KR101198953B1 - The simultaneous measuring method and equipment of neutron and gamma-ray dosage using one PIN diode - Google Patents

Abstract

The present invention is configured using a single PIN diode sensor, including a constant current driver for measuring neutron radiation and a pulse amplitude detector for measuring gamma radiation, high sensitivity amplifier circuit for removing and amplifying the noise of the signal generated from each signal detector The analog signal output by using an analog digital converter is digitized, and the signal analysis through digital signal processing function for the measurement dose for neutrons and gamma rays using the digital measurement data from the control unit including the microcontroller. The present invention relates to a neutron and gamma ray measuring device using a single sensor including a storage function.
The neutron and gamma ray measuring apparatus of the present invention includes a PIN diode sensor for radiation measurement; A current pulse detector for detecting a pulsed current due to ionization phenomenon proportional to the energy of gamma rays using the PIN diode sensor; A constant current output unit for sensing the voltage across the diode due to the current limiting effect of the lattice structure damage when the forward direction current is applied as the PIN diode sensor reacts with the neutron particles; A signal processor for measuring output signals of the current pulse detector and the constant current output unit and extracting information; And a control unit for calculating, storing and managing a neutron accumulation dose or a gamma dose through the output signals of the signal processor.

Description

A device for measuring neutrons and gamma rays using a single sensor {The simultaneous measuring method and equipment of neutron and gamma-ray dosage using one PIN diode}

The present invention relates to a device for measuring radiation, and more particularly, to a device for measuring neutron and gamma rays using a single sensor capable of detecting both gamma and neutron radiation using a single PIN diode. .

More specifically, it is configured using a single PIN diode sensor, and includes a constant current driver for measuring neutron radiation and a pulse amplitude detector for measuring gamma rays, and a high sensitivity amplification for removing and amplifying the noise generated from each signal detector. It is equipped with a circuit, and digitalizes the analog signal output by using an analog digital converter and analyzes the signal through the digital signal processing function for the measurement dose to the neutron and gamma ray by using the digital measurement data from the control unit including the microcontroller. And a measuring device for neutrons and gamma rays using a single sensor including a storage function.

As the alternative to power generation, the utilization of radiation is increasing in various fields such as nuclear power plants, which are receiving great attention recently, medical radiation devices that are gaining attention as efficient cancer treatment methods, and radiation and inspection devices at airports and industrial sites. have.

However, such radiation can adversely affect the human body, so it must be accompanied by strict management and strict regulations.

In order to ensure safety when using radiation, measurement of radiation is an essential procedure, and in order to accurately measure radiation, not only the radiation dose but also the type of radiation must be simultaneously measured. Among these various radiations, gamma radiation (hereinafter referred to as "gamma radiation") And neutrons are radiations that are most demanding in general industrial and medical settings, and mainly measure instantaneous melodies and dose values that are cumulative over time.

In general, radiation dosimeters for measuring neutrons and gamma rays are used separately, but recently, integrated dosimeters that can simultaneously measure neutrons and gamma rays in a single device are used.

These integrated dosimeters are each equipped with a sensor that independently measures each radiation, each sensor has a structure and function to measure the radiation separately, so the two dosimeters are only attached in a small form.

When neutron and gamma ray information is measured using a separate sensor, various errors such as error occurrence caused by non-uniform characteristics of sensors, mutual interference due to overlapping signal source, increase of applied power node, and increase of power consumption There is a problem, and in addition, due to the increase in the sensor installation space and the measurement circuit, the volume is also difficult to carry.

In order to improve these shortcomings, radioactive measuring devices using semiconductor devices capable of measuring neutrons and gamma rays at the same time have been developed and commercialized in the commercialization stage. However, a method and apparatus for measuring neutrons and gamma rays using a single sensor have not been developed.

Therefore, there is a need for an apparatus and method capable of performing various functions, for example, neutron and gamma-ray simultaneous measurement functions, from a single sensor.

The present invention has been developed to solve the problems of the prior art, and an object of the present invention is to provide a neutron and gamma ray measuring device using a single sensor that can automatically measure neutron and gamma rays simultaneously with a single PIN diode sensor. .

