ET44 status. 18-May-1995

 
Short introduction
 In general the acceptance of the ET44 and also the minimum value
 y_min = 1-E(e)_max/E0 is determined by a distance from e-beam. The minimum
 size of the beam-pipe is constrained by beta-function. For example,
 at z=-44 m (the place of the present ET44) this size is 5.2 cm
 (full dimension in the horizontal direction).
 This limitation however, is only important for the injection and
 the ramping stages. During the luminosity stage the size of the beam-pipe
 could in principle be reduced.

 
New project
 A new project has been prepared by HERA (for both H1 and ZEUS) with moving beam-pipe.
 The beam-pipe has two different positions: 1) during the injection and ramping, 
 2) during the luminosity run. (Click here to see a sketch of this suggestion.)                               
  
 This new project is more advantageous compared to the original H1 proposal   H1-09/94-383.
 Modification of a beam-pipe will be done only in one place.
 This gives the possibility to have only one additional calorimeter with
 9 channels situated not so far from the old ET.             
  
 The first MC simulation for this new future geometry 
 gives the following acceptance for Wgp:
     a) 1994
        Wgp = 150-250 GeV, -- present ET,

     b) Original proposal                       
        Wgp = 60-76  GeV, -- for ET1 at z=-188 m,
        Wgp = 95-135 GeV, -- for ET2 at z= -38 m,

     c) Prototype ET44 (1995)
        Wgp = 90-115 GeV, -- ET44 at z=-44 m,

     d) New project (moving beam-pipe in 1996)
        Wgp = 60-115 GeV, -- new ET44 at z=-44 m.