Results from the 2009 Beam Commissioning of the CERN Multi-Turn Extraction

Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 11

Results from the 2009 Beam Results from the 2009 Beam Commissioning of the CERN Commissioning of the CERN

Multi-Turn ExtractionMulti-Turn ExtractionE. Benedetto, A. Blas, T. Bohl, S. Cettour Cave, K. E. Benedetto, A. Blas, T. Bohl, S. Cettour Cave, K. Cornelis, D. Cotte, H. Damerau, M. Delrieux, J. Cornelis, D. Cotte, H. Damerau, M. Delrieux, J. Fleuret, T. Fowler, F. Follin, A. Franchi, P. Fleuret, T. Fowler, F. Follin, A. Franchi, P. Freyermuth, H. Genoud, S. Gilardoni, Freyermuth, H. Genoud, S. Gilardoni, M. GiovannozziM. Giovannozzi, , S. Hancock, O. Hans, Y. Le Borgne, D. Manglunki, E. S. Hancock, O. Hans, Y. Le Borgne, D. Manglunki, E. Matli, E. Métral, G. Métral, M. Newman, L. Pereira, F. Matli, E. Métral, G. Métral, M. Newman, L. Pereira, F. Peters, Y. Riva, F. Roncarolo, L. Sermeus, R. Peters, Y. Riva, F. Roncarolo, L. Sermeus, R. Steerenberg, B. Vandorpe, J. WenningerSteerenberg, B. Vandorpe, J. Wenninger

Summary:Summary:

New multi-turn extraction New multi-turn extraction (MTE)(MTE)

Commissioning results Commissioning results 2009/102009/10

Outlook Outlook


Multi-turn extractionMulti-turn extraction – I – I

The main ingredients of The main ingredients of the novel extraction:the novel extraction:

The beam is separated in The beam is separated in the horizontal phase space the horizontal phase space using using

Nonlinear magnetic elementsNonlinear magnetic elements (sextupoles ad octupoles) to (sextupoles ad octupoles) to create create stable islandsstable islands..Slow (Slow (adiabaticadiabatic) horizontal ) horizontal tune variation to cross an tune variation to cross an appropriate resonance.appropriate resonance.

CERN-specific CERN-specific requirementsrequirements

Extraction over five turns -> Extraction over five turns -> 44thth order resonance order resonanceEqually populated turns -> Equally populated turns -> (20±1)%(20±1)%

33IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010

Electrostatic septum Electrostatic septum bladeblade

Length Length

Kic

ker

Kic

ker

str

en

gth

str

en

gth Four Four

turnsturns

Fifth Fifth turnturn

XX

X’X’

1133 55

22

44

EEfieldfield=0=0

EEfieldfield≠0≠0

Multi-turn extractionMulti-turn extraction – III – III

Final stage after 20000 turns (about 42 ms for CERN Final stage after 20000 turns (about 42 ms for CERN PS)PS)

About 6 cm in physical About 6 cm in physical spacespace

BBfieldfield ≠ 0≠ 0BBfieldfield = = 0 0At the septum locationAt the septum location

Courtesy S. Courtesy S. GilardoniGilardoni

Courtesy S. Courtesy S. GilardoniGilardoni

Massimo GiovannozziMassimo Giovannozzi

The predecessor of MTE: Continuous The predecessor of MTE: Continuous Transfer (CT)Transfer (CT)


Implementation of MTEImplementation of MTE

Sext/oct

Sext/oct


Transverse dynamics - ITransverse dynamics - I

Sextupoles and octupoles are used toSextupoles and octupoles are used to

Generate stable islandsGenerate stable islands

Control size/position of islandsControl size/position of islands

Control linear chromaticityControl linear chromaticity

Control non-linear coupling (Control non-linear coupling (using an additional set using an additional set of octupoles, normally used to combat instabilitiesof octupoles, normally used to combat instabilities))

yxy

yxx

JhJhQ

JhJhQ

2,01,1

1,10,2

hh2,02,0 -> detuning with amplitude (H-plane) -> -> detuning with amplitude (H-plane) -> xx22

KK33

hh1,11,1 -> non-linear coupling -> -> non-linear coupling -> xxy y KK33

hh0,20,2 -> detuning with amplitude (V-plane) -> -> detuning with amplitude (V-plane) -> yy22

KK33


Transverse dynamics - IITransverse dynamics - II

-600

-400

-200

0

200

400

600

0.00.10.20.30.40.50.60.70.80.91.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Curr

ents

(A)

B-fi

eld

(T)

Cycle time (s)

B-field Sextupole 39Sextupole 55 Octupole 39Octupole 55 Octupoles

-600

-400

-200

0

200

400

600

0.00.10.20.30.40.50.60.70.80.91.0

0.72 0.74 0.76 0.78 0.80 0.82

Curr

ents

(A)

B-fi

eld

(T)

Cycle time (s)

B-field Sextupole 39Sextupole 55 Octupole 39Octupole 55 Octupoles

Injection: 0.170 sInjection: 0.170 s

Extraction: 0.835 sExtraction: 0.835 s

Transverse dynamics - IIITransverse dynamics - III


Phase space at Phase space at septum septum

0.72 0.74 0.76 0.78 0.80 0.82

-3000

-2000

-1000

0

1000

2000

3000

0.00

0.05

0.10

0.15

0.20

0.25

0.72 0.74 0.76 0.78 0.80 0.82

Seco

nd o

rder

chr

omati

city

, de

tuni

ng, n

on-li

near

cou

plin

g

Frac

tion

al tu

ne a

nd c

hrom

atici

ty

Cycle time (s)

Qx Qx'/QxQx'' h2,0h1,1

Transverse dynamics - IVTransverse dynamics - IV


To achieve good sharing of beam intensity To achieve good sharing of beam intensity between islands and core various parameters between islands and core various parameters optimised (hoptimised (h1,11,1 is rather crucial). is rather crucial).

