Przystosowywanie cyklotronu AIC-144 do protonowej radioterapii oka część 5. Stabilność wiązki protonów w cyklotronie AIC-144: wybrane parametry, przyczyny i przeciwdziałania niestabilności

Abstract

The cyclotron AIC – 144 at IFJ PAN in Krakow has been intended to the proton therapy of the eye tumor. The non-standard requirements of the protons beam parameters for therapy, forced screw of the machine to do adaptation and improvement of the cyclotron systems. The last few years was dedicated to exchange the old systems to the new like: vacuum system, main magnet power supply, RF system, beam line system, beam line powers supplies. That work allowed doing the tests on the proton beam in treatment room. During tests the problems of protons beam stability of current and repeatability of protons beam of parameters has bean notice. Two themes have been presented in following article: the stability of the protons beam current in short time period; the repeatability of the protons beam parameters in long time period. Several factors can affect stability of current of protons beam. The most important are: work of ion source, long time of thermal stabilization of cyclotrons elements, variable of network of power supply. The main reason of repeatability of the protons beam parameters is capability of relocation acceleration chamber with respect to main magnet yoke.