Minutes of HERA/Experiments Coordination Meeting Monday, 19.11.2001 _________________________________________________________________________

Agenda

 - Present status
   (Progress on HERA commissioning, understanding of background conditions,...)

 - Luminosity run after November access
   (Expected HERA performance, requests by experiments, ...) 

 - Work during Christmas break
   (Fix dates of Christmas break)

 - Schedule for HERA operation in 2002
   (Fix access days)
 
 - Conditions/Date for switching to electrons
   (Unless there are new convincing arguments, we should not reenter into a
    physics discussion.)   

 - First discussion on polarity of spin rotators and time between changes
   (HERA prefers to have only 2 different setups, i.e. all rotator positions
    should be changed at the same time if possible.)

 - First discussion on longterm planning of shutdowns.


 - Date of next meeting
 
 - AoB


Presentations:

   News from the DESY Scientific Council (WR)   R.Klanner

    The evaluation of the TESLA TDR was very positive. The WR congratulated 
    DESY for the good performance. 

    The WR agrees with the recommendations of the PRC.

    The WR agrees with the "Policy concerning the operation of HERA and PETRA.
    This should include a fixed date for the modification of PETRA and end
    of the HERA II program (31.12.2006). The HERA II physics program should 
    have highest priority. The WR strongly recommends building an additional
    ring in the PETRA tunnel (2nd option in the paper). Proposals for a 
    HERA III program should be submitted until end of 2003. 

    Joachim Mnich, Aachen will be new PRC member (H1 referee).


   HERA          F.Willeke transparencies 
 
   ZEUS          W.Zeuner transparencies 
 
   H1            E. Elsen transparencies 

   HERMES        J.Stewart Detector Status transparencies  Beam loss monitors transparencies 

   HERA B        A.Spengler transparencies 

   Polarimeter   T.Behnke  transparencies 


Schedule

  First luminosity running  starting  22.11.2001

  Turning on rotators in December might be postponed. Understanding background
  conditions has priority.

  Christmas shutdown: end of beam operation  21.12.2001  07:00hrs, interlocks
  set/start beam operation 16.01.2002

  Access days: first Tuesday of every month

  Two days of machine studies (4 shifts + 1 shift setup for collisions) every
  week until end of April. 
  Probably no machine studies at the end of the running period.

  Switch to electron beam operation in May 2002.

  The rotator positions will probably be changed once per month. 

  The present plan is to run until at least November 2002, depending on 
  the available manpower (HERA shift personnel). A shutdown of 3 months is 
  required to install the H1 Very Forward Proton Spectrometer.


Discussion on switching to electrons

 Three dates for switching to electron beam operations were discussed: 

    Christmas break  2001/2002
        This could be the most efficient way to switch to electrons. It is
        however important to have a thorough understanding of the electron 
        machine including background conditions with positron beam. 

    Spring 2002 (favored by ZEUS)
        This would enable the machine group to have a good understanding of 
        the electron machine with positron beam operation. The switch-over 
        should be done after high luminosity operation is achieved, as agreed 
        in the last HERA coordination meeting in May 2001.  A rough
        time estimate for this is April 2002. Since there is some lead time
        required to do the shift-over, the date should be fixed and should 
        include some time for possible delays, i.e. shift over in May 2002. 
                
    Winter shutdown 2002/2003 (favored by H1).
        This would maximize the integrated luminosity (e+ p collisions) in
        2002. Possible problems with electron beam operation would, however,
        only be recognized in 2003.

  There was no agreement between the experiments on the shift-over date. 
  ZEUS preferring to take electron data as soon as possible, in order to 
  quickly increase the e- p data sample. H1 favoring maximum integrated 
  luminosity with positrons to present a first result on electroweak physics 
  from the upgraded HERA for the summer conferences 2002. HERMES favoring 
  maximum integrated luminosity regardless of the lepton charge. 

  In the end, Robert Klanner proposed to change to electrons in May 2002
  and to decided this in the meeting of the directorate. 

  Since the meeting the date of the switch-over date has been defined as May
  20. 2002 and approved by the directorate.  

  

Date of next meeting

The date of the next meeting is Monday, 13.05.2002  10:00hrs


             Uwe Schneekloth