Rate-capability of the VMM3a front-end in the RD51 Scalable Readout System

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 from an application point-of-view.Peer reviewe

Development of a high-rate scalable readout system for gaseous detectors

The RD51 collaboration developed the Scalable Readout System (SRS) as part of its R&D; activities on Micro-Pattern Gaseous Detectors. This common multi-purpose readout system allows to read out small R&D; detectors (0.2k channels) up to mid-sized experiments with multiple detectors (2.5k to 5k channels). To cope with increased demands on detectors, electronics and readout speed, a new front-end ASIC—the VMM3a—was integrated into the SRS. This led to the development of a scalable, self-triggered high-rate readout system that provides energy, space and time information of the interacting particles at the same time