阅读说明：本技术 伽马射线探测装置及系统 (Gamma ray detection device and system ) 是由 王振 张峰 梁国武 王祥 张守林 高舒婷 张兰兰 周清 于 2020-11-03 设计创作，主要内容包括：本公开实施例提出了一种伽马射线探测装置及系统,所述装置包括：探测器,设置为接收伽马射线,并将接收到的伽马射线转换为可见光光子,将可见光光子转换为第一电脉冲信号,并对所述第一电脉冲信号进行采样,得到采样数据；第一控制器,设置为接收所述采样数据,并将采样数据还原成离散脉冲信号,根据所述离散脉冲信号获取第二电脉冲信号。其中,所述探测器包括高速闪烁晶体；所述高速闪烁晶体,设置为接收伽马射线,并将所述伽马射线转换为可见光光子；其中,所述高速闪烁晶体为相对于碘化钠闪烁晶体的光输出不低于120％、衰减时间不高于100ns的闪烁晶体。(The embodiment of the present disclosure provides a gamma ray detection device and system, the device includes: the detector is used for receiving gamma rays, converting the received gamma rays into visible light photons, converting the visible light photons into first electric pulse signals and sampling the first electric pulse signals to obtain sampling data; and the first controller is used for receiving the sampling data, restoring the sampling data into a discrete pulse signal and acquiring a second electric pulse signal according to the discrete pulse signal. Wherein the detector comprises a high-speed scintillation crystal; the high-speed scintillation crystal is arranged to receive gamma rays and convert the gamma rays into visible light photons; the high-speed scintillation crystal is a scintillation crystal with the light output not lower than 120% and the decay time not higher than 100ns relative to the sodium iodide scintillation crystal.)

1. A gamma ray detection apparatus, comprising:

the detector is used for receiving gamma rays, converting the received gamma rays into visible light photons, converting the visible light photons into first electric pulse signals and sampling the first electric pulse signals to obtain sampling data;

the first controller is used for receiving the sampling data, restoring the sampling data into a discrete pulse signal and acquiring a second electric pulse signal according to the discrete pulse signal;

wherein the detector comprises a high-speed scintillation crystal; the high-speed scintillation crystal is arranged to receive gamma rays and convert the gamma rays into visible light photons; the high-speed scintillation crystal is a scintillation crystal with the light output not lower than 120% and the decay time not higher than 100ns relative to the sodium iodide scintillation crystal.

2. The apparatus of claim 1,

the detector further comprises a photomultiplier tube and a second controller;

the photomultiplier tube is arranged to convert the visible light photons into first electrical pulse signals;

the second controller is configured to sample the first electrical pulse signal and send the sampled data to the first controller.

3. The apparatus of claim 2,

the second controller comprises a comparator and a converter;

the comparator is configured to compare the amplitude of the first electric pulse signal with at least 2 preset voltage thresholds and record the moment when the amplitude of the first electric pulse signal is equal to any one of the preset voltage thresholds;

the converter is arranged to convert the recorded time and send the converted time back to the comparator;

the comparator is further configured to receive the converted time, and send the converted time and the amplitude of the first electric pulse signal as sampling data to the first controller.

4. The apparatus of claim 2,

the temperature tolerance range of the photomultiplier is 0-500 ℃.

5. The apparatus of claim 2, wherein:

the device further comprises a third controller arranged to adjust and measure the supply voltage of the second controller and/or the gain of the first electrical pulse signal.

6. The apparatus of claim 5, wherein:

the device also comprises a temperature sensor, wherein the temperature sensor is connected with the third controller, so that the third controller adjusts the power supply voltage of the second controller according to the temperature acquired by the temperature sensor.

7. The apparatus of claim 2, wherein:

the apparatus also includes a cooler configured to cool the first controller and the second controller.

8. The apparatus of claim 2, wherein:

the apparatus also includes a light guide positioned between the high speed scintillation crystal and the photomultiplier tube.

9. The apparatus of claim 1, wherein:

the number of the detectors is at least two, and each detector is connected with the first controller respectively.

10. The apparatus of claim 1, wherein:

the device further comprises a housing, and the detector and the first controller are accommodated in the sealed housing.

11. A gamma ray detection system characterized by:

the gamma ray detection system comprises a neutron source, a master controller and a gamma ray detection device, wherein the master controller is connected with the gamma ray detection device through a communication cable;

wherein the neutron source is arranged to generate neutron rays such that when the neutron rays encounter a predetermined material, gamma rays are excited;

the gamma ray detection apparatus includes:

the detector is used for receiving gamma rays, converting the received gamma rays into visible light photons, converting the visible light photons into first electric pulse signals and sampling the first electric pulse signals to obtain sampling data;

the first controller is used for receiving the sampling data, restoring the sampling data into a discrete pulse signal and acquiring a second electric pulse signal according to the discrete pulse signal;

wherein the detector comprises a high-speed scintillation crystal; the high-speed scintillation crystal is arranged to receive gamma rays and convert the gamma rays into visible light photons; the high-speed scintillation crystal is a scintillation crystal with the light output not lower than 120% and the decay time not higher than 100ns relative to the sodium iodide scintillation crystal.

