TCSPM Scenarios with New WP5 Baseline - PowerPoint Presentation

Slide1

Slide2

TCSPM Scenarios with New WP5 Baseline

20 Sep 2019

A.Mereghetti

2

A. Mereghetti, on behalf of the LHC Collimation Team

Slide3

HL-LHC IR7 Impedance Upgrade

Recent

change of baseline

of the IR7 impedance upgrade in the context of the HL-LHC project: 9 TCSPMs instead of the 11 initially foreseen

;4 TCSPMs will be installed during LS2;

5 TCSPMs will be installed during LS3;

2 slots will remain equipped with the present hardware;

The installation slots for the LS2 upgrade have been identified by optimizing impact on impedance while taking into account also:Expected cleaning performance – no particular change expected;Expected levels of energy deposition and foreseen deformations;The most exposed MoGr TCSPMs (first TCSG slot) is subject to a total jaw deformation of 500mm towards the beam in case of 0.2h BLT with HL-LHC beam parameters – present tolerance: 100mm;We decided not to install the TCSPM in LS2 in this slot (first TCSG);Elastic deformation: the collimator deforms during the load, but then recovers the initial condition  no permanent damage;Considerations on MKD-TCSG phase advance and likelihood of direct beam impacts (e.g. injection failure scenario, asynchronous beam dump);Final installation slots:TCSG.D4L7.B1 / TCSG.D4R7.B2 (IV IR7 TCSG);TCSG.B4L7.B1 / TCSG.B4R7.B2 (V IR7 TCSG);TCSG.E5R7.B1 / TCSG.E5L7.B2 (last but one TCSG);TCSG.6R7.B1 / TCSG.6L7.B2 (last TCSG);More details available in CERN-ACC-2019-0001;

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Still to be decided!

Slide4

Run III IR7 Layout

Foreseen IR7 layout for Run III:

4 TCSPMs per beam;

2 TCPPMs per beam will replace the present TCP.D (V plane) and TCP.C (H plane) – thanks to the Consolidation project;

A TCLD per beam in-between two 11T dipoles in cell 9 – improvement of IR7 cleaning;

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Slide5

Choice of Slots for Installation in LS3

Installation slots for LS3 still to be identified;

We can deal with the problem as

choosing the two slots not to be upgraded

;As for the installation slots of LS2, a choice based on optimizing impedance may conflict with a choice taking into account energy deposition considerations;

In the following: we consider as post-LS3 baseline all TCSGs replaced by TCSPMs but the two most exposed to energy deposition;

Impact on impedance evaluated by S.

Antipov (see next presentation):He will compare the present post-LS3 baseline scenario against two others, where he focuses on optimizing impedance only;20 Sep 2019A.Mereghetti5The first and third TCSGs are those most exposed to energy deposition;Choice of LS3 installation slots based on total Endep in collimators in case of 2015 proton quench test, B2H;B2Does the pattern change with losses on the vertical plane?

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Total

Endep

in collimators (

SixTrack-Fluka coupling  Fluka) in case of 2015 proton quench testBLM signals from qualification LMs, 2018, post-TS1, B1No detailed endep simulations in case of B2V losses;We cannot check that also for Ver losses the first and third TCSGs are the most exposed TCSGs;…but BLM signals qualitatively reproduce the total load on the collimators;Inelastic interactions in collimators, HL-LHC, v1p3, all TCSPsB2B1Qualitative pattern from total endep is reproduced by BLM signals also for a different optics, jaw material and beam;BLM pattern at TCSGs does not qualitatively change with the plane of losses;Choice of Slots for Installation in LS3 (II)Most exposed TCSGs are the first and third one

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Post-LS3 IR7 Upgrade Baseline

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B1 Collimator

Length [m]

Material

InstallationTCPPM.D6L7.B10.6MoGr (uncoated)LS2 (consolidation)TCPPM.C6L7.B10.6MoGr (uncoated)LS2 (consolidation)TCP.B6L7.B10.6CFC (uncoated)-TCSG.A6L7.B11CFC (uncoated)-TCSPM.B5L7.B11Mo-coated, MoGrLS3 (HL-LHC)TCSG.A5L7.B11CFC (uncoated)-TCSPM.D4L7.B11Mo-coated, MoGrLS2 (HL-LHC)TCSPM.B4L7.B1

1Mo-coated,

MoGr

LS2 (HL-LHC)

TCSPM.A4L7.B1

1Mo-coated, MoGrLS3

(HL-LHC)

TCSPM.A4R7.B1

1

Mo-coated,

MoGr

LS3

(HL-LHC)

TCSPM.B5R7.B1

1

Mo-coated,

MoGr

LS3

(HL-LHC)

