Radiation detection data processing method and radiation detection device

Abstract

The invention relates to the technical field of radioactivity detection instruments, and discloses a radiation detection data processing method which comprises the following steps: step 1, acquiring detection data of a CZT detector, and boosting and amplifying the detection data to form a gain signal source; 2, processing the gain signal source by adopting a first preset filtering algorithm, extracting a pulse signal amplitude value, setting a comparison threshold value, comparing the pulse signal amplitude value with the comparison threshold value, and when the pulse signal amplitude value is greater than the comparison threshold value, adding 1 to pulse counting to obtain a pulse counting result; when the amplitude value of the pulse signal is smaller than a comparison threshold value, rejecting; and step 3, converting the pulse counting result to obtain a radiation dose value, and processing the radiation dose value by adopting a second preset filtering algorithm. The method can improve the stability and accuracy of the detection result. Meanwhile, the invention further provides a radiation detection device.

Description

Technical Field

[0001] The present invention relates to the technical field of radioactive detection instruments, and in particular to a radiation detection data processing method and a radiation detection device. Background Art

[0002] Cadmium zinc telluride (CdZnTe, CZT) is a new room-temperature compound semiconductor material with a combination of advantages, including small size, high resistivity, and a wide bandgap. Its small size makes CZT detectors highly compatible in group detection, offering significant advantages in space detection. Its high resistivity and wide bandgap also contribute to its low dark current at room temperature, surpassing the low-temperature application requirements of commonly used Si and Ge semiconductor detectors and effectively reducing the complexity of detection systems. Research on radiation detection technology based on CZT materials could provide new detection technologies for medical diagnosis, industrial flaw detection, and space radiation detection.

[0003] However, external electromagnetic interference and periodic pulse signals can affect the detection results of radiation detection devices. Currently, this problem is generally solved by setting components such as filters and inductors during circuit design or by adjusting the detection results. However, the results achieved are not ideal.

[0004] CN201810412050 discloses a portable radiation dosimeter and dose monitoring equipment, and a segmented processing method, including: a CZT detector, a signal processing system, a processor and a shielding cover made of metal material. The CZT detector, the signal processing system, and the processor are coupled, and the CZT detector, the signal processing system, and the processor are all arranged in the shielding cover. The signal processing system is used to amplify, shape, and filter the electrical signal output by the CZT detector in sequence and then output it to the processor. The processor is used to pre-process the electrical signal output by the signal processing system according to preset standards. The signal processing system includes a preamplifier module, a preprocessing module, and a comparison module. The CZT detector, the preamplifier module, the preprocessing module, the comparison module, and the processor are sequentially coupled. The preamplifier module is configured to amplify the electrical signal received from the CZT detector and output it to the preprocessing module. The preprocessing module is configured to shape and amplify the electrical signal output from the preamplifier module and output it to the comparison module. The comparison module is configured to output signals from the electrical signal output from the preprocessing module that meet preset standards to the processor for processing. This portable radiation dosimeter primarily addresses the issues of electromagnetic interference and the influence of periodic pulse signals through hardware circuitry, and improves detection accuracy by calculating detection results in segments.

[0005] Therefore, the technical problem to be solved by the present invention is: how to improve the stability and accuracy of the detection results of the radiation detection device. Summary of the Invention

[0006] The main purpose of the present invention is to provide a radiation detection data processing method, which can continuously remove noise and reduce the error of the gain signal by performing a first preset filtering algorithm on the acquired gain signal source, and then make the output radiation dose value more stable by performing a second preset filtering algorithm on the radiation dose value, thereby improving the stability and accuracy of the detection results.

[0007] At the same time, the present invention also provides a radiation detection device.

[0008] To achieve the above objectives, the technical solutions adopted in this application are:

[0009] A method for processing radiation detection data comprises the following steps:

[0010] Step 1: Acquire the detection data of the CZT detector, boost and amplify the detection data to form a gain signal source;

[0011] Step 2: Use the first preset filtering algorithm to process the gain signal source, extract the pulse signal amplitude value, set a comparison threshold, compare the pulse signal amplitude value with the comparison threshold, and when the pulse signal amplitude value is greater than the comparison threshold, the pulse count is increased by 1 to obtain the pulse counting result; when the pulse signal amplitude value is less than the comparison threshold, it is eliminated;

[0012] Step 3: Convert the pulse counting result to obtain a radiation dose value, and use a second preset filtering algorithm to process the radiation dose value.

[0013] Preferably, the first preset filtering algorithm is a wavelet filtering algorithm combined with a delayed difference filtering algorithm; and the second preset filtering algorithm is a limited average filtering algorithm.

[0014] Preferably, the step 1 comprises the following steps:

[0015] Step A1: Acquire detection data of the CZT detector, connect an external power supply, stabilize the external power supply, suppress electromagnetic interference, and then boost the external power supply and output it to the CZT detector to generate an analog signal;

[0016] Step A2: The analog signal is amplified by the amplifier circuit to form a gain signal source.

[0017] Preferably, step 2 further includes: the number of comparison thresholds is at least four; and the gain signal source is compared with different comparison thresholds respectively to obtain multiple pulse counting results.

[0018] Preferably, the method for setting the comparison threshold is: setting n thresholds at preset time intervals, comparing the gain signal source with the n thresholds respectively, obtaining n corresponding pulse counting results, establishing an image based on the n thresholds and the corresponding pulse counting results, and then setting the comparison threshold according to the shape of the image, where n is a positive integer, n≥4.

[0019] Preferably, step 3 specifically comprises: calculating the radiation dose value of each pulse counting result according to the formula y=kx+b, then calculating the radiation dose values ​​of multiple pulse counting results using the root mean square formula to obtain a final radiation dose value, and processing the final radiation dose value using a second preset filter;

[0020] Where y is the radiation dose value, x is the product of the comparison threshold and the pulse counting result, k is the calibration coefficient, and b is the correction value.

[0021] Preferably, the method further includes step 4: after the detection is completed, when the radiation dose value decreases to zero, the radiation dose value is processed in a direct manner.

[0022] At the same time, a radiation detection device is also provided, comprising the following units:

[0023] Data acquisition unit: used to acquire the detection data of the CZT detector, boost and amplify the detection data to form a gain signal source;

[0024] Data comparison unit: used to process the gain signal source using a first preset filtering algorithm, extract the pulse signal amplitude value, set a comparison threshold, compare the pulse signal amplitude value with the comparison threshold, and when the pulse signal amplitude value is greater than the comparison threshold, the pulse count is increased by 1 to obtain the pulse counting result; when the pulse signal amplitude value is less than the comparison threshold, it is eliminated;

[0025] Data processing unit: used for converting the pulse counting result to obtain the radiation dose value, and processing the radiation dose value using the second preset filtering algorithm;

[0026] Shell: used to place data acquisition unit, data comparison unit, and data processing unit.

[0027] Preferably, the data acquisition unit includes a boost module, a preamplifier module, and a CZT detector;

[0028] The boost module includes a voltage stabilizer, an inductor, a boost converter, and an RC filter; the voltage stabilizer, the inductor, the boost converter, the RC filter, and the CZT detector are electrically connected in sequence.

[0029] Preferably, the preamplifier module includes a field effect tube and an operational amplifier; the CZT detector, the field effect tube and the operational amplifier are electrically connected in sequence.

[0030] Compared with the existing technology, this solution has the following beneficial effects:

[0031] The data processing method of the present invention utilizes a first preset filtering algorithm to process the acquired gain signal source, thereby continuously removing noise and reducing gain signal errors. Furthermore, by processing the pulse counting results using a second preset filtering algorithm, the output radiation dose value is stabilized, thereby improving the stability and accuracy of the detection results. Furthermore, by processing the radiation dose values ​​using the second preset filtering algorithm, common-mode noise can be effectively removed, extracting a pure signal. By applying different filtering algorithms to both the gain signal source and the radiation dose values, both process and result quantities can be optimized, improving detection accuracy and stability.

[0032] Furthermore, the first preset filtering algorithm is a wavelet filter combined with a delayed differential filter, and the second preset filtering algorithm is a clipped average filter. Wavelet filtering has excellent localization characteristics and can continuously remove noise. The delayed differential filter can effectively remove common-mode noise and extract a pure signal. Digital filtering is achieved through software without additional hardware costs. The gain signal is processed by the wavelet filter combined with the delayed differential filter to effectively and accurately extract the pulse signal amplitude value. The pulse counting result is then processed by the clipped average filter to reduce the fluctuation of the pulse counting result, thereby improving the stability of the radiation dose value.

[0033] Secondly, after the detection is completed, when the radiation dose value drops to zero, the radiation dose value is processed in a direct manner to improve the response efficiency of the radiation dose value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the radiation detection data processing method in Example 1;

[0035] Figure 2 is a block diagram of the radiation detection device in Example 2;

[0036] Figure 3 This is a block diagram of the data acquisition unit in Example 2. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the present application shown here can be arranged and designed in various different configurations.

[0038] Example 1

[0039] refer to Figure 1 , a radiation detection data processing method, comprising the following steps:

[0040] Step 1: Acquire the detection data of the CZT detector, boost and amplify the detection data to form a gain signal source;

[0041] Preferably, step 1 comprises the following steps:

[0042] Step A1: Acquire detection data of the CZT detector, connect an external power supply, stabilize the external power supply, suppress electromagnetic interference, and then boost the external power supply and output it to the CZT detector to generate an analog signal;

[0043] The external power source is the battery on the radiation detection device. The battery power is passed through the TPS7A03 voltage regulator in the hardware circuit, outputting 200mA current and 3.3V voltage. The voltage passes through the ferrite bead inductor to suppress electromagnetic interference. The voltage is then boosted to 38V by the LT8410 boost converter and output to the CZT detector. When the CZT detector is close to the radiation source, it generates detection data. By applying pressure to the CZT detector, an analog signal is generated.

[0044] Step A2: The analog signal is amplified by the amplifier circuit to form a gain signal source.

[0045] After the analog signal enters the field effect tube, it passes through the operational amplifier model LTC6256 and outputs the amplified gain signal source.

[0046] It should be noted that step 1 is to achieve preliminary noise reduction and electromagnetic interference resistance on the detection data through hardware circuits, and to amplify the signal of the detection data through hardware circuits.

[0047] Step 2: Use the wavelet filtering algorithm combined with the delayed differential filtering algorithm to process the gain signal source, extract the pulse signal amplitude value, set the comparison threshold, and compare the pulse signal amplitude value with the comparison threshold. When the pulse signal amplitude value is greater than the comparison threshold, the pulse count is increased by 1 to obtain the pulse counting result; when the pulse signal amplitude value is less than the comparison threshold, it is eliminated; the number of comparison thresholds is at least four; the gain signal source is compared with different comparison thresholds respectively to obtain multiple pulse counting results.

[0048] In this embodiment, the gain signal source is a sinusoidal wave pulse, and a wavelet filtering algorithm is used to process the pulse signal to continuously and effectively remove noise from the gain signal source and retain the localized characteristics of the gain signal source. A delayed differential filtering algorithm is then used to process the gain signal source after being processed by the wavelet filtering algorithm. By calculating the difference between adjacent sampling points, the change trend of the useful signal can be amplified while suppressing the random fluctuation of the noise. After the gain signal source is processed by the wavelet filtering algorithm combined with the delayed differential filtering algorithm, the waveform of the gain signal source can be smoother and the error can be reduced. The gain signal source is sampled at the same time interval to obtain multiple pulse signal amplitude values, and then a comparison threshold is set. In this embodiment, four comparison thresholds are set, which can meet ordinary detection requirements and reduce power consumption. More comparison thresholds can also be set according to actual conditions. The comparison threshold can be set according to an arithmetic progression or a geometric progression, or according to actual experience. The pulse signal amplitude value is compared with the comparison threshold. If the pulse signal amplitude value is greater than the comparison threshold, the pulse count is +1. If the pulse signal amplitude value is less than the comparison threshold, the pulse count remains unchanged. In this way, after all the pulse signal amplitude values ​​are compared with each comparison threshold, four pulse count results corresponding to the four comparison thresholds are obtained.

