61 results about "Neutron yield" patented technology

The invention discloses a small neutron source adopting a windowless gas target, which belongs to the field of nuclear technology and application. In the invention, an ECR (Electron Cyclotron Resonance) ion source is used for generating a deuterium ion and directly extracted by a high-voltage extraction electrode for bombarding a windowless gas target sealed by a plasma; because the windowless deuterium gas target is sealed by adopting the plasma, the windowless deuterium gas target is allowed to bear high-flow-strength beam current; and because the energy loss of the deuterium ion when penetrating through a plasma window is less, the neutron yield is higher. Compared with a neutron pipe, the neutron source provided by the invention has high allowed beam current strength and high neutron yield. Compared with an accelerator neutron source with large size, complex system and high cost, the neutron source provided by the invention has small size, simple system and low cost. Compared with a neutron source for directly carrying out deuterium-tritium reaction on an ion source to generate neutron, the ion source has simple system, low cost and no tritium radioactive processing and circulating problem. The invention has very wide application prospect.

An accelerator-driven subcritical breeding reactor is operated with a neutron multiplication coefficient as large as possible in order to require a small input power from the accelerator, reducing its dimension and hence its cost and complexity. The beam-generated spallation neutron yield then becomes comparable to the fraction of delayed neutrons from the fissioned elements. This can be exploited to ensure an accurate on-line determination of the reactivity. Resulting changes can be adjusted with the help of neutron absorbing control rods and / or variations of the proton current. In addition, the temperature variations during operation can be continuously monitored and adjusted in order to avoid that the subcritical systems approaches too closely the (delayed) criticality condition and that the neutron multiplication coefficient remains within acceptable limits.

Methods and systems for non-intrusively detecting the existence of fissile materials in a container via the measurement of energetic prompt neutrons are disclosed. The methods and systems use the unique nature of the prompt neutron energy spectrum from photo-fission arising from the emission of neutrons from almost fully accelerated fragments to unambiguously identify fissile material. The angular distribution of the prompt neutrons from photo-fission and the energy distribution correlated to neutron angle relative to the photon beam are used to distinguish odd-even from even-even nuclei undergoing photo-fission. The independence of the neutron yield curve (yield as a function of electron beam energy or photon energy) on neutron energy also is also used to distinguish photo-fission from other processes such as (γ, n). Different beam geometries are used to detect localized samples of fissile material and also fissile materials dispersed as small fragments or thin sheets over broad regions. These signals from photo-fission are unique and allow the detection of any material in the actinide region of the nuclear periodic table.

The present invention provides a pulsed neutron generator. In a high vacuum and high pressure ceramic tube, when a trigger pulse is added between the source trigger pole and cathode of vacuum arc ion, the deuterium atom is ionized and the initial plasma is diffused, such that the anode and the cathode of the ion source is conducted, the arc current is formed, and the high density plasma is generated. Under the action of accelerating the high pressure, the deuterium ion beam interacts with the tritium titanium target, the deuterium tritium reaction produces, and the pulsed neutron with the energy of 14 MeV is generated. A circular magnetic field is set up at the lead pole of the vacuum arc ion source, which can focus on the formation of the deuterium ion, increase the deuterium ion beam to the target, improve the pulsed neutron yield; The combination of a dry pump, a molecular pump, an ion pump and an air pump is used to improve the vacuum degree of the system, and reduce the loss of deuterium ion beam in the transmission process. The aluminum film with the thickness of 400 nm is coated on the surface of the tritium titanium target, which prevents the heavy ion from reaching the tritium target, and reduces the damage of the target.

The invention discloses a compact type D-D neutron generator applicable to neutron activation analysis or neutron radiography. The compact type D-D neutron generator comprises a vacuum cavity body, an ion source system, a beam extraction acceleration system, a target system, a high voltage feed system and a vacuum pump system, wherein ion beams generated by the ion source are extracted, accelerated and subjected to a D-D nuclear fusion reaction with a deuterium target on the target system to discharge neutrons; the two ends of the vacuum cavity body are connected with the ion source system, the beam extraction acceleration system, the target system and the high voltage feed system through an ion source positive electrode flange and a second flange respectively; the vacuum cavity body, the ion source positive electrode flange and the high voltage feed system are sealed through an O-shaped ring; and the ion source is a dual-plasma source, and the D gas is pumped in the ion source. The neutron yield can be more than 1*108s(1) magnitude, and the ion source, or target sheet and other system and internal parts can be replaced quite conveniently; and meanwhile, the usage cost is greatly lowered.

