A method and apparatus for detecting gamma rays

Abstract

This invention belongs to the field of uranium resource exploration technology, specifically relating to a method and apparatus for detecting gamma rays. The method includes: utilizing... 241 The equivalent peak position after the interaction of Am and NaI(Tl) crystals serves as a self-stabilizing peak, providing a stable gamma-ray reference peak and achieving automatic spectrum stabilization. A digital high-speed multichannel module acquires gamma-ray signals, achieving full acquisition of gamma-ray signals in the energy range of 30keV to 3000keV. Multiple Regions of Interest (ROIs) are set for the acquired gamma-ray signals using digital energy thresholds, obtaining CPS counts for the quantitative gamma energy range, the natural gamma energy range, and the uranium-thorium-potassium (UHT) energy range of the gamma spectrum. Using the calibration coefficients of each parameter in the standard model, and based on the CPS counts for the quantitative gamma energy range, the natural gamma energy range, and the UHT / UHT energy range of the gamma spectrum, the quantitative gamma, natural gamma, and gamma spectrum detection results are output. This invention enables a single probe to simultaneously output measured data for quantitative gamma, natural gamma, and gamma spectra, improving the efficiency of acquiring these data.

Description

Technical Field

[0001] This invention belongs to the field of uranium resource exploration technology, specifically relating to a method and apparatus for detecting gamma rays. Background Technology

[0002] In my country, uranium resource exploration utilizes radiometric logging technology to quantitatively determine the uranium content of formations. For quantitative uranium exploration and the acquisition of other formation physical parameters, sandstone-type uranium deposits require both quantitative gamma logging and natural gamma logging, according to EJ / T1162-2018 "Specification for Geophysical Logging of In-situ Leaking Sandstone-Type Uranium Deposits". Quantitative gamma logging is used to calculate formation uranium content, while natural gamma logging is used for stratigraphic division and depth calibration of other physical parameters. In southern hydrothermal uranium deposits, to avoid the influence of thorium on quantitative uranium detection, gamma spectral logging or core analysis of the uranium-thorium relationship is necessary for correction. Currently, the detection of quantitative gamma, natural gamma, and gamma spectral logging faces challenges due to the different initial energy thresholds for each parameter and the need for real-time spectrum stabilization in gamma spectral logging. Existing multichannel simulation techniques and... 137 Cs、 133 Self-stabilizing source and spectrum stabilization technologies such as Ba cannot simultaneously detect all three radioactive parameters. Therefore, each requires a separate probe, necessitating three different probes and multiple well runs. As the depth of uranium exploration and development in my country gradually increases, the time required for a single logging operation or single-tube logging operation also gradually increases. Multiple well runs lead to problems such as longer drilling time, increased costs, and low efficiency.

[0003] In view of the above-mentioned technological status and practical needs, there is an urgent need to develop a method and device for detecting gamma rays, which can improve the efficiency of obtaining radioactive parameters, reduce logging costs, and enable a single probe to simultaneously detect three radioactive parameters: quantitative gamma rays, natural gamma rays, and gamma energy spectrum. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for detecting gamma rays, wherein the method involves... 241 Am self-stabilizing source spectral stabilization technology, digital high-speed multichannel technology, and digital ROI statistical output technology enable a single probe to simultaneously output measured data of three parameters: quantitative gamma, natural gamma, and gamma energy spectrum, according to the ROI threshold setting. This improves the efficiency of obtaining quantitative gamma, natural gamma, and gamma energy spectrum parameters in the field of uranium resource exploration and effectively solves the shortcomings of existing technologies.

[0005] Technical solution to achieve the purpose of this invention:

[0006] A method for detecting gamma rays, the method comprising:

[0007] Step 1: Using 241The equivalent peak position of Am and NaI(Tl) crystals serves as a self-stabilizing peak, providing a stable γ-ray reference peak and achieving automatic spectrum stabilization.

[0008] Step 2: Acquire gamma-ray signals using a digital high-speed multichannel module to achieve full acquisition of gamma-ray signals in the energy range of 30keV to 3000keV;

[0009] Step 3: By setting multiple ROIs for the collected gamma-ray signals using digital energy thresholds, the CPS counts for the quantitative gamma energy range, the natural gamma energy range, and the gamma-ray spectrum uranium-thorium-potassium energy range are obtained.

