lss6/tt60 beam commissioning on 24 th august 2006
DESCRIPTION
LSS6/TT60 beam commissioning on 24 th August 2006. On behalf of E.Carlier, E.Gaxiola, M.Gourber-Pace, E.Hatziangeli, L.Jensen, R.Jones, V.Kain, A.Koschik, M.Lamont, J.Uythoven, J.Wenninger and many more…. - PowerPoint PPT PresentationTRANSCRIPT
LSS6/TT60 beam commissioning on 24th August 2006
On behalf of E.Carlier, E.Gaxiola, M.Gourber-Pace, E.Hatziangeli, L.Jensen, R.Jones, V.Kain, A.Koschik, M.Lamont, J.Uythoven,
J.Wenninger and many more…
http://proj-lti.web.cern.ch/proj-lti/LTIcoordination/relatedmeetings/Extraction6/Extraction-test.htm
Overview• New fast extraction channel in LSS6 commissioned with beam
– LHC beam 1 through TT60 towards TI2: ~100 m of TT60 onto TED beam dump.
• Successful and efficient test– Beam extracted to TED on first attempt– Equipment all worked, eventually, almost perfectly.– Controls & SW all worked, almost perfectly.– Almost all planned measurements completed in ~16 hours.– ~3500 pilot extractions with 5 109 p+, 12 extractions with 12 bunches, 5 1011 p+.– No major issues discovered. First shot on BTV.610317 (TED), 12:35:03
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6273 6289 6305 6321 6337 6353 6369 6385 6401S [m]
X [
mm
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Test program & overview
1. PREPARATION………………………………..
2. CYCLE & EQUIPMENT SETTING UP………
3. LHC BEAM SETTING UP IN SPS…………..
4. PILOT EXTRACTION………………………...
5. APERTURE CHECKS………………………..
6. TPSG ALIGNMENT CHECKS……………….
7. STEERING AND OPTICS CHECKS………..
8. 3 of 4 KICKER TANK TEST………………….
9. KICKER WAVEFORM MEASUREMENT…..
10. REPRODUCIBILITY………………………….
11. MULTI-BUNCH EXTRACTION………………
12. RECOVERY……………………………………
OK
OK
OK
OK
OK
OK
Partial (during 5 and 6)
OK
OK
Skipped
OK
OK
How the time was used
• Total ~1.751013 p+ on TED (cf 51013 maximum announced)• About 3500 extractions made using fast LHC cycle
Preparation ~4.5 h Pilot extraction ~9 h
PilotIntermediate ~1 h
Intermediate extraction ~0.2 h
Recovery ~1.5 h
Extraction and aperture measurements
V.Kain
Verified positions of all extraction elements with circulating or extracted beam
• Detailed data reduction still in progress but no major surprises• Same measurements will be made for LHC extraction septa MSD and TCDS
Calibrated beam loss measurements and profile for circulating and extracted beams
• Different signatures along the extraction channel to LSS4, as expected from TPSG designs• Needed to set BLM interlock thresholds• Allows subsequent quantification of absolute loss levels
Measured aperture along TT60 with varying corrector/septum strengths
• Handicapped by lack of BPCKs and fact that BCT is halfway between extraction and TED• Used positions on screens to estimate maximum possible excursions• Results so far analysed fit well with expected aperture from model (madx plus physical layout)
Beam loss per proton
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Nr. BLM
[mG
y / 1
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p]
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circulating
extracted
Optics checks
V.Kain/A.Koschik
Using data taken for aperture and extraction calibration measurements
Only BTV data available at that time (BPCK firmware problem was being solved)
Automatic data analysis difficult• Positions not returned consistently by BTV device• SDDS used to get positions from 2-D profiles
Already see some interesting results: reasonably good agreement with MAD model
Will extend to all corrector/kicker/septum excitations and measured responses
• Preparing input files from raw data for thorough analysis – rather painstaking
Comparison: Screen positions (inversed sign) vs. MAD predictions
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0.00175 0.0018 0.00185 0.0019 0.00195 0.002 0.00205 0.0021
MSE angle [rad]
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m]
BTV_610018
MAD_610018
BTV_610252
MAD_610252
BTV_610317
MAD_610317
MKE results – saturation/calibration
J.Uythoven/E.Gaxiola
No evidence of non-linearity seen over the range tested
Would allow use of 3 MKE for extraction – merits being discussed
Varied MKE strength from nominal (26 kV) to 33% higher (35 kV).
