The Electronics of the H 1 Lead / Scintillating-Fibre Calorimeters

The electronic system developed for the SpaCal lead/scintillating-fibre calorimeters of the H1 detector in operation at the HERA ep collider is described in detail and the performance achieved during H1 data-taking is presented. The 10 MHz bunch crossing rate of HERA puts severe constraints on the requirements of the electronics. The energy and time readout are performed respectively with a 14-bit dynamic range and with a resolution of ∼0.4 ns. The trigger branch consists of a nanosecond-resolution calorimetric time-of-flight for background rejection and an electron trigger based on analog ‘sliding windows’. The on-line background rejection currently achieved is ∼10. The electron trigger allows a low energy trigger threshold to be set at ∼0.50 ± 0.08 (RMS) GeV with an efficiency ≥ 99.9%. The energy and time performance of the readout and trigger electronics is based on a newlydeveloped low noise (σnoise ∼0.4 MeV) wideband (f ≤200 MHz) preamplifier located at the output of the photomultipliers which are used for the fibre light readout in the ∼ 1 Tesla magnetic field of H1. Submitted to Nuclear Instruments and Methods A H1 SpaCal Group R.-D. Appuhn, C. Arndt, E. Barrelet, R. Barschke, U. Bassler, F. Blouzon, V. Boudry, F. Brasse, Ph. Bruel, D. Bruncko, R. Buchholz, B. Cahan, S. Chechelnitski, B. Claxton, G. Cozzika, J. Cvach, S. Dagoret-Campagne, W.D. Dau, H. Deckers, T. Deckers, F. Descamps, M. Dirkmann, J. Dowdell, C. Drancourt, O. Durant, V. Efremenko, E. Eisenhandler, A.N. Eliseev, G. Falley, J. Ferencei, M. Fleischer, B. Fominykh, K. Gadow, U. Goerlach, L.A. Gorbov, I. Gorelov, M. Grewe, L. Hajduk, I. Herynek, J. Hladký, M. Hütte, H. Hutter, M. Janata, W. Janczur, J. Janoth, L. Jönsson, I. Kacl, H. Kolanoski, V. Korbel, F. Kriváň, D. Lacour, B. Laforge, F. Lamarche M.P.J. Landon, J.-F. Laporte, H. Lebollo, A. Le Coguie, F. Lehner, R. Maraček, P. Matricon, K. Meier, A. Meyer, A. Migliori, F. Moreau, G. Müller, P. Muŕın, V. Nagovizin, T.C. Nicholls, D. Ozerov, J.-P. Passerieux, E. Perez, J.P. Pharabod, R. Pöschl, Ch. Renard, A. Rostovtsev, C. Royon, K. Rybicki, S. Schleif, K. Schmitt, A. Schuhmacher, A. Semenov, V. Shekelyan, Y. Sirois, P.A. Smirnov, V. Solochenko, J. Špalek, S. Spielmann, H. Steiner , A. Stellberger, J. Stiewe, M. Taševský, V. Tchernyshov , K. Thiele, E. Tzamariudaki, S. Valkár, C. Vallée, A. Vallereau, D. VanDenPlas, G. Villet, K. Wacker, A. Walther, M. Weber, D. Wegener, T. Wenk, J. Žáček, A. Zhokin, P. Zini and K. Zuber 1 School of Physics and Space Research, University of Birmingham, Birmingham, UK 2 Electronics Division, Rutherford Appleton Laboratory, Chilton, Didcot, UK a 3 Institute for Nuclear Physics, Cracow, Poland b 4 Institut für Physik, Universität Dortmund, Dortmund, Germany c 5 DSM/DAPNIA, CEA/Saclay, Gif-sur-Yvette, France 6 DESY, Hamburg, Germany c 7 Institut für Hochenergiephysik, Universität Heidelberg, Heidelberg, Germany c 8 Institut für Reine und Angewandte Kernphysik, Universität Kiel, Kiel, Germany c 9 Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic d 10 Queen Mary and Westfield College, London, UK a 11 Physics Department, University of Lund, Sweden e 12 CPPM, Université d’Aix-Marseille II,IN2P3-CNRS,Marseille,France 13 Institute for Theoretical and Experimental Physics, Moscow, Russia f 14 Lebedev Physical Institute, Moscow, Russia 15 LPNHE, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France 16 LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France 17 Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic d,g 18 Nuclear Center, Charles University, Prague, Czech Republic d,g α now at ILL, Grenoble, France β now at CRN, Université de Strasbourg, IN2P3-CNRS, Strasbourg, France γ permanent address: LBL, University of California, Berkeley, USA ∗ Corresponding author. Tel.: +33 1 6908 2583,fax: +33 1 6908 6428, e-mail: cozzika@hep.saclay.cea.fr.