Highlights of TI2-LHC Synchronization Test with Beam M. Lamont and - - PowerPoint PPT Presentation

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Highlights of TI2-LHC Synchronization Test with Beam M. Lamont and - - PowerPoint PPT Presentation

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CMS Commissioning Meeting August 15 th , 2008 CERN - Geneva (CH) Highlights of TI2-LHC Synchronization Test with Beam M. Lamont and S. Redaelli on behalf of the OP team Outline Introduction: goals / layouts Beam and magnet availability

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SLIDE 1

Highlights of TI2-LHC Synchronization Test with Beam

CMS Commissioning Meeting August 15th, 2008 CERN - Geneva (CH)

  • M. Lamont and S. Redaelli
  • n behalf of the OP team
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SLIDE 2
  • S. Redaelli, CMS Comm, 12-08-2008

Outline

2

  • Introduction: goals / layouts
  • Beam and magnet availability
  • List of “Firsts”
  • Detailed beam measurements
  • Conclusions
slide-3
SLIDE 3
  • S. Redaelli, CMS Comm, 12-08-2008

Acknowledgments

3

Hardware Commissioning Coordination (HCC) Survey group Access System team Cryogenics Magnets [PO, MPP, QPS, PIC...] Accelerator systems: Injection team, beam instrumentation, (BPM, BLM, BCT, screens ...), beam interlock system, radio-protection, collimators, controls ... Contributions of many people who actively participated to the first LHC beam studies. Comprehensive overview of achieved results at

http://cern.ch/lhc-injection-test/meetings/120808/injection-test-120808.htm

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SLIDE 4
  • S. Redaelli, CMS Comm, 12-08-2008

Layout of beam path

4 6.5 6.6 6.7 6.8 6.9 7 100 200 300 400 500 Longitudinal coordinate, s [ km ] ! functions [ m ]

  • 3
  • 1.5

1.5 3 4.5 Dispersion function [ m ] Dx !y !x Q6.L D4 D3 Q5.L Q4.L Q4.R Q5.R D4 D3 DS Q6.R

TI2

(1) Commission end of TI2 (beam on TDI on IP2-left) (2) Steer beam up to IR3 (3) Stop beam on the collimators (5 Carbon primary+secondary colls;

4 Tungsten absorbers)

Beam 1

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SLIDE 5
  • S. Redaelli, CMS Comm, 12-08-2008

Details of injection region

5

TI2

  • B. Goddard

Septum (MSI), beam offset in Q5, kicker (MKI) Beam instrumentation: beam position and current monitors, screens TDI collimator to protect ALICE during injection steering

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SLIDE 6
  • S. Redaelli, CMS Comm, 12-08-2008

Goals of beam test

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  • M. Lamont: http://lhc-injection-test.web.cern.ch/lhc%2Dinjection%2Dtest/
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SLIDE 7
  • S. Redaelli, CMS Comm, 12-08-2008

Beam on the injection region screens

7

(1) (2) (3) (4)

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SLIDE 8
  • S. Redaelli, CMS Comm, 12-08-2008

Beam on screen at IR3 (first shot!)

8

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SLIDE 9
  • S. Redaelli, CMS Comm, 12-08-2008

Extracted beams (9th to 11th Aug.)

9

Ibunch [ 1e10 ]

First shot

  • n TDI

First beam through an LHC arc First beam- induced quench First recovery after pre-cycle First arc aperture scans First access during beam

  • peration
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SLIDE 10
  • S. Redaelli, CMS Comm, 12-08-2008

Availability of cryo-magnets

10

Weekend of the beam tests Current in dipoles of ARC23

Also sector 56 kept at Einj throughout the weekend

(connected to energy tracking system)

Injection plateau (757A) Quench Pre-cycles (4655A)

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SLIDE 11
  • S. Redaelli, CMS Comm, 12-08-2008

Outline

11

  • Introduction: goals / layouts
  • Beam and magnet availability
  • List of “Firsts”
  • Detailed beam measurements
  • Conclusions
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SLIDE 12
  • S. Redaelli, CMS Comm, 12-08-2008

First trajectory (after a few corrections)

12

  • J. Wenninger et al.

Beam position monitors (BPM’ s) triggered at the first passage (asynchronous acq.) Orbit correction to ± 10 mm in both planes within a few shots!

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SLIDE 13
  • S. Redaelli, CMS Comm, 12-08-2008

First optimized trajectory

13

  • J. Wenninger et al.

Peak-to-peak: ± 3 mm (LHC design specs: ± 4mm!)

