Wireless, Accumulation Dosimeters Monitor Pulsed and Non-pulsed Germicidal Lamps

ABSTRACT

Infectious diseases such as the COVID-19 pandemic demands simple and effective disinfection techniques. Ultraviolet germicidal irradiation (UVGI) is one such method in common use for decontamination of hospital rooms. Practical technologies designed to monitor UVGI ensure the delivery of effective dose for reliable germicide. Existing UVGI dosimeters rely on intermittent measurements of intensity as the basis for a numerical integration scheme that approximates dose. Traditional devices are ineffective particularly with pulsed UVGI lamps that emit ms pulses of duration shorter than the interval of measurement. Here, we present a compact, accumulation mode dosimeter (AMD) that detects continuously, as opposed to intermittently, at single or multiple UVGI wavelengths. AMD utilizes an array of photodiodes and supercapacitors to passively transduce and capture photocurrent generated by UVGI without the use of an external power. The accumulated voltage across the supercapacitors then serves as a measure of UVGI dose. A key result is that sampling intervals of AMD do not constrain measurement accuracy. When implemented with a wireless transponder, AMD supports light-adaptive sampling scheme designed to adjust sampling interval to intensity and period of UVGI exposure. Compared to time-based sampling adopted by conventional sensors, light-adaptive sampling autonomously optimizes expanded power by minimizing current consumption during periods of low or no UVGI. Benchtop studies of its use with pulsed Xenon lamps (pulse 5 ms) sampled at long intervals (>1s) highlights key feature. Demonstration of AMD during UVGI of E. Coli cultures represents an example in dose dependent effects on disinfection. IEEE