[0049] The comparison threshold is set as follows: n thresholds are set at preset time intervals, the gain signal source is compared with the n thresholds respectively, and n corresponding pulse counting results are obtained. An image is established based on the n thresholds and the corresponding pulse counting results, and then the comparison threshold is set according to the shape of the image, where n is a positive integer and n≥4.

[0050] In this embodiment, the threshold is a voltage value, and the preset time interval is specifically 0.1ms. Ten thresholds are set, and the gain signal source is compared with each of the ten thresholds to obtain ten corresponding pulse count results. The pulse count results are then used as the vertical axis and the threshold as the horizontal axis. The 10 threshold comparisons and the ten corresponding pulse count results are then input into an Excel spreadsheet to generate an image. Based on the image, an appropriate value is extracted as the comparison threshold. This method allows the comparison threshold to be inferred from the threshold, providing a reference for setting the comparison threshold and avoiding the impact of empirical or arbitrary setting of the comparison threshold on the detection results.

[0051] It should be noted that the comparison threshold can be set through the DAC (digital-to-analog conversion) module in the MCU. In this way, the comparison threshold can be dynamically adjusted according to actual needs. The DAC digital control accuracy can reach 1mV and the response is fast, avoiding the situation in which the existing technology uses a voltage divider resistor to set the comparison threshold, resulting in the comparison threshold being unchangeable.

[0052] Step 3: Convert the pulse counting result to obtain a radiation dose value, and use a second preset filtering algorithm to process the radiation dose value.

[0053] Preferably, step 3 is specifically as follows: according to the formula y=kx+b, the corresponding radiation dose value of each pulse counting result is calculated, wherein y is the radiation dose value, x is the product of the comparison threshold and the pulse counting result, k is the calibration coefficient, the specific data is obtained by calibration with the standard radiation field, and b is the correction value, which is the error compensation caused by the environmental background or other factors.

[0054] In this embodiment, a total of four radiation dose values ​​are calculated, and then the root mean square formula is used to calculate all the radiation dose values ​​to obtain the final radiation dose value.

[0055] The root mean square formula is:

[0056] Where n is the number of pulse counting results, is the ith radiation dose value;

[0057] Since the radiation dose value is detected in real time and is constantly updated, when the radiation dose value is displayed, the radiation dose value may fluctuate greatly, thereby affecting the judgment of the staff. Therefore, after obtaining the new radiation dose value, the final radiation dose value is processed using the limited average filtering algorithm to make the final radiation dose value fluctuate within a certain range, thereby improving the stability of the radiation dose value calculation result.

[0058] Preferably, the method further includes step 4: after the detection is completed, when the radiation dose value decreases to zero, the radiation dose value is processed in a direct manner.

[0059] After the test is completed and the patient is away from the radiation source, the radiation dose value displayed has no reference value. Therefore, during the process of the radiation dose value decreasing to zero, the radiation dose value is processed in a direct way. In other words, the radiation dose value is not calculated at all and is directly reduced to zero. This method can improve the response efficiency of the radiation dose value.

[0060] Example 2

[0061] refer to Figure 2 、 3 , a radiation detection device, comprising the following units:

[0062] Data acquisition unit: used to acquire the detection data of the CZT detector, boost and amplify the detection data to form a gain signal source;

[0063] Data comparison unit: used to process the gain signal source using a first preset filtering algorithm, extract the pulse signal amplitude value, set a comparison threshold, compare the pulse signal amplitude value with the comparison threshold, and when the pulse signal amplitude value is greater than the comparison threshold, the pulse count is increased by 1 to obtain the pulse counting result; when the pulse signal amplitude value is less than the comparison threshold, it is eliminated;

[0064] Data processing unit: used for converting the pulse counting result to obtain the radiation dose value, and processing the radiation dose value using the second preset filtering algorithm;

[0065] Shell: used to place data acquisition unit, data comparison unit, and data processing unit.

