39 results about "Epithermal neutron" patented technology

The invention provides a while-drilling neutron porosity density measuring device and a clock labeling method, and the while-drilling neutron porosity density measuring device comprises an ultra-short pulse neutron generator which is used for generating ultra-short pulse neutrons with a specified time sequence; the fast neutron detector is used for monitoring the yield of the ultrashort pulse neutron generator; the thermal neutron detector group is used for recording thermal neutron flux; and the gamma detector group is used for recording inelastic gamma flux. According to the technical scheme, through the double-epithermal neutron double-gamma structure model, the influence of the stratum density on porosity measurement is effectively eliminated, and the measurement precision is improved.

The invention discloses a method for inverting snow water equivalent and soil water content based on neutron flux, and relates to the technical field of meteorological science, and the method comprises the steps: carrying out a calibration experiment in an experiment site, measuring a thermal neutron counting rate, an epithermal neutron counting rate, the soil water content and the snow water equivalent, substituting an experiment result into a database, and calibrating parameters Ne0 and Nt0; an epithermal neutron detector is arranged at an experimental site, and any one of the thermal neutron detector, a soil water content sensor and a snow water equivalent sensor is selected for detection at the experimental site; and taking the detection result as original data, and finding sample point data closest to the original data in the database, namely inversion results of the snow water equivalent and the soil water content. According to the method, the snow water equivalent influence is corrected in the actual measurement of the soil water content by the cosmic ray neutron method, or the soil water content influence is corrected in the snow water equivalent measurement, and the snow water equivalent soil water content can be determined by measuring the counting rates of ground epithermal neutrons and thermal neutrons.

The invention relates to the technical field of cable logging, and particularly discloses a mineral component and content testing device and method suitable for a uranium-bearing reservoir, and the device comprises a cable logging system, a logging depth calibration system and a time synchronization system, the logging tool assembly comprises a spectral logging tool, a natural gamma-ray spectrum logging tool, an epithermal neutron logging tool and a neutron capture gamma-ray spectrum logging tool. The method comprises the steps of combining a logging tool assembly and a cable logging system, configuring a logging depth calibration system, configuring a time synchronization system, carrying out PTP time synchronization on the cable logging system and the logging depth calibration system, collecting original logging time and original logging data, carrying out time resampling and depth correction on the original logging data, and carrying out time synchronization on the logging depth calibration system and the cable logging system. And resampling the logging data according to the logging depth and time to divide a stratum structure. According to the method, acquisition and data fusion of the mineral components, the radioactive element content and the porosity characteristics of the stratum around the well can be realized, and the exploration precision, efficiency and evaluation accuracy are improved.

The invention provides a mountain freeze-thaw desertification early warning method and related equipment. The method comprises the following steps: acquiring thermal neutron intensity and epithermal neutron intensity of a target area; based on a target intensity ratio and a pre-obtained empirical fitting parameter set, target parameters are determined, and the target intensity ratio is the ratio of the thermal neutron intensity to the epithermal neutron intensity of the target area; determining a target moisture content according to the target parameter and the thermal neutron intensity or epithermal neutron intensity of the target area; and when the target moisture content is lower than a preset critical soil moisture threshold value, carrying out mountain freeze-thaw desertification early warning. Soil moisture is inverted through a cosmic ray neutron detection technology, environmental interference factors such as a non-soil water hydrogen source are corrected, local soil moisture of different vegetation types and soil types is accurately captured, freeze-thaw desertification is judged in combination with a critical soil moisture threshold, and early warning is given.