12. The system of claim 11,

the detector further comprises a photomultiplier tube and a second controller;

the photomultiplier tube is arranged to convert the visible light photons into first electrical pulse signals;

the second controller is configured to sample the first electrical pulse signal and send the sampled data to the first controller.

13. The system of claim 12,

the second controller comprises a comparator and a converter;

the comparator is configured to compare the amplitude of the first electric pulse signal with at least 2 preset voltage thresholds and record the moment when the amplitude of the first electric pulse signal is equal to any one of the preset voltage thresholds;

the converter is arranged to convert the recorded time and send the converted time back to the comparator;

the comparator is further configured to receive the converted time, and send the converted time and the amplitude of the first electric pulse signal as sampling data to the first controller.

14. The system of claim 12,

the temperature tolerance range of the photomultiplier is 0-500 ℃.

15. The system of claim 12, wherein:

the device further comprises a third controller arranged to adjust and measure the supply voltage of the second controller and/or the gain of the first electrical pulse signal.

16. The system of claim 15, wherein:

the device also comprises a temperature sensor, wherein the temperature sensor is connected with the third controller, so that the third controller adjusts the power supply voltage of the second controller according to the temperature acquired by the temperature sensor.

17. The system of claim 12, wherein:

the apparatus also includes a cooler configured to cool the first controller and the second controller.

18. The system of claim 12, wherein:

the apparatus also includes a light guide positioned between the high speed scintillation crystal and the photomultiplier tube.

19. The system of claim 11, wherein:

the number of the detectors is at least two, and each detector is connected with the first controller respectively.

20. The system of claim 11, wherein:

the device further comprises a housing, and the detector and the first controller are accommodated in the sealed housing.

Technical Field

The disclosure relates to the field of geological resource exploration, in particular to a gamma ray detection device and system.

Background

The well logging technology is an important technical means in the field of petroleum exploration, combines electronic technology and computer technology together through various modes such as electricity, acoustics, radiology and the like to obtain various physical parameters of a stratum, and further obtains oil and gas information through data analysis. Common well logging technologies include electrical well logging, acoustic well logging, nuclear magnetic well logging and the like, wherein the nuclear well logging is based on the nuclear physical properties of substances, well drilling geological profiles are researched according to the nuclear physical properties of rocks, pore fluids and mediums in wells, mineral deposits such as coal, petroleum and the like are found, and the nuclear well logging includes well logging technologies and matched instrument equipment such as natural gamma rays, density, neutrons, stratum elements and the like.

In neutron logging, an americium-beryllium (AmBe) neutron source and a neutron generator are generally used as excitation sources, and are made to react with a formation to obtain returned high-energy rays, such as gamma rays, and further a high-energy ray detector is used to detect returned ray information, and corresponding formation information can be obtained through further data analysis. Generally, high-energy ray detectors use scintillation crystal detectors. In order to convert the high-energy radiation into an electrical signal for analysis, a scintillation crystal (or called a scintillation crystal) is usually used to convert the high-energy radiation into visible light, a photomultiplier tube is used to convert the visible light into an electrical signal, and then the electrical signal is sampled and analyzed. Common scintillation crystals include cesium iodide, sodium iodide, and the like, and common photomultiplier tubes include photomultiplier tubes (PMTs) and silicon photomultiplier tubes (sipms). Firstly, most of scintillation crystals used in the prior art are cesium iodide and sodium iodide, the relative light output of the cesium iodide and the sodium iodide is about 85% and 100%, and the relative light output value of the cesium iodide and the sodium iodide is lower than that of a lanthanum bromide scintillation crystal of about 178%, and the low light output directly causes the energy resolution performance of scintillation crystal detectors such as sodium iodide and cesium iodide to be weaker than that of the lanthanum bromide scintillation crystal detector; the decay times of the two are about 250ns and 600ns, which is longer than the decay time of about 18ns of lanthanum bromide scintillation crystal. The scintillation crystal in the prior art can detect at a low gamma ray dose rate (for example, the dose rate is lower than 1mGy/h), but is difficult to perform the task of detecting at a high dose gamma ray dose rate (for example, the dose rate is higher than 1 mGy/h). Secondly, in the application of neutron oil well logging, the ray energy spectrum and the counting spectrum within a short time (5ms period) after neutron emission need to be analyzed, and the radiation pulse signals need to be digitized and analyzed at high speed. The first is a method for directly digitizing a high-speed ADC (analog to digital converter), which needs to shape and broaden an electric pulse signal first and then digitally sample by using the high-speed ADC (1GSps), however, digitizing one pulse in engineering practice and acquiring more accurate energy information needs to acquire at least 20 sampling points, and meanwhile, the sampling rate performance of an ADC chip working under a high temperature (175 ℃) condition is usually not very high and the cost is very high, so that the digitization of the high-speed scintillation crystal pulse signal cannot be completed, and the high-speed scintillation crystal pulse signal is difficult to apply to petroleum logging; the second method is a peak holding method, which uses a peak holding circuit to lock the amplitude of an electric pulse signal, and then uses an ADC to acquire the amplitude to acquire the energy information of the pulse, although the peak holding method can process the pulse of a high-speed scintillation crystal, due to the existence of the peak holding locking establishment and peak holding circuit recovery process, the dead time is very long, usually reaching the order of several hundred microseconds, which extremely limits the pulse passing rate (the number of processed pulses per unit time) of the digitized part, in the petroleum logging, the number of pulse events often increases explosively, in the common petroleum logging, the number of pulses reaches 100KCPS, one pulse is generated every 10us on average, and the dead time of the peak holding method causes the digitized process to lose many pulse signals, thereby causing the measurement result deviation.

