Novel improvement method of energy resolution for superconducting tunnel junction X-ray detectors

We propose a novel signal processing method to improve the energy resolution of superconducting tunnel junction X-ray detectors with quasiparticle trapping. Current signals produced in the detectors are amplified by a fast current preamplifier with a bandwidth of 110 MHz, and divided into two parts, i.e., the rise part and the decay part. It was found that the best energy resolution was obtained by using the integrated charge of the rise part. This indicates that the charge of the decay parts has a charge scatter larger than that of the rise part.