Design of a Large Area Digital SiPM with High Fill Factor and Fully Serial Digital Readout for Single Photon Detection in Liquid Noble Gas Detectors

TL;DR

This paper introduces a large-area digital SiPM chip with high fill factor and fully digital serial readout, enabling efficient single photon detection in liquid noble gas detectors for rare event searches.

Contribution

The paper presents a novel digital SiPM design combining high fill factor, large area, and digital readout, suitable for scalable detector arrays in rare event physics.

Findings

Achieved 72.5% photo-sensitive area in a large chip

Records photon hit position and timing with 10 ns granularity

Enables scalable detector modules with digital daisy chaining

Abstract

We present a 'digital SiPM' photo-detection chip combining single photon sensitive avalanche photo diodes and CMOS readout electronics on a single die. The chip has a size of $8046\times9032\,\mu m^2$ with $72.5\%$ of photo sensitive area. It is subdivided into $32\times30$ pixels with an average size of $250\times291\,\mu m^2$. For each photon hit, the chip records the pixel coordinate and the arrival time with a granularity of $\approx 10\,ns$. Readout and chip control are purely digital, requiring only 4 CMOS signals. Several chips can be daisy chained and grouped on larger modules so that detector planes with $\approx70\%$ photo sensitive area can be build. Our chip may be used in experiments that need to detect rare scintillation events, for instance dark matter searches using liquid noble gases.