The cathode read-out of the DELPHI hadron calorimeter

I V Ajinenko ,V Falaleev ,H Herr ,N Khovansky ,Z Krumstein ,K Kurvinen ,I Lapin ,Rupert Leitner ,A G Olchevski ,J Ridky ,Yu Sedykh ,O Solovianov ,Z Tomsa ,Vladimir Nikolaenko ,Jiri Masik ,Jiri Chudoba ,Sandor Czellar ,O G Tchikilev ,Peter Kluit ,Vaclav Vrba ,Oxana Smirnova ,Petr Sicho ,L G Tkatchev ,W.s.c Williams ,A M Wetherell ,J Zaslavsky

doi:10.1109/23.467924

Abstract

To improve the identification and separation of leptons in the Hadron Calorimeter of DELPHI, one of the four LEP experiments at CERN, the possibility of a direct read-out of the cathodes of the 20,000 limited streamer tubes was studied and successfully tested on a small scale. A larger scale test started in June 1994. This new system which is independent of the present pad read-out provides a ``yes/no`` information. The combination of both read-out systems makes it possible to use the Hadron Calorimeter as a track detector. The result of these test show that the cathode read-out provides a better {pi}/{micro} separation, and improved detection of neutral long lived particles, enhanced discrimination of two showers and a more precise hadron energy measurement. It was decided to equip the whole detector with the new read-out, starting during the 94/95 shutdown.

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