A pulsed neutron elemental scanning system for extraterrestrial exploration

Abstract

The application provides a pulse neutron element scanning and analyzing system for extraterrestrial exploration, which comprises a shell, a support, a neutron generator, a shielding body and a gamma spectrometer, the support is installed in the shell, the neutron generator, the shielding body and the gamma spectrometer are all installed on the support, and the shielding body is located between the neutron generator and the gamma spectrometer. The neutron generator, the shielding body and the gamma spectrometer are integrally installed on the support, the controllable neutron source is combined with the gamma spectrometer, the stratum is activated by the controllable pulse neutron generator, the element components are detected by gamma analysis, or the gamma generated by the natural radioactive nuclides and the cosmic background radiation is directly detected, element component analysis is carried out, the element measurement precision is improved, the detection time is shortened, more kinds of elements can be measured, and the application provides strong support for the measurement of more kinds of elements, and is suitable for lunar geology and resource exploration.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lunar exploration and planetary exploration, and in particular to a pulsed neutron element scanning and analyzing system for extraterrestrial exploration. BACKGROUND

[0002] The lunar exploration project is scientific in aspect, and is used for studying how the moon is formed and evolved, the origin and evolution of the earth-moon system, and the origin and evolution of the solar system, which is a basic problem worth exploring forever. In addition, the applications on the moon mainly include three aspects: (1) resources, which are the narrow-sense mineral resources. There are extremely rich mineral resources on the moon; (2) energy, the fossil energy on the earth will eventually be exhausted. Humans are looking for another kind of energy to replace the fossil energy; (3) environmental resources on the moon surface, which are super-high vacuum, no magnetic field, great temperature change, no volcanic activity, no strong moonquakes, very stable, and no pollution.

[0003] The exploration of the elements in the superficial layer, especially the rare earth elements and volatile components, is an important content of lunar geology and resource exploration, and is the basis for compiling regional geological maps and resource distribution maps. The currently commonly used technical means in planetary element exploration has different focuses in element analysis and detection methods. The first kind is to use passive gamma-ray detection, which has the following characteristics: (1) multi-element energy spectrum analysis; (2) relying on cosmic background neutrons; (3) detection speed needs time accumulation, etc. The second kind is a neutron detector, which can detect a small number of elements.

[0004] The neutron activation analysis technology is used on the foreign Mars explorer. Compared with the X-ray method, the neutron activation analysis technology can achieve a detection depth of meter level in the oil well logging field, while the X-ray method can only achieve a detection distance of micrometer level. The controllable neutron source can reach an energy of 14.1 MeV, which can cover the energy section of most required analysis elements. Without applying a high-voltage electric field, the controllable source will not generate neutrons, and there is no environmental pollution problem. In addition, another advantage of the controllable neutron source is that the neutron pulse generation can be realized through the design of the power supply and control system. The pulsed neutron generator can be used not only for detecting common non-radioactive elements, but also for detecting radioactive isotopes (such as 235 U and 3 He) by measuring secondary neutrons in the case of narrow pulse width. Therefore, to realize accurate exploration of the moon surface depth, the neutron activation analysis technology has an irreplaceable advantage.

[0005] The foreign country first uses the active neutron detection technology to scan the surface of Mars to analyze the H content, to find the existence and distribution of water, and the maximum detection depth is 1m. Cosmic rays are absorbed by the Mars stratum to produce secondary neutrons, and the transmission of the secondary neutrons in the stratum is different because of the different H content and the different absorption coefficients of the epithermal neutrons, which can be used as a passive detection method without a radioactive source to indicate the H content in the stratum.

[0006] Some countries use the "pulse neutron-neutron method" to analyze the geological section of the oil well, so that the inflatable neutron tube enters the commercial production stage, and these neutron tubes are mainly used for oil logging. After entering the 1970s, the application of neutron radiation in the field of science and technology is more extensive. The strong current neutron source for neutron cancer treatment, semiconductor devices and material irradiation effect emerges as the times require, and many key technologies have been improved, and the performance of each system has been improved. For example, by using new technologies such as strong current ion source, small size high power high voltage power supply, ion acceleration tube and beam transport system, the D-T neutron yield of a medium-sized neutron generator can reach 10 12 n / s. However, the basic design idea and structure form of the neutron tube developed in the early stage has been used until now.

[0007] The early neutron generator technology of the domestic neutron tube is mainly used for the ignition of nuclear reactions, and the technical parameters are not high, only a high-yield neutron pulse is needed. In the past decade, the demand of the application of the neutron tube technology in the industry, especially in the oil exploration and coal quality analysis, has made great progress and development, and the stratum element logging technology is now in the stage of gradual maturity. In the prior art, the element measurement accuracy is low, and the detection time is long. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a pulse neutron element scanning and analyzing system for extraterrestrial exploration.

[0009] The technical scheme for solving the above technical problem is as follows: a pulse neutron element scanning and analyzing system for extraterrestrial exploration, comprising: a shell, a support, a neutron generator, a shielding body and a gamma spectrometer, the support is installed in the shell, the neutron generator, the shielding body and the gamma spectrometer are all installed on the support, and the shielding body is located between the neutron generator and the gamma spectrometer.