The invention discloses a uranium-radium balance correction method, device, medium and equipment, and relates to the field of sandstone type uranium mine uranium exploration, and the method comprises the steps: obtaining an industrial uranium mine hole, carrying out the geophysical logging of the industrial uranium mine hole, determining a mineralized section through quantitative gamma interpretation, and carrying out the geological logging and geophysical exploration logging of a rock core, uranium and radium samples are collected and analyzed in the mineralization section; uranium fission instant neutron logging is carried out on the mineralization section, and the uranium ore section depth range is determined according to the ratio of the epithermal neutron time spectrum to the thermal neutron time spectrum of uranium fission instant neutron logging; according to the uranium radium sample analysis result of the mineralization section, determining a single sample section uranium radium balance coefficient, and according to the single sample section uranium radium balance coefficient, determining a single engineering uranium radium balance coefficient; determining a uranium radium balance coefficient partition map according to the single-project uranium radium balance coefficient; and correcting the quantitative gamma logging curve in the uranium ore section depth range of uranium instantaneous neutron logging by utilizing the coefficients in different uranium-radium balance regions to obtain the actual depth range, thickness and grade of the uranium ore section.

The present invention relates to a cyclotron comprising first and second internal ion sources configured to form first and second beams of identical charged particles wherein the cyclotron is further configured to generate a local asymmetry of an accelerating electric and / or magnetic field, the first beam and the second beam are combined to form a combined beam and the combined beam passes through a single extraction outlet. The invention also relates to an acceleration system comprising N cyclotrons, where M cyclotrons are the cyclotrons according to the invention, Mgt; 0. The invention also relates to a device for treating a patient by BNCT, comprising: an acceleration system according to the invention; a target configured to emit an epithermal neutron beam when bombarded with the proton or deuteron multi-combination beam; and a treatment region configured to hold a patient to be treated within the treatment region.

A logging tool is used to measure formation porosity. The tool has a pulsed neutron generator and multiple dual-function detectors that can detect neutrons and gamma rays. The ratios of thermal neutrons, epithermal neutrons, and captured gamma rays from multiple detectors are used to obtain multiple neutron porosities and multiple gamma-ray porosities at different exploration depths. The neutron porosity and gamma-ray porosity can be further corrected by excluding peak regions attributed to hydrogen and / or chlorine to reduce shale effects and / or chlorine effects. The neutron porosity and gamma-ray porosity can be combined to provide a better porosity assessment at different exploration depths in the formation over the entire porosity measurement range (0-100 p.u.).

The invention discloses a uranium mine logging instrument based on ultrashort pulse neutrons and a working method thereof, and relates to the field of uranium mine exploration logging. The logging instrument comprises a control communication short section, an ultrashort pulse neutron generator used for emitting fast neutron pulses with the pulse width smaller than 1 microsecond to a stratum, a shielding body and a double-thermal-neutron detection assembly used for detecting thermal neutrons and epithermal neutrons on measuring points consistent in space, all of which are sequentially arranged in the axial direction of the logging instrument. The gamma detector is used for detecting inelastic scattering gamma rays emitted by stratum elements and capturing gamma rays, and the fast neutron detector is used for detecting and outputting source intensity monitoring signals of fast neutron pulses in real time. According to the logging instrument, the ultra-short fast neutron pulse is emitted, the neutron yield is detected in real time, the neutron time spectrum and gamma-ray energy spectrum multi-dimensional information with an accurate timestamp are obtained in a combined mode, high-precision and anti-interference inversion is conducted on the stratum uranium content, and stratum information is obtained efficiently and accurately.

The invention discloses a borehole influence factor aperture correction method for uranium fission instant neutron logging, and aims to solve the problem of neutron counting rate response deviation caused by borehole size change in a uranium mine logging process. Time spectrums of thermal neutrons and epithermal neutrons in different apertures in uranium fission instant neutron logging are obtained, and the rule that the time spectrums of the thermal neutrons and the epithermal neutrons change along with the hole diameter is researched. And based on a numerical simulation result, a fitting formula and a correction coefficient of the aperture influence factors are solved. The correction method can be used for analyzing the influence of the aperture size change on the counting rate of the neutron detector, effectively improves the uranium mine grade evaluation accuracy under the complex borehole condition, and is especially suitable for well logging interpretation of non-standard borehole diameters and diameter-expanded stratums.