[0066] Preferably, the data acquisition unit includes a boost module, a preamplifier module, and a CZT detector;

[0067] The boost module includes a voltage stabilizer, an inductor, a boost converter, and an RC filter; the voltage stabilizer, the inductor, the boost converter, the RC filter, and the CZT detector are electrically connected in sequence.

[0068] Preferably, the preamplifier module includes a field effect tube and an operational amplifier; the CZT detector, the field effect tube and the operational amplifier are electrically connected in sequence.

[0069] The specific working process of the radiation detection device is as follows: the staff brings the radiation detection device close to the radiation source, the CZT detector in the data acquisition unit converts the optical signal of the radiation source into an electrical signal, and an external power supply supplies power to the boost module. In this embodiment, the external power supply is a battery. The current passes through a voltage regulator with a model number of TPS7A03, outputting a 200mA current and a 3.3V voltage. The 3.3V voltage passes through a magnetic bead inductor, which suppresses electromagnetic interference. The 3.3V voltage is then passed through a boost converter with a model number of LT8410 to increase the 3.3V voltage to 38V. The 38V voltage passes through an RC filter and is then input to the CZT detector. When the CZT detector converts the optical signal of the radiation source into an electrical signal, the CZT detector generates an analog signal. The analog signal passes through a field-effect transistor with a model number of BF682 and is then input into an LTC6256 operational amplifier. The operational amplifier outputs a gain signal source with amplified gain, and the gain signal source is input into the data comparison unit.

[0070] The data comparison unit uses a wavelet filtering algorithm combined with a delayed differential filtering algorithm to process the gain signal source and extract the pulse signal amplitude value. The staff sets four comparison thresholds, compares the pulse signal amplitude value with each comparison threshold, obtains the pulse counting result, and then inputs the pulse counting result into the data processing unit.

[0071] The data processing unit uses the formula y=kx+b to calculate the radiation dose value corresponding to each pulse counting result, and then calculates multiple radiation dose values ​​through the root mean square formula to obtain the final radiation dose value. The final radiation dose value and the previously displayed radiation dose value are calculated using the limited average filtering algorithm to obtain the final displayed radiation dose value. In this way, the stability of the displayed radiation dose value can be improved.

[0072] It should be noted that the data comparison unit and data processing unit are both implemented within the MCU. The wavelet filtering algorithm, combined with the delayed differential filtering algorithm and the clipped average filtering algorithm, are all implemented within the MCU's software programming. The comparison threshold is set using the MCU's internal digital-to-analog converter (DAC). The pulse signal amplitude is compared with the comparison threshold using the MCU's internal comparator (OPAMP).

[0073] By using the MCU's internal comparator and digital-to-analog converter instead of an external comparator circuit, power consumption and PCB layout space can be reduced, reducing product size and cost.

[0074] The CZT detector fabrication process involves cutting a cadmium zinc telluride (CZT) crystal with a resistivity greater than 1011 Ω / cm into small crystals measuring 5 mm × 5 mm × 1 mm. After cutting, the cathode and anode of the small crystals are wet-plated with gold. Excess side metal layers are removed by grinding and polishing, and then passivated with hydrogen peroxide to form a high-resistance oxide layer. The PCBs are then placed in a jig, and the small crystals are arranged in order. Conductive silver paste is applied to the PCB housing, and the chip is picked up and mounted into the housing. Conductive silver paste is applied to the PCB pins and the surface of the small crystals. The small crystals are connected to the silver paste via copper wires and cured by low-temperature baking at 80°C for 1 hour. Finally, underfill is injected into the PCB housing to completely cover the small crystals. The underfill is cured by low-temperature baking at 100°C for 1 hour, resulting in a packaged CZT detector.

