A Self-Powered Thin-Film Radiation Detector Using Intrinsic High-Energy Current (HEC) (Author's Final Version)
Dana-Farber Cancer Institute and Harvard Medical School Boston United States
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A new radiation detection method relies on high-energy current HEC formed by secondary charged particles in the detector material, which induces conduction current in an external readout circuit. Direct energy conversion of the incident radiation powers signal formation without need for external bias voltage or amplification. The detector is a thin-film multilayer device, composed of alternating disparate electrically conductive and insulating layers. The optimal design of HEC detectors consists of micro- or nanoscopic structures. Theoretical and computational developments are presented to illustrate the salient properties of the HEC detector and to demonstrate its feasibility. In this work, we examine single-sandwiched and periodic layers of Cu and Al, and Au and Al, ranging in thickness from 100 nm to 300 microns and separated by similarly sized dielectric gaps, exposed to a 120-kVp x-ray beam half-value thickness of 4.1 mm of Al. The energy deposition characteristics and high-energy current were determined using radiation transport computations. In a dual-layer configuration the signal is in the measurable range. For a defined total detector thickness in a multilayer structure the signal sharply increases with decreasing thickness of the high-Z conductive layers. This paper focuses on the computational results a companion paper reports the experimental findings. Significant advantages of the device are that it does not require an external power supply and amplification to create a measurable signal it can be made in any size and geometry, including very thin submillimeter to submicron flexible curvilinear forms, and it is inexpensive. Potential applications include medical dosimetry both in-vivo, and external, radiation protection, and other settings where one or more of the above qualities are desired.