The utility model provides a dose distribution shifting member and a beam shaping device for boron neutron capture therapy, the dose distribution shifting member comprises one or more material layers along the neutron emission direction, and the material layers comprise an epithermal neutron moderation material layer and / or a thermal neutron absorption material layer; the shape of the dose distribution shifting part is matched with the shape of the neutron beam exit port. The dose distribution shifting part can be adjusted according to the specific position of a tumor in a human body, so that the maximum dose value caused by thermal neutrons is deposited in the center of the tumor, and the effects of the maximum killing effect on the tumor and the minimum damage to normal tissue are achieved.

The present invention discloses a method for inverting snow water equivalent and soil water content based on neutron flux, which relates to the field of meteorological science and technology, and includes: conducting a calibration experiment at an experimental site, measuring the thermal neutron count rate, epithermal neutron count rate, soil water content and snow water equivalent, substituting the experimental results into a database, and calibrating parameter N e0 and N t0 ; setting an epithermal neutron detector at the experimental site, and then selecting any one of the thermal neutron detector, soil water content sensor, and snow water equivalent sensor to conduct detection at the experimental site; taking the detection result as the original data, and finding the sample point data closest to the original data in the database, which is the inversion result of the snow water equivalent and soil water content. The method of the present invention corrects the influence of snow water equivalent in the actual measurement of soil water content by the cosmic ray neutron method, or corrects the influence of soil water content in the measurement of snow water equivalent, and can also determine the snow water equivalent and soil water content simultaneously by measuring the ground epithermal neutron and thermal neutron count rates.

Alkylphosphocholine analogs incorporating a chelating moiety that is chelated to gadolinium are disclosed herein. The alkylphophocholine analogs are compounds having the formula:or a salt thereof. R1 includes a chelating agent that is chelated to a gadolinium atom; a is 0 or 1; n is an integer from 12 to 30; m is 0 or 1; Y is —H, —OH, —COOH, —COOX, —OCOX, or —OX, wherein X is an alkyl or an arylalkyl; R2 is —N+H3, —N+H2Z, —N+HZ2, or —N+Z3, wherein each Z is independently an alkyl or an aroalkyl; and b is 1 or 2. The compounds can be used to detect solid tumors or to treat solid tumors. In detection / imaging applications, the gadolinium emits signals that are detectable using magnetic resonance imaging. In therapeutic treatment, the gadolinium emits tumor-targeting charged particles when exposed to epithermal neutrons.

The invention discloses a compact high-resolution epithermal neutron resonance absorption spectrum method and a compact high-resolution epithermal neutron resonance absorption spectrum device in the technical field of nuclear physics application, and aims to solve the problems of large size, high cost and limited application of a traditional epithermal neutron source. The method comprises the following steps: generating an epithermal neutron source with high repetition frequency and microsecond-level pulse by using a kilohertz femtosecond laser, accelerating an electron beam through a laser plasma wake field, bombarding a metal target to generate fast neutrons, and processing the fast neutrons through a polyethylene body to obtain an epithermal neutron energy spectrum with ultrahigh energy resolution; the device comprises a femtosecond laser, a vacuum target chamber, a supersonic nozzle, a high-atomic-number metal target, polyethylene, a collimator, an EJ-420 detector and other key components, and is compact in design, convenient to move and convenient for multi-scene application. The technology can realize accurate diagnosis of the type and abundance of nuclides in nuclear fuel and nuclear waste and non-contact temperature measurement in a special environment, and has important nuclear safety and nuclear guarantee application values.