In addition, in well logging, a detector needs to work in an underground high-temperature high-humidity environment, in order to prevent heat from influencing electronic devices inside the detector, an independent space isolated from the external environment is often adopted as a heat insulation layer in an internal component of the detector, and meanwhile, in order to overcome the influence of high humidity, various sealing measures are often adopted in the independent space. Under this condition, because received a large amount of rays when surveying, electronic device often can release the heat when signal acquisition, causes the inside temperature rise of independent space, when the temperature rose to certain extent, with the accuracy of very big influence acquisition signal, for example the signal receives the temperature influence can drift, causes signal distortion, the detector can not continue work again.

Disclosure of Invention

The embodiment of the present disclosure provides a gamma ray detection device, including:

the detector is used for receiving gamma rays, converting the received gamma rays into visible light photons, converting the visible light photons into first electric pulse signals and sampling the first electric pulse signals to obtain sampling data;

the first controller is used for receiving the sampling data, restoring the sampling data into a discrete pulse signal and acquiring a second electric pulse signal according to the discrete pulse signal;

wherein the detector comprises a high-speed scintillation crystal; the high-speed scintillation crystal is arranged to receive gamma rays and convert the gamma rays into visible light photons; the high-speed scintillation crystal is a scintillation crystal with the light output not lower than 120% and the decay time not higher than 100ns relative to the sodium iodide scintillation crystal.

In an exemplary embodiment, the apparatus further comprises the following features:

the detector further comprises a photomultiplier tube and a second controller;

the photomultiplier tube is arranged to convert the visible light photons into first electrical pulse signals;

the second controller is configured to sample the first electrical pulse signal and send the sampled data to the first controller.

In an exemplary embodiment, the apparatus further comprises the following features:

the second controller comprises a comparator and a converter;

the comparator is configured to compare the amplitude of the first electric pulse signal with at least 2 preset voltage thresholds and record the moment when the amplitude of the first electric pulse signal is equal to any one of the preset voltage thresholds;

the converter is arranged to convert the recorded time and send the converted time back to the comparator;

the comparator is further configured to receive the converted time, and send the converted time and the amplitude of the first electric pulse signal as sampling data to the first controller.

In an exemplary embodiment, the apparatus further comprises the following features:

the temperature tolerance range of the photomultiplier is 0-500 ℃.

In an exemplary embodiment, the apparatus further comprises the following features:

the device further comprises a third controller arranged to adjust and measure the supply voltage of the second controller and/or the gain of the first electrical pulse signal.

In an exemplary embodiment, the apparatus further comprises the following features:

the device also comprises a temperature sensor, wherein the temperature sensor is connected with the third controller, so that the third controller adjusts the power supply voltage of the second controller according to the temperature acquired by the temperature sensor.

In an exemplary embodiment, the apparatus further comprises the following features:

the apparatus also includes a cooler configured to cool the first controller and the second controller.

In an exemplary embodiment, the apparatus further comprises the following features: the apparatus also includes a light guide positioned between the high speed scintillation crystal and the photomultiplier tube.

In an exemplary embodiment, the apparatus further comprises the following features:

the number of the detectors is at least two, and each detector is connected with the first controller respectively.

In an exemplary embodiment, the apparatus further comprises the following features:

the device further comprises a housing, and the detector and the first controller are accommodated in the sealed housing.

The embodiment of the disclosure provides a gamma ray detection system, which comprises a neutron source, a master controller and a gamma ray detection device, wherein the master controller is connected with the gamma ray detection device through a communication cable;

a neutron source arranged to generate neutron rays such that when the neutron rays encounter a predetermined material gamma rays are excited;

wherein the gamma ray detection apparatus includes:

the detector is used for receiving gamma rays, converting the received gamma rays into visible light photons, converting the visible light photons into first electric pulse signals and sampling the first electric pulse signals to obtain sampling data;

the first controller is used for receiving the sampling data, restoring the sampling data into a discrete pulse signal and acquiring a second electric pulse signal according to the discrete pulse signal;

wherein the detector comprises a high-speed scintillation crystal; the high-speed scintillation crystal is arranged to receive gamma rays and convert the gamma rays into visible light photons; the high-speed scintillation crystal is a scintillation crystal with the light output not lower than 120% and the decay time not higher than 100ns relative to the sodium iodide scintillation crystal.

In an exemplary embodiment, the system further comprises:

the detector further comprises a photomultiplier tube and a second controller;

the photomultiplier tube is arranged to convert the visible light photons into first electrical pulse signals;

the second controller is configured to sample the first electrical pulse signal and send the sampled data to the first controller.

In an exemplary embodiment, the system further comprises:

the second controller comprises a comparator and a converter;

the comparator is configured to compare the amplitude of the first electric pulse signal with at least 2 preset voltage thresholds and record the moment when the amplitude of the first electric pulse signal is equal to any one of the preset voltage thresholds;

the converter is arranged to convert the recorded time and send the converted time back to the comparator;

the comparator is further configured to receive the converted time, and send the converted time and the amplitude of the first electric pulse signal as sampling data to the first controller.

