No abstract

Parallel plate ionization chambers with segmented strips or pixels are developed for proton beam monitoring and dose measurement. 256 channels of readout electronics together with high voltage power supplier, FPGA and USB are built on a single PCB and readout by LABVIEW based DAQ system. With replaceable resistors, sensitivity of each channel varies from 1 ADC / 1 nA to 1 ADC / 5 pA to handle large dynamical range in proton therapy. Chambers are tested with 100,200 and 394 MeV proton beams with narrow beam widths. Beam profiles obtained by strip and by pad chambers are compared. Depth dose distributions of protons in water are obtained with 100 and 200MeV proton beams. Results from the GEANT4 simulation reproduce measurement reasonably.