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Quenches at B1Q3

This article provides a chronology of collider operation, detailing quenches due to lightning strikes, orbit issues, and changes to MP02. It also discusses the challenges faced in alignment during shutdown and suggests possible solutions for future shutdowns.

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Quenches at B1Q3

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  1. Quenches at B1Q3 April 25, 2008

  2. Chronology of Collider Operation • Normal store 6028 Killed by Lightning strike. • Orbit smoothing with BPM problems • Store 6035 Quench because of a bad orbit at sequence 23 only. • MP02 Change and Tevatron (CDF) access • More orbit corrections • Higher losses at LMB1Q3 and frequent quenches • Slow progress to return to reliable operation

  3. Store 6028 – Lightning strike drops safety system quenching B0 and D0 Store 6035 – 9 house quench at lbseq 24 (bad orbit in one slot) Store 6047 to HEP but higher losses in squeeze Store 6048 – Quench B1 Q3 in squeeze Quench A4 Q3 during turn on w/o beam Store 6051 – HEP store with losses in squeeze Store 6054 – Quench B1 Q3 in squeeze Quench B1 Q3 in parse 6 stores to HEP while reducing losses 2 Unrelated quenches at different locations More Details of recent operation

  4. Losses at the B1 Q3 Blue stores before MP02 change Black store 6035 Red stores after MP02 change Green stores are recent

  5. Losses at separator Blue stores before MP02 change Black store 6035 Red stores after MP02 change Green stores are recent

  6. Orbit errors on Store 6028

  7. Orbit errors resulting from smoothing with bad BPMs

  8. Store 6035 minus 6028

  9. 6035 – 6028 B0 Close up

  10. 6047 – 6035 (Changes after MP02 replacement)

  11. Store 6054 - 6028

  12. Store 6071 – 6028 (Low Losses)

  13. 6071 - 6028

  14. Record store and store 6065

  15. Contributors to confusion • There were at least two different causes of quenches (A-side and B-side quenches were definitely different circumstances) • We changed the orbit using non-functioning BPMs • Returning to previous BPM readings did not eliminate quenches • LMB1Q3 does not seem to have the same sensitivity as other BLMs (unless B1Q3 has deteriorated).

  16. What’s left to do? • Finish correcting arcs without changing CDF positions • Fix vertical position at D14 • Establish a new nominal orbit • Insure our TOP setups keep us on a good trajectory through CDF • Return to automatic orbit control • Verify aperture and orbits are OK? • Figure out what to do with alignment next shutdown?????????????

  17. Last shutdown alignment at CDF What do we do next shutdown when we need to move the IP and get correctors back in range?

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