6th Evian Workshop

Session

Performance and limitations - part I

15 Dec 2015, 16:40

Hotel Hilton

Conveners

Performance and limitations - part I

• Rogelio Tomas Garcia
• Belen Maria Salvachua Ferrando

Presentation materials

summary_performance_and_limitations.pdf

10. LHC Emittance Growth until Stable Beams

Maria Kuhn

15/12/2015, 16:40

In 2012 emittance calculations from luminosity indicated that about 30 % potential peak performance was lost due to transverse emittance blow-up through the LHC cycle. The origin of the blow-up was only partially understood. The available emittance measurement systems gave inconsistent results. During Long Shutdown 1 the LHC transverse profile monitors underwent important upgrades to improve...

11. Luminosity, Emittance Evolution & OP Scans

Michi Hostettler

15/12/2015, 17:00

During 2015 proton physics operation, beam size estimates were derived from the luminosities acquired during small VdM-like beam separation scans (the so called "OP scans"). This talk recalls the main results from such scans, e.g. fill-by-fill differences and emittance evolution in stable beams. In particular, it is shown that emittance shrinking due to synchrotron light damping was observed...

12. Luminosity modeling for the LHC

Fanouria Antoniou

15/12/2015, 17:15

In this talk, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on a Fill-by-Fill and a bunch by bunch analysis and observations, other sources of luminosity degradation will be discussed. Finally missing pieces and next steps will be briefly discussed.

13. How to survive a UFO attack

Bernhard Auchmann

15/12/2015, 17:30

UFOs in the LHC have proven to be a potential threat to machine availability. While the correlation of peak losses with beam intensity had initially indicated a potential limitation, the fast advance of the conditioning effect appears to have saved the day. In this presentation we will present our current understanding of the UFO threat, the BLM strategy to optimize machine availability and...

14. LHC aperture and ULO restrictions: are they a possible limitation in 2016?

Daniele Mirarchi

15/12/2015, 17:50

Frequent multiple-UFOs events in C15R8 that trigger a beam dump were often observed during the LHC commissioning in April 2015. Detailed local aperture measurements revealed the presence of an unidentified lying object that induces such losses. A quantitative and systematic overview of all the observations and measurements performed in 2015 it is shown. In conclusion the present situation and...