Acceptance of ET44 in 1999.

V.Andreev, 30-March-2000

 The 1999 H1 running period is consisted of two big samples.
 The first half of 1999 HERA operated with the electron beam
 and the second part with the positron beam. Each sample was
 devided on the several subsamples which are differed mainly
 by the X_off position and the tilt of the electron beam in the
 interaction point. 

 The electron running period was devided on 6 subsamples and
 for the positron case 8 subsamples were selected. The acceptance
 curves were determinated with the procedure described in H1 note #493 
 and then DB was updated with the new set of LET1 banks :

 a) the electron case
 
TransActID  Rtyp Dtyp  1.Run     Words    Author      Date   

   2410882  e-p  data  231700      68    vladimir    000328    
   2410883  e-p  data  233490      68    vladimir    000328    
   2410884  e-p  data  235614      68    vladimir    000328    
   2410885  e-p  data  236173      68    vladimir    000328    
   2410886  e-p  data  237494      68    vladimir    000328    
   2410887  e-p  data  239823      68    vladimir    000328    
 
 b) the positron case

TransActID  Rtyp Dtyp  1.Run     Words    Author      Date   

   2413097  e-p  data  246156      68    vladimir    000330    
   2413098  e-p  data  248679      68    vladimir    000330    
   2413099  e-p  data  251080      68    vladimir    000330    
   2413100  e-p  data  251662      68    vladimir    000330    
   2413101  e-p  data  253307      68    vladimir    000330    
   2413102  e-p  data  256936      68    vladimir    000330    
   2413103  e-p  data  258544      68    vladimir    000330    
   2413104  e-p  data  259438      68    vladimir    000330   
 
 The y-dependence of ET44 acceptance for different run periods is
 shown on picture and the same distributions for the previous years
 are also given for the comparision on the next picture.

 The systematic error of the acceptance determination for ET44
 in 1999 is formed by the next parts:

   a) uncertainty in the energy scale determination  --> 1.9 % , 

   b) trigger efficiency                             --> 1.0 % ,

   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 fit procedure   --> 0.5 % ,

   e) uncertainty connected with the limited y-range --> 0.6 % .
   
 So the overall systematic error in the acceptance determination
 of ET44 in 1999 is equal 4.5 % .

 More details for the previos years one can also find in the 
 description of 1998 , 1997 and 1996 .