HERA II

• HERA home page
   
• Lumi upgrade docu in TUOVI. Login as guest, no password.
   
• Expected lumi for 2002 by Ferdinand Willeke
   
• Interaction region design report by Mike Seidel
   
• Views of the interaction region by Bernhard Holzer:

  Left and right:

  

  Only left side:

  

  Right side
   

• Extended to 110 m for e-beam by Ingo Bloch:

  
   

• There are 7 movable colliamtors against synchrotron radiation and off-momentum positrons:
  • Name suffix:
    a = von aussen = from outward
    i = von innen = from inward
    o = von oben = from top
    u = von unten = from bottom
  • NL 52a against synrad from BH 64
  • NL 40i against off-momentum e⁺
  • NL 19i against synrad from BN 41
  • NL 15a against off-momentum e⁺
  • NL 6o, 6u against synrad in the vertical
    Only needed for safety against mis-steering.
    Closing to +-8 mm already causes increased background due to outgassing and e⁺ beam-gas interactions.
    Also edge-scattered synrad contributes to chamber currents.
  • NL 5a (Lohrmann's Kleiderbuegel) against horizontal outward synrad tail
  
   
• Simplified beam line view:

  

  The StarOffice source is here.
   

• Beam steering with bumps(May 2002):
  • Close collimator 52a to get rid of BH radiation.
  • For e⁺: positive current moves downward and inward.
  • A horizontal 3-coil bump around GJ is most effective: CH 44 11 02
  • Also CH 75 44 02 helps a bit.
  • Vertical bump CV 56 27 04 also helps
  • In addition there are the standard 4-coil lumi bumps CH 75 44 44 75 and CV 56 27 27 56. 'Symmetric' moves the beam position at the IP, 'asymmetric' changes the angle. These are used to steer the Bremsstrahlungs beam into the lumi photon detector. The p beam is then moved to achive collisions.
  
   
• Magnet listing:

  

• Synchrotron radiation by Daniel Pitzl:

  

  Zoomed

  Note the different scales for x and z.
   

• Side view of H1: