LSC May 2013 Outcome of the magnets tests from the PS, Leir and transfer lines Dominique Bodart

LSC May 2013 The PS main magnets The PS auxiliary magnets The TT2 transfer line The Leir Conclusions Introduction

LSC May 2013 Preventive maintenance, piquet & planning in the PS All intervention performed in the machines are recorded in the Norma database to ensure traceability, preventive and corrective maintenance. Last recorded event in the PS machine is a Bus Bar water pipe burst on 18 th January, repair organized between two LHC beam filling up. PS Hardware test period: 1 week assigned for hardware testing in the PS, 3 weeks needed with 2 weeks of night shifts re- scheduled. PS coordination planning

LSC May 2013 The PS main magnet The main coil The pole face winding The figure of 8 Winding The Back Leg Winding : Campaign of installation of provisional pole clamps (delamination of the yoke) 1974 : Manufacture of 10 additional spare coil sets by ALSTHOM : Installation of second generation PFW (narrow and wide independent circuits) : Installation of new F8W as 2 x 8 loop (Tune & Chromaticity, 26.3 GeV for SPS) : Consolidation Phase I for 51 magnets (1/2 of the machine). The main coils produce the main dipole field and the quadrupole field The Pole Face Windings provide a compensation for iron saturation and eddy currents The Figure of 8 Windings participate to the compensation of the quadrupole The Back Leg Windings provide a correction field at injection.

LSC May 2013 main coils High voltage tests: –High voltage test to ground at 7 kV successful –Increased testing voltage to ground for the upgrade of the Bdot from 23 to 26 Gauss/ms at 10 KV: failure at 8.5 kV in february and march, successful after repeating tests (3) in May. External bus bars from machine to the main circuit breaker located outdoor suspected. Leakage current related to weather conditions, presence of green plants sometimes found in the bus bar case in the past, best results achieved after maintenance of “espaces verts”. Visual inspections: –Insulation to ground degraded but still efficient on old magnets –Decomposition of the main coil shimming especially in magnet #34 (not refurbished) –General state for not refurbished magnets: several repair made in the past by adding protection pads made of ebonite, and using epoxy paint. Thermal inspection: –Overheating of lower pancakes on magnet #75 (not refurbished) Degradation of the ground insulation Degradation of the rubber shims MU 34 Overheating of the lower coil MU75

LSC May 2013 Magnet yoke Status of the poles: –All magnets equipped with pole clamps on the first and last magnet blocks. –All magnets have fine shimming between the lamination and the figure of eight winding to avoid damages of the winding insulation and lamination rupture (1). –Degradation of the pole clamps on MU32 & 75: Loosen poles located at the magnet ends shall be consolidated because the lamination mouvement impacts the Pole Face Winding reliability – Blocks 5 & 6: Yearly visual inspection during pulsing, 40 locations identified having from 1 up to 6 lamination moving. The situation does not degrade thanks to the fix performed on renovated magnets ( ) and to the fine shimming made in the machine. Delamination of end pole MU 75 Fine shimming of the lamination to avoid winding insulation breakdown Delamination effects on magnet yoke Magnet top view and block identification

LSC May 2013 Pole Face Windings HV failure MU55 Location of the crimpings in the PFW High voltage tests: –High voltage test to ground at 3 kV successful for all circuit –High voltage test at 2 kV between windings of each PFW failed on MU55 Internal resistance measurement (crimping resistance): –All the 100 magnets were measured and classified in the five categorization. –Magnets MU 55, 69, 75 have out of tolerance values Visual inspections: –Degradation of the cables insulation on many PFWs. (see next slide) Thermal inspection: –Overheating of PFW in magnet MU69 and MU25 (both are renewed units) –MU69: Connection cable crimping not properly done on upstream lower connection –MU25: Internal crimping of the upstream lower PFW creating high heat dissipation on the connection end. MU25 overheating PFW MU69 connection cable crimping overheating

LSC May 2013 Pole Face Windings Lorentz forces acts on opposite direction

LSC May 2013 Figure of eight windings Degradation of the “special” Figure of Eight Winding View of the MU57 magnet with unused extraction shims High voltage test to ground at 3 kV successful Resistance test shows values within tolerances Special case for MU57 having an old and obsolete configuration used for electron operation. –Degradation of the insulation, –permanent removal of the extraction shim –Standard vacumm chamber and standard Figure of Eight Winding to be installed

LSC May 2013 PS auxiliary magnets Visual inspections: –Water leaks on 205 bumper located in SS19 –Corrosion on coil connection in magnet 414 in SS25 –Magnet 210 located in SS35 having soft water piping will be replaced with a hard piping –Magnet 209 located in SS42 is noisy: Shimming to be checked Thermal inspection: –The test campaign had to be cancelled due to unforeseen priorities given by the machine operation. It will be performed in 2014 before the machine start-up.

LSC May 2013 TT2 transfer line magnets Visual inspections: –Delamination of the soft cooling pipe on 3 magnets –Coil soft shimming made of rubber material shows severe mechanical degradation on 2 magnets –Four magnets having hard cooling pipes show corrosion at the brazed joints due to a non conform brazing flux. The magnets shall be renovated. –Delaminated water hoses will be replaced –Magnet QFO 105 have mis-aligned vacuum chamber and soft water piping. It will be replaced during LS1 with a hard piping and new vacuum chamber. –A consolidation program for all magnets shall be implemented to ensure reliable operation for the next 20 years. Examples of rubber pipe delamination Examples of coil shimming degradation

LSC May 2013 Leir and Ion Beam Line Visual inspections: –All magnet are in good conditions Thermal inspection: –No overheating detected Study / upgrade –DHV12 corrector shall be removed to perform maintenance and magnetic measurement.

LSC May 2013 Conclusions The main coils insulation to ground is OK at 10 kV Replacement of the PFW during LS1: –14 due to dummy septum installation –55, 57, 75 because defective –98 to be taken out for BPM installation –25, not absolutely necessary now, however desirable Renovation of the following magnets is necessary during LS1: –MU75 main coils due to overheating and lamination consolidation –MU34 degradation of the main coil shimming by the radiation Replacement of the cooling water soft piping for all auxiliary magnets in PS and all magnets in TT2 Replacement of the QFO105 magnet from F16 line, magnet inSS35. A strategy shall be discussed for the magnets equipped with the old PFWs These works will require an additional effort from many teams, and a specific coordination from EN-MEF-INJ.