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Acknowledgement. Many thanks to: Theodoros A., Thomas B., Fritz C., Stephan C. C., Heiko D., Mounir D. M., Juan E. M., Silke F., Fabio F., Steve H., Michael H., Wolfgang H., Holger N., Yannis P., Giovanni R., Benoit S., Elena S., Mauro T., Helga T., Adrian U., Urs W. - PowerPoint PPT Presentation
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Acknowledgement
Many thanks to:Theodoros A., Thomas B., Fritz C., Stephan C. C., Heiko D.,
Mounir D. M., Juan E. M., Silke F., Fabio F., Steve H., Michael H., Wolfgang H., Holger N., Yannis P., Giovanni R., Benoit S., Elena S.,
Mauro T., Helga T., Adrian U., Urs W.
8 10 12 14 16 18 20 22 0 2 4 6 8
500
1000
1500
2000
2500
3000
3500
Time [h]
BC
T S
ign
al
Monday 26-03-2012
No
beam
(PS
~1h)
No
beam
(In
jecti
on s
eptu
m ~
4h)
Setup 25ns Q26 cycles
MKE1 cool-down (~3h)
Set MKQV for uncaptured beam
cleaning
Problem with PSB kicker -> tests on
micro-batch filling scheme
Dalay last batch position to study
ecloud decay(on microbatch and
nominal 25)
LHCMD2 (25ns Q20 26GeV)
LHCMD1 (25ns Q26 26GeV)
LHCFAST2 (50ns Q26 accel)
LHCFAST3 (25ns Q26 accel)
8 10 12 14 16 18 20 22 0 2 4 6 8
500
1000
1500
2000
2500
3000
3500
Time [h]
BC
T S
ign
al
Tuesday 27-03-2012
No
beam
(A
cces
s BA
5 ~3
h)
Setup 25ns Q20 cycleMKE1
cool-down (~4h)
Switch off/on ion pumps near ecloud
monitors
Tests on uncaptured beam
No
beam
(P
S - S
PS sy
nchr
o ~1
.5h)
Dalay last batch position to study ecloud decay
(on 50ns beam)Investigating
longitudinal instability
Decreasing number of batches to limit MKE1 heating
LHCMD2 (25ns Q20 26GeV)
LHCMD1 (25ns Q26 26GeV)
LHCFAST2 (50ns Q26 accel)
LHCFAST3 (25ns Q26 accel)
8 10 12 14 16 18 20 22 0 2 4 6 8
500
1000
1500
2000
2500
3000
3500
Time [h]
BC
T S
ign
al
Wednesday 28-03-2012
MKE1 cool-down
Tests on clearing electronde (B scan in ecloud monitor)
Solved longitudinal instability on LHCMD1 cycle (feedback gain)
No
beam
(PS
~1h)
Finish damper settings on Q20
Tests on aC coated drift
Dalay last batch position to study ecloud decay
(on 50ns beam)
Bunch by buch emittance
measurements
No
beam
(RF
~1h)
Study effect on ecloud of bunch length and uncaptured beam
LHCMD2 (25ns Q20 26GeV)
LHCMD1 (25ns Q26 26GeV)
LHCFAST2 (50ns Q26 accel)
LHCFAST3 (25ns Q26 accel)
8 10 12 14 16 18 20 22 0 2 4 6 8
500
1000
1500
2000
2500
3000
3500
Time [h]
BC
T S
ign
al
Thursday 29-03-2012
LHCMD2 (25ns Q20 26GeV)
LHCMD1 (25ns Q26 26GeV)
LHCFAST2 (50ns Q26 accel)
LHCFAST3 (25ns Q26 accel)
No
beam
(Vac
. val
ve ~
1h)
High intensity tests (25ns 1.8e11ppb up to 3 batches)
PS-SPS stransmission studies
Orbit bump for ecloud localiz.