In an exemplary embodiment, the system further comprises:

the temperature tolerance range of the photomultiplier is 0-500 ℃.

In an exemplary embodiment, the system further comprises:

the device further comprises a third controller arranged to adjust and measure the supply voltage of the second controller and/or the gain of the first electrical pulse signal.

In an exemplary embodiment, the system further comprises:

the device also comprises a temperature sensor, wherein the temperature sensor is connected with the third controller, so that the third controller adjusts the power supply voltage of the second controller according to the temperature acquired by the temperature sensor.

In an exemplary embodiment, the system further comprises:

the apparatus further comprises a cooler configured to cool the first controller and the second controller;

in an exemplary embodiment, the system further comprises: the apparatus also includes a light guide positioned between the high speed scintillation crystal and the photomultiplier tube.

In an exemplary embodiment, the system further comprises:

the number of the detectors is at least two, and each detector is connected with the first controller respectively.

In an exemplary embodiment, the system further comprises:

the device further comprises a housing, and the detector and the first controller are accommodated in the sealed housing.

The gamma ray detection device and the gamma ray detection system can achieve rapid acquisition of high-flux gamma ray energy, can enable the interval time of adjacent electric pulse signals to be reduced to 100ns or even shorter, can enable the counting rate to be higher than 1Mcps, and enable the effect to be obviously improved compared with the time interval and the counting rate index of the traditional detector for detecting the adjacent electric pulse signals.

Drawings

Fig. 1 is a schematic diagram of a gamma ray detection apparatus according to an embodiment of the present disclosure.

Fig. 2 is a schematic plan view of a gamma ray detection device according to an embodiment of the disclosure.

Fig. 3 is a schematic diagram illustrating a sampling principle of a gamma ray detection apparatus according to an embodiment of the present disclosure.

FIG. 4 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure.

FIG. 5 is a schematic plan view of another gamma ray detection device according to an embodiment of the disclosure.

FIG. 6 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure.

FIG. 7 is a schematic plan view of another gamma ray detection device according to an embodiment of the disclosure.

FIG. 8 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure.

FIG. 9 is a schematic diagram of a gamma ray detection system according to an embodiment of the disclosure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that, in the present disclosure, the embodiments and features of the embodiments may be arbitrarily combined with each other without conflict.

Fig. 1 is a schematic diagram of a gamma ray detection device according to an embodiment of the disclosure, and as shown in fig. 1, the gamma ray detection device according to the embodiment includes:

the detector is used for receiving gamma rays, converting the received gamma rays into visible light photons, converting the visible light photons into first electric pulse signals and sampling the first electric pulse signals to obtain sampling data;

the first controller is used for receiving the sampling data, restoring the sampling data into a discrete pulse signal and acquiring a second electric pulse signal according to the discrete pulse signal;

wherein the detector comprises a high-speed scintillation crystal; the high-speed scintillation crystal is arranged to receive gamma rays and convert the gamma rays into visible light photons; the high-speed scintillation crystal is a scintillation crystal with the light output not lower than 120% and the decay time not higher than 50ns relative to the sodium iodide scintillation crystal.

Wherein the predetermined substance comprises petroleum.

Wherein, the gamma ray can be generated by the following method: neutron rays are generated by a neutron source, and gamma rays are excited when the neutron rays encounter a predetermined material.

The light output is the efficiency of the scintillation crystal to convert high-energy rays into visible light photons, and is a relative value, for example, the industry usually takes the light conversion of sodium iodide crystal as a reference, which is recorded as 100%, the conversion capability of other crystals is compared with sodium iodide, the capability is greater than 100%, and the capability is less than 100%.

In an exemplary embodiment, the first electrical pulse signals are piled up and the second electrical pulse signals are not piled up. In one exemplary embodiment, the neutron source may be a neutron emitter.

In an exemplary embodiment, the first controller may be configured to control the operating conditions of the neutron source and the detector simultaneously.

In an exemplary embodiment, the detector further comprises a photomultiplier tube and a second controller;

the photomultiplier tube is arranged to convert the visible light photons into first electrical pulse signals;

the second controller is configured to sample the first electrical pulse signal and send the sampled data to the first controller.

In an exemplary embodiment, the second controller has an amplifying function.

In an exemplary embodiment, the second controller includes a comparator and a converter;

the comparator is configured to compare the amplitude of the first electric pulse signal with at least 2 preset voltage thresholds and record the moment when the amplitude of the first electric pulse signal is equal to any one of the preset voltage thresholds;

the converter is arranged to convert the recorded time and send the converted time back to the comparator;

the comparator is further configured to receive the converted time, and send the converted time and the amplitude of the first electric pulse signal as sampling data to the first controller.

The recorded time of day is a relative clock count that can be converted to absolute time by conversion. For example, a clock count of 1000 (i.e., when the clock count is 1000, the first electrical pulse signal is equal to the preset voltage threshold), may be converted to a corresponding 10 nanoseconds.

In one exemplary embodiment, the photomultiplier tube has a temperature tolerance range of 0-500 ℃.

In an exemplary embodiment, the apparatus further comprises a third controller arranged to adjust and measure a supply voltage of the second controller and/or a gain of the first electrical pulse signal.