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SLIDE 14
  • S. Redaelli, CMS Comm, 12-08-2008

First aperture scan...

14

LHC Project Report 44 (1996) "The intensity of the bunch shall therefore not be much larger than 3 10^9 protons." Indeed, we quenched a main dipole in the region Q8→Q7 left of IP3 with a pilot beam of less than 4 x 109p!!

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SLIDE 15
  • S. Redaelli, CMS Comm, 12-08-2008

... and first beam-induced quench!

15

Threshold of Quench Protection System (QPS): 100 mV over 10 ms Voltage Transition to normal conducting state triggered by quench heaters

200 ms

Extracted from QPS post-mortem buffer

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SLIDE 16
  • S. Redaelli, CMS Comm, 12-08-2008

First beam loss analysis

16

BLM measurements Dipole quench threshold (B2)

  • Quad. quench threshold (B1)

LHC beam loss monitors

During “gentle” aperture scans: Up to a factor 4 higher then calculated limit, but did not quench!

  • B. Dehning et al.

Room for improvement/fine tuning on the definition of quench thresholds! Comprehensive collection of data!

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SLIDE 17
  • S. Redaelli, CMS Comm, 12-08-2008

First solution

17

Baseline: pilot “probe” beams of ~5x109 protons to trigger asynchronous BPM acquisitions (no fine timing) By reducing the injected beam intensity, we established that the BPMs can trigger also at <2 x 109 protons! More margin during commissioning phases!

  • M. Lamont, R. Jones, PSB operations, at al.
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SLIDE 18
  • S. Redaelli, CMS Comm, 12-08-2008

Outline

18

  • Introduction: goals / layouts
  • Beam and magnet availability
  • List of “Firsts”
  • Detailed beam measurements
  • Conclusions
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SLIDE 19
  • S. Redaelli, CMS Comm, 12-08-2008

Injection aperture scans

19

  • B. Goddard,
  • I. Agapov et al.

Bottleneck in injection region found, now fixed!

Probe the aperture in the injection region by inducing beam oscillations at the end of TI2.

Aperture model Simulated beam trajectories

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SLIDE 20
  • S. Redaelli, CMS Comm, 12-08-2008

Arc aperture measurements

20

MEASURED beam trajectories

Horizontal arc aperture of 18-20 mm!! Vertical limitation at Q8/Q7-L3 of about 10 mm.

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SLIDE 21
  • S. Redaelli, CMS Comm, 12-08-2008

Understanding of optics model

21

Matrix response measurements by using ~50% of the correctors Check BPM/corrector polarities (only 1 wrong BPM found) BLM calibrations: good within 15-20% Compare with design optics model Slight mis-match found close to IP3-left, under investigation

IP2 IP3 ARC-23

  • J. Wenninger, K. Fuchsberger
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SLIDE 22
  • S. Redaelli, CMS Comm, 12-08-2008

6.5 6.6 6.7 6.8 6.9 7 100 200 300 400 500 Longitudinal coordinate, s [ km ] ! functions [ m ]

  • 3
  • 1.5

1.5 3 4.5 Dispersion function [ m ] Dx !y !x Q6.L D4 D3 Q5.L Q4.L Q4.R Q5.R D4 D3 DS Q6.R

Beam 1

Loss response at collimators

22

TCP.6L3 TCSG.5L3 TCSG.4R3 A5R3 B5R3 TCLA’s 20 LHC collimators on the beam path (7 in TI2 + 4 in IP2 + 9 in IP3) First BLM response measurements in IR3 Carbon (TCP/TCSG’s) vs Tungsten (TCLA’s) response

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SLIDE 23
  • S. Redaelli, CMS Comm, 12-08-2008

Conclusions

23

Access system looks good Very good condition during the weekend

CRYO, QPS, PIC, BIS, power converters

Aperture looks very good

No significant limitations found in the arc 23 Bottle neck in injection region now fixed No time to measure the insertions

Optics looks good

Small phase advance error in arc Something suspicious left of 3.

Instrumentation looks very good

BPMs in asynchronous mode BLMs up and running from first shot Screens etc

Magnet model looks good Controls/Databases looks good (some features…) Beam transfer, RF synchronization looks good

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SLIDE 24
  • S. Redaelli, CMS Comm, 12-08-2008

Outlook

24

TI8

Results of first beam tests are very encouraging... ...but there is still a long way to go! Next challenge in one week!

A journey of a thousand miles begins with a single step!

Lao-tzu, The Way of Lao-tzu Chinese philosopher (604 BC - 531 BC)