This invention is related to equipment and techniques for fast neutron activation analysis of explosives and / or other warfare agent. The techniques are based on 14 MeV fast neutrons from D-T fusion reaction, the kinematics of the nuclear reaction and fast coincidence between α-particles of the D-T reaction and γ-quanta from fast neutron induced reactions. A fast neutron generator with effective target cooling and different operation modes provides high neutron yield, long life, and simple maintenance of the equipment and good geometric resolution of the directional neutron beam. High positional resolution of the directionally scanning neutron beam, high time resolution of the coincidence and high neutron yield provide the real time robust screen of explosives with high speed and / or high sensitivity, flexibility for big and small items and overall high probability of detection (PD) and low probability of false alarms (PFA). The remote video scan device also has zooming capability to change solid angle.

The invention discloses a neutron source, and the neutron source comprises an ion source, a low-energy transmission segment, an RFQ accelerator, a high-energy transmission segment, a radio frequency power source, a target station device, and a control system. The ion source is used for generating ions. The low-energy transmission segment is used for adjusting an ion beam. The RFQ accelerator is used for increasing the speed of the ion beam, so as to enable the energy of each ion to be within the range from 0.1MeV to 10MeV. The high-energy transmission segment is used for adjusting the ion beam after speed increase. The radio frequency power source is used for providing a radio frequency signal for the RFQ accelerator. The target station device is used for generating neutrons and leading the neutrons out. The control system is used for controlling the ion source, the low-energy transmission segment, the RFQ accelerator, the high-energy transmission segment, and the target station device. The neutron source can employ the independent RFQ accelerator, is small in size, is small in occupied space, is high in neutron yield, and is convenient for production and installation.

The invention belongs to an improved turn-off neutron source and in particular relates to a Penning anion source ceramic neutron tube. The Penning anion source ceramic neutron tube adopts a PIG type anion source to generate anions of deuterium (D) and tritium (T). The anion source adopts a lateral lead-out or eccentric lead-out mode; positive high voltage is added on a target; and under the condition of removing electrons from lead-out beams, the lead-out beams are monatomic anions and the utilization ratio of the beams generating neutrons can reach 100 percent. The neutron yield of the neutron tube with the structure is increased by about 2 orders of magnitude compared with that of the former neutron tube under the conditions of the same high voltage and beams. A tube of phi 50 is taken as an example, the life of the improved Penning anion source ceramic neutron tube is prolonged by more than 10 times, the yield is increased by about 100 times, the stability is not more than 3 percent and the rate of the finished products is more than 90 percent.

The invention discloses a small neutron generator which outputs high-flux neutrons in a specific direction. A rectangular penning ion source educes deuterium ions or deuterium tritium mixed ions with a certain width, and the ions bombard a long directional target under the coaxial electric field acceleration so as to generate high-flux neutrons in the axis direction of the target. Because the rectangular penning ion source and the long direction target can be prolonged randomly according to the requirements, the intensity of the ion beam output from the ion source, the power bore by the long directional target and the corresponding neutron yield are greatly improved. The axial projected area of the long directional target is small, so that the neutron flux level is 1 to 2 higher than that of the normal neutron generator in the axial direction; the small directional high-flux neutron generator is applicable to the fields which have direction requirements, such as neutron therapy, picture taking and explosive detection.

The invention relates to a preparation method of a tritium impregnated target slice. The method comprises the steps of 1, selecting a circular high-purity molybdenum slice as a tritium target substrate material; 2, ultrasonically washing the circular molybdenum slice through an acetone solution to remove oil dirt on the surface; 3, plating a titanium film on the upper surface of the circular molybdenum slice by the magnetron sputtering coating process, synchronously transforming the titanium film into a Ti-Mo alloy film by the high-temperature vacuum heat processing method, and forming a Ti-Mo alloy dispersion layer with a certain thickness the circular molybdenum slice and the target film; 4, degassing the tritium impregnated target slice at high temperature under high vacuum, absorbing / discharging tritium to a target film to activate, and then gradually absorbing tritium to the target film at proper rate until reaching saturation. With the adoption of the preparation method of the tritium impregnated target slice, the separated out brittle hybride can be decreased, and the brittleness can be effectively controlled; the attaching force of the target film is improved; the carbon pollution is reduced, the oxygen is stopped dispersing inside, and therefore, the purity of the target film is improved, and the tritium absorbing activity of the target film can be improved; the neutron yield of a neutron tube or a neutron generator is increased, and the service life is prolonged.