The embodiment of the invention provides a neutron flux determination method and device applied to dating of a samarium-neodymium isotope system, and the method comprises the steps: carrying out the isotope measurement of a sample, and determining the isotope measurement data of the sample; simulating a neutron irradiation effect based on the sample, and determining neutron irradiation model data; comparing the isotope measurement data with the neutron irradiation model data to determine a comparison result; an epithermal neutron flux is determined based on the comparison result. The epithermal neutron flux is obtained through sample isotope data simulation, the application range is wide, the method can be used for well drilling samples, return samples, aerolite samples and the like, the accuracy of dating results of isotope systems with different depths is improved, and a reliable basis is provided for researching the renovation rate of well drilling lunar soil samples.

The invention discloses a single-source multi-beam boron neutron capture therapy system, and relates to the field of radiotherapy equipment. The system comprises a set of low-energy proton accelerator, an electromagnetic field steering part and two or more treatment rooms, wherein each treatment room is provided with a corresponding target material and a neutron moderation device. The method comprises the following steps of: guiding proton beams to respectively bombard a plurality of target materials to generate fast neutrons through an electromagnetic field steering part by utilizing the electrification characteristic of protons, moderating the fast neutrons into thermal neutrons (suitable for superficial tumors) or epithermal neutrons (suitable for deep tumors) through a neutron moderating device made of a hydrogen-containing or fluorine-containing moderating material, and guiding the thermal neutrons or epithermal neutrons to a corresponding treatment room. Through a single-source multi-beam architecture, multi-energy neutron beam output and multi-patient parallel treatment are realized on the basis of one set of accelerator, the treatment adaptation disease range is greatly expanded, the equipment cost and the occupied area are reduced, and the treatment flexibility and the equipment utilization rate are improved.

The embodiment of the specification provides a neutron flux determination method and device applied to samarium-neodymium isotope system dating, wherein the neutron flux determination method applied to the samarium-neodymium isotope system dating comprises the following steps: performing isotope measurement on a sample to determine isotope measurement data of the sample; performing simulation on a neutron irradiation effect of the sample to determine neutron irradiation model data; comparing the isotope measurement data and the neutron irradiation model data to determine a comparison result; and determining the epithermal neutron flux based on the comparison result. The size of the epithermal neutron flux is obtained by simulating the isotope data of the sample, the method is widely applicable, and can be used for drilling samples, return samples, meteorite samples and the like, thereby improving the accuracy of the dating results of isotope systems at different depths and providing a reliable basis for studying the drilling lunar soil sample turnover rate.

The invention discloses a neutron source based on an FRC linear magnetic confinement nuclear fusion device, and relates to the technical field of fusion devices. The neutron source comprises a vacuum chamber for providing a vacuum environment for fusion reaction; the magnet system is arranged outside the vacuum chamber and is used for ionizing gas in the vacuum chamber and generating fusion reaction; the neutron extraction system is arranged in the fusion reaction generation area of the vacuum chamber and is used for extracting epithermal neutrons; the neutron lead-out system comprises a neutron lead-out channel, a shielding and reflecting device and a filter, the shielding and reflecting device is arranged outside the lead-out channel and used for shielding and reflecting neutrons, and the filter is arranged in the neutron lead-out channel and used for filtering fast neutrons, thermal neutrons and photons; the neutron source provided by the invention has the advantages of higher neutron yield, simple and compact structure, effectively reduced overall device volume, low construction and maintenance cost and small nuclear safety prevention and control pressure, and can be used in various fields of medical treatment, scientific research, military industry and the like.

The invention discloses a same-position integrated double neutron detector, a logging instrument and an application method, and belongs to the field of uranium exploration logging. The double-neutron detector comprises a thermal neutron detector and an epithermal neutron detector which are arranged in a nested mode. The thermal neutron detector is arranged to be a first microstructure gas detector and comprises an annular cavity structure, a cathode drift electrode and an anode reading electrode, wherein the annular cavity structure is provided with an axial through hole and is filled with He gas. The detection part of the epithermal neutron detector is embedded in the axial through hole, and the epithermal neutron detector can be a scintillation crystal detector coated with a shielding moderation layer or a second microstructure gas detector. Compared with the prior art, the nested structure fundamentally solves the inherent problem of space inconsistency of a traditional separation detector, and the uranium content calculation precision is greatly improved; meanwhile, the epithermal neutron detector has two implementable schemes, and the structural flexibility is high.

