Which bias voltage shall be used for measurements with the PPC05 for Proteus ONE?
During the characterization of the PPC05 with an IBA S2C2 accelerator, a charge collection efficiency loss of up to 1.1% has been measured for maximum clinical range (226MeV) at 1 MU/spot (with a maximum beam charge of 4.5 pC/pulse). This efficiency loss, , has been observed using the PPC05 with a bias voltage of +300 V (specification for PPC05) and a DOSE1 electrometer.
Using a bias voltage of +500 V, the efficiency loss is reduced to 0.5 % in the same conditions. We therefore recommend to use the PPC05 with a bias voltage of 500 V, and to do the calibration accordingly.