The INFN HASPIDE project investigates hydrogenated amorphous silicon (a-Si:H) as an innovative detector technology for dosimetry in FLASH radiotherapy. Conventional dosimeters, such as ionization chambers, show non-linear behavior when exposed to ultra-high dose-per-pulse beams used in FLASH radiotherapy, where several Grays are delivered in microsecond pulses. Thanks to its radiation hardness, mechanical flexibility and compatibility with large-area deposition, a-Si:H is a promising material for in-vivo and surface dosimetry. This work presents the response of a thin a-Si:H detector exposed to a high-dose-per-pulse 10 MeV electron beam, together with an analytical model used to describe the single-pulse dynamics and extract quantitative parameters. Measurements were performed at the University of Torino using a modified clinical LINAC operated in Ultra High Dose Rate regime, where the single-pulses satisfy the FLASH criteria. The a-Si:H detector, read out with a TetrAMM picoammeter (100 kHz sampling frequency), resolves individual radiation pulses with high repeatability. Both pulse charge and peak current scale linearly with the applied electric field up to 6 V (2.4 V/mu m), beyond which the readout electronics saturates. The analytical model is validated through direct comparison with raw data, showing excellent agreement in extracted pulse parameters.
Response modelling of a-Si:H detector read by TetrAMM picoammeter exposed to a clinical electron beam
Kanxheri, K.;Talamonti, C.;Vignati, A.;Caputo, D.;de Cesare, G.;Croci, T.;Ionica, M.;Morozzi, A.;Passeri, D.;Petasecca, M.;Peverini, F.;Placidi, P.;Quaranta, A.;Stabile, A.;Tosti, L.;Servoli, L.
2026
Abstract
The INFN HASPIDE project investigates hydrogenated amorphous silicon (a-Si:H) as an innovative detector technology for dosimetry in FLASH radiotherapy. Conventional dosimeters, such as ionization chambers, show non-linear behavior when exposed to ultra-high dose-per-pulse beams used in FLASH radiotherapy, where several Grays are delivered in microsecond pulses. Thanks to its radiation hardness, mechanical flexibility and compatibility with large-area deposition, a-Si:H is a promising material for in-vivo and surface dosimetry. This work presents the response of a thin a-Si:H detector exposed to a high-dose-per-pulse 10 MeV electron beam, together with an analytical model used to describe the single-pulse dynamics and extract quantitative parameters. Measurements were performed at the University of Torino using a modified clinical LINAC operated in Ultra High Dose Rate regime, where the single-pulses satisfy the FLASH criteria. The a-Si:H detector, read out with a TetrAMM picoammeter (100 kHz sampling frequency), resolves individual radiation pulses with high repeatability. Both pulse charge and peak current scale linearly with the applied electric field up to 6 V (2.4 V/mu m), beyond which the readout electronics saturates. The analytical model is validated through direct comparison with raw data, showing excellent agreement in extracted pulse parameters.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
