SRAM-based heavy ion beam flux and LET dosimetry

This paper explores the possibility of enhancing the capability of static random access memories (SRAMs) as heavy ion beam detectors starting from the multiple-cell upsets (MCUs) measured in some well characterized beams. In particular, the two main enablers brought by the MCU analysis are (1) the determination of the beam flux even when the LET of the beam is not known [whenever the LET is > 10 MeV/(mg/cm2)] and (2) the estimation of the LET of the heavy ion beam without reliance on any other instrument. The methods designed to determine these quantities are explained in the paper and are calibrated using well characterized heavy ion beams. They are then put to test in less known heavy ion beams. Overall, the flux estimation, which exploits the saturation of the coverage, i.e., the ratio between MCU and beam fluence, instead of the unsaturated SEU cross section, can point out issues with beam calibration that can be corrected by the facility. The LET estimation, for which two different methods are proposed, when compared to Monte-Carlo simulations, showed a general agreement with an uncertainty of ~3 MeV/(mg/cm2), which is acceptable for typical measurements in which the LET data-points are spread by a larger range.