In an exemplary embodiment, the apparatus further includes a temperature sensor connected to the third controller, so that the third controller adjusts the supply voltage of the second controller according to the temperature acquired by the temperature sensor.

The third controller may adjust a parameter of the second controller in response to a change in temperature.

In an exemplary embodiment, the first controller, the second controller, and the third controller may be circuit boards. The second controller may be a preprocessing and acquisition circuit and the first controller may be a fitting circuit. The first controller and the second controller are arranged on the same PCB.

In an exemplary embodiment, the apparatus further comprises a cooler configured to cool the first controller and the second controller.

In one exemplary embodiment, the apparatus further comprises a light guide positioned between the high speed scintillation crystal and the photomultiplier tube.

In an exemplary embodiment, the number of the detectors is at least two, and each detector is connected with the first controller respectively. On the one hand, the detector can be prevented from suddenly failing in the detection process of the detection device, the detection process can still be carried out, on the other hand, the diversity of detected data can be increased, and the data of the two detectors can be complemented, so that the detection result is more accurate.

In an exemplary embodiment, the apparatus further comprises a housing, the probe and the first controller being housed within the sealed housing.

A temperature sensor monitors the temperature inside the housing and a third controller is used to acquire data from the temperature sensor to monitor changes in the ambient temperature.

The gamma ray detection device and the gamma ray detection system can achieve rapid acquisition of high-flux gamma ray energy, can enable the interval time of adjacent electric pulse signals to be reduced to 100ns or even shorter, can enable the counting rate to be higher than 1Mcps, and enable the effect to be obviously improved compared with the time interval and the counting rate index of the traditional detector for detecting the adjacent electric pulse signals.

Fig. 2 is a schematic plan view of a gamma ray detection device according to an embodiment of the disclosure. As shown in fig. 2, the scintillation detector comprises a first controller 10, a detector 30 and a housing 60, wherein the first controller 10 and the detector 30 are both accommodated in the housing 60, the first controller 10 is respectively connected to the neutron source 20 and the detector 30, the first controller 10 is configured to control an operating state of the neutron source 20, such as controlling the neutron source 20 to emit neutrons or interrupting emission, and the first controller 10 is configured to control the detector 30 and receive a radiation signal detected by the scintillation crystal detector 30; the neutron source 20 may emit neutrons or interrupt emission according to the instructions of the first controller 10; the detector 30 may detect gamma rays according to instructions of the first controller 10, convert them into electrical signals and transmit them to the first controller 10 for processing. The first controller 10 may be connected to the neutron source 20 and the detector 30 through a plurality of interfaces, or connected to the neutron source 20 and the detector 30 through a fixed interface.

The first controller 10 may be configured as any processor or controller, such as an FPGA chip or microprocessor, etc., capable of transmitting control instructions and processing electrical signals. It should be noted that, in order to adapt to the high-temperature and high-magnetic environment in the well in the oil exploration, the first controller 10 is preferably made of high-temperature resistant material, and the type of the first controller 10 can be adjusted appropriately according to the type of the detector for matching.

The neutron source 20 may be configured as any device capable of generating neutrons, such as an isotopic neutron source, an accelerator neutron source, or a reactor neutron source, which is generally preferred in radioactive logging, is stable and easy to use, and is capable of acquiring desired detection data. In the disclosed embodiment, the neutron source 20 is preferably a small portable neutron source to facilitate installation and reduce costs.

The detector 30 may be configured as any detector capable of converting gamma rays into an electrical signal, for example, a scintillation detector or a semiconductor detector, or the like. When the detector 30 is a scintillation detector, it may include a scintillation crystal 33, a photomultiplier tube 32, and a second controller 31, where the scintillation crystal 33 and the photomultiplier tube 32 are coupled to each other, the second controller 31 is connected to the photomultiplier tube 32, the scintillation crystal 33 is configured to receive gamma rays and convert the gamma rays into visible light, the photomultiplier tube 32 is configured to convert the visible light into electrical signals, the second controller 31 is configured to collect the electrical signals, and the second controller 31 may further perform preliminary processing on the collected electrical signals, such as noise removal, data packing, and the like.