In addition, the present invention miniaturizes the detector by using a single sensor for measuring neutron and gamma rays, and improves the signal-to-noise ratio for radiation measurement by using a high sensitivity amplifier circuit for removing signal amplification and noise of the detector, and measuring system The purpose of the present invention is to provide a neutron and gamma ray measuring device using a single sensor using digital noise reduction technology through a signal processing algorithm in digitizing and processing digitized radiation measurement information on the firmware of the control processing unit.

The neutron and gamma ray measuring apparatus using a single sensor of the present invention and the PIN diode sensor for radiation measurement; A current pulse detector for detecting a pulsed current due to ionization phenomenon proportional to the energy of gamma rays using the PIN diode sensor; A constant current output unit for sensing the voltage across the diode due to the current limiting effect of the lattice structure damage when the forward direction current is applied as the PIN diode sensor reacts with the neutron particles; A signal processor for measuring output signals of the current pulse detector and the constant current output unit and extracting information; And a control unit for calculating, storing and managing a neutron accumulation dose or a gamma dose through the output signals of the signal processor.

The present invention can measure neutrons and gamma rays using a single sensor can simplify the sensor signal processing logic and reduce the number of sensors for radiation measurement, thereby reducing the size and weight of the conventional radiation measuring device .

In addition, by configuring the digital filtering unit in the digital signal processing unit to reduce the measurement error caused by the glitch signal to improve the reliability of the signal detection, and by applying the automatic measurement processing method according to the current pulse detection signal independent of the control unit It has the effect of minimizing the load for signal processing. The digital filtering part can be designed in the VHDL language, and can be miniaturized by developing into a single IC with ASIC.

Furthermore, when the PIN diode sensor is used as a gamma-ray detection sensor, the gamma dose in a radiation environment in which ionizing radiation and core ions are combined through a correction algorithm for deterioration due to lattice structure damage caused by core ions on a single sensor By reducing the measurement error of the sensor during the measurement has the effect of enabling more accurate measurement of the radiation.

1 is a block diagram of an apparatus for measuring neutron and gamma rays using a single sensor according to the present invention,
2 is a configuration diagram of a current pulse detection unit constituting a measuring device according to the present invention;
3 is a configuration diagram of a constant current driver constituting a measuring device according to the present invention;
4 is a block diagram of a signal processing unit constituting a measuring device according to the present invention;
5 is a block diagram of a control unit constituting a measuring device according to the present invention;
6 is a block diagram of a digital signal processing unit constituting a measuring device according to the present invention;
7 is a configuration diagram of a digital filtering unit constituting a digital signal processing unit;
8 is a configuration diagram of a digital signal processing unit constituting a digital signal processing unit,
9 is a configuration diagram of an ADC control unit constituting a digital signal processing unit,
10 is a configuration diagram of all the switching unit.

Hereinafter, a measuring device for neutrons and gamma rays using a single sensor according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in Figure 1, the measuring device of the neutron and gamma rays using a single sensor according to the present invention is a PIN diode sensor (1) for radiation measurement; A current pulse detector (2) for detecting a pulsed current due to ionization in proportion to the energy of gamma rays by using the PIN diode sensor (1); A constant current output unit (3) for sensing the voltage across the diode due to the current limiting effect caused by the lattice structure damage upon application of forward constant current as the PIN diode sensor (1) reacts with the neutron particles; A signal processor (4) for measuring output signals of the current pulse detector (2) and the constant current output unit (3) and extracting information; And a control unit 5 for calculating, storing and managing neutron accumulation dose or gamma dose through the output signals of the signal processor 4.

The PIN diode sensor 1 has a property of damaging the lattice structure when reacting with neutron particles. That is, when forward constant current is applied, the voltage across the diode increases due to the current limiting effect due to damage to the lattice structure.

In addition, the PIN diode sensor 1 has a characteristic of generating a photocurrent output due to ionization which is proportional to the energy of incident radiation when reacting with gamma rays that are ionizing radiation.

The PIN diode sensor 1 is capable of measuring a neutron dose of 1 krad displacement at 1 rad, has a high purity thick (approximately 1 mm to 2 mm) silicon cube body, and when the neutron is exposed to damage to the lattice inside the device The resulting grid damage acts as a recombination center of mobile charges, which is represented by an increase in external resistance of the device.

