Seminars Archive

Development of a real-time beam monitor for the transferlines of a hadrontherapy synchrotron

Abstract
Hadrontherapy is a radiotherapy technique using protons or ligth ions to irradiate tumors. The Bragg ionization peak, the variation of the beam profile and energy are the main parameters used to optimize the dose and minimize the damage to the normal tissue surrounding the lesion. In this technique the ion or proton beam is accelererated to the energy required by the treatment, extracted from the accelerator and tranported via transferlines at the treatment areas. In order to control optimun dose delivery and the patient safety, the beam intensity and profile should be continuously monitored during the treatment. For this reason a non-interceptive beam monitor for transfer lines was developed. The monitor working principle is based on secondary electron emmission from a sub-micron Al foil placed directly in the extracted beam path. Secondary electrons are detected by a monolithic silicon position-sensitive sensor, which provides the beam intensity and its position with a precison of 1 mm at a 10 Hz frame rate. The detector design, the results of laboratory tests with thermoionic electrons and the measurements performed on the proton beam of the Ispra Cyclotron will be presented and discussed.