[0010] The beneficial effects of the technical scheme of the present application are: the neutron generator, the shielding body and the gamma spectrometer are integrated and installed on the support, the controllable neutron source and the gamma spectrometer are fused, the stratum is activated by the controllable pulse neutron generator to detect gamma and analyze element components, or directly detect the gamma generated by the natural radioactive nuclides and the cosmic background radiation to analyze the element components, improve the element measurement accuracy, shorten the detection time, provide strong support for measuring more types of elements, and be suitable for lunar geology and resource exploration.

[0011] Further, a plurality of grooves are arranged on the outer side wall of the bracket, and a damping rubber ring is arranged in each groove.

[0012] The above-mentioned technical scheme has the beneficial effect that the grooves facilitate the arrangement of the damping rubber ring, and ensure that the bracket is damped after being inserted into the shell.

[0013] Further, a top cover is arranged at one end of the shell, and a lifting ring and a connector are arranged on the top cover, and the connector is connected to the neutron generator and the gamma spectrometer.

[0014] The above-mentioned technical scheme has the beneficial effect that the connector is thrown out of the top cover in the form of a wire, and is convenient for quick connection with other devices.

[0015] Further, a bracket lap joint step and a movable locking head are arranged at one end of the shell, one end of the bracket is lap jointed to the bracket lap joint step, and the top cover is screwed to the movable locking head; a wire hole and a wrench slot are arranged on the top cover.

[0016] The above-mentioned technical scheme has the beneficial effect that the bracket lap joint step on the bracket is axially constrained with the shell. Then the top cover is rotated through the trapezoidal thread, and the bracket lap joint step is compressed. The movable locking head is compressed with the shell on one side, and can be freely rotated on the other side, and is connected with the top cover through the trapezoidal thread. It can be ensured that the top cover does not rotate when the two are connected, and that the cable does not entangle in the wire hole, and only the movable locking head is rotated. The wrench slot is used to apply torque, and the wire hole is used to lead the internal cable out. The wire hole is left to facilitate the arrangement of the cable.

[0017] Further, the neutron yield of the neutron generator in the direct current mode and the pulsed beam mode is 10 8 The energy resolution of the gamma spectrometer is 3.16% @662keV, and the observation energy range of the gamma spectrometer is 0.15MeV-10.3MeV.

[0018] The above-mentioned technical scheme has the beneficial effect that the neutron yield is an index of the neutron generator, and the higher the yield, the better the activation effect on the element. The energy resolution, i.e. the resolution, is a parameter of the gamma spectrometer, and the smaller the value of the energy resolution, the higher the resolution. The observation energy range uses the neutron generator to excite known substances to produce a series of known characteristic gamma rays, and the energy points can cover 0.3MeV-9MeV; the gamma spectrometer is used to measure the energy spectrum produced by the neutron generator, and the positions of each energy point in the energy spectrum are obtained by fitting, so that the observation energy range of the gamma spectrometer is obtained, and the energy linearity of the gamma spectrometer is also obtained.

[0019] Further, the other end of the support is wedge-shaped, and a plurality of pulleys are mounted on one end of the support.

[0020] The beneficial effects of the above further technical solutions are that the bottom of the support is designed as a wedge shape, and a plurality of pulleys are arranged on the upper part of the wedge shape, so that the overall structure of the support can be smoothly inserted into the shell.

[0021] Further, the shielding body comprises a shielding body pressing plate, and two pieces of metal bismuth are arranged in the shielding body pressing plate, or one piece of metal bismuth and boron-containing polyethylene are arranged in the shielding body pressing plate.

[0022] The beneficial effects of the above further technical solutions are that the neutron generator and the gamma spectrometer are separated by the compact small shielding body.

[0023] Further, a groove is arranged on one side wall of the support, and the neutron generator, the shielding body and the gamma spectrometer are all mounted in the groove, the neutron generator is adjacent to one end of the support, and the gamma spectrometer is adjacent to the other end of the support.

[0024] The beneficial effects of the above further technical solutions are that the groove is arranged to facilitate the installation and maintenance of the neutron generator, the shielding body and the gamma spectrometer.

[0025] Further, a weight-reducing groove, a wiring groove and a lapping boss are arranged on the other side wall of the support, and the lapping boss abuts against the inner wall of the shell.

[0026] The beneficial effects of the above further technical solutions are that the wiring groove is left to facilitate the arrangement of the cable, the weight-reducing groove and the wiring groove / hole are designed at the back of the installation position of the shielding body and the gamma spectrometer to facilitate the leading-out of the cable of the neutron generator, and the lapping boss is arranged at the top of the support to limit the lapping of the shell.

[0027] Further, a drill bit is mounted at the other end of the shell, and a gap is arranged between the drill bit and the other end of the support.

[0028] The beneficial effects of the above further technical solutions are that the drill bit facilitates the downlink of the pulsed neutron element scanning system for extraterrestrial exploration with the deep drilling equipment, the drill bit is finally mounted at the bottom of the support and cooperates with the gap of the bottom of the support, and the shell is connected with the drill bit through a countersunk screw. The drill bit can be selected according to the specific application requirements.

