A new multi-strip ionization chamber used as online beam monitor for heavy ion therapy

Abstract A multi-strip ionization chamber has been built for precise and fast monitoring of the carbon beam spatial distribution at Heavy Ion Researched Facility of Lanzhou Cooling Storing Ring (HIRFL-CSR). All the detector's anode, cathode and sealed windows are made by 2 μ m aluminized Mylar film in order to minimize the beam lateral deflection. The sensitive area of the detector is ( 100 × 100 ) mm 2 , with the anode segmented in 100 strips, and specialized front-end electronics has been developed for simplifying the data acquisition and quick feedback of the relevant parameters to beam control system. It can complete one single beam profile in 200 μ s .