Therefore, the increase in the forward resistance of the PIN diode sensor 1 is proportional to the neutron dose information incident to the sensor, so that the increase in the resistance component of the PIN diode sensor 1 can be used as a measurement variable of the neutron dose information. When implemented in a circuit it is used in the forward application state to the PIN diode sensor (1).

When measuring the gamma ray rate, it operates in the reverse bias state, and when the diode is exposed to the gamma ray while applying reverse power, electrons are generated inside the device due to photoelectric effect, compton scattering, electron pair generation effect, and the like. The former is represented as an output signal in the form of a pulse in an external measuring circuit, and the number of pulses indicates the melody information of the incident gamma ray, which can be used as melody information immediately.

That is, in order to be able to simultaneously use the neutron dose and the gamma-ray melody using one PIN diode sensor 1, the change amount of the resistive component is measured in the forward external bias state to obtain 'neutron dose' information, and the reverse bias state. It is possible to measure the gamma ray melody information by counting the number of output charge pulses at. The current pulse detector 2, the constant current output unit 3, and the mode converter 6 described below for bias and signal processing circuits in two directions. ) Is configured.

Once again the action of the PIN diode sensor 1, when the PIN diode sensor 1 is exposed to neutrons, which are high energy particles according to the above characteristics, due to the effect of non-ionizing radiation in the Si layer of the semiconductor device The displacement of the turn-on voltage of the PIN diode sensor increases proportionally from the displacement damage caused by the grid structure damage, thereby detecting the presence of neutrons.

When detecting gamma rays, as described above, when the gamma rays are incident on the PIN diode sensor 1, the pulsed photocurrent signals due to ionization effects may be measured.

As described above, the measuring device of the present invention, which is capable of measuring neutrons and gamma rays by using one PIN diode sensor 1, detects the current pulse detector 2 and the neutrons for detecting gamma rays as described above. And a switching means for switching to either the current pulse detection unit 2 or the constant current output unit 3 according to the radiation detected, and mode switching with the switching means. The part 6 is provided.

That is, between the PIN diode sensor 1, the current pulse detection unit 2, and the constant current output unit 3, a mode conversion unit 6 for switching the direction of the voltage applied to the PIN diode sensor 1 is configured. have.

As described above, the mode conversion unit 6 is a switching means for connecting the PIN diode sensor 1 to either the current pulse detection unit 2 or the constant current output unit 3, as shown in FIG. The bias voltage applied to the PIN diode sensor 1 is controlled by switching the relay 61.

In other words, in order to detect neutrons, a constant current is applied to the PIN diode sensor in a forward direction in order to detect displacement of turn-on voltage due to displacement damage inside the PIN diode according to the absorbed dose of the neutrons. In order to detect, a bias voltage in the reverse direction is applied to measure the photocurrent pulse signal emitted by the ionization phenomenon generated inside the PIN diode due to the gamma ray irradiation.

As described above, the current pulse detector 2 is a component for detecting the photocurrent pulse signal by the gamma ray, and as shown in FIG. 2, for converting the photocurrent of the PIN diode sensor 1 into a voltage. IV converter 21; A preamplifier 22 for amplifying the output of the I-V converter 21; A band pass filter 23 for passing only outputs of some bands of the outputs of the preamplifiers; It consists of a log amplifier 24 for non-linear conversion of the output signal of the band pass filter 23.

The internal ionizing effect of gamma irradiation is output in the form of instantaneous current pulse, the amount of current is determined according to the irradiation dose and energy, and is generally output as an impulse signal in pA ~ nA unit. .

Therefore, the IV converter 21 is configured to measure the small current amount and count the number of pulses, and a band pass filter 23 for amplifying the signal using a preamplifier and removing the noise signal. It is.

In addition, a log amplifier 24 for improving sensitivity and extending the measurement range (minimum and maximum) is provided.

As described above, the detection of the neutron is performed by sensing the voltage across the diode increasing due to the current limiting effect caused by the lattice structure damage when the PIN diode sensor 1 is exposed to the neutron, and the forward constant current is applied. The constant current output unit 3, which is a means for detecting the voltage across the diode, comprises: a voltage detector 31 which detects a turn-on voltage V _TH changed by a forward constant current supplied to the PIN diode sensor 1; And an amplifier 32 for amplifying the output of the voltage detector 31.