[0029] The advantages of the additional aspects of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Fig. 1 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to an embodiment of the present application.

[0031] Figure 2 Fig. 2 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to another embodiment of the present application.

[0032] Figure 3 Fig. 3 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to another embodiment of the present application.

[0033] Figure 4 Fig. 4 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to another embodiment of the present application.

[0034] Figure 5 Fig. 5 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to another embodiment of the present application.

[0035] Figure 6 Fig. 6 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to another embodiment of the present application.

[0036] Figure 7 Fig. 7 is a structural schematic diagram of a pulse neutron element scanning analysis system for extraterrestrial exploration according to another embodiment of the present application.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS 1, housing; 2, bracket; 3, neutron generator; 4, shielding body; 5, gamma spectrometer; 6, groove; 7, shock-absorbing rubber ring; 8, top cover; 9, lifting ring; 10, connector; 11, bracket lap joint step; 12, movable locking head; 13, wiring hole; 14, wrench clamping groove; 15, pulley; 16, wire outlet hole; 17, shielding body pressing plate; 19, weight-reducing groove; 20, wiring groove; 21, lap joint boss; 22, drill bit; 23, M5 screw; 24, countersunk M3 screw; 25, nylon binding tape. DETAILED DESCRIPTION

[0038] The principles and features of the present application are described below in conjunction with the accompanying drawings, in which the examples are used to explain the present application and are not intended to limit the scope of the present application.

[0039] As shown in Figures 1 to 7 Fig. 1, an embodiment of the present application provides a pulse neutron element scanning analysis system for extraterrestrial exploration, which comprises a housing 1, a bracket 2, a neutron generator 3, a shielding body 4, and a gamma spectrometer 5. The bracket 2 is installed in the housing 1, the neutron generator 3, the shielding body 4, and the gamma spectrometer 5 are all installed on the bracket 2, and the shielding body 4 is located between the neutron generator 3 and the gamma spectrometer 5.

[0040] The beneficial effects of the technical scheme of the present application are that the neutron generator, the shielding body and the gamma spectrometer are integrated and installed on the support, the controllable neutron source is fused with the gamma spectrometer, neutrons are emitted by the controllable pulsed neutron generator to activate the stratum, elements are detected and analyzed, the natural radioactive nuclides and the gamma generated by the cosmic background radiation are directly detected, element composition analysis is performed, the element measurement accuracy is improved, the detection time is shortened, more types of elements can be measured, and the present application is suitable for lunar geology and resource exploration.

[0041] The pulsed neutron element scanning and analyzing system for extraterrestrial exploration provided by the present application fuses the controllable neutron source with the gamma spectrometer, can greatly improve the element measurement accuracy, has obvious advantages in the detection time (up to seconds), provides strong support for measuring more types of elements, and is very suitable for lunar geology and resource exploration.

[0042] The pulsed neutron element scanning and analyzing system for extraterrestrial exploration provided by the present application can be used for carrying out element detection of the lunar surface and the shallow surface layer of a planet, has high element measurement accuracy, and has obvious advantages in the detection time. The present application has two working modes: 1) active mode: neutrons are emitted by the controllable pulsed neutron generator to activate the stratum, and elements are detected and analyzed; 2) passive mode: the neutron generator is turned off, the natural radioactive nuclides and the gamma generated by the cosmic background radiation are directly detected, and element composition analysis is performed. The present application also has two use methods: (1) deep detection mode: the pulsed neutron element analysis system is dragged into a drill hole when drilling soil on the lunar surface or the surface of a planet by using a deep drilling system, and the element types and content information of the depth profile are collected in real time. (2) large-range patrol detection mode: the pulsed neutron element analysis system is carried on a lunar rover or a planetary rover, and the element types and content information of the travel path are collected in real time during the travel of the rover.

[0043] The neutron generator can be a D-T neutron generator, the active radioactive neutron source (D-T neutron generator) is used, the deep drilling technology is used to penetrate the lunar soil to a depth of 3-5 m for full-energy spectrum element analysis, and the element characteristic spectrum can be obtained through neutron activation. After the gamma spectrum is collected, the element contribution of the non-elastic spectrum and the capture spectrum is distinguished and analyzed through the stripping technique, and the content of each element is obtained.

[0044] The active mode can accurately determine the element content in the lunar soil, can pay special attention to key elements, can reduce the relative weight of other elements, and can quickly find and quantitatively analyze H, 3 He and other important elements. Meanwhile, the instrument can analyze the secondary gamma rays generated by the elements in the stratum under the action of cosmic rays in the passive mode of turning off the neutron source, analyze whether K, Th, He and other elements of interest exist or not, and quantitatively analyze.

[0045] Using controllable D-T neutron source, in the lunar lack of water geological environment, the detection of penetration depth can reach more than 2m, which is the longitudinal information that X-ray detection can not obtain. Controllable neutron source has no high pressure and no nuclear radiation safety hazard. Neutron activation analysis is a typical non-destructive analysis method, which does not form permanent damage to the lunar soil after detection.