[0010] Step 4: Using the calibration coefficients of each parameter in the standard model, and based on the CPS counts in the quantitative γ energy range, the natural γ energy range, and the γ energy spectrum uranium-thorium-potassium energy range, obtain the output of quantitative γ, natural γ, and γ energy spectrum detection results.

[0011] In step one 241 The Am self-stabilized source releases alpha particles through its own decay, which, upon interacting with the NaI(Tl) crystal, produce an equivalent gamma energy peak. 241 The Am self-stabilizing source collimator is adjusted so that the equivalent gamma characteristic peak energy is greater than 3000 keV, which is outside the energy range of quantitative gamma, natural gamma, and gamma spectrum, thus avoiding interference with the measurement of radioactive parameters of quantitative gamma, natural gamma, and gamma spectrum.

[0012] The digital high-speed multichannel module in step two includes a detector crystal / PMT, a preamplifier, a high-speed ADC processor, and an FPGA digital signal processor. The gamma-ray signal is converted by the detector crystal / PMT, the preamplifier, and the high-speed ADC processor and then enters the FPGA processor for FPGA digital signal processing to obtain multichannel spectra.

[0013] The FPGA digital signal processor includes a filtering and shaping unit, a fast and slow dual-channel processing unit, a baseline control unit, and a peak extraction unit. After the gamma-ray signal is converted by the high-speed ADC processor, it is sequentially passed through the filtering and shaping unit, the fast and slow dual-channel processing unit, the baseline control unit, and the peak extraction unit to obtain multi-channel spectra.

[0014] An apparatus for detecting gamma rays, the apparatus comprising: a probe 241 Am self-stabilizing source, probe crystal, probe photomultiplier tube, high-speed digital multichannel module; probe 241 The Am self-stabilizing source is in close contact with the probe crystal surface. 241 The opening of the Am self-stabilizing source faces the probe crystal; the probe crystal is coupled to the probe photomultiplier tube, and the probe photomultiplier tube is connected to the high-speed digital multichannel module, transmitting the output signal of the probe photomultiplier tube to the high-speed digital multichannel module.

[0015] The device also includes: a probe shielding housing, and a probe. 241 The Am self-stabilizing source, probe crystal, probe photomultiplier tube, and high-speed digital multichannel module are placed inside the probe shielding shell, and the probe crystal, probe photomultiplier tube, and high-speed digital multichannel module are fixed in position through the probe shielding shell.

[0016] The device further includes: a probe data output interface, the probe shielding shell surface is provided with a probe data output interface, a high-speed digital multichannel module is connected to the probe data output interface, and data results are output through the probe data output interface.

[0017] The device further includes a connecting cable, which is placed inside the probe's shielding housing. The probe's photomultiplier tube is connected to the high-speed digital multichannel module via the connecting cable, and the output signal of the probe's photomultiplier tube is transmitted to the high-speed digital multichannel module via the connecting cable.

[0018] The probe 241 Am self-stabilizing sources include: 241 Am self-stabilizing power supply mounting base, 241 Am self-stabilizing collimator base, 241 Am self-stabilizing source collimation via, 241 Am self-stabilizing source fixed top cover; 241 Am self-stabilizing collimator base, 241 Am self-stabilizing source collimation via, 241 Am self-stabilizing source fixed top cover placed 241 Inside the Am self-stabilizing power supply mounting base, 241 Am self-stabilizing collimator base and 241 The bottom of the Am self-stabilizing power supply mounting base is coaxially aligned. 241 Am self-stabilizing source collimation via placed in 241 Above the Am self-stabilizing collimator base 241 Am self-stabilizing source fixed top cover and 241 Align the top of the Am self-stabilizing source mounting base coaxially, and... 241 Am self-stabilizing source placed 241 Above the Am self-stabilizing source collimator base, and with the source aperture aligned. 241 Am self-stabilizing source collimated through the aperture, and then through 241 Am self-stabilizing source fixed top cover and 241 Am self-stabilizing power supply mounting base fixed connection, ultimately achieving 241 Am self-stabilizing source fixed purpose.