The invention discloses a method and a system for detecting a neutron yield. The method comprises the following steps of: receiving characteristic gamma rays generated when neutrons generated by a neutron generator under a preset voltage bombard surrounding objects which at least contain a feedback object, and converting the characteristic gamma rays into an electric pulse signal; carrying out analog-to-digital conversion on the electric pulse signal and storing converted data; according to a preset time interval, reading the stored converted data and analyzing a count of the characteristic gamma rays generated when the neutrons bombard the feedback object according to characteristic gamma ray energy of the feedback object; and obtaining the neutron yield by using a relation of the neutron yield and the count of the characteristic gamma rays of the feedback object. In the method for detecting the neutron yield, the neutron field is detected by detecting the characteristic gamma ray strength of the feedback object and novel equipment and instruments are not required to be added. The method is simple and is easy to implement. In the whole detecting process, a neutron detector is notrequired to be used, so that the cost of equipment is reduced and the reaction effect and the stability of an analysis result are improved.

The invention provides a stratum density measuring while drilling instrument based on a deuterium-tritium accelerator neutron source. The stratum density measuring while drilling instrument is used for measuring the density of a stratum around a well hole in the well drilling process, and meanwhile can measure the neutron porosity. According to the stratum density measuring while drilling instrument, a U-shaped groove is formed in one side of a drill collar, a fast neutron monitoring detector and a neutron generator are arranged inside a neutron generator module compression resistance cylinder, a neutron shielding body, a first thermal neutron detector, a neutron shielding body, a second thermal neutron detector, a gamma ray shielding body, a gamma detector and a control processing circuit are sequentially installed inside a detector installation skeleton from top to bottom, and the neutron generator module compression resistance cylinder and the detector installation skeleton are connected and fixed into the U-shaped groove through a coupling connector. The stratum density measuring while drilling instrument adopts the deuterium-tritium accelerator neutron source for measuring the stratum density, a chemical gamma radioactive source is prevented from being used, damage to people and environment is eliminated, and the measuring precision is effectively improved by monitoring the neutron yield in real time.

The invention discloses a The invention discloses a 252Cf source distribution irradiation device used for plant seed neutron irradiation. The 252Cf source distribution irradiation device comprises a cylindrical shielding body, an air channel, a 252C neutron source, and sample irradiation areas. The high neutron yield of the 252C neutron source meets the requirements of the neutron irradiation plant seeds, and at the same time, by taking the 252C neutron source as a sphere center, three semispherical areas having sequentially increased radiuses are used as the sample irradiation areas. The seeds having ant neutron absorption doses can be acquired according to gradients, and the absorption doses of the seeds of every gradient are uniform. The plant seed absorption doses of the three252Cf neutron source doses distribution semispherical areas are directly provided without tedious measurement and calculation, and therefore a standardized dose distribution characteristic is provided, and most of leguminous plant seed neutron irradiation scientific research requirements are satisfied, and the irradiation device can be used for irradiation of other types of plant seeds, and also can be used for neutron irradiation agricultural production and mutagenic breeding.

An accelerator-driven subcritical breeding reactor is operated with a neutron multiplication coefficient as large as possible in order to require a small input power from the accelerator, reducing its dimension and hence its cost and complexity. The beam-generated spallation neutron yield then becomes comparable to the fraction of delayed neutrons from the fissioned elements. This can be exploited to ensure an accurate on-line determination of the reactivity. Resulting changes can be adjusted with the help of neutron absorbing control rods and / or variations of the proton current. In addition, the temperature variations during operation can be continuously monitored and adjusted in order to avoid that the subcritical systems approaches too closely the (delayed) criticality condition and that the neutron multiplication coefficient remains within acceptable limits.

