Ion beam kinetic energy dissipater apparatus and method of use thereof

Abstract

The invention comprises a method and apparatus for reducing a kinetic energy of positively charged particles, comprising the steps of: (1) transporting the positively charged particles from an accelerator into an exit nozzle system along a beam line; (2) providing a first chamber of the exit nozzle system, the first chamber comprising: an incident side comprising an incident aperture, an exit side comprising an exit aperture, and a beam path of the positively charged particles from the incident aperture to the exit aperture; (3) filling the beam path in the chamber with a liquid; and (4) using the liquid to reduce the kinetic energy of the positively charged particles. The kinetic energy dissipater is optionally used in combination with a proton therapy cancer treatment system and/or a proton tomography imaging system.

1 . A method for reducing a kinetic energy of positively charged particles, comprising the steps of:
 transporting the positively charged particles from an accelerator, along a beam line, and into an exit nozzle system;   providing a first chamber of said exit nozzle system, said first chamber comprising:
 an incident side comprising an incident aperture; 
 an exit side comprising an exit aperture; and 
 a beam path of the positively charged particles from the incident aperture to the exit aperture; 
   filling the beam path in said chamber with a liquid; and   using the liquid to reduce the kinetic energy of the positively charged particles.   
     
     
         2 . The method of  claim 1 , further comprising the step of:
 dissipating radioactivity of the liquid using a pump to move a second volume of the liquid into said first chamber.   
     
     
         3 . The method of  claim 1 , further comprising the step of:
 changing a pathlength of the beam path between the incident aperture and the exit aperture by moving said first chamber radially across a longitudinal axis of the positively charged particles.   
     
     
         4 . The method of  claim 3 , said step of changing the pathlength further comprising the step of:
 increasing the pathlength of the beam path between the incident aperture and the exit aperture, wherein an additional volume of the liquid in the beam path functions to slow the positively charged particles.   
     
     
         5 . The method of  claim 4 , further comprising the step of:
 co-moving said first chamber and an exit nozzle of said exit nozzle system about a cancer patient position in a treatment room.   
     
     
         6 . The method of  claim 4 , further comprising the steps of:
 providing a second chamber of said exit nozzle system; and   transmitting the positively charged particles through a fluid of said second chamber.   
     
     
         6 . The method of  claim 6 , further comprising the step of:
 altering a mean incident path of the positively charged particles passing through the incident aperture to a mean deflected path using said first chamber; and   altering the mean deflected path of the positively charged particles toward the mean incident path using said second chamber.   
     
     
         8 . The method of  claim 3 , further comprising the step of:
 replacing the liquid in the beam path between the incident aperture and the exit aperture with a gas; and   after said step of replacing, using the positively charged particles in a cancer therapy system.   
     
     
         9 . The method of  claim 8 , further comprising the step of:
 alternating said steps of: (1) filling the beam path with the liquid and (2) replacing the liquid in the beam path between the incident aperture and the exit aperture with a gas.   
     
     
         10 . The method of  claim 3 , further comprising the step of:
 determining a first axis position of the positively charged particles using a first ionization strip detector, said first ionization strip detector comprising a first element of a water tight seal over the incident aperture.   
     
     
         11 . The method of  claim 10 , further comprising the step of:
 determining a second axis position, orthogonal to the first axis position, of the positively charged particles using a second ionization strip detector, said second ionization strip detector proximate and within one inch of said first ionization strip detector.   
     
     
         12 . An apparatus for reducing a kinetic energy of positively charged particles, comprising:
 an exit nozzle system linked to an accelerator by a beam line, wherein the positively charged particles move from said accelerator, along said beam line, and into said exit nozzle system during use;   a first chamber of said exit nozzle system, said first chamber comprising:
 an incident side comprising an incident aperture; 
 an exit side comprising an exit aperture; and 
 a beam path of the positively charged particles from the incident aperture to the exit aperture, 
 wherein a liquid in the beam path reduces the kinetic energy of the positively charged particles during use. 
   
     
     
         13 . The apparatus of  claim 12 , said first chamber further comprising:
 a non-uniform distance between said incident side and said exit side.   
     
     
         14 . The apparatus of  claim 13 , further comprising:
 a first motor configured to move said first chamber radially through a longitudinal axis of the positively charged particles.   
     
     
         15 . The apparatus of  claim 14 , further comprising:
 a second chamber of said exit nozzle system positioned in a path of the positively charged particles.   
     
     
         16 . The apparatus of  claim 14 , further comprising:
 a second motor configured to move said second chamber radially through the longitudinal axis of the positively charged particles; and   a main controller configured to direct movement of said first chamber in a first direction and movement of said second chamber in a second direction opposite said first direction as a function of time.   
     
     
         17 . The apparatus of  claim 12 , said second chamber further comprising:
 a shape matching said first chamber, said second chamber rotated one hundred eighty degrees in the beam path relative to said first chamber.   
     
     
         18 . The apparatus of  claim 12 , further comprising:
 a first ionization strip detector comprising an element of a seal over the incident aperture, said first ionization strip detector configured to, responsive to passage of the positively charged particles, emit electrons used to determine a first axis position of the positively charged particles.   
     
     
         19 . The apparatus of  claim 18 , further comprising:
 a second ionization strip detector proximate said first ionization strip detector, first longitudinal strips of said second ionization strip detector orthogonal to second longitudinal strips of said first ionization detector.