HERA Beam Dynamics Meeting / Minutes : 09.10.2003

Attending :
D.Barber, M.Bieler, W.Decking, S.Herb, M.Hoffmann, J.Keil, M.Minty, D.Pitzl, M.Vogt, R.Wanzenberg, F.Willeke.

1. Venting of flange SR11 : orbit controll
   • apearently horizontal offset of +20mm in GI/GJ SR !!
   • immediate preventive actions :
     • PT100's installed at downstream flanges of absorber 4 (SR11)
     • console program : submenue of local-history-viwer (M.Lomperski)
   • short-term plans :
     • new, more stringent procedures for assigning files
     • tracking/ energy disposition simulations
   • vacuum seems to recover faster than expected
2. Hot spot OR34 :
   • last weekend : hot spot (35μS) of 5-10cm length found on plain beam pipe OR34. [20cm left of bellow and 30cm right of getter pump]
   • aperture in that region seems to be reduced
   • however, injection OK, lifteime OK
   • no obvious obstacle found
   • later today the aperture will be measured with beam
3. QC's OR12/OR14 :
   The QC's have been lowered. Improvement not yet veryfied with beam. ⇒ later today
4. Vakuum leak at Cavities OR 75/76 :
   
   • all 4 plungers changed
   • since then : vacuum conditioning with RF on and warercooling off
   • water leak found in one of the old plungers
   • 04:00 this morning : RF off and ``adiabtic'' cool down ; then water on
   • next : condition cavity vaccum during operation
5. Short to ground at BU NL :
   • short still not better localizes than BU NL section (most likely center magnet or one towards hall N)
   • PS now operated with virtual ground moved from symmetry point (O) to BU NL
   • ramp & fast dump tests finished. Result :
     temporary operation in this mode up to 920GeV seems OK
   • mid-/long-term plans : buy some spare coils and start replacing the most suspicious looking and obviously defect coils
     --- until then : let's hope for the best ! ---
6. NMR / Zanon reference magnet :
   During thies weeks p-Injektion studies, the magnet compensation (NMR inside reference magnets hall W) seemed to be unstable. Experts are working on the problem.
7. Cable length compensation for HIT to be switched to ``winter'' eitehr this or next week
8. Agenda for next week's meting :
   orbit analysis / orbit steering / orbit interlock / file assignment procedures / ...

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