HERA Beam Dynamics Meeting / Minutes : 15.04.2004
F.Brinker, E.Kot, E.Negodin, U.Schneekloth, M.Vogt, F.Willeke.
- Program for HERA improvements (see meeting 17.07.03) :
- several extra meetings planned for April/May 2004
(probably timeslot from former ``lumi upgrade meeting''
- organisation → E.Negodin
- HERA : today 08:30 : TSP @ absorber SR11 : vacuum leak ⇒ IR-S vented
- Plans for machine studies after next maintanance day (06.05.04)
- p / longitudinal :
[involve S.Choroba & R.Wagner]
- 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
- 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
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
- p / operation
- test of p tune controll program
- test of p orbit feedback
- p injection :
commission OTR monitor → E.K., K.W. & ???
- e+ injection : optimization
- Polarization of ca. 50% achieved with flipped rotator polarities
- 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 :
⇒ suggested scenario (if an early switching seems preferrable) :
- flipping the polarity of all power supplies
- different orbit @ IP's ← shifted IR-quads !
- ``the aftermath of the summer-shut-down''
- 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<>
- In 2 weeks : dedicated BD-meeting on
- EPAC 04 :
(see minutes / 29.01.04)
- people who have submitted an abstract should write a
``ReiseAntrag'' a.s.a.p. !
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