The invention relates to a fractured sandstone uranium mine prompt neutron logging numerical simulation method based on a disperse multi-angle random statistical theory. The method comprises the steps of firstly establishing a geological model of the fractured sandstone-containing uranium mine based on a dispersion multi-angle theory; then the simulation pulse neutron source emits neutrons to the stratum, the neutrons and uranium in the cracks are subjected to fission reaction, and instant neutrons are released; then simulating the movement and reaction process of neutrons in the stratum; and finally, recording logging response by a neutron flux counter, and obtaining epithermal neutron count and thermal neutron count according to the energy range. Through tests, the fractured sandstone uranium mine prompt neutron logging numerical simulation method based on the scattered multi-angle random statistical theory can effectively simulate prompt neutron logging responses of sandstone uranium mines under fractures of different angles, and epithermal neutron counting and thermal neutron counting are obtained.

The present invention relates to the field of wireline logging technology, specifically disclosing a device and method for testing the mineral composition and content of uranium-bearing reservoirs. The device comprises a wireline logging system, a logging depth calibration system, and a time synchronization system. The logging tool assembly comprises a spectral logging tool, a natural gamma ray spectroscopy logging tool, an epithermal neutron logging tool, and a neutron capture gamma ray spectroscopy logging tool. The method comprises: combining the logging tool assembly with the wireline logging system, configuring a logging depth calibration system, configuring a time synchronization system, performing PTP time synchronization on the wireline logging system and the logging depth calibration system, collecting raw logging time and raw logging data, performing time resampling and depth correction on the raw logging data, and demarcating the formation structure based on the logging depth and time resampled logging data. The present invention enables the acquisition and data fusion of the mineral composition, radioactive element content, and porosity characteristics of the formation surrounding the wellbore, thereby improving exploration precision, efficiency, and evaluation accuracy.

This invention provides a uranium content detection method, device, storage medium, and electronic device, belonging to the field of mineral exploration technology. The uranium content detection method includes: acquiring well logging data, which includes hyperthermal neutron counts, thermal neutron counts, and macroscopic scattering cross-section information, obtained by logging after emitting pulsed neutrons into the well to be logged; calculating the formation uranium content based on the hyperthermal neutron counts, thermal neutron counts, and macroscopic scattering cross-section information using a pre-set formation uranium content calculation model, which is based on a numerical simulation model of uranium content, mineralization, and porosity conditions established using the Monte Carlo method. This method can eliminate the errors caused by formation porosity and mineralization in the uranium content calculation process, improving the accuracy of formation uranium content evaluation and the efficiency of uranium ore detection.

The invention discloses a method for automatically extracting inelastic gamma rays in pulsed neutron logging, and belongs to the technical field of oil field logging. The method comprises the following steps: a, carrying out pulsed neutron logging to obtain a gamma ray energy spectrum during a time gate period; b, deducting a gamma ray energy spectrum in an early capture time gate period and a gamma ray energy spectrum in a late capture time gate period according to a certain proportion from the gamma ray energy spectrum in the pulse time gate period, and fitting to obtain optimal coefficients under different porosity conditions; and c, establishing a relationship between the coefficient and the counting rate measured by the detector, so that the inelastic spectrum counting rate can be obtained as long as the counting rate of the detector is obtained. According to the method, the epithermal neutron capture is considered, that is, the capture spectrum is considered to be epithermal neutron capture and thermal neutron capture, so that the net inelastic gamma rays are extracted more accurately, and a good foundation is laid for realizing a high-precision controllable source density logging method.

