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Abstract-This work provides information pertaining to the performance of Silicon-On-Insulator (SOI) microdosimeters in heavy ion radiation fields. SOI microdosimeters have been previously tested in light ion radiation fields for both space and therapeutic applications, however their response has not been established in high energy, heavy ion radiation fields which are experienced in space. Irradiations were completed at the NASA Space Radiation Laboratory at BNL using 0.6 GeV/u Fe and 1.0 GeV/u Ti ions. Energy deposition and lineal energy spectra were obtained with this device at various depths within a Lucite phantom along the central axis of the beam. The response of which was compared with existing proportional counter data to assess the applicability of SOI microdosimeters to future deployments in space missions.

Abstract-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 with almost 100% charge collection.

-This paper is dedicated to the characterization of a novel diamond microdosimeter prototype with 3D sensitive volumes produced by high energy boron implantation. Diamond has been chosen in order to further improve solid state based microdosimeter in terms of radiation hardness and tissue equivalency. IBIC measurements were undertaken to determine the charge collection efficiency map of the device. It was demonstrated that the proposed ion implantation technology allows for the formation of an array of well defined 3D SVs. A Geant4 application was developed to explain the effect of Al electrode thickness on observed anomaly in deposited energy. Specifics of the results and an update on the current status of the project is presented.

Abstract-The microdosimetric spectra derived by silicon microdosimeter in a proton radiation field traversing heterogeneous structures were simulated using the GEANT4 toolkit.