[0046] As shown in Figures 1 to 7 , further, the outer side wall of the bracket 2 is provided with a plurality of grooves 6, and a plurality of damping rubber rings 7 are sleeved on the grooves 6. The outer ring of the damping rubber ring 7 abuts against the inner wall of the shell 1.

[0047] The beneficial effects of the above further technical solutions are: setting grooves can facilitate the placement of damping rubber rings, and ensure the damping of the bracket after the overall structure of the bracket is inserted into the shell.

[0048] As shown in Figures 1 to 7 , further, one end of the shell 1 is provided with a top cover 8, the top cover 8 is provided with a lifting ring 9 and a connector 10, and the connector 10 is connected with the neutron generator 3 and the gamma spectrometer 5.

[0049] The beneficial effects of the above further technical solutions are: the connector is thrown out of the top cover in the form of wire throwing, which facilitates quick connection with other equipment.

[0050] As shown in Figures 1 to 7 , further, one end of the shell 1 is provided with a bracket lap joint step 11 and a movable locking head 12, one end of the bracket 2 is lapped on the bracket lap joint step 11, and the top cover 8 is screwed on the movable locking head 12; the top cover 8 is provided with a wire hole 13 and a wrench clamping groove 14.

[0051] The beneficial effects of the above further technical solutions are: the bracket lap joint step on the bracket is axially constrained with the shell. Then the top cover is rotated through the trapezoidal thread, and the bracket lap joint step is pressed. The movable locking head is pressed on one side of the shell and can rotate freely, and the other side is connected with the top cover through the trapezoidal thread. It can be ensured that the top cover does not rotate when the two are connected, and the cable does not wind in the wire hole. Only the movable locking head is rotated. The wrench clamping groove is used to apply torque, and the wire hole is used to lead the internal cable out. The wire hole is left to facilitate the arrangement of the cable.

[0052] Further, the neutron yield of the neutron generator in the direct current mode and the pulsed beam mode is 10 8 per second, the energy resolution of the gamma spectrometer is 3.16% @662keV, and the observation energy range of the gamma spectrometer is 0.15MeV-10.3MeV.

[0053] The beneficial effects of the further technical scheme are: the neutron yield is an index of the neutron generator, the higher the yield, the better the activation effect on the element. The energy resolution, i.e. the resolution, is a parameter of the gamma spectrometer, the smaller the energy resolution value, the higher the resolution. The observation energy band uses the neutron generator to excite known substances to produce a series of known characteristic gamma rays, and the energy points can cover 0.3 MeV-9 MeV; the gamma spectrometer is used to measure the energy spectrum produced by the neutron generator excitation, and the positions of each energy point in the energy spectrum are obtained by fitting, so that the observation energy band range of the gamma spectrometer can be obtained, and the energy linearity of the gamma spectrometer can be obtained.

[0054] Main performance requirements: (1) detectable elements: H, O, and main elements and radioactive elements of the moon including K, Th, U, Fe, Mg, Si, Ti, Al, etc., and the total number of analyzable elements is not less than 10; (2) the detection accuracy of key elements is not less than 1.5%; (3) the detection radius is 1 m; (4) neutron yield: better than 10 8 @662keV; (6) observation energy band: 0.3 MeV-9 MeV.

[0055] Test content: use 137 Cs radioactive source to measure the energy resolution of the gamma spectrometer, and the test corresponds to the examination index of the energy resolution of the gamma spectrometer: better than 3.2% @662keV.

[0056] Test method and principle

[0057] Natural radioactive source 137 Cs can produce 662keV single-energy gamma rays, which are used to calibrate the energy resolution of the gamma spectrometer. Use 137 Cs radioactive source to irradiate the gamma spectrometer, and observe 137 the energy spectrum of Cs: 137 Cs has a clear characteristic peak at 662keV, which is in Gaussian distribution at 662keV of the energy spectrum of the gamma spectrometer. Gaussian fitting obtains the full width at half maximum (FWHM=2.355*sigma) of the distribution, so that the energy resolution of the gamma spectrometer at 662keV can be calculated, and the calculation formula is as follows:

[0058] EnergySolution=FWHM / 662keV..................(1)

[0059] Since the collected original signal of the detector is an ADC value, the acquisition circuit itself has a baseline level (denoted as ADC -662keV ), and the actually measured ADC value is the result of superimposing the baseline level on the detector signal. Therefore, the calculation formula of the energy resolution is usually expressed as:

[0060] Energy Solution = FWHM / (ADC) -662keV -ADC -0keV )..................(2)

[0061] The acquisition circuit is designed so that the energy of the incident particle has a linear relationship with the ADC, which can be expressed as:

[0062] ADC -Energy = a*Energy+ADC -0keV .................(3)

[0063] To accurately obtain the specific baseline level of the acquisition circuit, the ADC -0keV Typically, two energy points are needed to establish the correspondence between the ADC and the energy to obtain the baseline level, i.e., the number of ADC channels at 0 keV.

