Köln 2004 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 12: Poster Session: Instrumentation and Applications

HK 12.19: Poster

Tuesday, March 9, 2004, 13:30–15:30, Foyer

Proton detection in aSPECT — •Gerd Petzoldt¹, Stefan Baeßler², Jim Byrne³, Ferenc Glück², Joachim Hartmann¹, Werner Heil², Raquel Muñoz Horta², Igor Konorov¹, Marius Orlowski², Yuri Sobolev², Maurits van der Grinten³, and Oliver Zimmer¹ — ¹Physik Department E18, Technische Universität München — ²Institut für Physik, Universität Mainz — ³University of Sussex, Falmer, Brighton, UK

Present neutron decay data indicates that unitarity tests of the Cabbibo-Kobayashi-Maskara matrix fail by about 3σ. With the retardation spectrometer aSPECT, we will measure the electron-antineutrino correlation coefficient in neutron decay a by determinig the shape of the proton recoil spectrum, which is sensitive to a. We hope to increase the precision of the measurement by at least one order of magnitude, compared to older experiments. Determinig the upper left element V_ud from a will allow an independent test of CKM unitarity.

The measurement requires a very sensitive detection system. We will use segmented Si-PIN diodes, which allows us to supress correlated electron background by applying an E×B drift in front of the detector. The structure also reduces capacitive noise of the detector. For the readout of the detector, a fast, low-noise electronics has been developped.

The detection system and calculations on the systematic effects on a to be expected from the detector properties, will be presented in this poster.

This work is supported by the MLL Garching and the BMBF.