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

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2000

2500

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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

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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

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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

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3500

Obs

cur

rent

[nA

]

Channel

max=2.213333e+003

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BC

T

Time [s]

0 5 10 15 200

1

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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

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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

Kicker heating

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 …)

Effect of bunch length

Uncaptured beam

Small effect but quite repeatable

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]

0 1 2 3 4 5 6 7

-0.05

0

0.05

e-c

lou

d s

ign

al

Time [s]

0 1 2 3 4 5 6 7

-0.2

0

0.2

0.4

Be

am

sig

na

l

Time [s]

0 1 2 3 4 5 6 7

-0.01

0

0.01

Be

am

sig

na

l

Time [s]

0 1 2 3 4 5 6 7

-0.2

0

0.2

0.4

e-c

lou

d s

ign

al

Time [s]

Raw data 20MHz high pass filtered

Shielded pick-up measurement – 08/03/2012