TCSPM.D5R7.B1

1

Mo-coated,

MoGr

LS3

(HL-LHC)

TCSPM.E5R7.B1

1

Mo-coated,

MoGr

LS2

(HL-LHC)

TCSPM.6R7.B1

1

Mo-coated,

MoGr

LS2

(HL-LHC)

In the following, we will show reference loss maps (simulated) for this baseline

In the present post-LS3 baseline, IR7 TCLAs (1m,

Inermet

) will not be replaced, and the TCLD (0.6m,

Inermet

) is kept between 11T magnets in cell 9;

Slide8

Simulation Set Up

HL-LHC v1p3, 7

TeV

,

b*=15cm;B1H / B1V LMs with 2s

-retraction settings;

TCLD between 11T dipoles in cell 9;

Fluka-SixTrack coupling  get LMs and touches for endep simulations;High luminosity IRs:Horizontal TCTs in CuCD, Vertical TCTs in Inermet180;All TCLs are in Inermet180;Collimator settings: usual 2s-retraction (referred to eN=3.5mm) configuration;20 Sep 2019A.Mereghetti8IRFamiliesSettings [s] eN=2.5mmSettings [s] eN=3.5mmIR3TCP / TCSG / TCLA17.7 / 21.3 / 23.715 / 18 / 20IR7TCP / TCSG / TCLA / TCLD6.7 / 9.1 / 12.7 / 16.65.7 / 7.7 / 10.7 / 14

IR6

TCSP / TCDQ10.1 / 10.1

8.5 / 8.5IR1/5

TCT / TCL4 / TCL5 / TCL610.4 / 14 / 14 / 14

8.8 / 11.8 / 11.8 / 11.8IR2

TCT

43.8

37

IR8

TCT

17.7

15

In addition to the presented baseline, settings with 1

s

-retraction (referred to

e

N

=3.5

m

m) are also explored (only IR7 TCSGs/TCSPMs settings are changed), as option for a pushed collimation configuration;

~10M primary protons per case, 1% surviving at most

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B1 LMs – Post-LS3 Baseline – 2

s

Clean machine, as expected

B1H

B1V

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B1 LMs – Post-LS3 Baseline – 1

s

1

s

retraction settings make the machine even cleaner wrt 2s retraction, as expectedB1HB1V

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B1 LMs – Post-LS3 Baseline – 2

s

Location of highest cold losses at upstream 11T (as expected): average cleaning inefficiency at 7-8 10

-6

m-1, peak at 2-3 10-5 m-1;B1HB1V

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B1 LMs – Post-LS3 Baseline – 1

s

Location of highest cold losses at upstream 11T (as expected): cleaning inefficiency lower than with

2

s retraction settings, i.e. average at 4-6 10-6 m-1, peak at 1-2 10-5 m-1;B1HB1V

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B1H LMs – Post-LS3

Baseline –

1

s

vs 2s1s-retraction2s-retractionHigher load on TCSGs when using 1s-retraction settings wrt 2s-retraction ones, up to x2.5

Slide14

Further Cases Studied

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The previous analysis shows that:

Presented post-LS3 baseline keep the machine clean;

Overall, B1V losses are slightly lower than B1H;

Overall, 1s-retraction settings are more effective than 2s-retraction settings;Actual margins to quench in IR7 DS should be assessed taking into account also particle-showers  simulations with FLUKA;In addition to the presented baseline, alternative configurations have been explored, where the material of the first and third TCSGs changed, in the effort of mitigating the large jaw deformation expected for the most exposed TCSG:Mo-coated, MoGr (as all the other TCSGs) – this configuration, taken as reference, corresponds to the previous upgraded baseline;R4550 TCSGs – coated and uncoated;Post-LS2 scenario is shown as well, as reference;LMs are available in the back up slides;Results shown in the following concentrate on variations wrt post-LS2 baseline with 2s-retraction settings;MaterialDensity [g/cm3]MG6400 (MoGr)2.48R4550 (graphite)1.83AC-150-K (CFC)1.67Cleaning inefficiencies in the IR7 DS are expected to change very little with TCSG material, whereas loads on TCSGs can change more clearly;

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Average Cleaning Inefficiency in IR7 DS

2

s

-retraction

1s-retractionB1HB1VWrt the post-LS2 configuration, any post-LS3 configuration with 2s-retraction settings brings a minor (almost negligible) improvement;Using 1s-retraction settings clearly improves the cleaning wrt 2s-retraction settings no matter the scenario;Results for the various scenarios with 1s-retraction settings can be regarded as basically equivalent;Results rely on a statistics of <1k protons locally lost;

Slide16

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Peak Cleaning Inefficiency in IR7 DS

2

s

-retraction

1s-retractionB1HB1VResults rely on a statistics of ~20 protons locally lost (10cm binninb);Wrt the post-LS2 configuration, no definite trend is there for post-LS3 configurationsUsing 1s-retraction settings clearly improves the cleaning wrt 2s-retraction settings no matter the scenario;Results for the various scenarios with 1s-retraction settings can be regarded as basically equivalent;

Slide17

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Load on TCLD

2

s

-retraction

1s-retractionB1VB1HAs for the average cleaning inefficiency, wrt the post-LS2 configuration, any post-LS3 configuration with 2s-retraction settings brings a minor (almost negligible) improvement;Using 1s-retraction settings clearly improves the cleaning wrt 2s-retraction settings no matter the scenario;Results for the various scenarios with 1s-retraction settings can be regarded as basically equivalent;B1VB1H

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Load on IR7 TCSGs – 2

s

B1H

B1V

Installation in LS2Installation in LS2Installation in LS3Installation in LS3Higher loads on TCSPMs installed in LS3Lower loads on TCSPMs already installed in LS2First TCSG affected only by change of its own jaw material

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Load on IR7 TCSGs – 1

s

B1H

B1V

Installation in LS2Installation in LS2Installation in LS3Installation in LS3First TCSG affected only by change of its own jaw material1s

-retraction settings imply generally higher loads on all secondary collimators;

If compared to post-LS2, 1

s

-retraction settings, the pictures is very similar to the plots in the previous page;

Slide20

Load on IR7 TCSGs

The post-LS3 baseline (i.e. replacing 5 TCSGs with TCSPMs in the chosen slots) will imply higher total loads on the exchanged collimators and lower loads on the TCPMs installed in LS2, no matter the retraction settings;

As expected, since we equip some collimators with a material with higher density than the present one;

Estimated numbers are based on number of inelastic events;Actual numbers should be evaluated with

Fluka simulations, since change of jaw material changes also development of secondary particle showers, especially in a region where cross-talk is important, as in IR7;Changing the material of the first and third TCSGs them in Mo-coated MoGr

, graphite or Mo-coated Graphite implies an increase in their total loads, especially on the first one, and a re-distribution of the loads on the downstream collimators;

Again, final numbers to be computed with

Fluka;Inputs for Fluka endep studies available;Important to estimate the deformation of the jaw, and its impact on cleaning performance;20 Sep 2019A.Mereghetti20

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Conclusions

The post-LS3 IR7 baseline has been presented;

Wrt

the post-LS2 configuration, 5 TCSPMs are planned for installation in LS3;

The first and third TCSGs are planned to be kept as they are, to avoid big elastic deformation in case of BLT drops to 0.2h;B1H/V LMs with post-LS3 upgrade have been presented;HL-LHC v1p3, b*=15cm, 2s-retraction settings;Input for endep studies with Fluka available  important to finalise estimation of jaw deformation and definition of tolerances;B2H/B2V still to be simulated;Simulations with 1s-retraction settings (pushed cleaning perfromance) have been simulated as well for comparison;Load on TCSGs is expected to increase – number of inelastic interactions increase by at most x2.5;Options with different jaw materials for the un-changed TCSGs have been explored;Inputs ready for endep simulations with Fluka;

Slide22

Back-up Slides

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Slide23

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B1H LMs – Post-LS2 Baseline – 2

s

Slide24

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B1V LMs – Post-LS2 Baseline – 2

s

Slide25

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B1H LMs – 11 TCSPMs – 2

s

Slide26

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B1V LMs – 11 TCSPMs – 2

s

Slide27

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B1H LMs – 2 R4550 TCSGs – 2

s

Slide28

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B1V LMs – 2 R4550 TCSGs – 2

s

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B1H LMs – 2 R4550 TCSGs Mo-coated – 2

s

Slide30

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B1V LMs – 2 R4550 TCSGs Mo-coated – 2

s

Slide31

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B1H LMs – Post-LS2 Baseline – 1

s

Slide32

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B1V LMs – Post-LS2 Baseline – 1

s

Slide33

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B1H LMs – 11 TCSPMs – 1

s

Slide34

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B1V LMs – 11 TCSPMs – 1

s

Slide35

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B1H LMs – 2 R4550 TCSGs – 1

s

Slide36

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B1V LMs – 2 R4550 TCSGs – 1

s

Slide37

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B1H LMs – 2 R4550 TCSGs Mo-coated – 1

s

Slide38

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B1V LMs – 2 R4550 TCSGs Mo-coated – 1

s