LHC Emittance Studies in LHC During BI MD

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LHC Emittance Studies in LHC During BI MD 3 Effect of WS Gain and

LHC Emittance Studies in LHC During BI MD 3 Effect of WS Gain and Filter Change on Beam Size M. Kuhn, V. Kain, F. Roncarolo, B. Dehning, A. G. Ollacarizqueta, J. Emery 1

Wire Scanner Measurements o Fill 3140 o Only beam 1 available − 16 individual

Wire Scanner Measurements o Fill 3140 o Only beam 1 available − 16 individual bunches , ~ 1. 3 x 1011 ppb q Nominal transverse emittance q plots only show 4 bunches as example o Wire scanner measurements at injection for B 1 H and B 1 V o Systematic change of wire scanner voltage and filter o o LHC − Filter: 0. 2 % - 100 % transmission − Voltage: 600 – 2000 V (different for different filters) Goals: − Find out if photomultipliers are saturating − Find best working point of wire scanners Caveat: not enough time! − No B 2, B 1 with orbit bumps for BSRT calibration − First 2 bunches are blown up 2

Comparison with Previous studies o Fill 3056 o Only beam 1 protons o −

Comparison with Previous studies o Fill 3056 o Only beam 1 protons o − 15 low intensity bunches , ~ 1. 2 x 1010 ppb − Beam size ~ 3 x smaller LHC Wire scanner measurements at flattop for B 1 H and B 1 V 3

Transverse Profiles at Injection o LHC Horizontal: Cores of transverse profiles fitted with a

Transverse Profiles at Injection o LHC Horizontal: Cores of transverse profiles fitted with a Gauss o Vertical: 4

Norm. Transverse Emittance B 1 H o LHC Wire scans at injection − Horizontal

Norm. Transverse Emittance B 1 H o LHC Wire scans at injection − Horizontal plane: IBS, emittance growth of ~ 10 % in 20 min 5

Norm. Transverse Emittance B 1 V o LHC Vertical plane: no IBS − Still

Norm. Transverse Emittance B 1 V o LHC Vertical plane: no IBS − Still growth Same filter but differentbeam sizes 6

Summary o o o LHC wire scanner analysis at injection − Only beam 1

Summary o o o LHC wire scanner analysis at injection − Only beam 1 − Single bunches with nominal intensity Next MD: − Both beam with nominal intensity bunches − Gain and filter variations at injection and flattop Find a good working point! 7

LHC BACKUP 8

LHC BACKUP 8

Beam Size vs Gain B 1 H o LHC Beam size for one bunch

Beam Size vs Gain B 1 H o LHC Beam size for one bunch as function of wire scanner gain for different filters − Cores of transverse profiles fitted with a Gauss − Sigma averaged for same gains Don’t use Default filter 9

Beam Size vs Gain B 1 V LHC 10

Beam Size vs Gain B 1 V LHC 10

Combined Amplification B 1 H o Beam size as in previous slide o Combined

Combined Amplification B 1 H o Beam size as in previous slide o Combined amplification = 8 -10 * gain 4. 057 * filter LHC Photomultiplier characteristics 11

Combined Amplification B 1 V LHC 12

Combined Amplification B 1 V LHC 12

Signal Integral B 1 H o LHC Bunch-by-bunch signal integral For fill 3056 with

Signal Integral B 1 H o LHC Bunch-by-bunch signal integral For fill 3056 with pilots at flattop: signal integral ~ 40*103 13

Signal Integral B 1 V LHC 14

Signal Integral B 1 V LHC 14

Signal Integral B 1 H – Fill 3056 pilots at flattop LHC 15

Signal Integral B 1 H – Fill 3056 pilots at flattop LHC 15

Signal Integral B 1 V – Fill 3056 pilots at flattop LHC 16

Signal Integral B 1 V – Fill 3056 pilots at flattop LHC 16

Accumulated signal integral over all bunches B 1 V LHC 17

Accumulated signal integral over all bunches B 1 V LHC 17

Accumulated signal integral over all bunches B 1 H LHC 18

Accumulated signal integral over all bunches B 1 H LHC 18