In order to adapt to detection under different kinds and different dose rates, the detector 30 preferably adopts a scintillation detector, wherein the scintillation crystal 33 is preferably a high-speed scintillation crystal, in the present disclosure, the high-speed scintillation crystal refers to a scintillation crystal with a relative light output of not less than 120%, or refers to a scintillation crystal with a relative light output of not less than 120% and a decay time of not more than 100ns, and the scintillation crystal has characteristics of high light output and short decay time, such as lanthanum bromide, lanthanum chloride and the like. It is noted that in the present disclosure, "relative light output" refers to light output relative to a sodium iodide scintillation crystal, and in the art, when a high-energy particle is incident and energy is deposited into the scintillation crystal, a large number of photons with different energies are excited, and in practice, the number of photons and the average energy of the photons are difficult to measure simultaneously, so that the light emission performance of the scintillation crystal is usually evaluated relative to the light output of the sodium iodide scintillation crystal, and when the light emission of the sodium iodide scintillation crystal with a standard size (diameter of 2.5cm and length of 2.5cm) is taken as a standard, namely 100%, to give a relative value of a sample of the scintillation crystal to be measured, and when the scintillation crystal is measured, a monoenergetic gamma source is selected to irradiate the scintillation crystal, and the size of the sample to be measured is the same as the standard size and is compared with the peak value of the gamma-ray full-energy absorption spectrum of the standard scintillation crystal. The "high light output" and "short decay time" in the present disclosure are relative performance characteristics for the prior art, for example, the relative light output of a sodium iodide scintillation crystal commonly used in the prior art is about 100%, and the relative light output of a lanthanum bromide scintillation crystal is about 178%, so that the lanthanum bromide scintillation crystal has the relative high light output characteristic; in the prior art, the decay time of a sodium iodide scintillation crystal which is commonly used is about 250ns, and the decay time of a lanthanum bromide scintillation crystal is about 18ns, so that the lanthanum bromide scintillation crystal has the characteristic of relatively short decay time. In the disclosure, the scintillation crystal with the light output not less than 150% of that of the scintillation crystal with the sodium iodide is preferably adopted for the relative light output, and the scintillation crystal with the decay time not higher than 50ns is also preferred, because the scintillation crystal with the performance is favorable for obtaining more accurate detection data, the detector is prevented from being halted due to signal accumulation or the temperature is increased too fast during signal acquisition, and meanwhile, the decay time greatly restricts the capability of the scintillation crystal for converting high-energy rays into visible light photons, thereby restricting the accuracy of signal acquisition. The skilled person can select suitable parameters of light output and decay time according to specific detection requirements, for example, when the detected radiation is gamma radiation and the dose rate is between 0.5 and 2mGy/h, the scintillation crystal is required to be compatible with detection, and in this case, a lanthanum bromide scintillation crystal with high light output and short decay time is preferably used. The rapid acquisition of the energy of the high-energy ray is realized by selecting the scintillation crystal with short decay time, and the high-energy ray detection with high flux (namely the number of scintillation pulses obtained in unit time) can be realized.

To accommodate high temperature, high magnetic environments downhole in oil exploration, the photomultiplier tubes 32 preferably employ high temperature resistant PMTs, such as PMTs that operate normally at 175 ℃ or higher.

The second controller 31 may be configured as any device capable of digitizing an electrical signal, such as a PCB board circuit control device or a different digitizing module, for example, sampling may be directly performed using an MVT (Multi-volt threshold, MVT for short) digitizing module or a tot (time over threshold) digitizing module, etc. After the sampling is completed, the second controller 31 may send the digitized signals to the first controller 10 for processing.

In order to enable the gamma ray detection device to detect gamma rays under different dose rates in an excellent state, a matched photomultiplier tube and a second controller are also needed to be configured, for example, because a scintillation crystal has the characteristics of high light output and short decay time, the conversion efficiency of the gamma rays in a specific time is high, a large number of visible light photons are output instantaneously, the photomultiplier tube needing to be matched also has high photon conversion efficiency, and simultaneously because a large number of visible light are converted into electric pulse signals (or called as electric signals) in a short time, the electric pulse signals are easy to accumulate, and pulse information cannot be accurately restored by adopting a traditional time interval sampling method, so that an MVT sampling method can be selected for processing.

The following further explains how the second controller 31 can successfully complete the sampling of the electrical pulse signal under the condition of high light output by using multi-voltage threshold sampling, in general, after the gamma ray is converted by the scintillation crystal, the electrical pulse signal as shown in fig. 3 is correspondingly generated, and the waveform of the electrical pulse signal has a relatively fast rising edge and a relatively slow falling edge. Whereas the multi-voltage threshold sampling method is to set at least two voltage thresholds, 3 voltage thresholds in fig. 3, V1, V2, and V3 respectively, the time when the electrical pulse signal crosses these voltage thresholds will be identified and converted into digital signals, for example, a comparator is used to identify the time when the electrical pulse signal crosses these thresholds, and a time-to-digital converter is used to digitize the corresponding time. The MVT sampling method using 3 thresholds will produce 6 sampling points, which are recorded as voltage-time pairs, e.g., (V)₁、T₁₁)、(V₂、T₂₁)、(V₃、T₃₁)、(V₃、T₃₂)、(V₂、T₂₂) And (V)₁、T₁₂) Where 3 pairs are on the rising edge of the pulse and 3 pairs are on the falling edge of the pulse. When 3 voltage thresholds are adopted, 3 comparators are usually needed to realize the comparison, and each comparator corresponds to one voltage threshold to identify the moment when the electric pulse signal exceeds or is lower than the voltage threshold, so that one comparator simultaneously relates to 2 sampling points, one is positioned on the rising edge of the electric pulse signal, and the other is positioned on the falling edge of the electric pulse signal. The waveforms of a large number of electric pulse signals arriving in a short time can be well restored through MVT sampling, and the accuracy of signal acquisition is greatly improved.

Based on this, the second controller 31 may be configured to include a comparator and a converter, wherein the comparator may be configured to compare the amplitude of the electrical pulse signal to be measured output by the detector in response to the received photons with a voltage threshold and output a corresponding comparison result; the converter may be configured to record time point data according to the comparison result, and provide the recorded time point data to the first controller 10 connected at the back end for data analysis processing, and the first controller fits and restores the time point data to obtain a digitized pulse signal, and may obtain information related to the electrical pulse signal through the digitized pulse signal, such as energy information extraction and the like.