Checked for saturation effects at higher current /field (up to 0.13 T).
y = -0.8165x + 26.065
y = 0.3921x - 14.356
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MKE setting [kV]
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siti
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m]
BPM
BTV
95.0
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8101214161820222426283032343638
MKE delay [us]
Kic
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BPCK
BTV
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8101214161820222426283032343638
MKE delay [us]
kic
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BPCK
BTV
MKE results - waveform
Find ±1% ripple • ±0.5% specification – needs improving
Flat-top about 18 s• Too long – needs shortening• Bunches kicked outwards on rising edge and make full SPS turn before extraction
See effect of non-linear QFA618 field• Should measure this explicitly
±1%
Varied MKE delay wrt beam position to measure kicker waveform
• as planned for MKD/MKB systems during commissioning of LHC dump system
J.Uythoven/E.Gaxiola
Bunches being kicked on the rising edge, making 1 turn and being extracted
Beam Instrumentation specifics
L.Jensen
Useful for AB/BI in verifying new electronics in place for LHC beam extraction
Found with beam: •Some cabling/SW inversions in LSS60 BPCEs were found with the beam• Firmware problem with BPCKs in TT60
Difficulties in accurate measurement of low intensity with TT60 BCT (kicker noise)
Certain problems remain to be solved:• Most difficult probably signal to noise ratio for the very low intensity pilot beam• Problem with BPMI firmware been investigated and fix believed available.• possible BTV vs BPCK scaling errors being investigated
BTVs had x10 smaller RMS (31 m) in position measurement than BPCKs!
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BTV
BPCK
BTV: RMS 31 m
BPCK: RMS 299
Measured position [mm]
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Controls & SW specifics
M.Gourber-Pace
Major progress made since earlier tests
All CO applications ran smoothly •LSA AP (EquipState, Cycle Manager ) •OASIS Viewer•Fixed Displays•DB Logging•SDDS Logging•ALARMS
Some adjustments performed on the fly to Fixed Displays and DB logging
Main outstanding issues concern logging• Systematic wrong data time stamping at source
for SPS Ring BLM + MUGEF• Septa logged asynchronously (NO timing in FE)• Sporadic holes in data • OASIS scope and channel settings
Missing alarms from mugefs
Fixed display showing all 7 LSS6/TT60 BTVs
Radiation protection
Heinz Vincke/N.Conan
Continuous monitoring of dose rate at accessible gates showed background levels during test – max. predicted was 1 Sv/h (pessimistic)
Radiation survey showed activation levels as expected – 450 Sv/h at TED
Waiting for results from dosimeters
Positive aspects
• High beam availability from SPS
• Fast 8.4 s LHC cycle and pilot bunch from SPS rapid data taking
• Controls & SW very stable and mature– Reaping the LSA harvest
• “Fast” switch to 12 bunches at midnight (~1 hour)
• Very few problems with equipment systems– Most problems shaken out in dry runs in preceding weeks
• Comprehensive and stable logging
• Excellent support from OP, BI and CO
Problems/issues encountered
• No time to condition MKE kickers to full voltage prior to the test– Sparks occurred in magnets - caused several vacuum interlocks
• SPS BPCEs with polarity/plane inversions – Could have been seen before the test, with another beam
• TT60 BPCKs needed several hours’ from experts to work correctly– Not available for aperture/response measurements
• Not possible to change polarity of MDLV for aperture tests– Still some LSA issues with polarity change and ‘zero’ current functions
• Synchronisation of logged data imperfect– TIMESTAMP data different within cycle from different equipment (BPCK, BTV, mugef)– Data 2 cycles late for BLMS!– Makes data analysis much more difficult: has to be properly addressed for 2007!!!
Outlook for 2006/2007
• Some measurements still to make in interleaved LSS4/6 test– Shorten MKE pulse and use only 3 kickers (tbc), and measure new waveform– Measure of non-linear field in QFA618– Full optics/response measurement with BPCKs– Repeat subset of aperture measurements, with BPCKs available
• Commissioning still to make in 2007– Interlock system available and to be tested– High intensity tests - full LHC beam extracted– Interleaved low and high intensity extraction with LSS4 and LHC injection
sequencing– Get ready for TI2 commissioning later in the year