Acceptance of ET44 in 1997.

V.Andreev, 05-June-1998

 The acceptance of ET44 for 1997 was determinated with the procedure
 described in H1 note #493.
 This is the same procedure which was used in previous years. The 1997
 H1 running period was devided on 18 samples differed by the one or
 several electron beam parameters which essential influence on 
 e-tagger acceptance: e-beam tilts (theta_x and theta_y) and the offset
 (X_off and Y_off) of the electron beam in the interaction point.
 The another crucial parameter is the distance of ET44 from the 
 electron beam. During the all 1997 running period ET44 operated in 
 the "Working position" at the distance ~1.8 cm from the electron
 beam. Only during short period, H1 runs 195919-196355, ET44 was 
 situated in the "Parking position" at the distance ~3.1 cm from
 e-beam.
 The new set of LET1 banks is written in DB and is shown below:

 TransActID Rtyp Dtyp 1.Run     Words    Author    Date

    1564128 e-p data  176421      68    vladimir  980529    
    1564129 e-p data  179558      68    vladimir  980529    
    1564130 e-p data  180109      68    vladimir  980529    
    1564131 e-p data  181599      68    vladimir  980529    
    1564132 e-p data  183602      68    vladimir  980529    
    1564133 e-p data  185336      68    vladimir  980529    
    1564134 e-p data  186660      68    vladimir  980529    
    1564135 e-p data  187741      68    vladimir  980529   
    1564136 e-p data  189542      68    vladimir  980529   
    1564137 e-p data  190007      68    vladimir  980529   
    1564138 e-p data  194493      68    vladimir  980529   
    1564139 e-p data  195022      68    vladimir  980529   
    1564140 e-p data  195919      68    vladimir  980529    
    1564141 e-p data  196356      68    vladimir  980529    
    1564142 e-p data  196674      68    vladimir  980529    
    1564143 e-p data  198790      68    vladimir  980529    
    1564144 e-p data  200359      68    vladimir  980529    
    1564145 e-p data  200444      68    vladimir  980529    
 
 The y-dependence of ET44 acceptance for the different run periods
 is shown in the picture.
 The same distributions for the previous years are also shown for 
 the comparision. For the analysis it is necessary to use the 
 average acceptance of ET44 (integrated over some y-range). This 
 y-range for 1997 can be choose as 0.04 < y < 0.24 for the whole H1
 running period. One could stress that the using of ACET44(IRUN,Y,MODE)
 function with MODE=1 recommend for the physical analysis. This
 mode is taken into account the trigger efficiency and anti-veto
 condition at the acceptance calculation. 

 The systematic error of the acceptance determination for ET44
 in 1997 is formed by the next parts:

    a) uncertainty in the energy scale determination  --> 3.0 % ,
 
    b) trigger efficiency                             --> 1.5 % ,

    c) error connected with the uncertainty in the position of
       ET44 with respect to the electron beam         --> 3.5 % ,

    d) error which reflects the averaging of the several
       calibration sets                               --> 1.5 % ,

    e) uncertainty connected with the limited y-range --> 1.0 % .

  The overall systematic error in the acceptance determination
  of ET44 in 1997 is equal 5.2 % .