[0019] The beneficial technical effects of this invention are as follows:

[0020] 1. The present invention provides a method for detecting gamma rays, which realizes the acquisition of gamma ray signals in the energy range of 30keV to 3000keV through digital high-speed multichannel technology, and then solves the problem of different threshold settings for three parameters: quantitative gamma, natural gamma, and gamma energy spectrum through digital energy threshold setting.

[0021] 2. The present invention provides a method for detecting gamma rays, by... 241 The interaction between Am and NaI(Tl) crystals resulted in an equivalent γ energy peak, which was used as a self-stabilizing peak. This solved the problem of the influence of the radioactivity intensity of the self-stabilizing source on the quantitative detection of three parameters: quantitative γ, natural γ, and γ energy spectrum.

[0022] 3. The present invention provides a method for detecting gamma rays, which enables a single probe to simultaneously detect three radioactive parameters: quantitative gamma rays, natural gamma rays, and gamma energy spectrum. Compared with the traditional method of using a single probe for each parameter, this method improves detection efficiency and reduces production costs. Attached Figure Description

[0023] Figure 1 Here is a flowchart of a method for detecting gamma rays provided by the present invention;

[0024] Figure 2 This is a schematic diagram of the digital high-speed multichannel principle in a method for detecting gamma rays provided by the present invention.

[0025] Figure 3 In a device for detecting gamma rays provided by the present invention 241 Schematic diagram of Am self-stabilizing source structure;

[0026] Figure 4 This is a schematic diagram of a device for detecting gamma rays provided by the present invention;

[0027] Figure 5 In a method for detecting gamma rays provided by this invention, actual measurements were performed. 241 Am self-stabilizing peak spectrum data.

[0028] In the diagram: 1- 241 Am self-stabilizing power supply mounting base; 2- 241 Am self-stabilizing collimation base; 3- 241 Am self-stabilizing source collimation via; 4- 241 Am self-stabilizing source fixed top cover; 5-probe 241 Am self-stabilizing source; 6-probe crystal; 7-probe photomultiplier tube; 8-probe shielding shell; 9-connecting cable; 10-high-speed digital multichannel module; 11-probe data output interface. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0030] like Figure 1 As shown, the present invention provides a method for detecting gamma rays, which specifically includes the following steps:

[0031] Step 1: Using 241 The equivalent peak position of Am and NaI(Tl) crystals serves as a self-stabilizing peak, providing a stable γ-ray reference peak and achieving automatic spectrum stabilization.

[0032] To simultaneously detect three parameters—quantitative gamma, natural gamma, and gamma spectrum—the required energy thresholds include: quantitative gamma detection energy range of 400 keV–3000 keV, natural gamma detection energy range of 30 keV–3000 keV, and uranium window (corresponding nuclide) in the gamma spectrum. 214 Bi) has an energy range of 1660 keV to 1860 keV, and a thorium window (corresponding to the nuclide is...). 208 Tl) energy range is 2400 keV to 2800 keV, potassium window (corresponding to nuclide) 40 The energy range of K is 1370keV to 1570keV.

[0033] This requires simultaneously counting gamma rays in five energy ranges: 30keV–3000keV, 400keV–3000keV, 1370keV–1570keV, 1660keV–1860keV, and 2400keV–2800keV. Traditional methods... 133 The characteristic energy peaks of the Ba self-stabilizing source are 80 keV, 160 keV, 223 keV, 296 keV, and 355 keV. 137 The characteristic peak energy of the Cs self-stabilizing source is 661.6 keV. Traditional self-stabilizing source characteristic peaks, scattered rays, and addition peaks all affect the statistics of the above five energy regions.

[0034] This invention utilizes 241 Am, acting as a self-stabilizing source, releases α particles through its own decay. These particles interact with NaI(Tl) crystals to produce an equivalent γ energy peak. 241 With the adjustment of the Am self-stabilized source collimator, the energy of this characteristic peak can exceed 3000 keV, located outside the energy region of interest for simultaneously detecting quantitative gamma, natural gamma, and gamma spectrum parameters. Therefore, it will not interfere with the measurement of these three radioactive parameters. Actual measurements... 241 Am self-stabilizing peak spectrum data, such as Figure 5 As shown. Figure 5 This indicates that the use of 241 As a self-stabilizing source, Am will not interfere with the measurement of the three radioactive parameters.

