Tevatron operations since the shutdown
This presentation is the property of its rightful owner.
Sponsored Links
1 / 21

Tevatron Operations Since the Shutdown PowerPoint PPT Presentation


  • 44 Views
  • Uploaded on
  • Presentation posted in: General

Tevatron Operations Since the Shutdown. Ron Moore Fermilab – Tevatron Dept. Shutdown/Startup Work. No big upgrades, but lots of maintenance Warmed up 4 houses for vacuum work Found/replaced unexpectedly a few (electrically) bad components

Download Presentation

Tevatron Operations Since the Shutdown

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Tevatron operations since the shutdown

Tevatron Operations Since the Shutdown

Ron Moore

Fermilab – Tevatron Dept.


Shutdown startup work

Shutdown/Startup Work

  • No big upgrades, but lots of maintenance

  • Warmed up 4 houses for vacuum work

    • Found/replaced unexpectedly a few (electrically) bad components

  • Unroll ~60 dipoles, lattice quads (including D16-1 ≈20 mrad)

  • Move CDF and D0 triplets to move IP and lower corrector currents

    • Adjusted CDF again after start-up since IP far off (?)

  • Start up with new helical orbits (horz & vert collision, vert injection)

    • Goal was to eliminate proton loss during helix transition in squeeze

    • Had to revert after high pbar loss in new transition

R. Moore - FNAL


Tevatron operations since the shutdown

R. Moore - FNAL


Tevatron operations since the shutdown

R. Moore - FNAL


Tevatron operations since the shutdown

As good as ever…

R. Moore - FNAL


Losses during squeeze

Losses during Squeeze

  • Proton loss is driven by beam-beam effects

  • New helix more complicated that initially thought

    • Flip horz collision helix in short arc to eliminate B17H separator polarity change

    • Also need vert collision helix flip to allow initiating collisions in usual way

    • Flip vert injection helix to prevent C17V separator polarity change in squeeze

  • Lost ~1/3 pbars during new helix transition in squeeze of 1st 36x36 store

    • Phase changes of helix allowed horz and vert separation minima to coincide

      • Nearly head-on collisions in many places around the ring

    • Some improvements made, but not good enough  revert to old helix scheme

  • Made improvements after tuning-up and making orbit bumps to reduce losses at CDF and D0

R. Moore - FNAL


Shot 5802 smaller proton loss during squeeze

Shot 5802 – (Smaller) Proton Loss during Squeeze

Low-β

LBSEQ

Proton Intensity

[109]

Proton Loss @ Helix Transition

Pbar Intensity

[109]

LBSEQ 14

D11 BLM

[Rad/s]

Loss Spikes

CDF BLM

[Rad/s]

R. Moore - FNAL


Improved proton efficiency in squeeze

Improved Proton Efficiency in Squeeze

R. Moore - FNAL


Tevatron operations since the shutdown

HEP

  • Luminosity ramping up with beam intensities

  • D0 luminosity lower than expected

    • Made 3% improvement with alpha-bumps (horz and vert β* offset longitudinally)

    • Still not understood completely

R. Moore - FNAL


Tevatron operations since the shutdown

R. Moore - FNAL


Lifetimes in hep

Lifetimes in HEP

  • Pbar lifetime is improved – almost entirely luminous

  • Proton lifetime suffering from small pbar emittances

    • Pbars 3-4 times smaller than protons

    • Greater fraction of proton bunch sees strongest beam-beam force

    • Highest head-on tune shifts for protons > 0.024

    • Trying to blow-up pbars last few stores (missteering at injection)

R. Moore - FNAL


Tevatron operations since the shutdown

R. Moore - FNAL


Proton burn rates store 5802

Proton Burn Rates – Store 5802

Mary Convery

Measured burn rate

Non-luminous burn rate

Non-luminous losses dominate early in HEP

Burn rate from luminosity

R. Moore - FNAL


Tevatron operations since the shutdown

Jerry Annala

R. Moore - FNAL


Tevatron operations since the shutdown

5 store running average

R. Moore - FNAL


Summary

Summary

  • Post-shutdown start-up longer than desired

    • Adjust CDF quads (again) and revert to old helix

  • Beam losses at injection, ramp, squeeze as good or better

  • Luminosity ramping up with beam intensities

  • Proton lifetime early in HEP is an issue

    • Exacerbated by small pbar transverse emittances

  • Want higher intensities to push integrated luminosity

    • 15-20% more protons and pbars to return to pre-shutdown

    • Get back to > 40 pb-1 per week reliably

R. Moore - FNAL


Pbars in the squeeze

Pbars in the Squeeze

R. Moore - FNAL


Tevatron operations since the shutdown

R. Moore - FNAL


  • Login