Rate-capability of the VMM3a Front End in the RD51 Scalable Readout System

TL;DR

This paper evaluates the rate-capability of the VMM3a ASIC within the RD51 Scalable Readout System, demonstrating optimized data handling and trigger logic to enable high-rate gaseous detector readout for laboratory and experimental use.

Contribution

It introduces firmware implementations and system optimizations that enhance the VMM3a's rate-capability in the RD51 SRS for gaseous detector applications.

Findings

Achieved high rate-capability of 3.6 Mhits/s per channel.

Developed two firmware implementations for continuous readout mode.

Demonstrated application in X-ray imaging with high data rates.

Abstract

The VMM3a is an Application Specific Integrated Circuit (ASIC), specifically developed for the readout of gaseous detectors. Originally developed within the ATLAS New Small Wheel (NSW) upgrade, it has been successfully integrated into the Scalable Readout System (SRS) of the RD51 collaboration. This allows, to use the VMM3a also in small laboratory set-ups and mid-scale experiments, which make use of Micro-Pattern Gaseous Detectors (MPGDs). As part of the integration of the VMM3a into the SRS, the readout and data transfer scheme was optimised to reach a high rate-capability of the entire readout system and profit from the VMM3a's high single-channel rate-capability of 3.6 Mhits/s. The optimisation focused mainly on the handling of the data output stream of the VMM3a, but also on the development of a trigger-logic between the front-end cards and the DAQ computer. In this article, two firmware implementations of the non-ATLAS continuous readout mode are presented, as well as the implementation of the trigger-logic. Afterwards, a short overview on X-ray imaging results is presented, to illustrate the high rate-capability rom an application point-of-view.