[0064] In this experiment, the gamma spectrometer detector material is LaBr3 crystal, which itself has a natural radioactive background at 36.8 keV, allowing it to be used in conjunction with... 137 The characteristic energy point generated by Cs at 662 keV yields the ADC. -0keV Then, by substituting into formula (2), we can obtain the energy resolution of the gamma spectrometer detector at 662 keV.

[0065] For safety reasons, a lower activity level should be selected in the actual test. 137 Cs exemption source.

[0066] Test conditions (environmental conditions, etc.): Temperature: 23℃; Relative humidity: 41%.

[0067] Experimental Procedure: Construct the ground-based experimental verification platform, including... 137 Cs exemption source, gamma spectrometer detector, gamma spectrometer readout electronics, general-purpose computer, lead chamber, etc. Among them, the gamma spectrometer detector and 137 The Cs exemption source is placed in the lead chamber.

[0068] a) Use 137 The Cs-exempt source irradiates the gamma spectrometer detector, while the ground testing equipment provides power and collects data from the detection unit, sending it to a general-purpose computer. Testing personnel then use the general-purpose computer to acquire and control the detection unit data.

[0069] b) Data obtained from gamma spectrometry 137 Gaussian fitting was performed on the Cs energy spectrum to obtain the FWHM at 662 keV, and its energy resolution was calculated.

[0070] Test Results

[0071] First, measure the environmental background spectrum, then place it... 137 Cs exemption source, measured environmental background and 137 Cs superposition energy spectrum (Background+) 137 Cs); subtracting the two yields a clean result. 137 Cs energy spectrum.

[0072] The background spectrum contains the characteristic peak of the LaBr3 crystal itself at 36.8 keV, and the ADC channel number obtained by Gaussian fitting is 3425.07.

[0073] 137 The Cs energy spectrum contains a typical characteristic peak at 662 keV. Gaussian fitting yielded the ADC. -662keV The value is 10165.0, the sigma is 95.62, and the FWHM = 2.355 × 95.62 = 225.185.

[0074] Thus, ADC is obtained. -0keV The number of channels is 3027.2.

[0075] The energy resolution of the detector at 662 keV is calculated to be...

[0076] EnergySolution-662keV=FWHM / (ADC -662keV -ADC -0keV )

[0077] =225.185 / (10165.0-3027.2)=3.155%

[0078] Test results show that the energy resolution of the gamma spectrometer meets the design specifications: ≤3.2%@662keV.

[0079] Experiment content: Neutron yield calibration, verification and determination of specific parameters of neutron yield, corresponding to technical indicator 4 (neutron yield: better than 10). 8 (units / s);)

[0080] Experimental Method and Principle: The actual yield of the neutron generator is determined using a neutron counting system calibrated to a standard. This device actually includes a neutron-slowing paraffin barrel. 3 The ignition device of the thermal neutron detector and neutron generator, at a fixed distance, detects a thermal neutron count rate that is proportional to the yield of the neutron generator. According to the calibrated curve, this can be converted into the actual yield of the neutron generator.

[0081] Test conditions (environmental conditions, etc.): Temperature: 22℃; Relative humidity: 38%.

[0082] Test results: The neutron yield is monitored by the primary ionizing radiation metrology station, and the maximum neutron yield can reach 3.6 x 10 8 / s.

[0083] Test content

[0084] The element detection type, accuracy, and radius verification test of the prototype is carried out. In theory, the related element spectrum is established, and the detector can detect the energy spectrum of the element, and the device can detect the existence of the element. However, in this project, the size of the detector LaBr3 is limited, and the detection ability of high-energy gamma photons is affected, which may cause the analysis accuracy to be low. This is one of the key problems that need to be considered in the engineering process. Through analysis or simulation, the maximum detection radius of the moon is demonstrated.

[0085] At the same time, the neutron generator generates fast neutrons, which bombard known substances to excite high-energy gamma photons of known energy; the gamma spectrometer observes the incident gamma photons to obtain the energy spectrum and the observation energy segment.

[0086] Corresponding technical indicators 1-3 and indicator 6:

[0087] 1) Detectable elements: H, O, and main elements and radioactive elements of the moon including K, Th, U, Fe, Mg, Si, Ti, Al, etc., and the total number of analyzable elements is not less than 10; 2) The detection accuracy of key elements is not less than 1.5%; 3) The detection radius is 1m; 4) The observation energy segment of the gamma spectrometer is 0.3MeV-9MeV.

[0088] Test method and principle: Using the model well with known element content, simulate the formation conditions of the moon, analyze the element content by measuring the spectrum. Test the performance of the device, including element analysis ability and accuracy. Establish a specific model well to test the detection accuracy of certain elements. Design a complete standard spectrum generator, which can simulate and calculate the corresponding standard gamma spectrum according to different detectors LaBr3 and different common elements in the formation, shorten the research period of element spectral logging and reduce the experimental cost. Use Monte Carlo method to simulate the generation of secondary gamma rays (including capture and inelastic scattering) in the atom, and count and analyze according to the element category and position of the atom. In this way, not only can the standard spectrum response of each element be distinguished, but also the influence of the same element in the non-target (here the target is the formation) can be automatically separated. The previous method of obtaining standard spectrum by experiment is a physical approximation, such as measuring the spectrum of pure graphite to approximate the standard spectrum response of C. In the case of complex lithology, the neutron distribution state is completely different from that of pure C element, which is often fatal to the element analysis with high accuracy. In this project, the verification of key technologies is mainly through experimental correction from the detector to the final device, from simple to complex. And through numerical method to verify the detection radius and other parameters in the lunar environment.