[0075] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A radiation detection data processing method, characterized in that: The following steps are involved: Step 1: Acquire the detection data of the CZT detector, boost and amplify the detection data to form a gain signal source; Step 2: Use the first preset filtering algorithm to process the gain signal source, extract the pulse signal amplitude value, set a comparison threshold, compare the pulse signal amplitude value with the comparison threshold, and when the pulse signal amplitude value is greater than the comparison threshold, the pulse count is increased by 1 to obtain the pulse counting result; when the pulse signal amplitude value is less than the comparison threshold, it is eliminated; Step 3: Convert the pulse counting result to obtain a radiation dose value, and use a second preset filtering algorithm to process the radiation dose value.

2. The radiation detection data processing method according to claim 1, characterized in that: The first preset filtering algorithm is a wavelet filtering algorithm combined with a delayed difference filtering algorithm; the second preset filtering algorithm is a limited average filtering algorithm.

3. The radiation detection data processing method according to claim 1, characterized in that: The step 1 comprises the following steps: Step A1: Acquire detection data of the CZT detector, connect an external power supply, stabilize the external power supply, suppress electromagnetic interference, and then boost the external power supply and output it to the CZT detector to generate an analog signal; Step A2: The analog signal is amplified by the amplifier circuit to form a gain signal source.

4. The radiation detection data processing method according to claim 1, characterized in that: The step 2 further includes: the number of comparison thresholds is at least four; and the gain signal source is compared with different comparison thresholds respectively to obtain multiple pulse counting results.

5. The radiation detection data processing method according to claim 4, characterized in that: The comparison threshold is set as follows: n thresholds are set at preset time intervals, the gain signal source is compared with the n thresholds respectively, and n corresponding pulse counting results are obtained. An image is established based on the n thresholds and the corresponding pulse counting results, and then the comparison threshold is set according to the shape of the image, where n is a positive integer and n≥4.

6. The radiation detection data processing method according to claim 4, characterized in that: Step 3 specifically comprises: calculating the radiation dose value of each pulse counting result according to the formula y=kx+b, then calculating the radiation dose values ​​of multiple pulse counting results using the root mean square formula to obtain a final radiation dose value, and processing the final radiation dose value using a second preset filtering algorithm; Where y is the radiation dose value, x is the product of the comparison threshold and the pulse counting result, k is the calibration coefficient, and b is the correction value.

7. The radiation detection data processing method according to claim 1, characterized in that: The method further includes step 4: after the detection is completed, when the radiation dose value decreases to zero, the radiation dose value is processed in a direct manner.

8. A radiation detection device, characterized in that: The following units are included: Data acquisition unit: used to acquire the detection data of the CZT detector, boost and amplify the detection data to form a gain signal source; A data comparison unit is used to process the gain signal source using a first preset filtering algorithm, extract the pulse signal amplitude value, set a comparison threshold, compare the pulse signal amplitude value with the comparison threshold value, and when the pulse signal amplitude value is greater than the comparison threshold value, the pulse count is increased by 1 to obtain a pulse counting result; When the pulse signal amplitude value is less than the comparison threshold, it is eliminated; Data processing unit: used for converting the pulse counting result to obtain the radiation dose value, and processing the radiation dose value using the second preset filtering algorithm; Shell: used to place data acquisition unit, data comparison unit, and data processing unit.

9. The radiation detection device according to claim 8, characterized in that: The data acquisition unit includes a boost module, a preamplifier module, and a CZT detector; The boost module includes a voltage stabilizer, an inductor, a boost converter, and an RC filter; the voltage stabilizer, the inductor, the boost converter, the RC filter, and the CZT detector are electrically connected in sequence.

10. The radiation detection device according to claim 9, characterized in that: The preamplifier module includes a field effect tube and an operational amplifier; the CZT detector, the field effect tube and the operational amplifier are electrically connected in sequence.

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