HERA Beam Dynamics Meeting / Minutes : 15.04.2004

Attending :
F.Brinker, E.Kot, E.Negodin, U.Schneekloth, M.Vogt, F.Willeke.

1. Program for HERA improvements (see meeting 17.07.03) :
   
   • several extra meetings planned for April/May 2004
     (probably timeslot from former ``lumi upgrade meeting'' [Friday mornings])
   • organisation → E.Negodin
2. HERA : today 08:30 : TSP @ absorber SR11 : vacuum leak ⇒ IR-S vented
3. Plans for machine studies after next maintanance day (06.05.04)
   • p / longitudinal :
     [involve S.Choroba & R.Wagner]
     1. PhaseLoop-I :
        
        • measure damping time
          (mutually create phase jump and measure response)
        • measure bandwidth
          (store train-of-10 and inject new train-of-10 with mutually wrong phase at various realtive bunch positions)
        • ??? measure transfer function ???
          → earlier plans for studies → R.W.&M.V
     2. further ideas [not for next machine studies !]
        • idea : possibly PhaseLoop-I and PhaseLoop-II can successfully damp modes l=0,1,2,3, (low order)
        • additional single-mode-feedback (l=164) might help
        • wide-band MB-FB probably not realistic before 2007
   • beam-beam
     study effect: p(strong)→e(weak)→ ?+impedance? →e-coherent-oscillation→p-emittance-blow-up [→ E.K.]
     fill 180 bunches p & view e & collide at both IPs simulataneously at various tunes .... ← measure e-transv.-MB-FB signal [→involve J.Klute]
   • p / operation
     1. test of p tune controll program
     2. test of p orbit feedback
   • p injection :
     commission OTR monitor → E.K., K.W. & ???
   • e⁺ injection : optimization
4. Polarization of ca. 50% achieved with flipped rotator polarities
5. e^- operation
   Not yet clear whether to switch before or directly after this year's summer-shut-down, or even later. → discussion with experiments.
   Three potential major causes of trouble :
   1. flipping the polarity of all power supplies
   2. different orbit @ IP's ← shifted IR-quads !
   3. ``the aftermath of the summer-shut-down''
   ⇒ suggested scenario (if an early switching seems preferrable) :
   • before shut down : test step 1 (power supplies)
   • get stored e-beam
   • shift magtnets
   • get stored & ramped e-beam
   • study SyLi on ramp and at lumi
   • start shut down and now principle pit-falls already ! /li<>
6. In 2 weeks : dedicated BD-meeting on ⁺ INJECTION
7. EPAC 04 : (see minutes / 29.01.04)
   
   • deadline for early registration expires 30.04.04
   • people who have submitted an abstract should write a ``ReiseAntrag'' a.s.a.p. !

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