Week in Review: 3/10/03

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Week in Review 3/10/03 3/16/03
Ron Moore FNAL

• Store Summary
• Record Store 2318
• Chronic High Proton Losses _at_ CDF
• Explanation of Tevatron Coupling
• Schedule for Week

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Store Summary
Store Initial Lumi D0 Delivd Lumi Termination Comments
2307 31.8 443 Abort 1st store after shutdown transverse longitudinal dampers ON B0Q5 VFC failure
2312 29.4 1064 Intentional High CDF proton halo losses
2309 18.8 484 Intentional Poor pbar coalescing due to not restoring changes after studies end-of-store studies to pursue high losses at start of store
2315 35.1 1298 Intentional Shot from 120 mA high CDF proton losses
2318 40.6 134 Abort Shot from 149 mA high CDF proton losses store lost while trying to tune on losses
2321 34.3 - ongoing Shot from 133 mA high losses again
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Record Store 2318

• Store 2318 ? 40.6 E30
• Previous best 1953 ? 36.9 E30

1953 2318
Protons _at_ HEP (E9) 5873 7411
Pbars _at_ HEP (E9) 907 902
Calculated Transverse Emit. 17.2 19.8
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Recent Improvements

• Last few stores among highest initial luminosity
• Increased proton intensity
• Better lifetime on helix _at_ 150 GeV (gt 3 hrs)
• No sign of instability
• 7200-7400 E9 protons at start of store (up from
  6400-6600)
• ARF4 cavity restored to pre-shutdown condition
• Reliable pbar extraction ? improved pbar
  coalescing
• Average pbar coalescing now gt 85 efficiency
  to HEP 65
• 800- 900 E9 pbars at start of store (up from
  500-600)
• Want to try bigger stacks (2138 shot from 150
  mA)
• Keep protons at current levels until high losses
  understood better

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FY03 Integrated Luminosity and Plan
stretch
base
Base 0.625 Stretch
As of today Stretch ? 127 pb-1 Base ? 80
pb-1 Actual ? 88 pb-1
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Chronic High Proton Losses _at_ CDF

• Very large proton background at CDF since A1 work
• Has required several hours each store to get
  losses down to level acceptable for silicon
  system
• Some tuning, some waitingno magic bullet
• D0 losses OK, typically proportional to proton
  intensity
• CDF much more sensitive to working point,
  collimators
• Will pursue collimator alignment, aperture scans,
  additional tune, coupling tweaking

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Proton Intensity (E9)
Store 2315
CDF Proton Halo (Hz)
Store 2264
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Explanation of Tev Coupling

• Some historyDon Edwards noticed global skew quad
  circuit SQ running a lot harder in Run II than in
  Run I
• Rolled quads not enough to explain the difference
• Mike Syphers found coupling _at_ 150 GeV can be
  explained by distributed skew quad elements
  around ring
• All dipoles have skew quad component a1 10-4 /
  inch
• Dipole coil sag within iron causes skew quad
  component
• TD personnel measured smart bolts on some Tev
  dipoles
• Coils sagged few (4-6) mils
• G11 blocks at ends of bolts have shrunk via
  compression
• Mike Syphers calculated the a1 component in such
  a sagging coil magnet
• For bolts 6 mils inward, coil sags by 4.2 mils
  ? a1 1.1 10-4 / inch
• What do we do about it?
• Probably nothingglobal skew quads compensating
  OKsag has reached its max
• Repeat orbit measurements with SQ on and look for
  sources of local coupling

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Coupling Study _at_ 150 GeV

• Beam missteered in P1 line
• TSQ global skew quad circuit at 0 amps
• Look at betatron oscillations coupling between
  horz vert
• Below are 4 turns of data 1st turn on left
  scale limits ? 4mm

Horizontal
Vertical
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Tevatron Dipole
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Weekly Schedule
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Sources of Downtime

• Proton Source
• Two failing Linac PAs necessitated
  swap/replacement
• Spare ? LRF4, LRF4 ? LRF1, LRF1 ? out
• Still have BNL tube as an emergency spare
• New tube from Burle delayed again (vacuum issues)
• Booster ORBMP water leak Friday evening
• Repaired leak replaced soggy and shorted
  components
• Tevatron
• D0QT2 (low ? quad trim magnet) supply caused
  quenches on Sat and Sun evening

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Summary

• Store 2318 record ? 40.6 E30
• Lost while tuning to reduce high CDF proton
  losses
• Tevatron running well overall recently
• 2 Linac PA tubes replaced/swapped last week
• Only have emergency spare from BNL
• Sagging coils in Tev dipoles explains coupling
  and why global skew quads run as hard as they do
• Stack Store this week
• Pursue CDF high proton losses with HEP stores and
  dedicated time if needed