1 / 12

Loss mechanisms

Losses at extraction from SPS LSS4 B.Goddard Input from E.Chapochnikova, W.Hofle, G.Arduini, E.Gaxiola, F.Roncarolo. Loss mechanisms. Scraping of transverse beam tails in H and V planes, on tight septum aperture Particles in the “beam-free” extraction kicker gap. Measured profiles.

tarik-miranda
Télécharger la présentation

Loss mechanisms

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. Losses at extraction from SPS LSS4B.GoddardInput from E.Chapochnikova, W.Hofle, G.Arduini, E.Gaxiola, F.Roncarolo

  2. Loss mechanisms • Scraping of transverse beam tails in H and V planes, on tight septum aperture • Particles in the “beam-free” extraction kicker gap

  3. Measured profiles

  4. Fitted profiles 1s normalised 1s

  5. Settings for extraction MPSH41402.41402[KICK] : 0.0000 MPLH41672.41672[KICK] : 0.5004 MPLH41994.41994[KICK] : 0.3394 MPSH42198.42198[KICK] : 0.1438 MKE1.F[KICK] : 0.110 MKE2.F[KICK] : 0.121 MSE418.F[KICK] : 2.0828 Bump amplitude 31.05 mm at BPCE.41801. Bump amplitude 33.0 mm at QFA.41810. Kicker Voltage 50 kV Opening at TPSG is 49.4 mm. Girder positions: Upstream 47.00 mm Downstream 110.00 mm

  6. Nominal H trajectory ±4 s envelope plotted TPSG diluter MSE septa 1 - 6

  7. Assumptions for loss calculations • Worst-case transverse emittance: factor ~2 above measured values: H: 12p mm.mrad V: 10p mm.mrad • MKE overshoot / ripple: maximum tolerable: ±1.5% • SPS orbit stability: factor ~2 above measured values: ± 0.2 sx/y • Setting-up precision and dynamic mechanical tolerances ± 2 mm

  8. H aperture and losses • Minimum aperture after all tolerances still above 5s. • Total losses <2x106, i.e. <5x10-8 level…seems negligible. • To reach 10-3 losses, ~5.8 mm error in trajectory.

  9. V aperture and losses • Minimum aperture after all tolerances still above 6s. • Total losses <3x102p+, i.e. negligible. • To reach 10-3 losses, ~5.9 mm error in trajectory.

  10. Losses during the extraction gap • 1.05 ms gaps between two PS batches • Gap does not look very clean (PS extraction) • 0.5 - 0.7% of the beam in one of the gaps • Filled bunches near the edges Photo: T.Bohl 9/04

  11. Losses during the extraction gap • Impact TPSG from 33-76% of MKE kick • Central 43% of sweep (bunch 70-160 of 210) • Filled bunches at the edges will scrape • Assuming constant sweep speed and constant 0.7% p+ density in gap • Total of 3x10-3 losses on TPSG • Need to reduce this population to about 0.2% to keep losses at 10-3 level • Lower would of course be better: 0.1%?

  12. Conclusion • Transverse plane : • Expect losses to be below level for nominal operation • Losses approach 10-3 level when trajectory / settings / tolerance errors reach about 5 mm • Extraction gaps • Studies of density profile in gap to complete picture • 0.7 % in gap give losses of about 0.3% on TPSG • Need to reduce population to 0.2 or 0.1% level

More Related