LBDS Testing Before Operation

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