[0035] Step 2: Acquire gamma-ray signals using a digital high-speed multichannel module to achieve full acquisition of gamma-ray signals in the energy range of 30keV to 3000keV.

[0036] like Figure 2 As shown, the digital high-speed multichannel module includes a detector crystal / PMT, a preamplifier, a high-speed ADC (Analog to Digital Converter) processor, and an FPGA (Field-Programmable Gate Array) digital signal processor. The gamma-ray signal, after being converted by the detector crystal / PMT, preamplifier, and high-speed ADC processor, enters the FPGA processor for FPGA digital signal processing to obtain multichannel spectra. The multichannel spectra, after gain control, preamplification, and high-speed ADC acquisition and conversion, are then processed as digital signals by the FPGA. The overall spectral peak positions are adjusted through high-voltage control and gain control to obtain spectral data for the required energy range. The FPGA digital signal processor includes a filtering and shaping unit, a fast and slow dual-channel processing unit, a baseline control unit, and a peak extraction unit. After conversion by the high-speed ADC processor, the gamma-ray signal sequentially passes through the filtering and shaping unit, the fast and slow dual-channel processing unit, the baseline control unit, and the peak extraction unit to obtain multichannel spectra.

[0037] The digital multi-channel system employs a fast / slow dual-channel forming technology, with a fast forming time of approximately 0.6 microseconds and a slow forming time of approximately 1 microsecond, enabling real-time acquisition and processing of energy ranges from 30keV to 3000keV.

[0038] The digital high-speed multichannel method detects and records all gamma rays in the energy range of 30keV to 3000keV, constructs the pulse amplitude spectrum of this energy range, and then realizes the acquisition of gamma rays in the corresponding energy range by measuring three parameters: quantitative gamma, natural gamma, and gamma energy spectrum.

[0039] Step 3: By setting multiple ROIs for the acquired gamma-ray signals using digital energy thresholds, the CPS counts for the quantitative gamma energy range, the natural gamma energy range, and the uranium-thorium-potassium gamma energy range are obtained.

[0040] Simultaneous detection of three parameters—quantitative gamma, natural gamma, and gamma spectrum—is different from traditional single-parameter CPS statistics. It requires simultaneous statistics of CPS in the quantitative gamma energy range of 400 keV to 3000 keV, the natural gamma energy range of 30 keV to 3000 keV, and the gamma spectrum in three energy ranges: uranium, thorium, and potassium. In other words, it requires simultaneous statistics of CPS data in five different ranges.

[0041] This invention employs FPGA programming to design ROI interval buffers for the five CPS parameters, and allows software-defined start and end addresses for each ROI. By using digital energy thresholds, multiple ROIs are set for the acquired gamma-ray signals to obtain CPS counts for quantitative gamma energy ranges, natural gamma energy ranges, and gamma-spectral uranium-thorium-potassium energy ranges.

[0042] Step 4: Using the calibration coefficients of each parameter in the standard model, and based on the CPS counts in the quantitative γ energy range, the natural γ energy range, and the uranium-thorium-potassium γ energy spectrum range, obtain the quantitative γ, natural γ, and γ energy spectrum detection results.

[0043] By utilizing the calibration coefficients of each parameter in the standard model, the channel address range corresponding to the five energy ranges can be determined, thereby realizing the cps statistical output of the target energy region ROI, and realizing the statistical output of gamma rays within the energy range corresponding to the measurement of the three parameters: quantitative gamma, natural gamma, and gamma spectrum, i.e., the output of detection results.

[0044] In summary, this invention combines 241 Am self-stabilizing source stabilizes spectrum in real time, acquires full spectrum data in the energy range of 30keV to 3000keV through high-speed digital multichannel acquisition, and then extracts the corresponding cps counts of three parameters: quantitative γ, natural γ, and γ energy spectrum according to the ROI interval set by digital energy threshold. Then, by using the calibration coefficients of each parameter in the standard model, the measurement application of the three parameters of quantitative γ, natural γ, and γ energy spectrum can be realized.

