Darmstadt 2008 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 38: Instrumentation und Anwendungen II

HK 38.9: Talk

Thursday, March 13, 2008, 18:45–19:00, 2D

Determination of the efficiency of an aerogel Čerenkov-detector^* — •Stefan Friedrich for the CBELSA/TAPS collaboration — II. Physikalisches Institut, University of Giessen

The CB-TAPS experiment at ELSA in Bonn is optimized for measuring neutral, photonic final states.

The identification of charged particles is normally done by mesuring time-of-flight and energy loss. Already at moderately high particle energies the discrimination becomes impossible. Using the Čerenkov-effect is a good method to improve the identification of the particles.

Aerogel is a very appropriate radiator-material due to its very low density, its high transparency and its refraction-index of about n ≈ 1.05. Exploiting the Čerenkov-effect on aerogel, electrons and most charged pions can be discriminated from protons. Therefore a diffusively reflecting aerogel Čerenkov-detector was built. Its performance was tested at the ELSA accelerator in Bonn with an electron-beam. In addition a test with a 1.1 GeV π⁻-beam at GSI, Darmstadt, was performed. Furthermore, the aerogel Čerenkov-detector has been employed in an experiment at ELSA searching for ω-mesic states. Results of these measurements will be presented.

^* funded by DFG (SFB/TR 16)