Powder sintering device for moderator

Abstract

A beam shaping assembly for neutron capture therapy includes a beam inlet, a target having nuclear reaction with an incident proton beam from the beam inlet to produce neutrons forming a neutron beam, a moderator adjoining to the target, a reflector surrounding the moderator, a thermal neutron absorber adjoining to the moderator, a radiation shield arranged inside the beam shaping assembly and a beam outlet. The material of the moderator is subjected to a powder sintering process using a powder sintering device so as to change powders or a power compact into blocks. The reflector leads the neutrons deviated from the main axis back. The thermal neutron absorber is used for absorbing thermal neutrons so as to avoid overdosing in superficial normal tissue during therapy. The radiation shield is used for shielding leaking neutrons and photons so as to reduce dose of the normal tissue not exposed to irradiation.

What is claimed is: 
     
         1 . A powder sintering device for a moderator, wherein the powder sintering device is configured to turn the material of the moderator into powder sintered blocks from powders or powder compacts, and the powder sintering device is a hot-press sintering device. 
     
     
         2 . The powder sintering device according to  claim 1 , wherein the hot-press sintering device comprises:
 a mold, wherein a predetermined amount of the powders or powder compacts are loaded in the mold;   a heating furnace for presetting pressure and temperature parameters;   a pressing assembly arranged in the heating furnace, wherein the pressing assembly is moved to press the powders or powder compacts in the mold; and   a controller for controlling the normal operation of the hot-press sintering device.   
     
     
         3 . The powder sintering device according to  claim 2 , wherein the pressing assembly is a lever type or a hydraulic type. 
     
     
         4 . The powder sintering device according to  claim 2 , wherein pressurized atmosphere is provided in the pressing assembly, the pressurized atmosphere is air, reducing atmosphere or inert atmosphere. 
     
     
         5 . The powder sintering device according to  claim 2 , wherein the heating furnace adopts electricity as a heat source, and a heating element is made of an SiC, MoSi or nichrome wire, a platinum wire, a molybdenum wire. 
     
     
         6 . The powder sintering device according to  claim 2 , wherein the mold is a graphite mold. 
     
     
         7 . The powder sintering device according to  claim 1 , wherein the powders or powder compacts is prepared by mixing a mixture containing one or more of PbF 4 , Al 2 O 3 , AlF 3 , CaF 2  and MgF 2  and a  6 Li element-containing material accounting for 0.1 to 5% in percentage by weight of the mixture. 
     
     
         8 . The powder sintering device according to  claim 7 , wherein the  6 Li element-containing material is  6 LiF or  6 Li 2 CO 3 . 
     
     
         9 . The powder sintering device according to  claim 1 , wherein the powders or powder compacts is prepared by mixing MgF 2  and  6 LiF accounting for 0.1 to 5% in percentage by weight of the MgF 2 . 
     
     
         10 . The powder sintering device according to  claim 1 , wherein the multiple powder sintered blocks are connected to form the moderator and a density of the moderator is 80 to 100 percent of theoretical density. 
     
     
         11 . A powder sintering device for a moderator, wherein the powder sintering device is configured to turn the material of the moderator into powder sintered blocks from powders or powder compacts, and the powder sintering device is a spark plasma sintering device. 
     
     
         12 . The powder sintering device according to  claim 11 , wherein the spark plasma sintering device comprises:
 a first electrode;   a second electrode;   a conductive mold arranged between the first electrode and the second electrode, wherein a predetermined amount of the powders or powder compacts are loaded in the mold;   a pulse current generator for providing pulse current for the mold and generating plasma, and thereby the surfaces of the powders or the powder compacts are activated and heat;   a pressing assembly for pressing; and   a controller for controlling the pulse current generator and the pressing assembly.   
     
     
         13 . The powder sintering device according to  claim 12 , wherein the pressing assembly comprises a first pressing member and a second pressing member, at least one of the first electrode and the second electrode or at least one of the first pressing member and the second pressing member is moved, so that the powders or powder compacts in the mold are pressed. 
     
     
         14 . The powder sintering device according to  claim 12 , wherein the conductive mold is made of lead or graphite. 
     
     
         15 . The powder sintering device according to  claim 12 , wherein the spark plasma sintering device further comprises:
 a position measurement system for measuring the position of the pressing member, wherein the position measurement system is controlled by the controller in order to ensure the normal operation of the position measurement system;   an atmosphere control system for controlling atmosphere in the mold, wherein the atmosphere control system is controlled by the controller in order to ensure that atmosphere in the mold is under the condition of normal operation;   a water cooling system for cooling the spark plasma sintering device, wherein the water cooling system is controlled by the controller in order to ensure the normal operation of the water cooling system; and   a temperature measurement system for measuring temperature in the spark plasma sintering device, wherein the temperature measurement system is controlled by the controller in order to ensure that temperature in the spark plasma sintering device is under the condition of normal operation.   
     
     
         16 . The powder sintering device according to  claim 13 , wherein the spark plasma sintering device further comprises a water-cooling vacuum chamber, the water cooling system control the water-cooling vacuum chamber to cool the spark plasma sintering device. 
     
     
         17 . The powder sintering device according to  claim 11 , wherein the powders or powder compacts is prepared by mixing a mixture containing one or more of PbF 4 , Al 2 O 3 , AlF 3 , CaF 2  and MgF 2  and a  6 Li element-containing material accounting for 0.1 to 5% in percentage by weight of the mixture. 
     
     
         18 . The powder sintering device according to  claim 17 , wherein the  6 Li element-containing material is  6 LiF or  6 Li 2 CO 3 . 
     
     
         19 . The powder sintering device according to  claim 11 , wherein the powders or powder compacts is prepared by mixing MgF 2  and  6 LiF accounting for 0.1 to 5% in percentage by weight of the MgF 2 . 
     
     
         20 . The powder sintering device according to  claim 11 , wherein the multiple powder sintered blocks are connected to form the moderator and a density of the moderator is 80 to 100 percent of theoretical density.