Review of the needs for a hollow e-lens for the HL-LHC

6 Oct 2016, 08:45 → 7 Oct 2016, 17:30 Europe/Zurich

30/7-018 - Kjell Johnsen Auditorium (CERN)

Following the experience of the 2016 LHC operation, this review aims to discuss the need and potential benefits of an active halo depletion system for the HL-LHC and give a recommendation for adopting it into the HL-LHC baseline.

The scope of this review is to examine the two initial motivations (loss spikes during operation and machine protection aspects for operation with Crab Cavities), to evaluate the needs in view of the recent project re-scoping and to compare the projected needs with the operational experience from the LHC during Run I and Run II.

Following the close-out by the review chair, the committee is required to compile a short report with findings, comments and recommendations within one month. The report will be delivered to Lucio Rossi, HL-LHC Project leader.

---

Review panel: Rudiger Schmidt (CERN, Chair), Rob Appleby (UNIMAN), Wolfram Fischer (BNL), Mike Lamont (CERN), Katsunobu Oide (CERN), Mike Seidel (PSI)

Oliver Bruning (CERN) is the link person.

The review is scheduled on 6^th and 7^th October 2016, at CERN.

E-lens-review-report-final.pdf

HL-LHC_e-lens_review_2016_charges.pdf

Thursday 6 October

Welcome

Convener: Oliver Bruning (CERN)

1 Introduction

Speaker: Oliver Bruning (CERN)

Intro Project and Review Goals V1.pptx

Introduction Session

2 Overview and introduction including an outline of the existing installation options, optics conditions, infrastructure requirements (cry, power), Tools for halo measurement and timeline (planning need for the technical design etc.)

Speaker: Stefano Redaelli (CERN)

SRedaelli_2016-10-06_print.pdf

3 Discussion

Session on operational experience and extrapolation to HL-LHC parameters

4 Loss and lifetime observations during nominal operation and their extrapolation to HL-LHC parameters.

Speaker: Belen Maria Salvachua Ferrando (CERN)

BSalvachua_SRedaelli_2016-10-06.pdf

5 Discussion

6 What did we learn about HALO population during LRBB studies and MDs?

Speaker: Yannis Papaphilippou (CERN)

e-lens_review_06_10_2016.pdf

e-lens_review_06_10_2016.pptx

7 Discussion

11:00 Coffee break & Group picture

8 What did we learn about HALO population during MDs and regular operation?

Speaker: Gianluca Valentino (University of Malta (MT))

Halo_MDs_operation_HEL_Review_20161006.pdf

9 Discussion

10 Observations and measurements on the impact of earthquakes and cultural noise on the LHC operation and their extrapolation to HL-LHC parameters.

Speaker: Michaela Schaumann (CERN)

EarthquakeAnalysis_HollowELensReview2016.pdf

EarthquakeAnalysis_HollowELensReview2016.pptx

11 Discussion

12:45 Lunch break

12 Operational experience from HERA and their extrapolation to the HL-LHC

Speaker: Mike Seidel (PSI)

hera_experience.pdf

hera_experience.pptx

13 Discussion

14 Operational experience of RHIC electron lenses and their effect on collimation and halo populations

Speaker: Wolfram Fischer (BNL)

2016-1006 CERN e-lens review, RHIC e-lens experience.pdf

2016-1006 CERN e-lens review, RHIC e-lens experience.pptx

15 Discussion

16 Operational experience from Tevatron and relevance for HL-LHC

Speakers: Alexander Valishev (Fermilab), Miriam Fitterer

2016-Tevatron_Experience_ELensReview-Miriam.pdf

2016-Tevatron_Experience_ELensReview-Miriam.pptx

2016-Tevatron_Experience_ELensReview-Sasha.pdf

2016-Tevatron_Experience_ELensReview-Sasha.pptx

17 Discussion

16:05 Coffee break

18 Expectations (extrapolated from LHC operation) for the beam lifetime and halo population based on scaling from the LHC observations for radiation damping and IBS excitation.

Speaker: Fanouria Antoniou (CERN)

eLensReview2016.pdf

19 Discussion

Session on HL-LHC system specifics

20 RF overview of the Crab Cavity system for HL-LHC with presentation on potential failure modes and summary of the KEK operation experience.

Speaker: Rama Calaga (CERN)

Elens_CrabTalks.pdf

Elens_CrabTalks.pptx

21 Discussion

22 Potential failure scenarios in the HL-LHC machine that can lead to very fast orbit changes (e.g. missing beam-beam kicks, damper failure scenarios, Crab cavity failure scenarios etc) and the resulting machine protection requirements for HL-LHC operation (with input from collimation team).

Speaker: Daniel Wollmann (CERN)

20161006_HollowELReview_MP_FastFailures_V2.pdf

20161006_HollowELReview_MP_FastFailures_V2.pptx

23 Discussion

Friday 7 October

Session on HL-LHC system specifics

24 Measured effects of depleted halo population with hollow e-lens and relevance for HL-LHC

Speaker: Giulio Stancari (Fermi National Accelerator Laboratory)

Stancari_20161006_CERN_e-lens_review_K09.pdf

25 Discussion

26 Alternative methods for halo depletion (damper and tune modulation [ and wire]), long range beam-beam and comparison of their performance / reliability to that of a hollow electron lens.

Speaker: Roderik Bruce (CERN)

2016.10.07-hollow_eLens_review--Alternative_methods.pptx

27 Discussion

28 Potential performance reach for the HL-LHC in case of a depleted beam halo

Speaker: Gianluigi Arduini (CERN)

elensreview_2016_06102016.pdf

elensreview_2016_06102016.pptx

29 Discussion

11:00 Coffee break

30 Reserve session for additional presentation requests from Day 1 of the Review

Work lunch for reviewers

Closed session for report writing

31 Closeout

Speaker: Rudiger Schmidt (CERN)