1 / 34

HOM Issues in LER Ring and IR. Recent measurements and calculations.

HOM Issues in LER Ring and IR. Recent measurements and calculations. Sasha Novokhatski SLAC. More LER & HER currents – more HOM Heating. LER ring TSP feed-through & Bellows Vacuum pumps & NEGs (new) HER ring Bellows (new) Interaction region Vertex bellows & near bellows.

jessica-ashley
Download Presentation

HOM Issues in LER Ring and IR. Recent measurements and calculations.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HOM Issues in LER Ring and IR.Recent measurements and calculations. Sasha Novokhatski SLAC PEP-II Machine Advisory Committee Meeting SLAC, April 15-17, 2004

  2. More LER & HER currents – more HOM Heating • LER ring • TSP feed-through & Bellows • Vacuum pumps & NEGs (new) • HER ring • Bellows (new) • Interaction region • Vertex bellows & near bellows PEP-II MAC Session

  3. Fight against high temperatures • Water and air cooling • Fans for bellows in all LER and HER regions • Special cooling for vertex bellows • Damping High Order Modes by water cooled RF absorbers • HOM absorber in LER arc chamber • Improving RF screens PEP-II MAC Session

  4. HOM measurements and computer simulations • HOM spectrum measurement: • Signals from BPMs • RF antenna near TSP feed-through • RF antenna near HV cable in vacuum pumps • HOM power measurement: • Thermocouples on input and output water cooling system with water-flow measurement • Computer simulation: • Calculations with MAFIA and other wake field programs PEP-II MAC Session

  5. HOM absorber in region 4 Bellows 2012 HOM Absorber TSP 1162 PEP-II MAC Session

  6. Absorber: ceramic tiles with large loss tangent and water cooling tube PEP-II MAC Session

  7. Effect of absorberon TSP feed-through Temperature LER current PEP-II MAC Session Nov. 2002-Apr. 2004

  8. TSP in the next arc chamber 1153 Nov. 2002-Apr. 2004 PEP-II MAC Session

  9. Analog TSPs in region 12 do not have high temperatures Artem Kulikov HOM detectors installed in June 2003 PEP-II MAC Session

  10. HOM spectrum measurement: antenna and spectrum analyzer near TSP 1163 PEP-II MAC Session

  11. HOM power measurement: digital water flow meter and thermocouples PEP-II MAC Session

  12. Power relations Now we are here PEP-II MAC Session

  13. The hottest bellows in the LER LER Bellow 2012 PR04 with ‘super” fan Nov. 2002-Apr. 2004 PEP-II MAC Session

  14. Examples of RF modes. S. Weathersby Magnetic field Electric field PEP-II MAC Session

  15. Proposal for absorber for arc bellows Copper buttons Water cooling tubes Absorber tiles PEP-II MAC Session

  16. MAFIA . Stephen Weathersby computation. Comparison of 1-tile thick covered flange absorber with azimuthal 2x3-tile mount and the no absorber Q values. PEP-II MAC Session

  17. HOM spectrum in IP region. PEP-II MAC Session

  18. Vertex bellows Bellow Cavity bunch field ‘‘Mode Converter” PEP-II MAC Session

  19. Vertex bellows. RF Modes .Stephen Weathersby computation. PEP-II MAC Session

  20. Quadruple mode PEP-II MAC Session

  21. Damping HOMs in vertex bellows. Simulation study by S. Weathersby. • Decreasing Q-value of a bellow cavity by placing absorber • Best position of absorber. • Low Q decreases power dissipation. PEP-II MAC Session

  22. Power dissipation a bellow cavity PEP-II MAC Session

  23. Absorber on the one side does not well damp modes! PEP-II MAC Session

  24. Absorber on the other side. Still not good damping. PEP-II MAC Session

  25. Absorber on the wall PEP-II MAC Session

  26. Power in a cavity PEP-II MAC Session

  27. HOMs in vacuum pumps PEP-II MAC Session

  28. Vacuum pump (LER PR2:3044) HOM spectrum. Frequency range 0-10 GHz Antenna in HV connector PEP-II MAC Session

  29. Frequency range 3-6 GHz PEP-II MAC Session

  30. Q-value estimation PEP-II MAC Session

  31. RF screen for vacuum pump PEP-II MAC Session

  32. RF screens for NEGs PEP-II MAC Session

  33. Other screen PEP-II MAC Session

  34. Summary • More water and air cooling • Damping High Order Modes by water cooled RF absorbers • Simulation studies on improvement of beam chamber elements and RF screens PEP-II MAC Session

More Related