[0045] like Figure 4 As shown, the present invention also provides a device for detecting gamma rays, comprising: a probe 241 5. Am self-stabilizing source; 6. Probe crystal; 7. Probe photomultiplier tube; 8. Probe shielding shell; 9. Connecting cable; 10. High-speed digital multichannel module; 11. Probe data output interface.

[0046] probe 241 The Am self-stabilizing source 5, probe crystal 6, probe photomultiplier tube 7, connecting cable 9, and high-speed digital multichannel module 10 are placed inside the probe shielding shell 8. The probe crystal 6, probe photomultiplier tube 7, and high-speed digital multichannel module 10 are fixed in position through the probe shielding shell 8.

[0047] probe 241 Am self-stabilizing source 5 is in close contact with the surface of probe crystal 6. 241 Am self-stabilizing source 5 241 The opening of the Am self-stabilizing source fixed top cover 4 faces the probe crystal 6; the probe crystal 6 is coupled to the probe photomultiplier tube 7, and the probe photomultiplier tube 7 is connected to the high-speed digital multichannel module 10 through the connecting cable 9, and the output signal of the probe photomultiplier tube 7 is transmitted to the high-speed digital multichannel module 10 through the connecting cable 9.

[0048] The probe shielding shell 8 has a probe data output interface 11 on its surface. The high-speed digital multichannel module 10 is connected to the probe data output interface 11 and outputs data results through the probe data output interface 11.

[0049] like Figure 3 As shown, the probe 241 Am self-stabilizing source 5 includes: 241 Am self-stabilizing power supply mounting base 1 241 Am self-stabilizing collimation base 2 241 Am self-stabilizing source collimation via 3, 241 Am self-stabilizing source fixed top cover 4.

[0050] 241 Am self-stabilizing collimation base 2 241 Am self-stabilizing source collimation via 3, 241 Am self-stabilizing source fixed top cover 4 placed 241 Inside the Am self-stabilizing power supply mounting base 1 241 Am self-stabilizing collimator base 2 and 241 Am self-stabilizing power supply mounting base 1 is coaxially aligned at the bottom. 241 Am self-stabilizing source collimation via 3 is placed 241 Above the Am self-stabilizing collimator base 2 241 Am self-stabilizing source fixed top cover 4 and 241 Align the top of the Am self-stabilizing power source mounting base 1 coaxially, and... 241 Am self-stabilizing source placed 241 Above the Am self-stabilizing source collimator base 2, and with the source hole aligned. 241 Am self-stabilizing source collimated through aperture 3, and then through 241 Am self-stabilizing source fixed top cover 4 and 241 The Am self-stabilizing power supply mounting base 1 is fixed by a threaded connection, ultimately achieving the goal of... 241 Am self-stabilizing source fixed purpose.

[0051] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.

Claims

1. A method for detecting gamma rays, characterized in that, The method includes: Step 1: Using 241 The equivalent peak position of Am and NaI(Tl) crystals serves as a self-stabilizing peak, providing a stable γ-ray reference peak and achieving automatic spectrum stabilization. Step 2: Acquire gamma-ray signals using a digital high-speed multichannel module to achieve full acquisition of gamma-ray signals in the energy range of 30keV to 3000keV; Step 3: By setting multiple ROIs for the collected gamma-ray signals using digital energy thresholds, the CPS counts for the quantitative gamma energy range, the natural gamma energy range, and the gamma-ray spectrum uranium-thorium-potassium energy range are obtained. Step 4: Using the calibration coefficients of each parameter in the standard model, and based on the cps counts in the quantitative γ energy range, the natural γ energy range, and the γ energy spectrum uranium-thorium-potassium energy range, obtain the quantitative γ, natural γ, and γ energy spectrum detection results output. In step one 241 The Am self-stabilized source releases alpha particles through its own decay, which, upon interacting with the NaI(Tl) crystal, produce an equivalent gamma energy peak. 241 The Am self-stabilizing source collimator is adjusted so that the equivalent gamma characteristic peak energy is greater than 3000 keV, which is outside the energy range of quantitative gamma, natural gamma, and gamma spectrum, thus avoiding interference with the measurement of radioactive parameters of quantitative gamma, natural gamma, and gamma spectrum.