12.0

12.5

13.0

13.5

14.0

14.5

15.0

15.5

16.0

16.5

17.0

0 100 200 300 400 500 600

Fra

ctio

n o

f tr

app

ed p

arti

cle

[%]

Octupole current [A]

h11=0

h11=100

h11=200

h11=300

h11=500

Last bit achieved by exciting the beam using the Last bit achieved by exciting the beam using the transverse damper. transverse damper.

Current in octupoles 39/55 (A)

99IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010Massimo GiovannozziMassimo Giovannozzi

y = -0.0185x + 0.896R² = 0.0026

y = -0.1852x + 4.3783R² = 0.2631

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

12 14 16 18 20

Rati

o of

cor

e em

ittan

ce (a

fter

and

bef

ore

splitti

ng)

Fraction of particles trapped in islands (%)

Improving capture: beam Improving capture: beam excitationexcitation

Effect of transverse excitation

revprev TtNtfAtx 25.016sin'

Noise componentNoise component


Evolution of beam Evolution of beam distributiondistribution

Horizontal beam profiles in Horizontal beam profiles in section 54section 54 have been have been taken during the capture process (total intensity taken during the capture process (total intensity ~~2.1×102.1×101313).).

Trapping performanceTrapping performance


0 50 100 150 200 250 300

37 nsbin

02.0x1010

6.0x1010

1.0x1011

1.4x1011

Inte

nsi

ty

0 50 100 150 200 250 300

37 nsbin

02.0x1010

6.0x1010

1.0x1011

1.4x1011

Inte

nsi

ty

12 14 16 18 20

200

400

600

800

1000

Trapping (%)

Fre

qu

en

cy

5000 10000 15000 20000 25000

Time elapsed from May 1st 15:00 (s)

12

14

16

18

20

Tra

pp

ing

(%

)

20% trapping

18% trapping

5 PS turns5 PS turns

Extraction efficiencyExtraction efficiency


Regular fluctuations in Regular fluctuations in the extraction efficiency the extraction efficiency are also observed and are also observed and seem well correlated to seem well correlated to spill fluctuations.spill fluctuations.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0

100

200

300

400

500

600

700

90.0

90.6

91.2

91.8

92.4

93.0

93.6

94.2

94.8

95.4

96.0

96.6

97.2

97.8

98.4

99.0

99.6

100.

2

100.

8

Freq

uenc

y

Extraction efficiency (%)

Frequency Cumulative %

90

91

92

93

94

95

96

97

98

99

100

14:24 15:36 16:48 18:00 19:12 20:24 21:36 22:48

Extr

acti

on e

ffici

ency

(%)

Time on May 1st

Distribution of Distribution of extraction efficiency is extraction efficiency is peaked at about 98% peaked at about 98% (NB: the beam is (NB: the beam is debunched at debunched at extraction! Unavoidable extraction! Unavoidable beam losses are beam losses are estimated at about 1-estimated at about 1-2%)2%)

CT extraction efficiency is about 93%

CT vs. MTE: extraction CT vs. MTE: extraction losseslosses

For the same extracted intensity, the CT features more For the same extracted intensity, the CT features more losses, about the double, compared to MTE.losses, about the double, compared to MTE.The CT losses are spread around the ring whereas for MTE The CT losses are spread around the ring whereas for MTE the losses are more concentrated on the extraction septum the losses are more concentrated on the extraction septum as anticipated in the MTE Design Report.as anticipated in the MTE Design Report.

CT MTE


MTE performance in SPSMTE performance in SPS

2009: the MTE beam was delivered to SPS as 2009: the MTE beam was delivered to SPS as of mid-September. Total intensity delivered of mid-September. Total intensity delivered was about 3×10was about 3×101717 p p

2010: commissioning activities started as of 2010: commissioning activities started as of February. Physics run started with MTE beam February. Physics run started with MTE beam instead of CT. instead of CT.


High intensity beam: peak performance

Lower trapping Lower trapping in islands in islands generates beam generates beam loading in the loading in the cavities, thus cavities, thus limiting the limiting the performance of performance of the SPS.the SPS.

IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 1515

Longitudinal Longitudinal dynamicsdynamics

Momentum

Massimo GiovannozziMassimo Giovannozzi

Longitudinal Longitudinal coupled-bunch coupled-bunch instability of instability of quadrupolar quadrupolar modemode

Transverse Transverse splittingsplitting

The beam is de-bunched prior to extraction


OutlookOutlook

First MTE beam delivered to the SPS by mid-First MTE beam delivered to the SPS by mid-September 2009 (about 1.5×10September 2009 (about 1.5×101313 p/extraction). p/extraction).Equal sharing between islands and core achieved by Equal sharing between islands and core achieved by the end of 2009.the end of 2009.In February 2010 the commissioning was resumed. In February 2010 the commissioning was resumed. High intensity beam was extracted (about 2.1×10High intensity beam was extracted (about 2.1×101313 p/extraction) with record intensity 2.6×10p/extraction) with record intensity 2.6×101313 p/extraction.p/extraction.2010 physics run at SPS was started using MTE 2010 physics run at SPS was started using MTE beam.beam.Open issues:Open issues:

Periodic variation of the fraction of particles trapped Periodic variation of the fraction of particles trapped in islands.in islands.Activation of extraction septum due to the extraction Activation of extraction septum due to the extraction losses related to the longitudinal structure of the losses related to the longitudinal structure of the extracted beam (de-bunched as needed by the SPS).extracted beam (de-bunched as needed by the SPS).

AcknowledgmentsAcknowledgments

G. