1. R2E impact of TCL settings: input for 2017 operation
LHC Collimation Working Group #216, 10 Apr 2017
Rubén García Alía, on behalf of the R2E project

2. LHC Collimation Working Group #216
Introduction
Quick overview of 2016 radiation levels related to TCL6 settings in P1 and P5
Projections for 2017 and impact on relevant equipment
R2E recommendation for 2017 TCL6 settings
April 10, 2017
LHC Collimation Working Group #216

3. TCL setting R2E impact: general overview
w/o TCL6
with TCL6
FLUKA studies on the radiation in the Point 5 Q6-Q7 area:Roman Pots, TCL6 and RR, L. Esposito et al, LHC Collimator Working Group #168, January 2014
April 10, 2017
LHC Collimation Working Group #216

4. TCL setting R2E impact: general overview
TCL6 effective in reducing losses in DS cell 9
Impact from collision debris: comparison of ATS and nominal optics, F. Cerutti et al, 3rd ATS optics preparation and validation meeting –December 7, 2016
April 10, 2017
LHC Collimation Working Group #216

5. TCL setting R2E impact: general overview
TCL6 open: larger levels in DS, beginning of cell 9
Normalized Losses (Gy/fb-1)
TCL6 closed: larger levels in RRs
2016 BLM measurements, proton-proton run (O. Stein, 25th MCWG, Feb 17)
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LHC Collimation Working Group #216

6. LHC Collimation Working Group #216
Levels in RR: 2016
2016 settings agreed with R2E input (174th LMC meeting, Feb 2014) – failures in the ARC were expected to dominate
Different scenario due to lower ARC levels and FGC sensitivity (and now FGClite deployment)
Similar levels per TCL operation mode and luminosity are expected for 2017
Point 1 (TCL6 open): ~5·107 HEH/cm2/40fb-1
Point 5 (TCL6 open): ~2.5·107 HEH/cm2/40fb-1
Point 5 (TCL6 closed): ~2.5·108 HEH/cm2/40fb-1
P1 & P5 UJ, RR and DS levels: 2016 measurements M. Kastriotou et al, MCWG #25, February 2017
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LHC Collimation Working Group #216

7. LHC Collimation Working Group #216
Levels in DS: 2016
P1 RadMON cell 9 location:
L1: Between MBB9 and MQ9
R1: between MQ9 and MBB9
P5 RadMON cell 9 location:
L5: between MQ9 and MBB9
R5: below MBB9
No visible impact of TCL settings on radiation levels
RadFET dose levels (40 fb-1):
9L1: 30 Gy
9R1: 4.2 Gy
9L5: 33 Gy
9R5: 5.4 Gy
Cell 8: visible impact of TCL settings, but low absolute values (<1 Gy/40 fb-1)
Analysis: Maria Kastriotou, Corinna Martinella
April 10, 2017
LHC Collimation Working Group #216

8. Impact on equipment: EPC
Sensitive systems and SEE cross sections in RRs (P1 and P5):
FGC2: 120A (x72), 600A (x56) and kA (x60): 1.5·10-10 cm2/unit
Power: 600A (x56): 3.0·10-10 cm2/unit
Roughly 17 R2E events estimated for 2017 (10x FGC2 + 7 power part) expected for 2017 with TCL6 closed settings (factor ~10 less for TCL6 open)
Uncertainty related to equipment SEE cross section and count statistics
Input from Yves Thurel and Slawosz Uznanski, TE-EPC
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LHC Collimation Working Group #216

9. Impact on equipment: QPS
DS area mainly affected by open TCL6: between MQ8 and MBA9
Possibly sensitive equipment: nQPS crate, underneath MBB
Therefore, hardly impacted by TCL6 settings
And shown to be robust during 2015 ion-ion run
Therefore, OK for TCL6 open settings
Input from Reiner Denz, TE-MPE-EP
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10. LHC Collimation Working Group #216
Conclusions
From an R2E perspective, operating with TCL6 open is preferred due to:
The reduced radiation levels in the RRs and therefore reduced number of EPC failures leading to dump
The acceptable increase in the DS radiation levels, mainly impacting MBA9
April 10, 2017
LHC Collimation Working Group #216

11. LHC Collimation Working Group #216
Extra slides
April 10, 2017
LHC Collimation Working Group #216

12. Impact of TCL on DS cell 8, IP5
TCL6 closed
April 10, 2017
LHC Collimation Working Group #216

13. LHC Collimation Working Group #216
DS levels in IP5 - left
Symmetric as to what is seen in right side
April 10, 2017
LHC Collimation Working Group #216

14. LHC Collimation Working Group #216
DS levels in IP1 - left
Similar to P5, TCL6 in (as expected)
April 10, 2017
LHC Collimation Working Group #216

15. LHC Collimation Working Group #216
DS levels in IP1 - right
DS BLM peak around MBA9 not visible for P1 right
April 10, 2017
LHC Collimation Working Group #216

16. LHC Collimation Working Group #216
Fill 5020 example
TCL6 in roughly 30 min before luminosity start
April 10, 2017
LHC Collimation Working Group #216