LED chip light source with the corresponding wavelength may be selected according to the excitation spectrum of the scintillator to be tested. The scintillator may be excited by photons in the deep ultraviolet band. For example, the excitation wavelength of the scintillator may be less than 300 nm. For example, fig. 5 shows an excitation spectrum of a GOS: Pr (praseodydymium-doped gadolinium oxysulfide) scintillator according to some embodiments of the present disclosure. As shown in FIG. 5, the peak position of the excitation spectrum of the low-afterglow GOS: Pr scintillator was 255 nm. Thus, the 255nm deep ultraviolet light has the highest excitation efficiency on GOS to Pr scintillators. Therefore, a 255nm deep ultraviolet LED chip light source can be selected as an excitation light source for afterglow test of the low-afterglow GOS-Pr scintillator.

In some embodiments, the LED chip light source can be easily replaced for meeting the testing requirements of different scintillators. For example, for different kinds of scintillators, the excitation light source (i.e., LED chip light source) of the optimal wavelength can be selected according to its excitation spectrum.

In some embodiments, the base material of the LED chip light source may include: at least one of GaAs, GaAsP, GaAlAs, GaP, and AlGaN. The LED chip light source is used as a light source and has the function of quickly turning off the light emission of the LED. The response time of LED chip light sources manufactured by different base materials is different. For example, the LED chip light source with GaAs, GaAsP or GaAlAs substrate material has response time of 10^-9And (5) s level. The LED chip light source with GaP as substrate material has response time of 10^-7And (5) s level. And the deep ultraviolet LED chip light source with the AlGaN material as the substrate material can realize microsecond-level or even nanosecond-level rapid turn-off.

The photodetector 102 is configured to receive the light signal 122 emitted from the scintillator 110 and convert the light signal into an electrical signal. The photodetector 102 transmits the electrical signal to a signal processor 103.

In some embodiments, the photodetector 102 may include a photomultiplier tube (PMT), a Silicon photomultiplier tube (SiPM), a multi-pixel photon counter (MPPC), or the like. The strength of the scintillation afterglow is generally weak, and devices such as photomultiplier tubes or silicon photomultiplier tubes are high-sensitivity photodetectors that multiply and amplify the received scintillation light to form charge signals, and thus improve the accuracy of photodetection.

The emission spectrum of the scintillator is generally broad. For example, the emission spectrum of the scintillator can range from ultraviolet light at a wavelength of 300nm to red light at a wavelength of 700nm, and even wider. The photodetectors can thus be selected according to the scintillator under test. Pr scintillators with low afterglow have an emission spectrum in the range of 500nm to 700nm, for example, and therefore photodetectors with higher quantum efficiency in this wavelength range can be selected. That is, the photodetector may be selected from devices whose spectral response ranges are biased toward long wavelengths.

In some embodiments, the photodetector 102 may include a window. Light signals from the scintillator can pass through the window into the photodetector. The material of the window may be a material that is opaque to ultraviolet light. For example, the material of the window of the photodetector may be a material that is opaque to ultraviolet light having a wavelength shorter than 300 nm. For example, the material of the window may include borosilicate glass. By using a material that is opaque to ultraviolet light as the material of the window, the influence of ultraviolet light (as excitation light) emitted from the LED chip on the detection of flare light by the photodetector can be reduced.

The signal processor 103 is used for performing signal processing on the electrical signal to obtain the intensity of the scintillation light of the scintillator 110. The signal processor 103 transmits the intensity of the flicker light to the information processing apparatus 104.

The information processing apparatus 104 is configured to receive the scintillation light intensity from the signal processor 103, fit a curve of the scintillation light intensity with time, and obtain afterglow characteristic parameters of the scintillator 110 according to the curve. Here, the afterglow characteristic parameter is an afterglow value at different times obtained from the curve. For example, the information processing apparatus 104 may be a computer.

To this end, a detection apparatus for scintillator afterglow according to some embodiments of the present disclosure is provided. The detection device comprises an LED chip light source, a photoelectric detector, a signal processor and information processing equipment. The LED chip light source emits ultraviolet light after being turned on and does not emit ultraviolet light after being turned off. The ultraviolet light impinges on the scintillator to cause the scintillator to emit a light signal. The photodetector receives the optical signal from the scintillator and converts the optical signal into an electrical signal. The signal processor performs signal processing on the electric signal to obtain the scintillation light intensity of the scintillator. The information processing device receives the intensity of the scintillation light from the signal processor, fits a curve of the intensity of the scintillation light changing with time, and obtains afterglow characteristic parameters of the scintillator according to the curve. The embodiment realizes convenient detection of the afterglow of the scintillator. The detection device has low cost and is convenient for realizing the purpose of detecting the afterglow of various scintillators.

