QBPM system commissioning and concerns ATF2 Project Meeting

1
QBPM system commissioning and concerns ATF2
Project Meeting

• System testing
• Installation
• Calibration
• Schedule

2
QBPM project in ATF2 context

• QBPM is the basis for most beamline tuning
• The QBPM system is the largest ATF2
  instrumentation system
• The system should be ready when operation begins
• 2008
• There will not be a stripline BPM system for
  commissioning

3
QBPM project in ILC instrumentation context

• No large, high performance, ILC quality cavity
  BPM exists
• This will be a demonstration project, in its own
  right, and will guide future ILC/FEL work
• This may generate some additional effort
• the QBPM system is large enough to provide
  experience with reliability and systematic errors
• The ILC BPM system will depend on cavities must
  be able to engineer a robust system and have it
  tested
• Initial experience with nanoBPM shows cavities
  can have significant systematic errors

4
Validation of performance comprehensive proof
specifications are met

• Accuracy the quality of being near to the true
  value
• Precision the quality of being reproducible
• Resolution the minimum difference between two
  discrete values that can be distinguished
• BBA provides the true value
• Connection to magnet center must succeed at the
  few micron level ? define 3 microns
• QBPM system must have adequate precision so that
  BBA need not be repeated too often ? define 1 day

5
Basic resolution requirement

• 100 nm over 10s time
• /- 200 micron range
• Relative alignment between magnet and BPM should
  be better than this
• These requirements support BBA

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100 nm routine performance is the goal, with 3
micron longer term stability

• Must be directly demonstrated.
• Must be done with a set (gt3) of BPMs
• How and where?
• Not easy disturbs ODR and feather equipment

7
Preparation for testing QBPM

• Test with or without quad?
• Maybe test one with quad for BBA test
• 2007
• Movers
• Precision of corrector current setting
• Tests with correctors complement mover
• Stiffeners for soft copper chambers
• New spool pieces

8
QBPM calibration

• Bench test plan
• Electronics bench calibration
• Electronics (cavity?) online calibration
• Continuous gain monitoring
• Initial phase offset measurements
• Sign
• Reference cavity(ies) performance and location

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ATF Cavity BPM system 12.05
ATF (Inoue) 6553
BINP (SLAC) 6429
ATF2 6423
R
R
ATF2 downmix
downmix
downmix
LO Cornell
downmix
Complicated multi-frequency system Reliability /
LO
Digitizer - Struck
714 / 2.16
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Mark Slater - Cambridge
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Schedule

• Initial testing December 2005
• Results not available calibration using mover
  not possible
• Many on-board mechanical failures ? now fixed (J.
  May)
• Second prototype complete April 10
• Testing at ATF during 2 weeks operation
• Assuming success production complete June 5,
  2006
• 1 (2?) VME crates and controllers with Struck
  (SIS) 14 bit digitizers
• 70 channels (35 BPMs) spares (10)
• RF infrastructure (LO, cal, triggering) complete
• Mechanical details?