# Development of a UV-transparent Lens Array for Enlarging the Effective Area of Multichannel SiPMs

## TL;DR

This paper presents a UV-transparent lens array designed to enhance the photon detection efficiency of multichannel SiPMs by concentrating incident photons onto sensitive regions, resulting in a 10-30% efficiency increase at certain angles.

## Contribution

The authors developed a novel UV-transparent lens array that effectively enlarges the active detection area of SiPMs, improving efficiency without increasing device complexity.

## Key findings

- Achieved 10-30% increase in photon detection efficiency.
- Demonstrated effectiveness at incident angles of 30-60 degrees.
- Validated the lens array with a prototype showing practical improvements.

## Abstract

We developed a UV-transparent lens array that can increase the photon detection efficiency of a silicon photomultiplier (SiPM) array comprising of 64 pixels ($3\times3$ mm$^2$ each) and 0.2-mm gaps. Through the plano-convex spherical lens on each $3.2\times3.2$ mm$^2$ region, we showed that the loss of photon detection efficiency due to the pixel gaps could be recovered as the incident photons get concentrated on the sensitive regions of the SiPM array. By using a prototype lens array, we achieved approximately 10%-30% relative increase in photon detection efficiency in our target angles of incidence of 30-60 deg.