In addition, because the LED chip light source has the characteristic of quick turn-off, the detection device can realize the quick stop of the exciting light irradiated on the scintillator, thereby improving the detection precision of the afterglow of the scintillator.

In the above embodiments, an ultraviolet light source (e.g., an LED chip light source that can emit ultraviolet light) is employed as the excitation source of the scintillator. The scintillator has the following light emission mechanism:

for a pure ion crystal scintillator, energy from incident particles is transferred to the scintillator to generate electron-hole pairs or excitons. Excitons can also absorb thermal kinetic energy and become free electron-hole pairs. An average of about 3 times the energy of the forbidden band width is required to generate an electron-hole pair. For a doped scintillator, electron-hole pairs generated by atom excitation migrate to the excited and ground states of impurity energy, leaving the impurity atoms in the excited state, forming a luminescent center or recombination center. Practical doped scintillators generally contain suitable impurities so that their excitation levels are lower than the conduction and excitation bands of the crystal, while the ground state is higher than the valence band, with the impurity level becoming the luminescence center.

Since the ionization energy of the impurity is smaller than that of a typical lattice point, electron-hole pairs generated by the excited atoms will rapidly migrate to the excited state and the ground state of the impurity level, leaving the impurity atoms in the excited state. The electrons jump from the excited state back to the ground state, emitting photons. The decay time of the luminescence of the scintillator is usually 10^-7Within s, is referred to as "fluorescence". Fluorescence is in a visible light range, and self-absorption of luminescence is effectively overcome, so that the emission spectrum and the absorption spectrum of the scintillator are effectively separated. The excited state is a metastable state in which electrons can remain for a long period of time, as they fall into a trap. These electrons gain energy from the lattice vibration, re-transit to the conduction band, and then are de-excited by the emitted photons, thus the decay time of the emitted light is longer, called "phosphorescence". It is often a significant source of "afterglow" of the scintillator.

For most scintillators, the scintillator can be excited efficiently as long as the energy of the excitation photons is greater than a certain limit, regardless of the excitation mode, the principle of the scintillator de-excitation luminescence is the same.

Thus, ultraviolet excitation can be substituted for X-ray excitation to induce scintillator luminescence. For example, the most efficient excitation wavelength of a CsI: Tl (thallium-doped cesium iodide) scintillator commonly used in the field of radiation imaging is 297nm, and the most efficient excitation wavelength of a GOS: Pr scintillator is 255 nm. The deep ultraviolet LED chip has multiple selectable emission wavelengths and is convenient to control power. Therefore, the deep ultraviolet LED chip light source can be used as an excitation light source for the afterglow test of the scintillator.

In some embodiments, as shown in fig. 1, the detection device may further include an object stage 105. The stage 105 is used to carry a scintillator 110. For example, as shown in FIG. 1, the LED chip light source 101, photodetector 102, and scintillator 110 are on the same side of the stage 105.

As shown in fig. 2, ultraviolet light 121 is irradiated on a scintillator 110 to be measured, and the scintillator is excited to emit scintillation light 122, which is dispersed into space. For scintillators with lower light transmittance and greater thickness (e.g., ceramic scintillators such as GOS: Pr scintillators with thickness greater than 2 mm), the scintillation light 122 is difficult to penetrate the scintillator well to reach the back of the scintillator, so the LED chip light source, the photodetector and the scintillator can be arranged on the same side of the stage, and the scintillator is coupled to the window of the photodetector through air, thereby facilitating the reception and detection of the scintillation light. In this embodiment, the reception and detection of scintillation light is realized in such a manner that scintillation light emitted from the scintillator surface is received.

FIG. 2 is a block diagram illustrating a detection apparatus for scintillator afterglow according to further embodiments of the present disclosure. As shown in fig. 2, the detection means may include an LED chip light source 101, a photodetector 102, a signal processor 103, an information processing device 104, and a stage 105.

