A New High Energy Photon Tagger for the H1 - Detector at HERA
  The H1 detector at HERA has been upgraded by the addition of a new electromagnetic calorimeter. This is installed in the HERA tunnel close to the electron beam line at a position 8m from the interaction point in the electron beam direction. The new calorimeter extends the acceptance for tagged photoproduction events to the high y range, 0.85 < y < 0.95, and thus significantly improves the capability of H1 to study high energy gamma-p processes. The calorimeter design, performance and first results obtained during the 1996-1999 HERA running are described. 
V.F. Andreev, A.S. Belousov, A.M. Fomenko, L.A. Gorbov, T. Greenshaw,   S.V. Levonian, E.I. Malinovski, S.J. Maxfield, I.P. ...