Proton linear accelerator system for irradiating tissue with two or more rf sources

Abstract

A proton linear accelerator system that irradiates tissue with improved beam energy control, providing RF energy from a first RF energy source during on-time of the proton beam operating cycle for changing the energy of the proton beam, and providing RF energy from a second distinct RF energy source during off-time of the proton beam operating cycle for increasing or maintaining the temperature of the cavity. Each RF source is operated independently, allowing higher RF pulse rates to reach the cavity, supporting a smaller time between proton beam energy pulses. In addition, the peak power requirements for the second RF energy source may, in general, be less than for the second RF energy source, allowing a less costly type to be used for the second source. The use of a first and second RF source may reduce the cavity settling time from minutes to less than 10 seconds.

I/We claim: 
     
         1 . A proton linear accelerator system for irradiating tissue, the accelerator system comprising:
 a proton source for providing a pulsed proton beam, the proton beam including an on-time and an off-time;   an accelerator unit including:
 a proton beam input, 
 a proton beam output, 
 a first RF energy source, 
 second RF energy source, and 
 at least one cavity extending from the proton beam input to the proton beam output, the first RF energy source and the second RF energy source being connected to the at least one cavity; and 
   an RF energy controller connected to the first RF energy source and the second RF energy source, the RF energy controller being configured to provide RF energy from the first RF energy source during the on-time of the proton beam and to provide RF energy from the second RF energy source during the off-time of the proton beam for increasing or maintaining the temperature of the at least one cavity during the off-time of the proton beam.   
     
     
         2 . The proton linear accelerator system of  claim 1 , including a coupler including a first input, a second input, and an RF output, the first RF energy source being connected to the first input, the second RF energy source being connected to the second input, and the RF output being connected to the at least one cavity. 
     
     
         3 . The proton linear accelerator system of  claim 2 , the first RF energy source and the second RF energy source being input into the coupler from a direction that is perpendicular to the at least one cavity. 
     
     
         4 . The proton linear accelerator of  claim 2 , the RF output extending from the cavity in a direction that is perpendicular to the at least one cavity. 
     
     
         5 . The proton linear accelerator system of  claim 1 , the second RF energy source having a lower peak RF power than the first RF energy source. 
     
     
         6 . The proton linear accelerator system of  claim 2 , wherein each of the first RF energy source and the second RF energy source is directly connected to the coupler. 
     
     
         7 . The proton linear accelerator system of  claim 2 , wherein the RF output is directly connected to the at least one cavity. 
     
     
         8 . A proton linear accelerator system for irradiating tissue, the accelerator system comprising:
 a proton source for providing a pulsed proton beam, the proton beam including an on-time and an off-time;   an accelerator unit including:
 a proton beam input, 
 a proton beam output, 
 a first RF energy source, 
 second RF energy source, 
 at least one cavity extending from the proton beam input to the proton beam output along a first direction, and 
 a coupler including a first RF input, a second RF input, and an RF output, the coupler being connected to the at least one cavity along a second direction that is transverse to the first direction; and 
   an RF energy controller connected to the first RF energy source and the second RF energy source, the RF energy controller being configured to provide RF energy from the first RF energy source during the on-time of the proton beam and to provide RF energy from the second RF energy source during the off-time of the proton beam for increasing or maintaining the temperature of the at least one cavity during the off-time of the proton beam.   
     
     
         9 . The proton linear accelerator system of  claim 8 , the first RF energy source and the second RF energy source being input into the coupler from a direction that is perpendicular to the at least one cavity. 
     
     
         10 . The proton linear accelerator system of  claim 8 , the second RF energy source having a lower peak RF power than the first RF energy source. 
     
     
         11 . The proton linear accelerator system of  claim 8 , wherein each of the first RF energy source and the second RF energy source is directly connected to the coupler. 
     
     
         12 . The proton linear accelerator system of  claim 8 , wherein the RF output is directly connected to the at least one cavity.