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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….
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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 LTC 13th September 2006
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 LTC 13th September 2006
Test program & overview • PREPARATION……………………………….. • CYCLE & EQUIPMENT SETTING UP……… • LHC BEAM SETTING UP IN SPS………….. • PILOT EXTRACTION………………………... • APERTURE CHECKS……………………….. • TPSG ALIGNMENT CHECKS………………. • STEERING AND OPTICS CHECKS……….. • 3 of 4 KICKER TANK TEST…………………. • KICKER WAVEFORM MEASUREMENT….. • REPRODUCIBILITY…………………………. • MULTI-BUNCH EXTRACTION……………… • RECOVERY…………………………………… OK OK OK OK OK OK Partial (during 5 and 6) OK OK Skipped OK OK LTC 13th September 2006
How the time was used Intermediate extraction ~0.2 h PilotIntermediate ~1 h Recovery ~1.5 h Preparation ~4.5 h Pilot extraction ~9 h • Total ~1.751013 p+ on TED (cf 51013 maximum announced) • About 3500 extractions made using fast LHC cycle LTC 13th September 2006
Extraction and aperture measurements • 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) V.Kain LTC 13th September 2006
Optics checks • 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 V.Kain/A.Koschik LTC 13th September 2006
MKE results – saturation/calibration • 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). • No evidence of non-linearity seen over the range tested • Would allow use of 3 MKE for extraction – merits being discussed J.Uythoven/E.Gaxiola LTC 13th September 2006
MKE results - waveform • Varied MKE delay wrt beam position to measure kicker waveform • as planned for MKD/MKB systems during commissioning of LHC dump system Bunches being kicked on the rising edge, making 1 turn and being extracted • Find ±1% ripple • ±0.5% specification – needs improving • Flat-top about 18 ms • 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% J.Uythoven/E.Gaxiola LTC 13th September 2006
Beam Instrumentation specifics • 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 mm) in position measurement than BPCKs! L.Jensen LTC 13th September 2006
Controls & SW specifics • 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 M.Gourber-Pace LTC 13th September 2006
Radiation protection • Continuous monitoring of dose rate at accessible gates showed background levels during test – max. predicted was 1 mSv/h (pessimistic) • Radiation survey showed activation levels as expected – 450 mSv/h at TED • Waiting for results from dosimeters Heinz Vincke/N.Conan LTC 13th September 2006
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 LTC 13th September 2006
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!!! LTC 13th September 2006
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 LTC 13th September 2006