[0089] The controllable deuterium-tritium (D-T) neutron source generator has high neutron yield. Compared with chemical radioactive sources, it does not harm the health of workers when not working, and there is no major safety and environmental protection hidden danger. The yield and timing of the neutron generator can be controlled by circuit design. When the astronaut is present, the yield can be reduced to make the radiation dose equivalent to the radiation dose on the lunar surface. Although the detection speed will be reduced, the radiation safety of personnel can be ensured. The dose evaluation can be evaluated by experimental calibration and simulation of lunar surface working environment under the same conditions.

[0090] The verification test of the detection radius mainly demonstrates the maximum detection radius on the moon through testing or simulation. The main method is to pre-design at each detection depth in a relatively large simulation well, such as filling the arc-shaped test unit with water. After a certain detection distance, the value of H element cannot be analyzed on the spectrum, which is considered as the detection depth of the instrument.

[0091] The known substance is excited by the neutron generator to generate a series of known characteristic gamma rays, and the energy points can cover 0.3MeV-9MeV; the energy spectrum generated by the neutron generator is measured by using the gamma spectrometer, and the position of each energy point in the energy spectrum is obtained by fitting, so that the observation energy range of the gamma spectrometer can be obtained, and the energy linearity of the gamma spectrometer can be obtained. The SiO2 simulation well is excited by neutrons, and obvious characteristic gamma rays can be generated at 1.78MeV, 5.13MeV, 5.62MeV and 6.1MeV. Through simple linear fitting and backstepping, the observation energy range of the gamma spectrometer can be obtained.

[0092] The specific test procedure is as follows: a) the gamma spectrometer and the neutron generator are integrated into a pulse neutron element analyzer, and the entire pulse neutron element analyzer is placed in the simulation well;

[0093] b) the gamma spectrometer and the neutron generator are powered on and initialized;

[0094] c) the neutron generator generates a fast neutron pulse, and the gamma spectrometer collects the incident gamma photon energy spectrum;

[0095] d) the energy spectrum is obtained and analyzed every ten centimeters near the simulation result

[0096] e) the characteristic gamma rays in the energy spectrum are analyzed to obtain different characteristic gamma ray energy points, verify the observation energy range of the gamma spectrometer, and determine the detection element type, accuracy and depth of the device.

[0097] Test results: 4) observation energy range of the gamma spectrometer

[0098] The SiO2 simulation well is used to test the observation energy range of the gamma spectrometer.

[0099] The ADC channel numbers at 1.78MeV, 5.13MeV, 5.62MeV and 6.1MeV are obtained by fitting, which are 4632.0, 7142.7, 7503.7 and 7849.5 respectively. The ADC and energy linear correspondence curve is established.

[0100] It can be seen that the ADC channel number coverage range of the gamma spectrometer observation energy spectrum is not less than 3400-11000. According to the curve backstepping, the observation energy range of the gamma spectrometer covers 0.15MeV-10.3MeV; among them, 0.3MeV corresponds to ADC channel number 3529.5; 9MeV corresponds to ADC channel number 10023.3, both of which are in the observation energy range of the gamma spectrometer. Therefore, the test results show that the observation energy range of the gamma spectrometer meets the test index: 0.3MeV-9MeV.

[0101] As shown in Figures 1 to 7 the other end of the support 2 is wedge-shaped, and a plurality of pulleys 15 and a wire outlet hole 16 are installed at one end of the support 2.

[0102] The beneficial effect of the further technical scheme is that the wedge-shaped bottom of the support and the plurality of pulleys on the upper part of the wedge-shaped bottom can ensure that the overall structure of the support is smoothly inserted into the shell.

[0103] As shown in Figures 1 to 7 Further, the shielding body 4 comprises a shielding body pressing plate 17, and two pieces of metal bismuth are arranged in the shielding body pressing plate 17, or one piece of metal bismuth and boron-containing polyethylene are arranged in the shielding body pressing plate 17.

[0104] The beneficial effect of the further technical scheme is that the compact small shielding body can realize the spacing of the neutron generator and the gamma spectrometer.

[0105] As shown in Figures 1 to 7 Further, a recess is arranged on one side wall of the support 2, and the neutron generator 3, the shielding body 4 and the gamma spectrometer 5 are all installed in the recess, the neutron generator 3 is adjacent to one end of the support 2, and the gamma spectrometer 5 is adjacent to the other end of the support 2.

[0106] The beneficial effect of the further technical scheme is that the recess is arranged to facilitate the installation and maintenance of the neutron generator, the shielding body and the gamma spectrometer.

