Rhodri Jones – AB/BIRhodri Jones – AB/BI LHC Injection Test – Beam 2 LHC Injection Test – Beam 2

BPM Issues in Sector 7-8BPM Issues in Sector 7-8● Asynchronous Trajectory Mode

● Worked on 1st Shot● All BPMs acquired

● BPM Problems● BPMIV.88104 – H / V flip suspected

● H pick-up on BI installation traveller – should be V ● Fibre mix-up on 8 BPMs Q1-Q7 Left of 8

● Corrected on Saturday morning● BPM.34R7.B2

● Horizontal plane inverted● BPM.28R7.B2

● B1-B2 mismatch of individual button signal● Reflectometry team?

● BPM.12R7.B2● H / V inversion – fibres crossed

● BPMWE.5L7.B2● H polarity error (nothing visible on photos)

Rhodri Jones – AB/BIRhodri Jones – AB/BI LHC Injection Test – Beam 2 LHC Injection Test – Beam 2

BPMWE.5L7.B2

Beam 2

BPMW.5L7.B2BPM.12R7.B2 BPM.28R7.B2 BPMSX.4L8.B2

IR7 IP8arc

BPMWE.5L7.B2

Beam 2Beam 2

BPMW.5L7.B2BPM.12R7.B2 BPM.28R7.B2 BPMSX.4L8.B2

IR7 IP8arcarc

BPM Issues in Sector 7-8BPM Issues in Sector 7-8

● Other Suspects● BPMW.5L7.B2

● both H & V - gain/polarity? optics? (*)

● BPMSX.4L8.B2● both H & V -

gain/polarity? optics?

● Beam is off centre in BPMSX by ~10mm (in between D1 & D2)

● Optics● phase advance error

● insufficient response data for further details Courtesy of R. Steinhagen

BPMWE.5L7.B2

Beam 2

BPM.12R7.B2

BPM.34R7.B2 BPMSX.4L8.B2

IR7 IP8arcarc

BPMWE.5L7.B2

Beam 2Beam 2

BPM.12R7.B2

BPM.34R7.B2 BPMSX.4L8.B2

IR7 IP8arcarcarcarc

Rhodri Jones – AB/BIRhodri Jones – AB/BI LHC Injection Test – Beam 2 LHC Injection Test – Beam 2

BPM Issues in Sector 7-8BPM Issues in Sector 7-8● Successful Tests of Synchronous Capture Mode

● BST successfully used to advance pre-pulse to 2 turns before injection● Data collected from a single front-end crate

● alternate BPMs from Q1L8 to Q32L8

● Conclusions● Pre-pulse to bunch timing stable to better than 3ns

● limited by resolution of BPM TDC● Reproducible

● Uncorrected & corrected data sets taken 2 shifts apart● Will now automate this to allow quick phasing in of all BPMs

Q1 D1 Q4 Q6 Q8 Q10 Q12 Q14 Q16 Q18 Q20 Q22 Q24 Q26 Q28 Q30 Q32Original Bunch Bucket 2775 2777 2807 2830 2847 2874 2908 2944 2979 3014 3050 3085 3121 3156 3191 3227 3262(no correction) Phase 1 1 3 1 4 6 0 6 2 1 6 2 7 3 2 5 3

Applied Bunch offset 2775 2777 2807 2830 2847 2873 2908 2943 2979 3014 3049 3085 3120 3156 3191 3226 3262Correction Bunch phase 6 6 1 6 0 13 8 12 4 6 12 4 11 2 4 15 2

After Bunch Bucket 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1Correction Phase 4 4 4 4 4 4 3 4 4 4 4 4 4 4 4 4 4