In some embodiments, as shown in fig. 2, the detection device may further include a chip controller 207. The chip controller 207 is electrically connected to the LED chip light source 101. The chip controller 207 may be used to control the turning on or off of the LED chip light source 101. For example, the time of the turn-off process when the chip controller controls the LED chip light source to turn off is 10 microseconds to 100 microseconds, so that the duration of the turn-off falling edge of the LED ultraviolet light output can be 10 microseconds to 100 microseconds. The chip controller may be implemented using known control circuitry. This can realize the quick turn-off of LED chip light source to be favorable to the detection of scintillator afterglow.

In some embodiments, the chip controller 207 may also be used to adjust the light emitting power of the LED chip light source 101 to adjust the intensity of the ultraviolet light emitted by the LED chip light source. This facilitates the adjustment of the appropriate LED luminous intensity during testing.

In some embodiments, the chip controller 207 may also be electrically connected to the information processing apparatus 104. The chip controller 207 may receive instruction information from the information processing apparatus 104 to perform a corresponding control operation on the LED chip light source. For example, the information processing apparatus may include a human-machine interface, and an operator operates on the information processing apparatus 104 or a preset program issues an instruction, which the controller 207 receives and executes.

In some embodiments, as shown in fig. 2, the detection device may further include a collimator 206. The collimator 206 is in contact with the light-emitting surface of the LED chip light source 101. The collimator 206 may be configured to collimate the ultraviolet light emitted by the LED chip light source 101 to obtain collimated ultraviolet light, and irradiate the collimated ultraviolet light on the scintillator 110. This facilitates irradiation of ultraviolet light on the scintillator.

In some embodiments, as shown in fig. 2, the detection device may also include a dark box 209. Because of the poor penetration ability of ultraviolet light, the ultraviolet light may be absorbed by the surface of the scintillator to excite scintillation light. In such a case, as shown in fig. 2, the LED chip light source 101, the photodetector 102, the scintillator 110, and the collimator 206 may be disposed within a dark box 209. This prevents ambient light from interfering with the test. In addition, the photodetector (e.g., photomultiplier tube) can also be prevented from being damaged under irradiation of strong ambient light. In addition, the LED chip light source 101, the collimator 206, the photodetector 102 and the scintillator 110 are on the same side of the stage 105. This facilitates the reception and detection of the scintillating light.

In some embodiments, as shown in FIG. 2, the detection device may also include a probe power supply 208. The detector power supply 208 is electrically connected to the photodetector 102. The detector power supply 208 is used to power the photodetector 102.

In some embodiments, as shown in fig. 2, the detection device may further include a display 211. The display 211 is electrically connected to the information processing apparatus 104. The display 211 may receive data of a curve of the intensity of the flickering light with time from the information processing apparatus 104, thereby displaying the curve. In addition, the display may also display afterglow characteristic parameter values and the like obtained after calculation processing by the information processing apparatus 104.

Thus, there is provided a detection apparatus for scintillator afterglow according to further embodiments of the present disclosure. In the detection device, an LED chip light source (such as a deep ultraviolet LED chip) can be used as an excitation light source of the scintillator to realize convenient and fast testing of the afterglow of the scintillator. The deep ultraviolet LED chip light source can effectively excite the scintillator to emit light, and the LED chip light source can be turned on and off very quickly. The detection device does not need to rapidly turn off the X-ray, so that a complex and thick shutter for blocking the X-ray is not needed, and a pulse excitation light source is not adopted, so that the scintillator can be continuously excited for a long time, and the more real reaction is close to the afterglow accumulation effect under the actual use condition. The detection device is convenient for testing the afterglow of the scintillator, low in cost and easy to realize.

In some embodiments, the electrical signal output by the photodetector 102 is an analog electrical signal.

Fig. 3 is a block diagram illustrating a signal processor according to some embodiments of the present disclosure.

In some embodiments, as shown in fig. 3, the signal processor 103 may include a signal amplification unit 1031 and a signal acquisition unit 1032. The signal collection unit 1032 is electrically connected to the signal amplification unit 1031.

The signal amplification unit 1031 may be used for receiving the analog electrical signal S from the photodetector 102_AAnd amplifying the analog electrical signal to obtain an amplified analog electrical signal S_{A_Am}. The signal amplifying unit 1031 amplifies the amplified analog electrical signal S_{A_Am}To the signal acquisition unit 1032. For example, the signal amplification unit may be an amplifier.

The signal collecting unit 1032 is used for collecting the amplified analog electrical signal S according to a predetermined sampling frequency_{A_Am}And the amplified analog electrical signal S is applied_{A_Am}Converted into a digital electrical signal S_DTo obtain the intensity of the scintillation light, and outputs the intensity of the scintillation light to the information processing apparatus 104. For example, the signal acquisition unit may be a signal acquisition card.