The application discloses a kind of uranium mine logging instrument based on ultrashort pulse neutron and working method thereof, it is related to uranium mine exploration well logging field;Logging instrument includes control communication nipple arranged in sequence along its axial direction, ultrashort pulse neutron generator for emitting fast neutron pulse with pulse width less than 1 microsecond to formation, shielding body, dual thermal neutron detection assembly for detecting thermal neutron and superhot neutron on spatially consistent measurement point, gamma detector for detecting non-elastic scattering gamma ray and capture gamma ray emitted by formation element, and fast neutron detector and multichannel synchronization and high-speed acquisition circuit for detecting and outputting source intensity monitoring signal of fast neutron pulse in real time;The logging instrument of the application emits ultrashort fast neutron pulse and detects neutron yield in real time, combines to obtain neutron time spectrum and multi-dimensional information of gamma energy spectrum with accurate time stamp, carries out high-precision, anti-interference inversion to formation uranium content, and efficiently and accurately obtains formation information.

The invention provides a method and related equipment for monitoring soil water by separating neutron energy spectrums, and the method comprises the following steps: constructing a first-order inverse calculation formula according to bare tube neutron intensity, bare tube thermal neutron intensity, moderator neutron intensity, moderator epithermal neutron intensity and sample plot soil moisture of a plurality of sample plots; obtaining a decision coefficient of each first-order inversion formula; taking the first-order inversion formula with the maximum decision coefficient as a target formula; and obtaining a target factor of the to-be-detected area, determining the soil moisture of the to-be-detected area based on the target factor, and generating a monitoring report graph including the soil moisture of all the to-be-detected areas. The neutron energy spectrum is separated, the inverse calculations corresponding to different factors are generated, the coefficient is determined, the inverse calculation with the best accuracy is determined to be used for soil moisture estimation of the to-be-measured area, and on the basis that manual monitoring is reduced and the monitoring cost is reduced, the efficiency and accuracy of soil moisture estimation are guaranteed.

The application discloses a uranium-radium balance correction method, device, medium and equipment, relates to the uranium detection field of sandstone type uranium mines, and comprises the following steps: obtaining an industrial uranium mine hole, performing geophysical well logging on the industrial uranium mine hole, determining a mineralization section through quantitative gamma interpretation, performing geological logging and geophysical logging on a core, collecting and analyzing uranium-radium samples in the mineralization section, performing uranium fission prompt neutron logging on the mineralization section, determining a uranium mine section depth range according to the ratio of epithermal neutrons to thermal neutrons in the time spectrum of the uranium prompt neutron logging, determining a single sample section uranium-radium balance coefficient according to the uranium-radium sample analysis result of the mineralization section, determining a single project uranium-radium balance coefficient according to the single sample section uranium-radium balance coefficient, determining a uranium-radium balance coefficient zoning map according to the single project uranium-radium balance coefficient, correcting the quantitative gamma logging curve in the uranium mine section depth range of the uranium prompt neutron logging by using the coefficients in different uranium-radium balance zones, and obtaining the actual uranium mine section depth range, thickness and grade.

The invention discloses a method for removing natural radioactive isotope 138La in lanthanum oxide powder by using neutron irradiation. The method comprises the following steps: firstly, according to a neutron capture cross section curve of 138La in an ENDF / B-VIII.1 nuclear evaluation database, determining the optimal neutron energy as 3 eV; lanthanum oxide powder is packaged in a high-purity quartz ampoule which is placed in a neutron irradiation channel of a reactor. Most neutrons are moderated into epithermal neutrons with the energy of 3 eV by a heavy water layer of the reactor, and then the epithermal neutrons are emitted into lanthanum oxide powder. The neutron capture efficiency of the 138La in the irradiation process is obtained according to a Monte Carlo simulation method, the irradiation time required for completely converting the 138La into the 139La can be calculated by combining neutron flux data of a reactor, the mass of lanthanum oxide powder and the abundance ratio of the 138La, and the yield of the by-product 140Ce is evaluated. After irradiation is finished, standing and cooling are conducted for a period of time, the lanthanum oxide powder is placed in a low-background lead chamber, the residual radioactivity level of the lanthanum oxide powder is evaluated through a high-purity germanium detector, and the removal effect of 138La in the lanthanum oxide powder can be determined.