The invention discloses a novel reactor starting neutron source. A neutron pipe neutron source is used to replace an isotope neutron source to become a reactor primary starting neutron source or / and secondary starting neutron source. Compared to the ordinary isotope neutron source, the novel reactor starting neutron source has a high neutron yield, a good power spectrum monochromaticity and no [gamma] background. Besides, pulse neutrons can be generated and the source can be cut off when it is not used. Therefore, it is easy to protect the source and convenient to store, manage and transport the source.

The invention discloses a large dynamic fast neutron yield measurement system which comprises a micrometer capillary scintillator array, an optical fiber cone, an ICCD and an image acquisition and processing system. A capillary in the micrometer capillary scintillator array is filled with a liquid scintillator to realize the sequence converting from a neutron signal to a proton signal to a visible light signal, and the visible light signal is transmitted to the optical fiber cone. The optical fiber cone is used to transmit the visible light signal to the ICCD, so that the micrometer capillary scintillator array matches the ICCD in pixel. The ICCD is used for recording the visible light signal. The image acquisition and processing system is used to acquire the visible light signal on the ICCD, and extract a proton track. According to the invention, the problem that large dynamic diagnosis of the same azimuth is difficultly acquired and the anti-gamma radiation noise capability is weak in the prior art are solved; the range ability is more than 104; and the system is at least 2 orders higher than a conventional neutron yield detector.

The invention discloses a preparation method for a deuterium-containing metal film target. The preparation method comprises the following steps: firstly, using high-purity molybdenum or high-purity copper as a substrate material of the deuterium-containing metal film target, and performing surface pretreatment on the substrate material; secondly, mounting and placing the substrate into a physical vapor deposition (PVD) vacuum coating machine, bombarding the surface of the substrate with argon ions, removing an oxide layer on the surface of the substrate by sputtering; thirdly, setting the coating temperature of the substrate, introducing high-purity deuterium gas in a vacuum cavity, starting the coating machine, and directly preparing the deuterium-containing metal film; fourthly, turning off the coating machine, continually introducing deuterium gas into the vacuum cavity, and turning off a deuterium gas flower meter until an appropriate air pressure is reached in the cavity. By adopting the preparation method, the mechanical performance of the deuterium-containing metal film target is improved, the brittleness and occurrence of cracks are controlled effectively, and adhesive force of the target film is enhanced; meanwhile, the thickness of a dead layer on the surface is decreased, the purity of the target film is increased, the neutron yield of a neutron generator is increased, and the service life of the target is prolonged.

The disclosure provides a tungsten alloy particle spallation target material. A tungsten alloy is a tungsten-nickel-iron alloy; and tungsten-nickel-iron alloy particles are of a sphere shape. The tungsten alloy particle spallation target material has the advantages of high neutron yield, high wear resistance, high radiation resistance, resistance to fatigue of a mechanical impact and a thermal shock, excellent thermal and magnetic properties, low machining preparation cost and the like, and is excellent in comprehensive performance.

The invention belongs to a neutron source capable of being turned off and particularly relates to an inertial static confinement type target-free neutron tube. The inertial static confinement type target-free neutron tube is designed by utilization of the inertial static confinement principle. The novel neutron tube is provided with a closed spherical metal cavity, a mouse-cage-shaped metal electrode is placed in the center of the spherical cavity, a storage device is sealed together with the metal electrode, and then the novel neutron tube is formed. The storage device is heated to send out mixed gas of deuterium and tritium, when a negative high voltage of 10KV-100KV is inflicted on the mouse-cage-shaped metal electrode, ions of deuterium (D) and tritium (T) are generated in the cavity body, and ion density in the central region is highest. The ions of deuterium and tritium are accelerated by an electric field in the cavity to head for the central region and continue to move forward relying on inertia after passing through the central region, when the speed drops to zero, the ions return, and the ions of deuterium and tritium carry out the reciprocating motion in the mode and mutually collide in the central region to generate neutrons. The neutron tube of the structure is obviously prolonged in service life and markedly improved in stability index. Under same neutron yield, the service life of the inertial static confinement type target-free neutron tube is prolonged by about one order of magnitude compared with that of a PIG source neutron tube.

