Large Area Silicon Microdosimeter for Dosimetry in High LET Space Radiation Fields: Charge Collection Study

• Published in: IEEE transactions on nuclear science Vol. 59; no. 6; pp. 3126 - 3132
• Main Authors: Livingstone, J., Prokopovich, D. A., Lerch, M. L. F., Petasecca, M., Reinhard, M. I., Yasuda, H., Zaider, M., Ziegler, J. F., Pisacane, V. L., Dicello, J. F., Perevertaylo, V. L., Rosenfeld, A. B.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2012; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Charge; Collection; Detectors; Diffusion; Dosimeters; Dosimetry; Electrodes; Heavy ion therapy; ion beams; Ions; Microdosimeters; microdosimetry; Radiation; Real-time systems; Silicon; Silicon on insulator technology; silicon-on-insulator (SOI); Space radiation; Space technology
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2012.2219069

Silicon microdosimeters for the characterisation of mixed radiation fields relevant to the space radiation environment have been under continual development at the Centre for Medical Radiation Physics for over a decade. These devices are useful for the prediction of single event upsets in microelectronics and for radiation protection of spacecraft crew. The latest development in silicon microdosimetry is a family of large-area n-SOI microdosimeters for real-time dosimetry in space radiation environments. The response of n-SOI microdosimeters to 2 MeV H and 5.5 MeV He ions has been studied to investigate their charge collection characteristics. The studies have confirmed 100% yield of functioning cells, but have also revealed a charge sharing effect due to diffusion of charge from events occurring outside the sensitive volume and an enhanced energy response due to the collection of charge created beneath the insulating layer. The use of a veto electrode aims to reduce collection of diffused charge. The effectiveness of the veto electrode has been studied via a coincidence analysis using IBIC. It has been shown that suppression of the shared events allows results in a better defined sensitive volume corresponding to the region under the core electrode where the electric field is strongest.