Unipolar Time-Differential Pulse Response with a Solid-State Charpak Photoconductor

TL;DR

This paper introduces a novel high-speed solid-state detector with unipolar time-differential response, achieving ultrafast pulse detection and approaching the physical speed limit, with potential for stable avalanche gain in large-area radiation detection.

Contribution

It presents the first demonstration of a unipolar time-differential pulse response in a solid-state detector, significantly improving speed and enabling stable avalanche gain.

Findings

Speed improvement factor of up to ~400

Achieves the intrinsic physical limit for detector pulse speed

Enables stable avalanche multiplication gain in large-area detectors

Abstract

We demonstrate, for the first time, a high granularity multi-well solid-state detector (MWSD) with the unipolar time-differential property for ultrafast pulse response. Results show a speed improvement factor of up to ~400 for amorphous selenium MWSD. The significance of the results presented here is the ability to reach the intrinsic physical limit for detector pulse speed by transitioning from the slow transit-time-limited response which depends on the bulk carrier transport mechanism, to the ultrafast dispersion-limited response which depends on the spatial spreading of the collected carrier packet. Furthermore, the proposed structure is the practical approach for achieving stable avalanche multiplication gain in large-area direct radiation detectors.