Neutron collimation device capable of adjusting fast neutron beam diameterTechnical Field
The invention relates to the technical field of neutron beam collimation devices, in particular to a neutron collimation device capable of adjusting the diameter of a fast neutron beam.
Background
The compact neutron generator is widely applied to various industrial applications such as drug explosive detection, neutron logging, coal analysis and the like due to the advantages of small volume, convenient control, safe use and the like. In neutron generator applications, a collimated neutron beam is often required, and therefore the design of a neutron collimation device is an important element. The neutron collimation is to make fast neutrons around the collimation holes be absorbed slowly, so that neutrons are emitted only from the collimation holes to form neutron beams. Since neutrons are not charged, much attention needs to be paid to selection of protective shielding materials, size design of collimators, and the like in order to achieve neutron collimation. Meanwhile, the neutron collimation device is added to the neutron generator, so that the interference of surrounding objects can be reduced, the radiation protection of the whole device is of great significance, neutrons can form neutron beams with fixed diameters after being emitted by the collimation device, and the diameters of the neutron beams cannot be changed after the existing neutron collimator is designed, so that the neutron beam with different diameters cannot be realized when the neutron beams are needed.
Disclosure of Invention
The invention provides a neutron collimation device capable of adjusting the fast neutron beam diameter.
The technical scheme of the invention is realized as follows:
The utility model provides a neutron collimation device that can adjust fast neutron beam footpath, includes neutron shielding pipe, neutron shielding pipe's one end be neutron incident end, neutron shielding pipe's the other end be neutron exit end, neutron exit end is connected with the shielding lid, shielding lid center is equipped with out the perforation, the diameter of out the perforation is less than neutron shielding pipe's internal diameter, still includes a annular regulator tube, the regulator tube set up in neutron shielding pipe and with neutron shielding pipe coaxial setting, the regulator tube is inside cavity setting, the inside wall of regulator tube is the slope setting, makes the internal diameter of regulator tube become the setting that grows gradually from being close to neutron incident end to keeping away from neutron incident end, still includes liquid storage pot and two water pumps, is equipped with inlet and liquid outlet on the regulator tube, the inlet is connected with the liquid storage pot through a water pump, the liquid outlet is connected with the liquid storage pot through another water pump, the regulator tube on be equipped with heavy water or boric acid solution.
The invention is further characterized in that the regulating pipe is vertically arranged, the inner diameter of the regulating pipe gradually increases from top to bottom, the ventilation port is arranged at the upper end of the regulating pipe, and the liquid outlet is arranged at the lower end of the regulating pipe.
The invention further provides that the neutron shielding tube and the shielding cover are both made of polyethylene materials, the neutron shielding tube and the shielding cover are hollow, and lead layers are filled in the neutron shielding tube and the shielding cover.
The invention further provides that the outer surfaces of the neutron shielding tube and the shielding cover are coated with boron shielding layers.
The invention further provides that the regulating tube is made of neutron penetrable material.
The invention is further arranged that the inclination angle of the inner side wall of the adjusting pipe is 30-60 degrees.
The invention has the beneficial effects that:
the neutron beam enters through the neutron incidence end of the neutron shielding tube and is emitted from the neutron emission end, if the neutron beam is emitted normally, the neutron beam is restrained by the shielding cover, the emitted beam diameter is the diameter of the emission hole on the shielding cover, heavy water or boric acid solution is injected into the adjusting tube through the water pump, the heavy water forms an annular slowing shielding ring in the adjusting tube, fast neutrons are slowly shielded when passing through the slowing shielding ring, and the diameter of the slowing shielding ring gradually increases along with the increase of the injected heavy water or boric acid solution due to the inclined arrangement of the inner wall of the adjusting tube, so that the emission diameter of the neutron beam can be adjusted according to the requirement.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic view of a neutron shielding tube according to the present invention;
FIG. 3 is a schematic view of the shielding cover of the present invention;
fig. 4 is a schematic structural view of the regulating tube of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention is illustrated below with reference to fig. 1-4:
the neutron collimation device capable of adjusting the fast neutron beam diameter comprises a neutron shielding tube 10, wherein one end of the neutron shielding tube 10 is a neutron incidence end 101, and the other end of the neutron shielding tube 10 is a neutron emergence end 102.
The neutron emitting end 102 is connected with a shielding cover 20, and an emitting hole 201 is arranged in the center of the shielding cover 20.
The diameter of the exit orifice 201 is smaller than the inner diameter of the neutron shielding tube 10.
The neutron shielding tube also comprises a circular adjusting tube 30, wherein the adjusting tube 30 is fixedly arranged in the neutron shielding tube 10 and is coaxially arranged with the neutron shielding tube 10.
The adjusting tube 30 is hollow inside, the outer side wall of the adjusting tube 30 is attached to the inner side wall of the neutron shielding tube 10, the inner side wall of the adjusting tube 30 is inclined, and the inner diameter of the adjusting tube 30 is gradually increased from being close to the neutron incidence end 101 to being far away from the neutron incidence end 101.
The liquid storage tank 40 and the two water pumps 50 are further included, a liquid inlet 301 and a liquid outlet 302 are formed in the adjusting pipe 30, the liquid inlet 301 is connected with the liquid storage tank 40 through one water pump 50, the liquid outlet 302 is connected with the liquid storage tank 40 through the other water pump 50, heavy water or boric acid solution is filled in the liquid storage tank 40, and a ventilation port 303 is formed in the adjusting pipe 30.
The water pump can be used for injecting heavy water or boric acid solution in the liquid storage tank into the regulating pipe, and also can be used for pumping liquid in the regulating pipe into the liquid storage tank so as to realize circulation.
The heavy water or the boric acid solution has strong neutron moderating and shielding effects, so that fast neutrons passing through the heavy water or the boric acid solution can be necessarily moderated and screened out or directly shielded out.
Wherein, the adjusting tube 30 is vertically arranged, the inner diameter of the adjusting tube 30 gradually increases from top to bottom, the ventilation opening 303 is arranged at the upper end of the adjusting tube 30, and the liquid outlet 302 is arranged at the lower end of the adjusting tube 30.
The neutron shielding tube 10 and the shielding cover 20 are made of polyethylene materials, the neutron shielding tube 10 and the shielding cover 20 are hollow, and lead layers are filled in the neutron shielding tube 10 and the shielding cover 20.
Wherein, the outer surfaces of the neutron shielding tube 10 and the shielding cover 20 are coated with a boron shielding layer.
Wherein, the regulating tube 30 is made of neutron penetrable material.
Wherein the inclination angle of the inner side wall of the adjusting tube 30 is 30-60 degrees.
The invention has the beneficial effects that:
According to the neutron collimation device capable of adjusting the beam diameter of fast neutrons, provided by the invention, the neutron beam enters through the neutron incidence end 101 of the neutron shielding tube 10 and is emitted from the neutron emission end 102, the emitted beam diameter is the diameter of the emission hole 201 on the shielding cover 20 under the constraint of the shielding cover 20 during normal emission, and heavy water or boric acid solution is injected into the regulating tube 30 through the water pump 50 to change the emitted beam diameter of neutrons, so that an annular slowing-down shielding ring is formed in the heavy water in the regulating tube 30, fast neutrons are slowly shielded when passing through the slowing-down shielding ring, and the diameter of the slowing-down shielding ring gradually increases along with the fact that the inner wall of the regulating tube 30 is obliquely arranged, so that the emission diameter of the neutron beam can be adjusted as required.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather to enable any modification, equivalent replacement, improvement or the like to be made within the spirit and principles of the invention.