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Tevatron Crystal Channeling T-980 Collaboration: FNAL, SLAC, BNL,CERN,PNPI,IHEP,INFN

Tevatron Crystal Channeling T-980 Collaboration: FNAL, SLAC, BNL,CERN,PNPI,IHEP,INFN. Dean Still April 13, 2009 All Experimenters Meeting. Overview. Explanation of crystal channeling Tevatron Crystal Setup End of Store (EOS) Measurements for 2008/2009

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Tevatron Crystal Channeling T-980 Collaboration: FNAL, SLAC, BNL,CERN,PNPI,IHEP,INFN

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  1. Tevatron Crystal Channeling T-980 Collaboration:FNAL, SLAC, BNL,CERN,PNPI,IHEP,INFN Dean Still April 13, 2009 All Experimenters Meeting

  2. Overview • Explanation of crystal channeling • Tevatron Crystal Setup • End of Store (EOS) Measurements for 2008/2009 • Moving to a Beginning of Store (BOS) Study • Preliminary Results from BOS • Conclusion AEM Crystal Channeling - D. Still

  3. Explanation of Crystal Channeling Ray Fliller- Halo 03 AEM Crystal Channeling - D. Still

  4. LE0PIN 23.731 m 33.115m LE033 BLM 23.731 m Channeled beam At E03H 3.5 mm crystal channeled beam Flying Wire Pin Diode E03H Collimator Tevatron E0 Crystal Layout

  5. EOS Measurement for 2008/2009 Thus far, T980 has requested 7 EOS studies since Sept 14, 2008 provide data and understanding on how to utilize crystal collimation. These 7 EOS can be broken down into 2 categories: • 1- 5 EOS establish channeling with reinstalled O shape crystal (installed AUG 2008) AND attempt to understand 2 fundamental questions about what has been demonstrated. • 6-7 EOS test for incorporating the crystal into the Tevatron automated halo removal system AEM Crystal Channeling - D. Still

  6. Summary of EOS Work • From very EOS on Sept 14 EOS demonstrated channeling & improved loss localization with new goniometer, characterized crystals, and enhanced beam diagnostics, BUT … there are 2 basic questions to understand: • Why channel width and VR efficiency are different and worse than 2005. • Why the channeled beam does not appear to have the correct displacement at E03H collimator. • All these are important questions to answer which tell us about crystal performance, efficiencies, … Analysis & Slide: Vladimir Shiltsev AEM Crystal Channeling - D. Still

  7. Learned Info from EOS Newly learned information from studies with new instrumentation included: 1) Mainly abort gap beam was being channeled. With this knowledge coupled with the fact that there is a large miscut angle maybe could answer some of the initial questions. - Is it related to beam dynamic or crystal property. Channeled abort gap beam Bunched beam AEM Crystal Channeling - D. Still

  8. Effects Due to Crystal Mis-Cut Angle According to most recent simulations Having wrong sign(+) of large miscut angle can explain broading of channel width& difference in displaced beam at collimator. February 3, 2009 A.Drozhdin, A,Apyan AEM Crystal Channeling - D. Still

  9. Overview • Plan and Motivation for 2009 • End of Store (EOS) Measurements for 2008/2009 • Moving to a Beginning of Store (BOS) Study • Preliminary Results from BOS • Conclusion AEM Crystal Channeling - D. Still

  10. Plan and Motivation for 2009 The ultimate goal of T980 for 2009 is to have enough understanding and practice to use single plane crystal collimation as part of the normal halo removal operation for every store. By having the capability of incorporating crystal channeling into every store or many stores gain benefits for: • More possible hours of utilizing crystal channeling over ONLY EOS. • Gain practical and operational experience using crystal channeling. • Hopefully demonstrate reduction of halo loss for either or both CDF and D0 detectors. Of Course the caveat to incorporating crystal channeling for every store: it can have NO negative impact on the Tevatron Collider Run AEM Crystal Channeling - D. Still

  11. Moving to Beginning of Store Studies (BOS) • Things for certain to this point: • Crystal channeled beam could be collimated • & intercepted locally (by E03H) thus improving collimation system efficiency • Results are reproducible contrary to earlier studies. • There are many questions about performance and efficiencies to still be answered but we felt we are very confident in the one fact that channeled • beam can be collimated. • We wanted to move to our main goal which • is to use the crystal during a store to start seeing if it can truly reduce proton halo back grounds. AEM Crystal Channeling - D. Still

  12. T-980 Review Process • Aug 7, 2008 : T-980 had a formal Installation review by Accelerator Division, CDF and D0 to confirm readiness and impact to collider program for crystal collimation. Additional mandatory review for determining readiness for conducting a BOS. • Feb 4, 2009: T-980 held BOS review which recommended BOS with EOS confirmation of automated placement of crystal. AEM Crystal Channeling - D. Still

  13. EOS for Store 6901 – Test for BOS Used EOS of 6901 to test full auto insertion of crystal and check that channeling Can be established. Auto insertion of crystal Horizontal worked well Setting the crystal angle To channeling After angle set to Channeling, completed E03H scan to verify channeling AEM Crystal Channeling - D. Still

  14. Overview • Plan and Motivation for 2009 • End of Store (EOS) Measurements for 2008/2009 • Moving to a Beginning of Store (BOS) Study • Preliminary Results from BOS • Conclusion AEM Crystal Channeling - D. Still

  15. Finding channeling point for BOS Store 6903 BOS No clear channel point Store 6901 EOS clear channeling Channeling should be ~-250urad AEM Crystal Channeling - D. Still

  16. Preliminary Look at 1st BOS - Store 6903 Crystal angle drifted ~ 90urad over 16 hours during store. This is most likely do to Thermal heating of Goniometer. Need better angular Control. Loss in bunch At E03H This is crystal channel point. Crystal Angle Drift ~ 90urad Losses in Abort gap at E03H AEM Crystal Channeling - D. Still

  17. Angle Scans at the End of Store 6903 AEM Crystal Channeling - D. Still

  18. Spread of Angles Around Channel -285 -252 AEM Crystal Channeling - D. Still

  19. Store 6903 BOS – Losses at the collimator Channeled Distribution Angles AEM Crystal Channeling - D. Still

  20. Halo Losses During BOS Store 6903 CDF proton halo loss D0 proton halo loss LE033 – local crystal loss CDF Luminosity Store 6906 – Normal store No crystal Store 6903 – Crystal Collimation used AEM Crystal Channeling - D. Still

  21. Crystal Angle Stabilization Software • Added software to correct for temp. effects that change crystal angle. • Corrects to ~ 4urad around a given set point. • Max deviation ~ 14 urad during motor reversal periods. Crystal Angular Motor counts 4 urad Crystal Laser Angle(urad) AEM Crystal Channeling - D. Still

  22. Conclusion • First big transition step in being able to use crystal collimation at the beginning of store (BOS). • There was no negative effect to the collider store from the BOS and hopeful that crystal collimation can be used for many stores. • The angle of the crystal changed by ~90urad of the store which has been addressed as a software angle feedback system. • Crystal collimation during the BOS showed signs of channeling at E0 but it is too early to demonstrate effect around the ring or benefits to CDF and D0 IP’s. • There is still much work to be done to understand and demonstrate effects to miscut angle and effect of losses around the ring. AEM Crystal Channeling - D. Still

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