That is, the neutron acts as a factor to change the turn-on voltage of the PIN diode according to the degree of lattice structure damage, and by measuring a change in the turn-on voltage (V _TH ) by applying a constant current source in the forward direction of the PIN diode. The neutron absorbed dose can be measured relatively, and this constant current output unit 3 is configured as shown in FIG.

In FIG. 3, the constant current output unit 30 is a means for providing a forward constant current to the PIN diode sensor 1, and the amplifier 32, the low pass filter 33, and the buffer 34 are provided by the voltage detector 31. It is a means for amplifying and filtering the detected signal and buffering with other components.

As described above, the signal is outputted by the current pulse detector 2 and the constant current output unit 3 while the mode is switched by the mode converter 6 and the mode is converted by the signal processor 4. The feature information is extracted from the measurement and the signal of.

As shown in FIG. 4, the signal processor 4 includes: a comparator 41 for detecting a trigger signal as a reference signal input; A DAC 42 for setting a lower limit threshold voltage of signal detection in the comparator 41; An analog multiplexer 43 for selectively switching the current pulse signal and the output voltage of the turn-on voltage V _TH according to the mode conversion; And an ADC 44 for converting the peak voltage of the current pulse and the analog voltage values of the turn-on voltage V _TH into digital.

Between the signal processor 4 and the controller 5, a digital signal processor 7 for converting the output signal of the signal processor 4 into a digital signal is configured.

As described above, the signal processor 4 controls the mode converter 6 and the signal processor 4 to output characteristic information of the analog signal output for each mode in a manner independent of the controller 5. The DAC 42 and the ADC 44 are provided for the purpose of automatically measuring the pulse width and the maximum peak voltage (V _peak ) of the current pulse output (V _pulse ) signal output from the detector (2). As shown in FIG. 6, the digital signal processor 7 includes an ADC controller 73 for controlling the DAC 42 and the ADC 44, and a pulse amplitude detector for detecting the amplitude of the current pulse. It comprises 72.

In addition, the digital signal processing unit 7 detects the signal detected from the current pulse detection unit 2 through the comparator 41 constituting the signal processing unit 4 to the glitch signal included in the trigger signal which is a signal for pulse detection. In order to prevent malfunction due to the digital filtering unit 71 is further provided.

The amplitude and peak voltage (V _peak ) information of the current pulse which is automatically detected by triggering the current pulse signal in the above manner is utilized as the main feature information for calculating the integral value for the detected single pulse and converting it into dose. In addition, there is an advantage in that the load of the controller can be minimized by storing and performing filtering and feature information extraction of the signal in a manner independent of the controller 5.

The control unit 5 is configured as a means for controlling the driving of the measuring device configured as described above, and the control unit 5 has a current pulse measured from the current pulse detection unit 2 as shown in FIG. 5. A microcontroller 51 having a control program for calculating the gamma dose rate using the detection information, calculating the neutron accumulation dose from the turn-on voltage (V _TH ) value obtained through periodic mode conversion, and storing and managing the information. )Wow ; And a display controller 52 for controlling a display for displaying the measurement information.

That is, the microcontroller 51 configured in the control unit 5 is the neutron accumulation dose obtained through the V _TH value obtained through the gamma dose rate calculation and the periodic mode conversion using the current pulse detection information measured from the digital signal processor 7. Built-in device control program for storing and managing information through calculation of.

In addition, the control unit 5 receives a detection signal from an address decoder and a digital signal processor for generating a chip select signal of a communication driver and a peripheral device for remote control and measurement through data transmission and reception with an external device or PC software. It further comprises a FIFO memory, wherein the current pulse information automatically detected from the digital signal processing unit 7 is automatically input through the FIFO memory, and input by the interrupt processing routine of the central processing unit of the controller It has software signal processing method to read current pulse detection information and calculate dose for single pulse using pulse width and peak voltage information.

In addition, the above control program compensates for the slope of the IV curve of the PIN diode according to the ambient temperature in calculating the cumulative dose, and the slope of the IV curve according to the degree of grid structure damage inside the PIN diode according to the neutron irradiation. Perform rewards together.

