Darmstadt 2008 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 26: Instrumentation und Anwendungen II

HK 26.9: Talk

Tuesday, March 11, 2008, 13:15–13:30, 2D

System performances of the HADES-tRPC wall — •Diego Gonzalez-Diaz for the HADES collaboration — GSI, Darmstadt, Germany

The HADES-tRPC is a Time-of-Flight wall in an end-cap configuration, designed for reaching a global time resolution of the order of 100 ps(σ) and an efficiency close to 100% over 8 m², with an average 180 tracks load, at a particle flux of several hundreds of Hz/cm². The design of the HADES experiment emphasizes a ToF wall that makes a cost-effective use of the electronic channels (2400 channels, 1ch/35 cm²) in order to keep the average channel occupancy below 10%, without further requirements on space resolution (kept in the current design at modest levels of 40-80 mm²). Based on that, phenomena like charge sharing, and of course cross-talk or electric coupling in between channels cannot be tolerated and are therefore suppressed to a large extent, through the careful electrical shielding of each individual tRPC cell.

We will present in-beam measurements (October 2007) at nominal flux loads, from a fully equipped sextant (1.3 m²), focusing on the time resolution and efficiency for different primary ionizations, together with performance studies at high local track density (that we refer as multi-hit capability). The preliminary achieved global time resolution of 85 ps(σ), efficiency above 98% with a comfortable plateau, self-calibration capability, stability and low cross-talk (below 1%) together with capability for double-hit recovery and compact FEE electronics with Q-ToT conversion on-board and high dynamic range are the main features of this new ToF wall.