PSD10: 10th International Conference on Position Sensitive Detectors

Large size hybrid GEM-Micromegas gaseous detectors for high particle flux at COMPASS

9 Sept 2014, 12:40

20m

AP1&2 (University of Surrey)

Oral Paper Gas-based detection methods Session 6: Applications in High Energy Physics

Speaker

Damien Neyret (CEA/IRFU,Centre d'etude de Saclay Gif-sur-Yvette (FR))

Description

Large size Micromegas gaseous detectors (40x40 cm² active area) are being developed in view of the forthcoming COMPASS experiment new physics programs which will use the CERN-SPS high intensity muon and hadron beams of a few hundred GeV scattered on thick fixed targets. The detectors have to be active also in the beam area, where intensities as high as a few hundred of kHz/mm² are expected, with the same performances (96% efficiency, spatial resolution better than 100 µm). In such a hot environment, with highly ionizing particles, spark generation is a major issue for MPGD detectors. We will show studies on two different technics used to reduce the park rate in presence of high particle flux. The first one is the use of a specific resistive layer on the read-out board, namely the *buried resistor* technology. The second one is the adding of a pre-amplifying GEM foil to a non-resistive Micromegas detector, leading to an *hybrid* detector. Comparative tests done in real beam conditions and in production environment will be presented. The very promising results obtained with the hybrid detectors lead to the finalization of the design using this technology. The aspect of the industrialization of the fabrication process will also be presented. The achievement of transferring to the industry the delicate technology of making *bulk* Micromegas boards (monolithic assembly of a micromesh and a board) for large size, low budget material, and complicated printed circuit drawing with vias at very small pitches, is also a great success.

Presentation materials

Transparents

Large-size_hybrid_MM_detectors_DNeyret_20140909.pdf