[0107] As shown in Figures 1 to 7 Further, a weight-reducing groove 19, a wiring groove 20 and a lapping boss 21 are arranged on the other side wall of the support 2, and the lapping boss 21 abuts against the inner wall of the shell 1.

[0108] The beneficial effect of the further technical scheme is that the wiring groove is arranged to facilitate the arrangement of the cable. The support is designed with the weight-reducing groove and the wiring groove / hole at the back of the installation position of the shielding body and the gamma spectrometer to facilitate the leading-out of the cable of the neutron generator; the lapping boss is arranged at the top of the support to limit the position of the shell.

[0109] As shown in Figures 1 to 7 Further, a drill bit 22 is installed at the other end of the shell 1, and the drill bit 22 has a gap with the other end of the support 2.

[0110] The beneficial effect of the further technical scheme is that the drill bit facilitates the downlink of the pulsed neutron element scanning system for extraterrestrial exploration with the deep drilling equipment. The drill bit is finally installed at the bottom of the support, and the shell and the drill bit are connected through a countersunk screw. The drill bit can be selected according to the specific application requirements.

[0111] The neutron generator, the shielding body and the gamma spectrometer are integrally installed on the bracket, grooves are arranged on the upper, middle and lower portions of the bracket, the shock-absorbing rubber ring is conveniently placed in the grooves, and a wiring hole and groove are left to facilitate the arrangement of the cable.

[0112] The extraterrestrial exploration pulse neutron element scanning analysis system mainly comprises the following parts: a neutron generator, a shielding body, a gamma spectrometer, a shell, a drill bit, a top cover, a lifting ring on the top cover and a plug-in connector. The bracket is designed, the neutron generator, the shielding body and the gamma spectrometer are integrally installed on the bracket, grooves are arranged on the upper, middle and lower portions of the bracket, the shock-absorbing rubber ring is conveniently placed in the grooves, and a wiring hole and groove are left to facilitate the arrangement of the cable.

[0113] The bracket bottom is designed as a wedge shape, four pulleys are arranged on the upper portion of the wedge shape, and the whole structure can be smoothly inserted into the shell. The wedge face is provided with an outlet hole and a wiring groove, the control and power supply shielding cable of the neutron generator is led out from the outlet hole and arranged in the wiring groove, and should be led out to the top of the analyzer (i.e. the extraterrestrial exploration pulse neutron element scanning analysis system) along the outlet hole. The bracket bottom is provided with a groove to accommodate the shock-absorbing rubber ring, so as to ensure the shock absorption of the whole structure after being inserted into the shell.

[0114] (1) The cable of the neutron generator is led out from the outlet hole and upwardly led out through the wiring hole; (2) the neutron generator is placed in the groove of the bracket, M5 screws 23 are respectively installed at the right center position, and two countersunk M3 screws 24 are respectively installed at the left and right bottom portions; (3) a plurality of nylon binding belts 25 are used to limit the bracket 2 in the groove and constrain the neutron generator and the cable led out from the neutron generator, so as to complete the installation and fixation of the neutron generator.

[0115] The shielding body can be realized by two compact schemes, (1) two pieces of metal bismuth, or (2) one piece of metal bismuth and boron-containing polyethylene. The two pieces of metal bismuth or the one piece of metal bismuth and boron-containing polyethylene are tightly installed by the shielding body pressing plate to form a shielding body unit.

[0116] The gamma spectrometer is installed and fixed at the top end of the bracket through four mounting lugs, and the cable of the gamma spectrometer is led out from the top end of the wiring groove / hole (wiring groove and wiring hole) to the outside of the instrument.

[0117] The bracket is designed with a weight-reducing groove and a wiring groove / hole at the back of the shielding body and the gamma spectrometer installation position, facilitating the lead-out of the lead-out cable of the neutron generator; a lap joint boss is arranged at the top of the bracket to lap and limit with the shell; a groove is arranged at the lower side of the shielding body and the upper side of the gamma spectrometer to accommodate a shock-absorbing rubber ring, so as to ensure the shock absorption of the whole structure after being inserted into the shell. After the above installation steps are completed, the internal components of the extraterrestrial detection pulse neutron element scanning analysis system are formed.

[0118] The internal components of the pulse neutron element analysis system are inserted into the shell as a whole, and are axially constrained by the bracket lap joint step on the bracket. Then the top cover is rotated through the trapezoidal thread, and the bracket lap joint step is pressed tightly.

[0119] The top cover is provided with a wiring hole and a wrench clamping groove. The wrench clamping groove is used to apply torque, and the wiring hole is used to lead out the internal cable.

[0120] One side of the movable locking head is pressed tightly with the shell and can rotate freely, and the other side is connected with the top cover through the trapezoidal thread. This design can ensure that the top cover does not rotate when the two are connected, and that the cable does not wind in the wiring hole, and only the movable locking head can be rotated.

[0121] The drill bit is finally installed at the bottom of the bracket, gap-fitted with the bracket bottom, and the shell is connected with the drill bit through a countersunk screw. The drill bit can be selected according to the specific application requirements.

