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Response of Radiation Detector Materials to Ions


EMSL Project ID
20897

Abstract

This project will provide a fundamental understanding of the physical processes that control the response of materials to ion energy deposition. The goal is to develop fast screening techniques to achieve information of intrinsic material properties relevant to detector performance, and determine key factors that affect signal variance and detection efficiency, which will provide validation of theoretical model predictions and a critical tool to enhance the discovery of novel detector materials. Applying state-of-art experimental techniques at the ion beam facility at Environmental Molecular Sciences Laboratory (EMSL) and other PNNL facilities, radiation performance will be investigated in thin films of candidate detector materials in terms of (1) energy variance and energy resolution over a wide energy range, (2) nonlinearity response and the dominating factors, (3) electronic energy loss and stopping power, (4) electron-hole (e-h) pair and photon production, (5) recombination, migration and annihilation of e-h pairs as function of energy density deposited in thin detector materials, and (6) collection and detection efficiency resulting from changes of detector bias and operation temperature. Initial materials that will be studied are low atomic number single element semiconductors, such as Si and Ge, which will demonstrate and validate the approach. Simple compound semiconductors, such as SiGe, SiC, BC and BN, will be used to study the effect of compounding. High atomic number semiconductors, such as CdTe and HgI2, and scintillators, such as NaI(Tl) and CsI(Tl) will also be investigated to further validate and demonstrate the approach and obtain insights into the high variance in these materials. Any candidate materials identified and fabricated under other initiative projects will be high priority materials for evaluation. Results from this project will form a database of structure-property relationships, which will be a physical basis for developing or predicting scale-up materials performance in both semiconductor and scintillation-based gamma-ray detectors, since any materials that show poor detector response to ions are unlikely candidates for further investigation.

Project Details

Project type
Exploratory Research
Start Date
2006-08-09
End Date
2007-09-26
Status
Closed

Team

Principal Investigator

Brian Milbrath
Institution
Pacific Northwest National Laboratory

Team Members

Yanwen Zhang
Institution
Oak Ridge National Laboratory