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LBDS Testing Before Operation

LBDS Testing Before Operation. Jan Uythoven (AB/BT) Based on the work of many people in the KSL, EC and TL sections. Outline. MKD and MKB Systems Testing before installation Calibration in the laboratory Testing in the machine Calibration Reliability run

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LBDS Testing Before Operation

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  1. LBDS Testing Before Operation Jan Uythoven (AB/BT) Based on the work of many people in the KSL, EC and TL sections

  2. Outline • MKD and MKB Systems • Testing before installation • Calibration in the laboratory • Testing in the machine • Calibration • Reliability run • Testing of the complete LBDS System • From local operation to running the complete system from the CCC • Conclusions LBDS Audit, 28 January 2008

  3. Calibration in the Laboratory before Installation MKD:2 x 15 Magnets2 x 15 Generators+ 2 x 2 Spares MKBH: 2 x 6 2MKBV: 2 x 4 2 30 metal coated ceramic chambers: partly calibrated! Inductive field probe ! LBDS Audit, 28 January 2008

  4. Why Calibration?MKD and MKB Systems • Calibration of individual components • Test all magnets with the same reference generator • Test all the generators with the same reference magnet • Test some of the ceramic chambers (different resistance of the coating) on the same magnet and the same generator • Determine the relation between measured field and current • Precise measurements of the magnet and generator performance gives: • Quality assurance • Find the “bad” magnets / generators and fix them, measure again and see if its better • Weak components were detected and replaced during the calibration process • Critical parameters determined • Method for the analysis of current waveforms developed • Later used by IPOC and XPOC • Comparison with specification / design • Just ok on rise time and overshoot • For MKD determination of individual trigger voltages as function of ‘beam energy’ • Necessity ‘discovered’ during the calibration process • Used for sorting and assigning equipment positions in the LHC LBDS Audit, 28 January 2008

  5. Results:Some MKD Calibration Results LBDS Audit, 28 January 2008

  6. MKBH Calibration Results LBDS Audit, 28 January 2008

  7. Measurements once installed in Tunnel • Repeat same calibration measurements in tunnel • Comparison of Reference Measurements • Example for measured Pulse Length Typical MKD generatorPulse length comparison calibration hall and two measurements in tunnel Measurement of pulse which is too short and continues to become shorter: Compensation capacitor replaced LBDS Audit, 28 January 2008

  8. Results XPOC over Several Weeks of Running (25/11/07 to 12/01/08) 100 % point, relative [%] OverShoot 1 [%] • 15 MKD systems, beam 1, at 2 TeV • Downwards trend on Amplitude not understood • Pearson transformer • Hysteresis • Comm. of Rogowski trans. • Capacitors • Temperature effects • Pulse length: replaced capacitors 1 1 2 Compensation capacitor replaced 2 Overshoot 2 [%] End point, after 91 s [%] LBDS Audit, 28 January 2008

  9. Reliability Run • A testing policy can be applied to 2x15 MKD generator branches per LBDS, 60 in total, in order to accept or reject the hypothesis that they are SIL3 at least. • The test considers the branch failures only and not the system failure. • A test of three months with 1 hour missions ensures that the system is SIL3 or better at 95% confidence level if less than 6 generator branch failures are observed. Failure rate Failures for a 3 months test 10-4 is the assumed failure rate of one generator branch in order that MKD system is SIL3 MKD SIL3 Decision threshold Observed failures Started running in NovemberSo far no failures detected ! LBDS Audit, 28 January 2008

  10. Energies Used during Reliability Run Philosophy is 12 hours stable at 7 TeV settings followed by one pulse, and series of 5 pulses at different energies (average ~ 1/hour). Always following realistic ramp rates. LBDS Audit, 28 January 2008

  11. System Commissioning • Connect up to non MKD – MKB equipment. Add equipment when they become available • Timing – Beam Interlock System (BIS) • To be done in the coming weeks, as LBDS – BIS is a safety critical link • Close BIS loop locally in point 6 • MSD: ramp synchronously with MKD/MKB • TCDQ: position to follow ramp • Beam Instrumentation (XPOC) • RF (synchronisation) • Q4 – possibly run in short circuit when magnet not cold • Main dipoles for BEM: connect when cold and available • Once connected up to the BIS, running from the LHC Control Room • Test as much of the equipment as possible • Operator experience with the LBDS equipment • First tests to start in two weeks LBDS Audit, 28 January 2008

  12. Conclusions • For the MKD and MKB systems standard, precise measurements have been made before installation and, once installed, during ’continuous’ pulsing • They have been successfully used to detect weak components during initial testing and also for one generator once installed • They will also be used for the IPOC and XPOC analysis • Today, the systems have been pulsing for several weeks as part of the reliability run • No failures detected so far. Would expect about two failures on the switches, according to dependability model. • Some trends are observed which are not yet fully understood • No risk to safety, as trends are slow and captured by the pulse analysis • Reliability run ongoing for the coming months, in parallel with other works • System commissioning starting in two weeks LBDS Audit, 28 January 2008

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