Here, the signal acquisition unit may convert the analog electrical signal into a digital electrical signal at a certain sampling frequency. For example, the sampling frequency may be greater than 1 KHz. As another example, the sampling frequency may be greater than 300 KHz. As another example, the sampling frequency may be greater than 1 MHz. This allows measurement of scintillator afterglow with at least millisecond resolution.

In the above embodiment, the signal processor includes a signal amplifying unit and a signal collecting unit, and obtains the scintillation light intensity data by performing amplification, sampling and analog-to-digital conversion on the analog electrical signal received from the photodetector.

FIG. 4 is a block diagram illustrating a detection apparatus for scintillator afterglow according to further embodiments of the present disclosure.

Similar to the detection apparatus shown in fig. 2, the detection apparatus shown in fig. 4 may include: LED chip light source 101, photodetector 102, signal processor 103, information processing device 104, collimator 206, chip controller 207, detector power supply 208, dark box 209, and display 211. In addition, a scintillator 410 is also shown in fig. 4.

The detection apparatus shown in fig. 4 is different from the detection apparatus shown in fig. 2 in that: the detection apparatus shown in fig. 4 employs a configuration of an afterglow test that receives scintillation light that has passed through a scintillator. As shown in fig. 4, the LED chip light source 101 and the photodetector 102 are respectively located at two sides of the scintillator 410. The scintillator 410 is coupled to the photodetector 102 by a photo-coupler.

The scintillator 410 is a scintillator having high light transmittance or a scintillator having low light transmittance but a small thickness. Such scintillators emit scintillation light excited by deep ultraviolet light, a large portion of which can penetrate the scintillator. The scintillator 410 can thus be coupled to the photodetector 102 via an optical coupling agent. The scintillation light is received by the photodetector 102, and processing thereafter is similar to that described above, and thus is not described in detail here.

FIG. 6 is a flow chart illustrating a method of detecting scintillator afterglow according to some embodiments of the present disclosure. As shown in fig. 6, the method may include steps S602 to S608.

In step S602, the LED chip is turned on to make the LED chip emit ultraviolet light, wherein the ultraviolet light irradiates on the scintillator to make the scintillator emit a light signal, and the LED chip is turned off after the LED chip is turned on for a predetermined time.

In step S604, a photo detector is used to receive the light signal emitted from the scintillator and convert the light signal into an electrical signal.

In step S606, the electrical signal is subjected to signal processing by the signal processor to obtain the scintillation light intensity of the scintillator.

In step S608, the intensity of the scintillation light is received from the signal processor by the information processing apparatus, and a curve of the change of the intensity of the scintillation light with time is fitted, and the afterglow characteristic parameter of the scintillator is obtained from the curve.

To this end, methods of detecting scintillator afterglow according to some embodiments of the present disclosure are provided. The method comprises the following steps: the method comprises the steps that an LED chip light source is started to enable the LED chip light source to emit ultraviolet light, wherein the ultraviolet light irradiates a scintillator to enable the scintillator to emit light signals, and the LED chip light source is turned off after the LED chip light source is started for a preset time; receiving an optical signal emitted by the scintillator by using a photoelectric detector, and converting the optical signal into an electric signal; performing signal processing on the electric signal by using a signal processor to obtain the scintillation light intensity of the scintillator; and receiving the intensity of the scintillation light from the signal processor by using the information processing equipment, fitting to obtain a curve of the intensity of the scintillation light changing along with time, and obtaining afterglow characteristic parameters of the scintillator according to the curve. The method can realize the detection of the afterglow of the scintillator, has low cost and can meet the aim of testing the afterglow of various scintillators.

The above method may be applied to scintillators that emit light in response to both ultraviolet light excitation and X-ray or gamma ray excitation. This type of scintillator has a relatively large proportion of scintillators. The method is convenient to implement, can be used for quickly measuring the afterglow of the scintillator, and is particularly suitable for afterglow test of industrial application scintillators such as radiation imaging security check, detectors in the medical field and the like.