After the second controller 31 completes the sampling of the electrical pulse signal, data analysis and processing, such as pulse signal reduction, time, energy, and position information extraction, may be performed according to the relationship between the time data and the amplitude of the electrical pulse signal and the corresponding energy thereof, which is easily implemented by those skilled in the art and is not described herein again.

Since the housing 60 needs to enter a complicated geological environment of high temperature, high humidity and high magnetism, it is necessary that the housing 60 be configured to have high strength performance, high temperature resistance performance, sealing performance and magnetic shielding performance. Specifically, the high strength performance means that the housing 60 can still remain undeformed during various underground impacts, and the electronic devices and the scintillation crystals housed inside are protected from damage, which can be determined by those skilled in the art through material and strength experiments, and will not be described herein again. High temperature resistance means that the housing 60 can withstand temperatures below 500 c while preferably the housing 60 has a low thermal conductivity, i.e. the housing 60 preferably can transfer as little heat to the interior as possible, avoiding heating the internal components too fast for as long a time as possible. The sealing performance means that the housing 60 can prevent external liquid or vapor from entering the inside. The housing 60 preferably has magnetic shielding properties to keep the interior as low as possible in magnetic environment so as to maintain the internal components in normal operation, which is well understood by those skilled in the art and will not be described herein.

In this embodiment, the high-speed scintillation crystal-based gamma ray detection apparatus may further be configured to include a third controller 40 and a temperature sensor 50, where the third controller 40 is connected to the first controller 10, the second controller 31 and the temperature sensor 50, respectively, the third controller 40 is configured to acquire data of the temperature sensor 50 to monitor changes in the ambient temperature, and simultaneously measure the power supply voltage in the second controller 31 and the signal gain of the detector, and such data acquired by the third controller 40 may be further sent to the first controller 10 and operated by receiving an instruction of the first controller 10. The third controller 40 may be any device capable of implementing the above functions, such as a circuit control device of a PCB, and the third controller 40 may be integrated with the second controller 31 on the same PCB and implement the above functions. The temperature sensor 50 may be any temperature sensor commonly used in the art for monitoring the temperature inside the housing 60 and will not be described herein.

In this embodiment, the gamma ray detection device in the above embodiment may also be configured to form a gamma ray detection system together with the overall controller 70, wherein the overall controller 70 is the overall control center of the gamma ray detection system, and is connected to the first controller 10 in the gamma ray detection device through a communication cable, and the communication cable may pass through the housing 60 and maintain a sealing fit with the housing 60. The overall controller 70 is used for monitoring or processing the working state of the gamma ray detection system and/or sending working instructions to various components of the gamma ray detection system, for example, the first controller 10 may be an upper computer, so as to store, analyze the detection data sent by the first controller 10 and monitor the working state of the components of the detection device, or send instructions to the detection device to start or stop the operation of the detection device. The overall controller 70 can also control the third controller 40 to adjust the gain of the output electrical pulse signal, so that the detection result of the detection device can be more accurate.

Fig. 4 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure, as shown in fig. 4, compared to the embodiment of fig. 2, wherein the same or similar components are denoted by reference numerals increased by "100", for example, 110 is a first controller, and only the differences compared to the embodiment of fig. 2 will be described below. In the embodiment of fig. 3, a light guide 134 is disposed between the scintillation crystal 133 and the photomultiplier tube 132, and the light guide 134 can transmit the visible light photons converted by the scintillation crystal 133 to the photomultiplier tube 132 more intensively, which is beneficial to improving the accuracy of the detected data. The light guide 134 may also be provided with a light-tight shielding material around its periphery so that photons can only pass from the scintillation crystal 133 to the photomultiplier tube 132, reducing photon transmission losses.

Fig. 5 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure, as shown in fig. 5, compared to the embodiment of fig. 2, wherein the same or similar components are denoted by reference numerals increased by "200", for example, 210 is a first controller, and only the differences compared to the embodiment of fig. 2 will be described below. In the embodiment of fig. 4, two detectors 230 are disposed in a housing 260 of the gamma ray detection apparatus, the two detectors 230 are respectively connected to the first controller 210, the second controller 240 is respectively connected to the two controllers 231, the structure and function of each detector 230 are the same as those described in fig. 2, the first controller 210 and the second controller 240 can respectively control or monitor the operations of the two detectors 230, which can prevent a detector of the detection apparatus from suddenly failing during the detection process, ensure that the detection process can still be performed, increase the diversity of detected data, and complement the data of the two detectors, so that the detection result is more accurate.

Fig. 6 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure, as shown in fig. 6, compared to the embodiment of fig. 4, wherein the same or similar components are denoted by reference numerals increased by "100", for example, 310 is a first controller, and only the differences compared to the embodiment of fig. 4 will be described below. In the embodiment of fig. 5, a light guide 334 is disposed between the scintillation crystal 333 and the photomultiplier tube 332, and the light guide 334 can transmit the visible light photons converted by the scintillation crystal 333 to the photomultiplier tube 332 more intensively, which is beneficial to improving the accuracy of the detected data. The light guide 334 may also be surrounded by a light-tight shield so that photons can only pass from the scintillation crystal 333 to the photomultiplier tube 332, reducing photon transmission losses.

