1. 18/March/2008OP-days S.Mataguez / O.Hans1 Hardware Problems in the PS complex LINAC 2 BOOSTER PS AD Thanks to all that helped and provided information, including Fabrice, Richard, Rende, Delphine, Ray, Klaus, Didier, Bettina, Jan, Pierre…. Wikipedia (Eng.): A problem is an obstacle which makes it difficult to achieve a desired goal, objective or purpose.

2. 18/March/2008OP-days S.Mataguez / O.Hans2 LINAC 2Source  During operation an increased number of flash over on the source, up to 60 in 24h (normal rate is 5/24h).  The problem was identified to be grains of “black dust”, coming from the air conditioning system.  The air conditioning conducts have an inner insulation layer (black), which went off.  First aid was to install filter.  During shutdown, vacuum cleaning of the air conditioning conducts and the filters will stay.  Richard is optimistic, that we will not have the black dust problem in 2008.  General remark for Linac2: Linac2 had an excellent run last year with 98.7% of beam availability.

3. 18/March/2008OP-days S.Mataguez / O.Hans3 LINAC 2RFQ  The RF tuner on the RFQ was blocked, which resulted in a reduced beam intensity.  The problem was found on the piston, where the thread went off.  During the technical stop tuners of the RFQ were replaced.  During shutdown all tuners (on RFQ, buncher and tanks) were inspected and mechanically improved.

4. 18/March/2008OP-days S.Mataguez / O.Hans4 LINAC 2RF amplifiers  During the run, Linac2 had a water leak on a RF amplifier.  Water hose needed to be exchanged, which means long down time.  During shutdown all water hoses were exchanged.

5. 18/March/2008OP-days S.Mataguez / O.Hans5 LINAC 2RF Tank 3  During operation 2006, vacuum problems on Linac2 RF tank 3  Repair in shutdown 2006/2007. A polymer skin was poured around the flange. No RF trips in 2007.  Vacuum in 2007 was better than in previous years.  This repair will stay until Linac4 comes.  Reminder: For 2008 the Linac vacuum control system moved to PVSS.

6. 18/March/2008OP-days S.Mataguez / O.Hans6 BOOSTERWire Scanner  Booster has for each ring one vertical and one horizontal wire scanner.  End of the run, 2 of the 8 wire scanner were broken. The situation for the start-up is:  All scanners were maintained and calibrated.  Vacuum valves were added to simplify their removal.  Ring 1 equipped with new (LHC) electronic. But not operational for the start-up.

7. 18/March/2008OP-days S.Mataguez / O.Hans7  Beam losses “ SFTPRO Normal Extraction” PSElectrostatic Septum SS31  Beam losses “ SFTPRO Bad Extraction”

8. 18/March/2008OP-days S.Mataguez / O.Hans8 PSElectrostatic Septum SS31  Reason for brake-downs is a weak insulation of a new installed power supply cable (in picture red cable).  Time to exchange the cable is approximate 3 hours (spare cable is stocked inside the PS). Including time to cool down. 19 th Aug.8 th Sep.29 th Sep.15 th Oct.  History of failure:

9. 18/March/2008OP-days S.Mataguez / O.Hans9 PSElectrostatic Septum SS31  On the outer tunnel side, septum connection side, a second resistor was added. This relieves mechanical stress on the cable.  The old (black and better) cable will be used.  What was done to solve the problem?

10. 18/March/2008OP-days S.Mataguez / O.Hans10 PSInternal Dump SS48  The PS has two internal dumps, in SS47 and SS48.  There very important for setting up of beams, like MTE.  Renovated for start up in 2006. 2007 equipped with new control system. Better performance as in previous days.  During last week of 2007 operation, a vacuum leak in SS48 was detected.

11. 18/March/2008OP-days S.Mataguez / O.Hans11 PSInternal Dump SS48  PS has one spare dump. Spare dump was previously used in the PS and is “hot” (~7mSv/h at contact).  During preparation of spare unit, a bearing broke. Difficult to repair.  Spare unit is installed and operational.  (the original dump SS48 has still the vacuum leak.)  Conclusion: The PS has both internal dumps back. But no operational spare dump.  We are lucky. We do not have to dump our beams like this Cast iron collimator block damaged by repeated P+/P- beam discharges.

12. 18/March/2008OP-days S.Mataguez / O.Hans12 PSPole Face Windings  For run 2007 PS changed from 3-current mode to 5-current mode.  Several switching between old and new power supply. PFW had numerous down time due to PFW switching and resets.  Serious impacts for operational beams (high ripple on EAST-spill) and beam set-ups (MTE).  Very brief presented in this talk. Will be detailed presented by:  On 26 th July the major problems were solved. 5-current mode is operational.

13. 18/March/2008OP-days S.Mataguez / O.Hans13  Beam sharing for East Area 35% towards North Branch 65% towards South Branch PSEast Area MNP23  During operation in 2006 magnet MNP23 failed. The magnet was replaced in the shutdown 2006/2007 by a MCB magnet. BHZ01 Magnet MNP23 Splitter  As a consequence the PS could not perform the shared beam operation.  North and south branch needed dedicated cycles. Loss of cycle efficiency.  Situation will not change for the 2008 run. 2009?

14. 18/March/2008OP-days S.Mataguez / O.Hans14  During operation 2007, three major magnets faults in the AD ADMagnet faults  QFC54, water leak  Repaired during shutdown.  Orbit jumps.  Reason: DHZ2908, internal short circuit.  After replacement, needed 10 days for bake-out.  Fire alarm in the AD hall.  Reason: BHZ12, ground fault.  Cut out the “Y” chamber and installed in refurbished spare magnet.

15. 18/March/2008OP-days S.Mataguez / O.Hans15  Three safety issues in 2007 ADSafety  Access door ATRAP4, and ASACUSA.  The doors were not safe.  Piquet solved both problems.  Beam stopper  Vacuum valve, which operated as second beam stopper caused problems.  Problem was a micro- switch. All micro-switches has been replaced.  Beam stopper (ALPHA)  Beam stopper had too low air pressure.  First aid: Added springs.  During shutdown new hose installed and 8bar pressure is assured

16. 18/March/2008OP-days S.Mataguez / O.Hans16 CPSSummary SolvedNot solved Linac 2 Amplifier (Water leak) RFQ tuner (blocked) Source (flashes) Vacuum on RF tank 3 BoosterFast Wire Scanner PS Septum SS31 Dump SS48 EAST beam sharing (MNP23) AD Magnets (3 faults) Safety (3 faults)

17. 18/March/2008OP-days S.Mataguez / O.Hans17 Hardware Problems in the PS complex End of talk Proverb about problems: “When you can't solve the problem, manage it.”