SPS start up 2014 SPS OP

SPS changes during LS1 New transformers and 18kV cables for MPS. New function generators (FGC’s) with lots of new and different features. SPS completely re-aligned. Parts of TT10 stripped out and re-installed. LSS1 (injection zone including dump systems), removed, re-cabled and re-installed. New low level RF-control. New damper low level control. TCC2 (splitter and target region) removed, re-cabled and re-installed.

Hardware Commissioning Priority to new transformers and MPS (8 weeks). Testing functionalities of new FGC’s (on, off, reset, pulse start, coast…) Polarity checks in transfer lines during nights and weekends when PC’s became available. Testing of all motorisation. Problems : Interruptions : Crash program to replace the severely damaged beam dump. Several magnets had to be replaced (water leaks, vacuum leaks, and short to earth) Slow conditioning of MKP and MKD due to vacuum interventions. Late availability of current measurements ( difficult to validate PC performance). Late availability of new FESA3 classes

A non existing cold check out 5 days stop due to cooled cable on QD which had to be replaced. Week of “Jeune Genevois” a lot of experts on holidays

Beam commissioning Night 12 to 13 September, first beam (SFT) came down TT10 immediately. Spent Saturday 13th on debugging orbit monitors.(e.g. factor of 1000 wrong for BPM in TT10) Sunday 14 th : Acceleration of SFT pro and 25nsec injected. Week spent on commissioning BPM system (kick response measurements, and repairing faulty BPM’s)

Beam commissioning Weekend of September 20 th, after 2 iterations of beam based alignment (see previous MSWG), setting up of slow extraction. SFTPRO after: h rms /v rms = 2.1/1.8 mm LHC (Q20) after: h rms /v rms = 2.3/1.6 mm

Beam commissioning Outgassing of MKP and MKD limiting LHC 25 nsec beam. (1)48 bunches (100msec) e-cloud regime. (2)12 bunches, 21 sec, heating due beam induced e.m. fields. After scrubbing run (beginning of November) nominal LHC 25nsec could be accelerated. 1 2

“Bilan” of the first weeks of beam commissioning 11 cables in LSS1 not connected, badly connected, or not existing (SEM grids, interlock cable to BHZ377, communication cable for MPS). Beam based alignment with two optics worked well. New RF controls, needed setting up, but working well. Damper software became available while commissioning new hardware.

Setting up TT20 Beam transfer to NA had to wait until TCC2 work was finished. Magnets still being connected 2 weeks before beam. Almost no time for hardware commissioning (PC commissioning and polarity checks). Friday 3 rd October, first beam on T2. T4 and T6 ready on October 9th

Issues with TT20 Two PC’s with wrong polarity. New FGC accept only negative current if bipolar. Before, negative strength resulted in systematically in negative current even for unipolar supplies. Lot of issues with power convertors: trips, difficult to start, reset not working preventing progress. (no real hardware commissioning) Cables of SEM grids on splitters had to be swapped. Opposite sign convention for moving monitors on target with ‘wobbling’. Target

Comparison Injection-acceleration12h 24hrs BPM set up+beam based alignment3days6days Extraction + TT20 transfer6 hours6days In 2014 no high intensity beams (> ) possible for the first month, due to outgassing of MKP, MKD, new beam dump and damper commissioning.

Conclusions After cabling campaigns it is up to the equipment groups to check their connections. Having “Jeune Genevois and scheduling Chamonix” during start up is perhaps not the best choice. In spite of many break downs during hardware commissioning and start up, SPS could deliver beam more or less as scheduled (first scrubbing run had to be moved). After all the changes during LS1 the machine restarted remarkably well. After the hard work during LS1 and the stressful end of LS1, the hardware groups wore running out of resources during start up.