Novel Silicon and GaAs Sensors for Compact Sampling Calorimeters

TL;DR

This study evaluates silicon and GaAs sensors for compact sampling calorimeters using a 5 GeV electron beam, focusing on their signal quality, response uniformity, and readout effects.

Contribution

It introduces novel silicon and GaAs sensors with integrated readout systems designed for compact electromagnetic calorimeters.

Findings

Silicon sensors show high signal-to-noise ratio.

GaAs sensors demonstrate uniform response across pads.

Readout trace effects are characterized and minimized.

Abstract

Two samples of silicon pad sensors and two samples of GaAs sensors are studied in an electron beam with 5 GeV energy from the DESY-II test-beam facility. The sizes of the silicon and GaAs sensors are about 9$\times$9 cm$^2$ and 5$\times$8 cm$^2$, respectively. The thickness is 500 micrometer for both the silicon and GaAs sensors. The pad size is about 5$\times$5 mm$^2$. The sensors are foreseen to be used in a compact electromagnetic sampling calorimeter. The readout of the pads is done by metal traces connected to the pads and the front-end ASICs at the edges of the sensors. For the silicon sensors, copper traces on a Kapton foil are connected to the sensor pads with conducting glue. The pads of the GaAs sensors are connected to bond-pads via aluminium traces on the sensor substrate. The readout is based on a dedicated front-end ASIC, called FLAME. Pre-processing of the raw data and deconvolution is performed with FPGAs. The whole system is orchestrated by a Trigger Logic Unit. Results are shown for the signal-to-noise ratio, the homogeneity of the response, edge effects on pads, and for signals due to the readout traces.