As described above, the neutron and gamma ray measuring apparatus using the single sensor of the present invention simultaneously measures the neutron dose and the gamma ray melody information using one PIN diode sensor.

That is, the dose and dose are in a calculus relationship with each other on the time axis, and the control program of the controller can time-differentiate the neutron dose information to measure the neutron dose value, and time-integrate the gamma dose information to obtain the gamma dose value immediately. Can be.

Instead of using two sensors separately, the use of one sensor not only has the simple economic and spatial benefits of reducing the number of sensors used, but also has the advantages of designing signal measurement circuits and analyzers and implementing signal processing algorithms. will be.

1: PIN diode sensor
2: Current pulse detector
3: constant current output unit
4: signal processing unit
5:
6: Mode conversion unit
7: digital signal processing unit

Claims (8)

PIN diode sensor 1 for radiation measurement; A current pulse detector (2) for detecting a pulsed current due to ionization in proportion to the energy of gamma rays by using the PIN diode sensor (1); A constant current output unit (3) for sensing the voltage across the diode due to the current limiting effect caused by the lattice structure damage upon application of forward constant current as the PIN diode sensor (1) reacts with the neutron particles; A signal processor (4) for measuring output signals of the current pulse detector (2) and the constant current output unit (3) and extracting information; It includes a control unit 5 for calculating, storing and managing the neutron cumulative dose or the gamma dose through the output signals of the signal processor 4,
The current pulse detection unit 2 includes an IV converter 21 for converting the photocurrent of the PIN diode sensor 1 into a voltage;
A preamplifier 22 for amplifying the output of the IV converter 21;
A band pass filter 23 for passing only outputs of some bands of the outputs of the preamplifiers;
A neutron and gamma ray measuring apparatus using a single sensor, characterized in that consisting of a log amplifier 24 for non-linear conversion of the output signal of the band pass filter (23). The method of claim 1,
Between the PIN diode sensor 1, the current pulse detection unit 2 and the constant current output unit 3, a mode conversion unit 6 for switching the direction of the voltage applied to the PIN diode sensor 1 is configured. Neutron and gamma ray measuring device using a single sensor. The method of claim 1,
A device for measuring neutrons and gamma rays using a single sensor, characterized in that a digital signal processing unit (7) is configured between the signal processing unit (4) and the control unit (5) to convert the output signal of the signal processing unit (4) into a digital signal. delete The method of claim 1,
The constant current output unit 3
A voltage detector (31) for detecting a turn-on voltage (V _TH ) which is changed by a forward constant current supplied to the PIN diode sensor (1);
A neutron and gamma ray measuring apparatus using a single sensor, characterized in that it comprises an amplifier (32) for amplifying the output of the voltage detector (31). The method of claim 5, wherein
The signal processor 4
A comparator 41 for detecting a trigger signal as a reference signal input;
A DAC 42 for setting a lower limit threshold voltage of signal detection in the comparator 41;
An analog multiplexer 43 for selectively switching the current pulse signal and the output voltage of the turn-on voltage V _TH according to the mode conversion;
A device for measuring neutrons and gamma rays using a single sensor, comprising: an ADC (44) for converting a peak voltage of a current pulse and an analog voltage value of a turn-on voltage (V _TH ) to digital. The method according to claim 6,
The control unit 5
The gamma dose rate is calculated using the current pulse detection information measured by the current pulse detection unit 2, the neutron accumulation dose is calculated from the turn-on voltage (V _TH ) value obtained through periodic mode conversion, and the information is stored. A microcontroller 51 having a control program for management;
A neutron and gamma ray measuring apparatus using a single sensor, characterized in that it comprises a display control unit 52 for controlling the display for displaying the measurement information. The method of claim 7, wherein
The digital signal processor 7
A digital filtering unit (71) for preventing malfunction due to a glitch signal included in a trigger signal of the current pulse signal output from the current pulse detection unit (2);
A pulse amplitude detection unit 72 for detecting an amplitude of a current pulse signal;
And an analog multiplexer 43 for measuring the pulse width and the maximum peak voltage (V _peak ) of the current pulse signal output from the current pulse detector 2 and an ADC controller 73 for controlling the ADC 44. Measuring device for neutrons and gamma rays using a single sensor.

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