[0122] Application scenario is introduced in detail:(1) depth detection mode

[0123] 1) The astronaut lays out the deep drilling equipment, and the extraterrestrial detection pulse neutron element scanning analysis system descends with the deep drilling equipment; 2) The astronaut starts the deep drilling equipment and moves away, and the extraterrestrial detection pulse neutron element scanning analysis system descends with the deep drilling equipment. 3) The astronaut starts the extraterrestrial detection pulse neutron element scanning analysis system at a safe distance. The element analysis equipment mainly includes two modes: active mode: emitting neutrons to activate the stratum by a controllable pulse neutron generator, detecting gamma to analyze element composition; passive mode: stopping the neutron generator, directly detecting natural radioactive nuclides and cosmic background radiation activated gamma to analyze element composition. 4) The extraterrestrial detection pulse neutron element scanning analysis system continuously descends with the deep drilling equipment, and continuously detects the element types and contents of different strata.

[0124] (2) Large-scale scanning

[0125] 1) The extraterrestrial detection pulse neutron element scanning analysis system is carried on the unmanned lunar (planetary) exploration vehicle; 2) During the process of the unmanned lunar (planetary) exploration vehicle, large-scale scanning is carried out to quickly obtain the element types and contents of the strata within the range of the vehicle's travel route.

[0126] (1) The extraterrestrial exploration pulse neutron element scanning analysis system adopts a controllable active radioactive neutron source (neutron generator function), activates the elements of the lunar or planetary surface layer, rock and soil, and uses a gamma spectrometer for quantitative analysis to determine the types and reserves of elements in the lunar surface (planetary surface layer) and shallow underground. It can be applied to lunar, Martian and other extraterrestrial exploration scenarios, and can be used with manned and unmanned exploration missions.

[0127] (2) The active mode detection radius of the detector (extraterrestrial exploration pulse neutron element scanning analysis system) is 0.5-1 meters in the lunar environment and 1 meter in the Martian environment.

[0128] (3) The extraterrestrial exploration pulse neutron element scanning analysis system has two modes: active detection (neutron activation) and passive detection (cosmic background radiation). In active mode, the detection speed is fast and the time is short (seconds); in passive mode, neutron radiation measurement can be reduced, and it can be adapted to different working conditions with astronauts.

[0129] (4) The extraterrestrial exploration pulse neutron element scanning analysis system can be applied to deep exploration in extraterrestrial environments, including two modes: 1) downhole detection with a sampler, and 2) cable logging detection in the wellbore after sampling.

[0130] (5) The extraterrestrial exploration pulse neutron element scanning analysis system can be applied to large-scale and large-area planetary surface and deep exploration with a rover in extraterrestrial environments.

[0131] (6) The extraterrestrial exploration pulse neutron element scanning analysis system uses a compact small shielding body to separate the neutron generator and the gamma spectrometer, which can be achieved by two schemes: 1) two pieces of metallic bismuth, or 2) one piece of metallic bismuth and a boron-containing polyethylene compression.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A pulsed neutron elemental scanning and analysis system for extraterrestrial exploration, characterized by, Include: The shell, support, neutron generator, shielding body, gamma spectrometer, the support is installed in the shell, the neutron generator, the shielding body and the gamma spectrometer are installed on the support, the shielding body is located between the neutron generator and the gamma spectrometer;The outer side wall of the support is provided with a plurality of grooves, a plurality of grooves are provided with a damping rubber ring, the outer ring of the damping rubber ring is in abutment with the inner wall of the shell;One end of the shell is provided with a top cover, the top cover is provided with a lifting ring and a connector, the connector is connected with the neutron generator and the gamma spectrometer.

2. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein, One end of the shell is provided with a support lap joint step and a movable locking head, one end of the support is lapped on the support lap joint step, and the top cover is installed on the movable locking head through threads;The top cover is provided with a wiring hole and a wrench clamping groove.

3. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein The neutron generator has a neutron yield of 10 8 The energy resolution of the gamma spectrometer is 3.16% @ 662 keV, and the observed energy range of the gamma spectrometer is 0.15 MeV-10.3 MeV.

4. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein, The other end of the support is wedge-shaped, and the one end of the support is provided with a plurality of pulleys and a wire outlet hole.

5. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein, The shielding body includes a shielding body pressing plate, two metal bismuth are arranged in the shielding body pressing plate, or a metal bismuth and a boron-containing polyethylene are arranged in the shielding body pressing plate.

6. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein, One side wall of the support is provided with a recess, the neutron generator, the shielding body and the gamma spectrometer are installed in the recess, the neutron generator is adjacent to one end of the support, and the gamma spectrometer is adjacent to the other end of the support.

7. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein The other side wall of the support is provided with a weight reduction groove, a wiring groove and a lap joint boss, and the lap joint boss is in abutment with the inner wall of the shell.

8. The pulsed neutron elemental scanning system for extraterrestrial exploration according to claim 1, wherein, The other end of the shell is provided with a drill bit, and the drill bit has a gap with the other end of the support.

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