Detection of ionising radiation using single photon avalanche diodes

Single photon avalanche diodes (SPADs) are highly sensitive solid-state photon detectors, and since their inception in 2003 into complementary metal oxide semiconductor (CMOS) technologies, have provided a platform of highly integrated and low-cost mass manufacture detectors, capable of rapid detection of single photons. The consequent commercial potential has led to the development and availability of a range of CMOS SPAD sensors and arrays. As a consequence of their mature development in advanced processes, detection sensitivity and timing capabilities, CMOS SPADs have found their way into multiple applications, most notably biomedical fluorescence lifetime imaging microscopy (FLIM), Light Detection and Ranging (LiDAR), Time-of-Flight (ToF) imaging, Single Photon Counting (SPC), high speed imaging, biological particle tracking and more recently visible light communications. Although, all current applications are constrained to the visible and near infrared spectrums. The advances and broad applications of CMOS SPADs has led to increased development towards further miniaturisation, performance improvements and developing highly integrated intelligent sensors. Therefore, the investigation of the application of SPADs in the detection of ionising radiation has significant commercial potential as an alternative technology to current detectors. The goal of this research is to explore the direct detection of ionising radiation with CMOS SPADs. The fundamental mechanism for detection is a depleted junction operated in Geiger mode, with an induced electric field that allows sensitive detection of generated electron-hole pairs as a result of incident radiation. Therefore, based on this principle it was hypothesised that SPADs can be applied beyond current photon specific detection applications into the detection of ionising radiation. Furthermore, high energy physics is transitioning towards CMOS processes with all the unprecedented advantages it provides. Therefore, it is believed that with SPAD advancement and maturity in CMOS technology, this parallel and continually developing technology may lend itself favourably towards progress and application in the detection of ionising radiation. This work reports on a 3D-stacked backside illuminated (BSI) CMOS SPAD image sensor for the detection of accelerated electrons, pions and X-rays, utilising a scanning electron microscope, synchrotron particle accelerators and X-ray tube sources respectively. For accelerated electron detection, electron energies from 5 to 30 keV were detected, and statistical significance was found that both SPAD excess bias voltage and/or incident accelerated electron energy result in a distinct output. Furthermore, the SPAD image sensor was able to achieve time-resolved imaging of the electron beam raster scan pattern. For X-ray detection, X-rays with peak photon energies from 30 to 160 keV were detectable using an X-ray tube, and it was found that an increase in either SPAD bias voltage, output beam voltage or beam intensity results in higher relative average counts per pixel, therefore demonstrating the potential application of SPAD image sensors in X-ray imaging. These results are the first demonstration and application of a CMOS SPAD in the detection of accelerated electrons and X-rays. Further investigation revealed that the attenuation of lower energy photons from an X-ray tube spectrum results in approximately 200 % increase in relative average counts. Furthermore, The BSI CMOS SPAD image sensor was irradiated with a high energy pion beam at 120 GeV, using the Super Proton Synchrotron (SPS) at CERN, and high energy electrons at 2.5 GeV, using an electron accelerator at ELSA. For the pion irradiation, pions were conclusively detected, and it was found that an increase in SPAD bias voltage results in higher relative average counts per pixel. No conclusive detection of higher energy electrons was observed as a result of low beam intensity. After the pion irradiation, radiation damage to the SPAD image sensor was observed. These results are the first demonstration and application of a CMOS SPAD in the detection of high energy charged particles

Strategic R&D Programme on Technologies for Future Experiments - Annual Report 2020

This report summarises the activities and achievements of the strategic R&D programme on technologies for future experiments in the year 2020

Strategic R&D Programme on Technologies for Future Experiments - Annual Report 2021

This report summarises the activities and main achievements of the CERN strategic R&D programme on technologies for future experiments during the year 2021

Annual Report 2022

This report summarises the activities and main achievements of the CERN strategic R&D programme on technologies for future experiments during the year 202

Extension of the R&D Programme on Technologies for Future Experiments

we have conceived an extension of the R&D programme covering the period 2024 to 2028, i.e. again a 5-year period, however with 2024 as overlap year. This step was encouraged by the success of the current programme but also by the Europe-wide efforts to launch new Detector R&D collaborations in the framework of the ECFA Detector R&D Roadmap. We propose to continue our R&D programme with the main activities in essentially the same areas. All activities are fully aligned with the ECFA Roadmap and in most cases will be carried out under the umbrella of one of the new DRD collaborations. The program is a mix of natural continuations of the current activities and a couple of very innovative new developments, such as a radiation hard embedded FPGA implemented in an ASIC based on System-on-Chip technology. A special and urgent topic is the fabrication of Al-reinforced super-conducting cables. Such cables are a core ingredient of any new superconducting magnet such as BabyIAXO, PANDA, EIC, ALICE-3 etc. Production volumes are small and demands come in irregular intervals. Industry (world-wide) is no longer able and willing to fabricate such cables. The most effective approach (technically and financially) may be to re-invent the process at CERN, together with interested partners, and offer this service to the community

Annual Report 2023 and Phase-I Closeout

This report summarises the activities of the CERN strategic R&D programme on technologies for future experiments during the year 2023, and highlights the achievements of the programme during its first phase 2020-2023