Fig. 7 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure, as shown in fig. 7, compared to the embodiment of fig. 2, wherein the same or similar components are denoted by reference numerals increased by "400", for example, 410 is a first controller, and only the differences compared to the embodiment of fig. 2 will be described below. In the embodiment of fig. 7, at least one cooler 480 is disposed inside the housing 460, the cooler 480 may be disposed in various forms, such as a sealed device with a coolant or an electronically controllable semiconductor cooling device, a heat conduction sheet 481 may be disposed on the cooler 480, and the cooler 480 may provide a heat sink inside the sealed housing 460, so that heat transfer between heat inside the sealed housing 460 and the cooler 480 may be achieved through the heat conduction sheet 481, thereby overcoming the problem that the temperature inside the sealed space is rapidly increased when the electronic devices (e.g., the first controller 410, the second controller 431, and the third controller 440) inside the sealed housing 460 operate, delaying the temperature increase time of the electronic devices through the heat transfer, and increasing the time that the detector can normally operate underground.

Fig. 8 is a schematic plan view of another gamma ray detection device according to an embodiment of the present disclosure, as shown in fig. 8, compared to the embodiment of fig. 7, wherein the same or similar components are denoted by reference numerals increased by "100", for example, 510 is a first controller, and only the differences compared to the embodiment of fig. 6 will be described below. In the embodiment of fig. 8, a plurality of heat-conducting plates 581 may be disposed on each cooler 580, and the shape of each heat-conducting plate 581 may be matched as required, for example, the heat-conducting plate 581 may be disposed as a special-shaped heat-conducting plate to increase a heat-conducting area and improve a heat balance effect, and the heat-conducting plates 581 may also be disposed close to the heat-generating electronic devices, for example, the first controller 510 and the second controller 531, respectively, so as to achieve heat transfer with as high efficiency as possible and prolong an excessive time of temperature rise in the enclosed space as long as possible.

The embodiment of the present disclosure further provides a gamma ray detection system, which may include the gamma ray detection device and the image reconstruction device in the embodiments shown in fig. 2 to fig. 8, and the gamma ray detection system may perform analysis processing according to the detection result of the gamma ray detection device, so as to achieve the purpose of geological resource exploration. As to how the data analysis process performs the specific process of the image reconstruction process, reference may be made to the related description in the prior art, which is not described in detail herein.

The systems, devices, modules, units, etc. set forth in the above embodiments may be implemented by semiconductor chips, computer chips and/or entities, or by products with certain functions. For convenience of description, the above devices are described while being divided into various units by functions, respectively. Of course, the functions of the various elements may be implemented in the same or multiple chips in practicing the disclosure.

When the gamma ray detection device/system based on the high-speed scintillation crystal provided by the disclosure is used for detecting, the gamma ray detection device is placed underground through a communication cable, a working instruction is sent out through a master controller to enable a neutron source to start working, neutron rays 1 (shown in figure 2) are released, when petroleum or other gas resources exist in a stratum, and the neutron rays 1 collide with hydrogen nuclei, due to the fact that the mass of the neutron rays is close to that of the neutron source, most kinetic energy of fast neutrons is transferred to the hydrogen nuclei to become slow neutrons, the slow neutrons are easily captured by the nuclei of various substances, a large number of gamma rays 2 are released, the gamma rays 2 are randomly emitted to the periphery and can be received by a detector, and the structure in the stratum can be judged through analyzing detection data.

The gamma ray detection device/system based on the high-speed scintillation crystal can detect high-energy ray energy with high flux (namely the scintillation pulse number obtained in unit time), can reduce the interval time of adjacent electric pulse signals to 100ns or even shorter, can increase the counting rate index to be higher than 1Mcps, and compared with the prior art, the time of the adjacent electric pulse signals of the detector cannot be less than 1us, the counting rate is usually less than 1Mcps, and the effect is obviously improved. Meanwhile, the neutron source and the electronic device are allowed to be turned on for a longer time, and more accurate and continuous data can be acquired. According to the embodiment of the disclosure, when the scintillation crystal with high light output is used for detection, compared with a detector in the prior art, the energy resolution can be improved by 5-7%. In addition, the gamma ray detection device and system based on the high-speed scintillation crystal provided by the disclosure have stable performance under high ambient temperature and a wide ray energy range of 600 KeV-10 MeV, and can obtain more accurate detection information.

Fig. 9 is a schematic diagram of a performance testing apparatus according to an embodiment of the disclosure, and as shown in fig. 9, the performance testing apparatus according to the embodiment includes: the gamma ray detection system comprises a neutron source, a master controller and any one of the gamma ray detection devices, wherein the master controller is connected with the gamma ray detection devices through communication cables.

It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by instructing the relevant hardware through a program, and the program may be stored in a computer readable storage medium, such as a read-only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, each module/unit in the above embodiments may be implemented in the form of hardware, and may also be implemented in the form of a software functional module. The present disclosure is not limited to any specific form of combination of hardware and software.

The foregoing is only a preferred embodiment of the present disclosure, and there are certainly many other embodiments of the present disclosure, which will become apparent to those skilled in the art from this disclosure and it is therefore intended that various changes and modifications can be made herein without departing from the spirit and scope of the disclosure as defined in the appended claims.