The invention relates to a composite neutron target suitable for a BNCT system. A target plate is included. The target plate comprises a tantalum target layer, a beryllium target layer and a heat dissipation base layer which are sequentially distributed. The tantalum target layer is made of metal tantalum and / or tantalum alloy, and is located on a front portion of the target plate. The beryllium target layer is made of metal beryllium and / or beryllium alloy and located between the tantalum target layer and the heat dissipation base layer. A coolant flow channel is arranged in the heat dissipation base layer and / or between the heat dissipation base layer and the beryllium target layer, and the coolant flow channel is provided with an inlet and outlet port. The heat dissipation base layer iscomposed of a heat dissipation single layer or a plurality of heat dissipation single layers, one or more connected grooves are arranged in an inner surface of the target body of at least one heat dissipation single layer, and the coolant flow channel is composed of the grooves arranged in the inner surface of the target body of the heat dissipation single layer. The neutron target is mainly applied to a device for generating neutrons by irradiating a target material with protons, such as a boron neutron capture therapy cancer system, and has advantages of a high neutron yield and a good heatdissipation effect.

The invention discloses a neutron yield control method for while-drilling neutron porosity measurement. The method comprises the following steps that 1, a current neutron yield is measured through a thermal neutron monitor; 2, if a difference value between the current neutron yield and a previous neutron yield exceeds a first threshold value, the needed neutron yield adjustment amount is calculated according to the difference value between the current neutron yield and the previous neutron yield and an expected neutron yield; 3, the expected supply voltage of a neutron generator is calculated according to the neutron yield adjustment amount and intrinsic parameters of the while-drilling neutron generator and the thermal neutron monitor, and then the supply voltage of the neutron generator is adjusted accordingly. According to the neutron yield control method, the stability and the reliability of the neutron yield of an accelerator neutron source are guaranteed, and therefore the accuracy and the authenticity of a while-drilling neutron porosity measurement result are achieved.

The invention relates to a device for generating and accelerating deuterium ions through a microwave ion source and generating high current neutrons through deuterium and deuterium (deuterium and tritium) reactions. A solid body with the quite high hydrogen absorbing ability is installed on the upper face of a subcooling target, deuterium is ionized by the microwave ion source and then accelerated to own quite high energy to be shot on the target, the high-energy ions shot on the target react with the deuterium adsorbed on the target, and the neutrons are generated. Compared with a penning ion source scheme commonly adopted at present, the size of the device is increased slightly, while the intensity of deuterium ion beam is increased by several times to dozens of times, the output of the neutrons is multiplied, in addition, the service life of the microwave ion source is long, and thus the service life of the whole device can be several years.

The invention discloses a small neutron source adopting a windowless gas target, which belongs to the field of nuclear technology and application. In the invention, an ECR (Electron Cyclotron Resonance) ion source is used for generating a deuterium ion and directly extracted by a high-voltage extraction electrode for bombarding a windowless gas target sealed by a plasma; because the windowless deuterium gas target is sealed by adopting the plasma, the windowless deuterium gas target is allowed to bear high-flow-strength beam current; and because the energy loss of the deuterium ion when penetrating through a plasma window is less, the neutron yield is higher. Compared with a neutron pipe, the neutron source provided by the invention has high allowed beam current strength and high neutron yield. Compared with an accelerator neutron source with large size, complex system and high cost, the neutron source provided by the invention has small size, simple system and low cost. Compared witha neutron source for directly carrying out deuterium-tritium reaction on an ion source to generate neutron, the ion source has simple system, low cost and no tritium radioactive processing and circulating problem. The invention has very wide application prospect.

The invention provides a gas discharging type ion source for a neutron pipe, belonging to the technical field of an accelerator. The gas discharging type ion source comprises magnetic steel, a lower cathode board, an anode cylinder, an upper cathode board, a magnetic ring, a foam metal active thin board and a lead-out electrode. When the gas discharging type ion source works, the anode cylinder is externally connected with pulse power voltage, and an upper cathode and a lower cathode are connected in series and then are externally connected with the pulse power voltage. The foam metal active thin board is connected with a low-voltage power supply relative to the upper cathode; and the lead-out electrode is externally connected with the high-voltage pulse power supply relative to a grate. Deuterium molecular ions emitted from the lower cathode can be converted to be deuterium atomic ions in foam metal due to the catalytic action of the foam metal active thin board, and a ratio of a deuterium atomic ion beam to a deuterium molecular ion beam can be tested by using an cyclotronic mass spectrometer after the deuterium atomic ions are accelerated by using the lead-out electrode. With the adoption of the gas discharging type ion source provided by the invention, the hydrogen (including isotopic deuterium or tritium) atomic ion beam with a high ratio can be output from the lead-out electrode, so that if the ion source is used in the neutron pipe, the service life of the neutron pipe can be prolonged, and the neutron yield is improved.

