Monitoring of Particle Flux and LET Variations with Pulse Stretching Inverters

This work investigates the use of pulse stretching inverters for monitoring the variation of flux and Linear Energy Transfer (LET) of energetic particles. The basic particle detector consists of two cascaded pulse stretching (skew-sized) inverters designed in CMOS technology, and the required sensing area is obtained by connecting multiple two-inverter pulse stretching cells in parallel, and employing the required number of parallel arrays. The particle strikes are detected in terms of the Single Event Transients (SETs), and the detector provides the information on the SET count rate and SET pulse width variation, from which the particle flux and LET can be determined. The main advantage of the proposed solution is the possibility to sense the LET variations using purely digital processing logic. The SPICE simulations done on IHP 130 nm bulk CMOS technology have shown that the SET pulse width at the output of detector changes by 550 ps over the LET range from 1 to 100 MeVcm2mg-1. The proposed solution is intended to operate as an on-chip particle detector within the self-adaptive multiprocessing systems.