M. Meurer | Searcharxiv

arXiv2025

Application of the VMM3a/SRS: A t0-less TWIN GEM-based TPC

Integrating the ATLAS/BNL VMM3a ASIC (Application Specific Integrated Circuit) into the RD51/SRS (Scalable Readout System) provides a self-triggered continuous readout system for various gaseous detectors. Since the system allows flexible parameters, such as switching the polarity, adjusting electronics gain or different peaking times, the settings can be adjusted for a wide range of detectors. The system allows particles to be recorded with a MHz interaction rate in energy, space, and time. The system will be introduced in the beginning, and short examples will be given for different applications. After, the Twin GEM TPC will be discussed in more detail to show the benefits of such a trigger-less system in combination with the Twin configuration. Last, a few results for the tracking performance and the possibility to operate as a tracking telescope will be shown. Thus, this presents the possibility of an extremely low material budget tracking system suitable for tracking from high to low-energy particle beams.

physics.ins-det↗

arXiv2025

The Ultra-Low material budget GEM based TPC for tracking with VMM3a readout

The Gaseous Electron Multiplier-based Time Projection Chamber (GEM-TPC) in TWIN configuration for particle tracking has been consolidated after extensive investigations in different facilities to study its tracking performance. The most attractive feature of this detector is its ultra-low material budget, which is 0.28\% X/X$_0$ and can be further reduced by decreasing the thickness of the gas traversed by the incident particles. Thus, it provides excellent position reconstruction and reduced multi-scattering. This detector consists of two GEM-TPCs with drift fields in opposite directions, achieved by rotating one 180 degrees in the middle plane with respect to the other. These two GEM-TPCs share the same gas volume, i.e., inside a single vessel. This configuration is called a TWIN configuration. The results presented in this work were measured using the newly integrated VMM3a/SRS readout electronics, an important milestone in improving overall performance and capabilities. In 2024, this detector was tested at the H4 beamline of the SPS at CERN, using muons and pions and with different gas mixtures like, for instance: Ar/CO$_2$ (70/30 \%), He/CO$_2$ (70/30 \%) and He/CO$_2$ (90/10 \%). The helium-based mixtures were used to commission the detector to track low momenta muons required in the PSI muon-induced X-ray emission (MIXE) experiment. The results obtained from these measurements, a brief discussion of the methodology used for the data analysis, and a comparison of the spatial resolution for different gas mixtures will be presented.

physics.ins-det↗