Patent Publication Number: US-6982430-B1

Title: Radiation case

Description:
The present invention relates to radiation case. The radiation case can be used to irradiate a quartz crystal with gamma rays. Radiation rods are located in vertical cavities of the radiation case. Each radiation rod holds a radioactive pellet. The quartz crystal is irradiated in a radiation chamber of the radiation case, by gamma rays emitted from a radioactive pellet in each of the radiation rods. 
   The vertical cavities are precisely positioned in the radiation case. The vertical cavities are formed so as to be in close proximity to a back wall of a back portion of the radiation case. A thin partition is formed between the vertical cavities and the back wall of the back portion of the radiation case. 
   Again, each of the radiation rods contains a radioactive pellet. The radioactive pellets emit gamma rays. The gamma rays pass through the thin partition of the radiation case, and into a radiation chamber of the radiation case. The gamma rays can then pass into the quartz crystal, to dislodge positive ions interstitially located in the quartz crystal. 
   The radiation case has a door and extended main section. The extended main section has a back portion, a floor portion, a ceiling portion, and side portions. The door, back portion, a floor portion, a ceiling portion, and side portions form a radiation chamber. 
   Vertical cavities are formed near to the back wall of the radiation chamber. A thin partition is formed between the vertical cavities and the back wall of the radiation chamber. The vertical cavities are designed to hold radiation rods. The thin partition is thin enough, so that gamma rays, that are emitted from the radiation rods, can pass from the vertical rods and into the radiation chamber. 
   One of the side portions of the main section has an channel through which an electrical cable and a vacuum hose pass, from beneath the radiation case, into the radiation chamber. The electrical cable and a vacuum hose are connected to an apparatus that is placed in the radiation chamber. The apparatus hold a quartz crystal that is irradiated within the chamber. 
   A dolly supports the apparatus. The dolly allows the apparatus to be quickly moved into and out of the radiation chamber. The apparatus has an ion pump coupling. The ion pump coupling is connected to the vacuum hose. The apparatus has two electrodes for holding a quartz crystal. One of two electrodes is supported by a frame of the apparatus. Electrical conductor lines, that are in the electrical cable, are connected to the two electrodes. 
   The door of the radiation case is quickly opened to place the dolly into the radiation chamber. Then the door is quickly closed, to prevent any undue amount of external radiation exposure. 
   SUMMARY OF THE INVENTION 
   A radiation case, comprising a radiation-proof door; and a radiation-proof main section, the radiation-proof main chamber section comprising a back portion, a floor portion, a ceiling portion and side portions, vertical cavities formed in the back portion, the vertical cavities being a distance from a surface of a back wall of the back portion, radiation rods located in the vertical cavities, each radiation rod containing cobalt-60 pellet, the distance between the vertical cavities and the surface of the back wall of the back portion being less than a penetration distance for gamma rays coming out of each cobalt-60 pellet. 

   
     DESCRIPTION OF THE DRAWING 
       FIG. 1  is a side sectional view of the radiation case. 
       FIG. 2  is a top sectional view of the radiation case. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows a sectional side view of a radiation case  10 . The radiation case  10  has a radiation proof door  12  and a radiation proof main section  13 . The radiation case  10  can contain gamma rays, such as gamma rays  11 , that are within radiation case  10 . The radiation-proof door  12  and radiation-proof main section are preferably made from a lead metal. 
   The radiation-proof door  12  can be quickly opened and quickly closed. The quick opening and closing of door  12  prevents an escape of an undue number of gamma rays from radiation case  10 . 
   The radiation-proof main section  13  has a floor portion  14 , a ceiling portion  15 , a back portion  16 , and side portion  17  and  18  shown in  FIG. 2 . The door  12 , floor portion  14 , ceiling portion  15 , back portion  16 , and side portions  17  and  18 , form a radiation chamber  20 . The radiation chamber  20  is positioned within the radiation case  10 . Gamma rays are held within the radiation chamber  20  of radiation case  10 , when door  12  is closed. 
   The back portion  16  is extended away from the door  12  of the radiation case  10 , to prevent an escape of an undue number of gamma rays from the chamber  20  of radiation case  10 , when door  12  is open. Since the main section  13  is extended, a lesser number of gamma rays will come out of the radiation case  10  from the back portion  16  of the radiation case  10 , when door  12  is open. 
   The back portion  16  has a back wall  19 . Aligned, cylindrical, vertical cavities, such as vertical cavity  24 , are formed in the back portion  16 . Such vertical cavities  23 ,  24 ,  25  and  26  are shown in  FIG. 2 . The vertical cavities are positioned close to the back wall  19 , within the back portion  16  of radiation case  10 . Between a surface  29  of the back wall  19  and the vertical cavities is a thin partition  30 . The partition  30  is thin enough to allow gamma rays, such as gamma rays  11 , to pass through partition  30  and into chamber  20 . 
   A separate cylindrical radiation rod is placed into each of the cylindrical, vertical cavities. Cylindrical radiation rod  31  is tightly placed into cylindrical, vertical cavity  24 . As shown in  FIG. 1 , the radiation rod  31  holds a radioactive pellet  36  near its longitudinal center. The radioactive pellet  36  is made from cobalt-60. The cobalt-60 pellet  36  emits gamma rays  11 . Each of the radiation rods  31 ,  32 ,  33  and  34  holds a cobalt-60 pellet. Each pellet emits gamma rays. 
   The cylindrical, vertical cavities are located 0.2 centimeters from the surface  29  of the back wall  19  of back portion  16 . The cavities are formed in the back portion  16  so that a 0.2 centimeter thick partition  30  is formed in back portion  16 . The 0.2 thick partition  30  is thin enough to allow 1.173 Mev gamma rays from a cobalt-60 pellet to pass from a cavity into radiation chamber  20 . The cavities are aligned to be parallel to the surface  29  of the back wall  19 . A selected distance between the vertical cavities and the surface  29  of the lead back wall  19  is made to be less than a maximum penetration distance through partition  30 , for gamma rays coming out of the cobalt-60 pellets in the radiation rods. 
   Again,  FIG. 2  shows a sectional top view of radiation case  10 .  FIG. 2  shows side portions  17  and  18  of radiation case  10 .  FIG. 2  shows cavities  23 ,  24 ,  25  and  26  of radiation case  10 . Radiation rods  34 ,  31 ,  32  and  33  are positioned, respectively, in the vertical cavities  23 ,  24 ,  25  and  26 . Each of the radiation rods holds a cobalt-60 pellet. 
     FIG. 2  shows a narrow channel  41  that is located in side portion  17 . An electrical cable  43  and vacuum hose  45 , from vacuum equipment and electrical power equipment located below the case  10 , pass through the channel  41 . The channel  41  are filled with a lead based sealer  42 , to keep gamma rays from passing through channel  41 . 
   While the present invention has been disclosed in connection with the preferred embodiment thereof, it should be understood that there may be other embodiments which fall within the spirit and scope of the invention as defined by the following claims.