The invention discloses a multichannel intelligent BF3 neutron yield monitor, which comprises a platform vehicle. A control box is mounted in the platform vehicle; a bracket is fixedly mounted on theupper side of the platform vehicle; an outer shell is mounted at the top end of the bracket; the outer shell is provided with a tubular slowing-down cavity; at least two types of BF3 counting tubes arranged in the axial direction of the slowing-down cavity are arranged in the slowing-down cavity; the BF3 counting tubes have different diameters, the BF3 counting tubes are connected with the controlbox through high-voltage coaxial cables, and slowing layers formed by filling neutron slowing materials are arranged between the outer walls of the BF3 counting tubes and the inner wall of the slowing-down cavity. The multichannel intelligent BF3 neutron yield monitor has the beneficial effects that the measurement dynamic range can be greatly improved, neutron signals in gamma signals can be effectively distinguished, and the interference of gamma rays is eliminated.

The invention discloses a synchronously controllable large dynamic pulse neutron measurement system. The system comprises a target bin for placing a target neutron source and a sample carrying assembly, the sample carrying assembly comprises a vacuum isolation straight cylinder and a sample fixing piece positioned in the vacuum isolation straight cylinder, under the driving of a driving mechanism,the vacuum isolation straight cylinder moves linearly to be close to or far away from the target neutron source positioned in the target bin, the sample fixing piece is provided with carrying holes with at least two diameter specifications and / or depth specifications, the carrying holes are used for fixing a to-be-activated sample, and the system also includes a centralized control box, a gamma measurement assembly for measuring the neutron yield of the activated sample, and a trigger synchronous controller for controlling the working time nodes of the centralized control box and the gamma energy spectrum recorder. A synchronous measurement control mechanism is cooperated with the movable vacuum isolation straight cylinder and the sample fixing piece with carrying holes of various specifications, the requirement for large-range neutron yield measurement is met, the time of each step is precisely controlled, and the measurement precision and efficiency are greatly improved.

The invention discloses a neutron generator neutron yield control system and method. A resistor is arranged in a voltage-multiplying pup joint, the output end of the voltage-multiplying pup joint is grounded and connected with a neutron tube target pressure end, and the voltage-multiplying pup joint target voltage output end is connected with the input end of a generator high-voltage control circuit; the high-voltage output end of an anode high-voltage module is connected with the anode end of the neutron tube; the negative electrode end of the anode high-voltage module is connected to the anode current Ia acquisition end of an ion source circuit; a filament circuit of the ion source circuit is connected with a neutron tube filament end; a control chip is arranged in the generator high-voltage control circuit, the DA output end of the generator high-voltage control circuit is connected with the control input end of the linear power module, the output end of the linear power module is connected with the center tap input end of a boosting transformer, and the PWM wave output end of the high-voltage drive circuit is connected with the input end of the boosting transformer. The outputend of the boosting transformer is connected with the input end of the voltage-multiplying circuit. The neutron generator can be controlled to maintain high-stability neutron yield output.

The invention provides an equivalent micro-focus target. After the accelerator accelerates the deuterium or deuterium-tritium mixed ion beam to the rated energy, the device uses a quadrupole lens to separate the beam spot of the large-diameter section into a beam parallel to the target surface. In the vertical direction, it is focused to the required micro-focal spot size, and defocused to a certain length in its vertical direction to form a fan-shaped ion beam. The fan-shaped ion beam bombards the moving target and produces an outgoing neutron beam equivalent to that of a microfocal spot neutron source in the spreading direction parallel to the target surface. Because the beam spot with large diameter section is expanded into a fan-shaped ion beam, the peak density of thermal power deposited on the target surface is greatly reduced, the average thermal power density is also greatly reduced, and the temperature rise of the target surface is greatly reduced accordingly. It is also possible to further increase the total power of the ion beam, thereby increasing the neutron yield, so as to reduce the equivalent spot size and increase the neutron yield at the same time. It is suitable for applications in high-yield accelerator neutron sources that require directional and point source characteristics.