2. The method for detecting gamma rays according to claim 1, characterized in that, In step two, the digital high-speed multichannel module includes a detector crystal / PMT, a preamplifier, a high-speed ADC processor, and an FPGA digital signal processor. The gamma-ray signal is converted by the detector crystal / PMT, the preamplifier, and the high-speed ADC processor and then enters the FPGA processor for FPGA digital signal processing to obtain multichannel spectra.

3. The method for detecting gamma rays according to claim 2, characterized in that, The FPGA digital signal processor includes a filtering and shaping unit, a fast and slow dual-channel processing unit, a baseline control unit, and a peak extraction unit. After the γ-ray signal is converted by the high-speed ADC processor, it is sequentially passed through the filtering and shaping unit, the fast and slow dual-channel processing unit, the baseline control unit, and the peak extraction unit to obtain multi-channel spectra.

4. An apparatus for detecting gamma rays, used to implement the method for detecting gamma rays according to any one of claims 1-3, characterized in that, The device includes: a probe 241 Am self-stabilizing source (5), probe crystal (6), probe photomultiplier tube (7), high-speed digital multichannel module (10); probe 241 The Am self-stabilizing source (5) is in close contact with the surface of the probe crystal (6). 241 The opening of the Am self-stabilizing source (5) faces the probe crystal (6); the probe crystal (6) is coupled to the probe photomultiplier tube (7), the probe photomultiplier tube (7) is connected to the high-speed digital multichannel module (10), and the output signal of the probe photomultiplier tube (7) is transmitted to the high-speed digital multichannel module (10).

5. The device for detecting gamma rays according to claim 4, characterized in that, The device further includes: a probe shielding housing (8), and a probe. 241 The Am self-stabilizing source (5), probe crystal (6), probe photomultiplier tube (7), and high-speed digital multichannel module (10) are placed inside the probe shielding shell (8), and the probe crystal (6), probe photomultiplier tube (7), and high-speed digital multichannel module (10) are fixed in position through the probe shielding shell (8).

6. The device for detecting gamma rays according to claim 5, characterized in that, The device further includes: a probe data output interface (11), a probe shield shell (8) surface is provided with a probe data output interface (11), a high-speed digital multichannel module (10) is connected to the probe data output interface (11), and data results are output through the probe data output interface (11).

7. The apparatus for detecting gamma rays according to claim 5, characterized in that, The device further includes a connecting cable (9), which is placed inside the probe shielding shell (8). The probe photomultiplier tube (7) is connected to the high-speed digital multichannel module (10) via the connecting cable (9). The output signal of the probe photomultiplier tube (7) is transmitted to the high-speed digital multichannel module (10) via the connecting cable (9).

8. The apparatus for detecting gamma rays according to claim 4, characterized in that, The probe 241 Am self-stabilizing sources (5) include: 241 Am self-stabilizing power supply mounting base (1) 241 Am self-stabilizing collimator base (2) 241 Am self-stabilizing source collimation via (3) 241 Am self-stabilizing source fixed top cover (4); 241 Am self-stabilizing collimator base (2) 241 Am self-stabilizing source collimation via (3) 241 Am self-stabilizing source fixed top cover (4) placed 241 Inside the Am self-stabilizing source mounting base (1), 241 Am self-stabilizing collimator base (2) and 241 Am self-stabilizing power source mounting base (1) bottom coaxial alignment, 241 Am self-stabilizing source collimation via (3) is placed 241 Above the Am self-stabilizing collimator base (2), 241 Am self-stabilizing source fixed top cover (4) and 241 Align the top of the Am self-stabilizing power source mounting base (1) coaxially, and... 241 Am self-stabilizing source placed 241 Above the Am self-stabilizing source collimating base (2), and with the source hole aligned. 241 Am self-stabilizing source collimation via (3), then through 241 Am self-stabilizing source fixed top cover (4) and 241 The Am self-stabilizing source mounting base (1) is fixedly connected, ultimately achieving the goal of... 241 Am self-stabilizing source fixed purpose.

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