A cell mixture for the patient-specific treatment of solid tumors comprises carrier cells with a special loading. Immunocompetent autologous cells and / or genetically transfected cells are used, loaded with a combination of immunocompetent components and / or theranostic nanoparticles. The target tissue is derived from a tumor and includes malignant tumor cells and deactivated intratumoral cells, which are subsequently separated. Liposomes are loaded with a patient- and tumor-specific combination of immunocompetent components, namely at least one stable isotope with a high affinity for (epi-)thermal neutrons and / or a β- +The process involves the use of "decay" isotopes and / or a sensitizer to perform photodynamic therapy. Additionally, the cells are loaded with theranostic nanoparticles, which also allow for monitoring of the cells and charges involved. The carrier cells are gently loaded with the loaded liposomes via passive fusion. The loading rate of the carrier cells is significantly higher than with conventional methods, and at the same time, the carrier cells are highly specific to the individual tumor of the patient.

The invention relates to an epithermal neutron measurement system for boron neutron capture therapy, and belongs to the technical field of epithermal neutron measurement, and the system comprises a collimation shielding body which is used for shielding and collimating an incident neutron beam to be measured; the thermal neutron absorber is used for absorbing thermal neutron components of the neutron beam passing through the collimation shielding body; the epithermal neutron regulation and control body is used for regulating and controlling the proportion and energy distribution of epithermal neutron beams passing through the thermal neutron absorber; the alpha particle shielding body is used for shielding alpha particles of the detector or the surrounding environment; the detector is used for detecting the total number of alpha particles generated by nuclear reaction between the target epithermal neutron beam passing through the epithermal neutron regulation and control body and elements in a detector material based on the set detection efficiency; and the data acquisition system is used for acquiring the measurement signal information, and calculating the number of epithermal neutrons of the neutron beam to be measured based on the measurement signal information, the detector counting rule and the detection efficiency. According to the invention, accurate and real-time monitoring of the number of epithermal neutrons is realized.

The invention discloses a neutron beam shaping system for a BNCT, and relates to the technical field of neutron regulation and control, the system comprises a moderation module which is used for decelerating high-energy fast neutrons from a target material into surface thermal neutrons or thermal neutrons, the moderation module is made of an aluminum fluoride material, and a value adding module which is arranged between the target material and the moderation module and is used for adding the surface thermal neutrons or the thermal neutrons into the surface thermal neutrons or the thermal neutrons. The value-added module is used for increasing the neutron yield, the value-added module is made of a metal molybdenum material with the thickness of 9 cm, the gamma absorption module is used for absorbing gamma rays generated in the moderation process, and the gamma absorption module is made of a bismuth material with the thickness of 2.5 cm; compared with an existing BSA system, the neutron beam shaping system for the BNCT is more efficient and reliable in the aspects of neutron yield, ray purification capacity and dose space control, and the dose precision and biological selectivity of BNCT treatment can be improved.

The present invention provides a method and system for calculating formation porosity based on an effective reaction cross section. The method comprises the following steps: determining a theoretical calculation formula for the effective reaction cross section based on fast neutron transport and gamma decay theory; determining the effective reaction cross sections and coefficients of the relationship for different materials by solving an overdetermined system of equations based on the theoretical calculation formula; measuring the effective reaction cross section using the inelastic gamma ratio and epithermal neutron ratio, and calibrating the measurement formula using the effective reaction cross sections of each material; and using the measured effective reaction cross sections to determine the porosity of the formation to be tested. Compared to traditional neutron porosity, the new parameter effective reaction cross section obtained by this method has higher porosity sensitivity, its logging response conforms to the volume physics model, is unaffected by the excavation effect, and is more suitable for porosity evaluation in complex reservoirs.