Wireless Signaling of Beta Detection Using Microdischarges

This paper explores the possibility of using microdischarges to generate broadband radio-frequency (RF) signaling from gas-based microdetectors of beta radiation. The concept is evaluated using two types of lithographically manufactured test structures: 1) a silicon/glass stack with etched detection cavities and 2) a planar metal-on-glass structure. The test structures include electrodes that bias a fill-gas region with a high electric field, in which incident beta particles initiate avalanche-driven microdischarge pulses that inherently transmit RF spectra with frequency content extending into the ultrawideband (UWB) range of communication. The discharge gaps range from 165 to 500 μm. The impact of operating pressure, fill gases (which are typically a mixture of Ne and N₂), and electrode materials (Ni and Cu) on operating voltage and wireless signaling performance is evaluated. Tests are performed in the proximity of weak (0.1-1.0-μCi) beta sources (⁹⁰Sr and ²⁰⁴TI). Both types of test structures are capable of producing UWB signals spanning > 1 GHz. Measurements in an anechoic chamber using various receiver antennas show that microdischarges can produce field strengths up to 90 dB · μV/m measured at 1.67 m from the test structure.