Formation and fast extraction of a very short-bunched proton beam for the investigation of free radicals

For the investigation of free radicals with regards to cancer radiotherapy by ions, short-bunch formation followed by fast extraction was applied to a 7 MeV proton beam at S-LSR after electron-beam cooling. Using phase rotation with an applied RF voltage of 800 V, a short-bunch with a duration of 3.1 ns at 2σ was created for a beam intensity of 1.4×108, and fast extracted by a kicker magnet. Short-bunch formation by bunched cooling with a minimum bunch length of 15.7 ns at 2σ was also carried out with an extraction efficiency of almost 100%.