View
213
Download
0
Category
Tags:
Preview:
Citation preview
#3271
Sat 08-Dec-12
R56 Injector – BC2 GS calibration
• First calibrate BC2• 1. Start with beam in centre of screen INJ-5. Read
INJ-DIP-01 current and convert to energy using magnet table
• 2. Increase BC2 gradient a little• 3. Bring the beam back to the centre of INJ-5 by
increasing INJ-DIP-01. Convert new dipole current to energy using magnet table
• 4. Repeat steps 2 to 3 several times so as to check linearity.
R56 Injector – BC2 GS calibration
• 1 unit increase in BC2 GS increases beam momentum by 0.237 MeV
Injector Path Length vs Energy• Use ST1-BPM-01, ¾ length stripline• Measure time of signal by 50% level
of peak
Relative path length (mm) vs fractional momentum change
INJ-Q06 Changed from 0.7 to 0.8A
Nominal BURT
INJ-QUAD10 changed from 0.7 to 0.8
Repeat Nominal BURT
R56 Injector Refine • Try to measure R56 for each setting. Restrict
data to parabolic section around dp/p = 0
“R56” varies considerably !!
5 to 136 mm
Analysis of nominal injector• Just take parabolic part of
data for nominal BURT
0 2 4 6 8 1 0 1 20 . 0 0
0 . 0 1
0 . 0 2
0 . 0 3
0 . 0 4
0 . 0 5
s m R
56m
0 2 4 6 8 1 0 1 20 . 0
0 . 2
0 . 4
0 . 6
0 . 8
s m T
566
m
ELEGANT model for nominal BURT
INJ DIP-01-04ST1 BPM 01
PRELIMINARY!!
NOT DEBUGGED
ST 1 EBPM 01 12.1479 0.05344141 0.8544566R56 (m) T566 (m)
Relative path length (mm) vs fractional momentum change
Analysis of nominal injector
• Agreement between model and measurement not too exciting.
• But, as the measurements show, injector path length quite sensitive to quad values (and thus quad degaussing).
• Also, in simulation, if I change INJ-QUAD-05 from 1.53 A to 1.63 A and INJ-QUAD-10 from 0.70 A to 0.75 A, I get R56 ~ 0.02 m and T566 ~ 1.20 m
• Also, more complications, could R51, R52 play a part? if booster exit trajectory is changed as BC2 gradient changes?
Dispersion Around Machine• Nominal set up, in which AR1-SEXT-01 is ON. • Note relatively small dispersion at AR1 exit and AR2
entrance
Dispersion Around Machine• With AR1-SEXT-01 off to see how this affects
things• Note relatively large dispersion at AR1 exit and
AR2 entrance
Dispersion Measurement Issues
• LC1 GS calibration was last measured carefully on #3058 at end of July 2012. Yuri measured LC1 GS on the shift after ours. Q. Any difference? A. Not significantly (see next slide).
• There is unresolved uncertainty in the BPM calibrations which also affects the dispersion value.
LC1 GS Calibration• 3058, (July 2012).
dE/dLC1GS = 0.264• 3272, (Dec 2012). 3
measurements scanning up-down-up in energy – dE/dLC1GS =
0.266,0.277, 0.280
3058
3272
Infer from this that dE/dLC1GS has remained constant over second half of 2012
AR2 R56
0.04 0.03 0.02 0.01 0.01 0.02
10
12
14
16
18
Measure TOA on AR2-BPM-06 vs energyFirst time this has been measured
0.015 0.010 0.005 0.005 0.010 0.015
8
9
10
11
E st im at e S t an d ardE rro r t-S t at ist ic P-V alu e
a 8 .3 6 1 6 9 0 .1 1 9 0 35 70 .2 4 5 9 2 .4 6 0 8 3 10 7
b 56 .5 7 3 7 25 .7 5 5 2 .1 9 6 6 2 0 .0 9 3 0 029c 3434 .5 2 2 0 35 .1 1 .6 8 7 6 4 0 .1 6 6 7 53d 389 368 . 2 6 3 5 74 . 1 .4 7 7 2 6 0 .2 1 3 6 64
Could argue R56 is consistent with zero
Recommended