In some embodiments, prior to step SS602, the method may further comprise: acquiring an excitation spectrum of a scintillator; and selecting an LED chip light source corresponding to the peak wavelength of the excitation spectrum according to the excitation spectrum of the scintillator. The LED chip light source is selected.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A detection apparatus for scintillator afterglow, comprising:

the LED chip light source is used for emitting ultraviolet light after being turned on and not emitting the ultraviolet light after being turned off, wherein the ultraviolet light irradiates on the scintillator so that the scintillator emits light signals;

the photoelectric detector is used for receiving the optical signal sent by the scintillator and converting the optical signal into an electric signal;

the signal processor is used for carrying out signal processing on the electric signal so as to obtain the scintillation light intensity of the scintillator; and

and the information processing equipment is used for receiving the scintillation light intensity from the signal processor, fitting to obtain a curve of the scintillation light intensity along with time change, and obtaining afterglow characteristic parameters of the scintillator according to the curve.

2. The detection apparatus according to claim 1,

the wavelength range of the ultraviolet light is 200nm to 350 nm.

3. The detection apparatus of claim 1, further comprising:

the chip controller is electrically connected with the LED chip light source and is used for controlling the LED chip light source to be turned on or turned off;

and the time of the turn-off process when the chip controller controls the LED chip light source to be turned off is 10 microseconds to 100 microseconds.

4. The detection apparatus according to claim 3,

the chip controller is also used for adjusting the luminous power of the LED chip light source so as to adjust the light intensity of the ultraviolet light emitted by the LED chip light source.

5. The detection apparatus according to any one of claims 1 to 4, further comprising:

and the collimator is in contact with the light emergent surface of the LED chip light source and is used for collimating ultraviolet light emitted by the LED chip light source to obtain collimated ultraviolet light and irradiating the collimated ultraviolet light on the scintillator.

6. The detection apparatus according to claim 5,

the LED chip light source, the photodetector, the scintillator, and the collimator are disposed within a dark box.

7. The detection apparatus of claim 5, further comprising:

the object stage is used for bearing the scintillator;

the LED chip light source, the collimator, the photoelectric detector and the scintillator are positioned on the same side of the objective table.

8. The detection apparatus according to claim 7,

the photoelectric detector comprises a window, and the material of the window is a material which cannot penetrate through ultraviolet light.

9. The detection apparatus according to claim 8,

the material of the window comprises borosilicate glass.

10. The detection apparatus according to claim 1,

the LED chip light source and the photoelectric detector are respectively positioned at two sides of the scintillator, and the scintillator and the photoelectric detector are coupled through an optical coupler.

11. The detection apparatus of claim 1, further comprising:

and the detector power supply is electrically connected with the photoelectric detector and used for supplying power to the photoelectric detector.

12. The detection apparatus according to claim 1,

the photodetector includes: photomultiplier tubes, silicon photomultiplier tubes, or multi-pixel photon counters.

13. The detection device of claim 1, wherein the electrical signal is an analog electrical signal;

the signal processor includes:

the signal amplification unit is used for receiving the analog electric signal from the photoelectric detector and amplifying the analog electric signal to obtain an amplified analog electric signal; and

and the signal acquisition unit is electrically connected with the signal amplification unit and used for acquiring the amplified analog electric signal according to a preset sampling frequency, converting the amplified analog electric signal into a digital electric signal to obtain the scintillation light intensity and outputting the scintillation light intensity to the information processing equipment.

14. The detection apparatus according to claim 12,

the sampling frequency is greater than 1 KHz.

15. The detection apparatus according to claim 1,

the substrate material of the LED chip light source comprises: at least one of GaAs, GaAsP, GaAlAs, GaP, and AlGaN.

16. A method for detecting afterglow of a scintillator using the detection apparatus as claimed in any one of claims 1 to 15, comprising:

turning on the LED chip light source to enable the LED chip light source to emit ultraviolet light, wherein the ultraviolet light irradiates on a scintillator to enable the scintillator to emit light signals, and the LED chip light source is turned off after the LED chip light source is turned on for a preset time;

receiving an optical signal emitted by the scintillator by using a photoelectric detector, and converting the optical signal into an electric signal;

performing signal processing on the electric signal by using a signal processor to obtain the scintillation light intensity of the scintillator; and

and receiving the scintillation light intensity from the signal processor by utilizing information processing equipment, fitting to obtain a curve of the scintillation light intensity along with time change, and obtaining afterglow characteristic parameters of the scintillator according to the curve.

17. The method of claim 16, wherein prior to turning on the LED chip light source, the method further comprises:

acquiring an excitation spectrum of the scintillator; and

and selecting an LED chip light source corresponding to the peak wavelength of the excitation spectrum according to the excitation spectrum of the scintillator.