The Belle II experiment running at the SuperKEKB e+e− collider will be upgraded during its Long Shutdown 2 (LS2), in order to reach its target instantaneous luminosity of 6×1035cm−2s−1. A fully pixelated vertex detector, VTX, is proposed as the upgrade for the Belle II experiment to cope with higher hit rates, increased background and radiation level at the target luminosity. The VTX utilizes CMOS Depleted Monolithic Active Pixel Sensors (DMAPS), OBELIX sensors, developed based on the TJ-Monopix2 prototype. In order to ensure reliable performance after irradiation during long-term operation, the impact of radiation damage on a detection performance of TJ-Monopix2 has been studied, including its dependence on operating temperature, which is a key parameter for defining the cooling requirements and safe operating limits. After irradiation to the target accumulated NIEL fluence, the DC front-end of TJ-Monopix2 is confirmed to maintain a detection efficiency of >99% at the NTC temperature of 40°C (chip temperature of about 47°C) with the detection threshold of approximately 350e−.
Impact of radiation damage to the performance of depleted monolithic active pixel sensors for Belle II vertex detector upgrade
Benfratello G. F.;Bettarini S.;Bosi F.;Casarosa G.;Corona L.;Forti F.;Massaccesi L.;Minuti M.;Mondal S.;Rizzo G.;Taffara A.;Bevan A.;
2026-01-01
Abstract
The Belle II experiment running at the SuperKEKB e+e− collider will be upgraded during its Long Shutdown 2 (LS2), in order to reach its target instantaneous luminosity of 6×1035cm−2s−1. A fully pixelated vertex detector, VTX, is proposed as the upgrade for the Belle II experiment to cope with higher hit rates, increased background and radiation level at the target luminosity. The VTX utilizes CMOS Depleted Monolithic Active Pixel Sensors (DMAPS), OBELIX sensors, developed based on the TJ-Monopix2 prototype. In order to ensure reliable performance after irradiation during long-term operation, the impact of radiation damage on a detection performance of TJ-Monopix2 has been studied, including its dependence on operating temperature, which is a key parameter for defining the cooling requirements and safe operating limits. After irradiation to the target accumulated NIEL fluence, the DC front-end of TJ-Monopix2 is confirmed to maintain a detection efficiency of >99% at the NTC temperature of 40°C (chip temperature of about 47°C) with the detection threshold of approximately 350e−.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