No
beam
(M
KE v
acuu
m ~
1h)
Dalay last batch position to study ecloud decay
(on 50ns beam)
Bunch length studyOrbit bump
Uncaptured beam study
MKE1 cool-down
No
beam
(PS
~1h)
Transverse stability for low chromaticity Q26
Pressure interlock on MKE
8 10 12 14 16 18 20 22 0 2 4 6 8
500
1000
1500
2000
2500
3000
3500
Time [h]
BC
T S
ign
al
Friday 30-03-2012
LHCMD2 (25ns Q20 26GeV)
LHCMD1 (25ns Q26 26GeV)
LHCFAST2 (50ns Q26 accel)
LHCFAST3 (25ns Q26 accel)
Transverse stability for low chromaticity Q20
Orbit bump (25ns)
Meas. with B=0 at ecloud monitors
E-cloud dedicated measurements
Taken along the entire week:
• E-cloud monitors
• Shielded pickup
• Microwave transmission
• Pressure gauges along the entire ring
• Bunch by bunch pickup
Post-processing is needed
Scrubbing?10 20 30 40
0
1
2
3
4
5
x 104
Rec
eive
d do
se p
er c
ycle
[nC
]
Channel
SCycle=2827
10 20 30 400
500
1000
1500
2000
2500
3000
3500
Obs
cur
rent
[nA
]
Channel
max=2.213333e+003
0 5 10 15 200
500
1000
1500
2000
2500
3000
BC
T
Time [s]
0 5 10 15 200
1
2
3
4
5
6
x 104
Tot
al c
urre
nt [
nA]
Time [s]
Gain = 0.150000 IntTime = 0.020000
50 60 70 80 900
2
4
6
8
10
12
14
16
18
x [channel] , (second)
time
[s]
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
8 - 03 - 2012 – Different calibration
26 - 03 - 2012
30 - 03 - 2012
Scrubbing?
10 20 30 400
1
2
3
4
5
x 104
Rec
eive
d do
se p
er c
ycle
[nC
]
Channel
SCycle=2827
10 20 30 400
500
1000
1500
2000
2500
3000
3500
Obs
cur
rent
[nA
]
Channel
max=2.213333e+003
0 5 10 15 200
500
1000
1500
2000
2500
3000
BC
TTime [s]
0 5 10 15 200
1
2
3
4
5
6
x 104
Tot
al c
urre
nt [
nA]
Time [s]
Gain = 0.150000 IntTime = 0.020000
50 60 70 80 900
2
4
6
8
10
12
14
16
18
x [channel] , (second)
time
[s]
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
8 - 03 - 2012 – Different calibration
26 - 03 - 2012
30 - 03 - 2012
Beam characteristics from PS – 25ns “nominal”
• ~1.25e11p/b
• εh~2.6μm / εv~2.3μm
• εl~0.3eVs/τl~3.7ns
Beam characteristics end of flat bottom – 25ns “nominal”
• Injected around 1.25e11p/b
• εh~2.9μm / εv~3μm (at 18s)
Beam characteristics flat top – 25ns “nominal”
• εh~3.0μm/εv~2.9μm after injection of first
batch
• εh~3.0μm/εv~2.9μm at flat top for 3 batches
• Almost no blow-up along flat bottom and along the ramp?
• Possible blow-up at injection?
?Ecloud? instability with 4 batches 25ns “nominal”
Lowering chromaticity after 4th injection …Losses on tail of 4th batch
Large emittance for bunches with losses No instability for this bunch pattern
Beam characteristics – Microbatch scheme
• 6x 2x(24 bunches + 24 empty)
• Less vacuum activity
• EFB around 1.18e11p/b
• εh~2.5μm/εv~2.5μm after injecting 5th batch
(batch spacing larger than kicker rise time)
• Better lifetime for 288 bunches
Beam characteristics from PS – 25ns “ultimate”• N~1.8e11p/b
• εh~4.1μm/εv~3.5μm
• εl~0.34eVs/τl~4.1ns
Beam characteristics end of flat bottom – 25ns “ultimate”
εh~4.7μm close to injection of first batch
εv~4.5μm close to injection of first batch
Εh~5.0μm @8s
εv~4.5μm @8.1s
• 2 (3 for short time) of 25ns ultimate beam (1.8e11p/b injected)
• Blow-up right at injection? (remember also problem with injection kicker rise time …)
Shielded pick-up measurement – 08/03/2012
0 10 20 30 40 50 60-0.1
-0.05
0
0.05
0.1
e-c
lou
d s
ign
al
Time [s]
0 10 20 30 40 50 60-0.4
-0.2
0
0.2
0.4
0.6
Be
am
sig
na
l
Time [s]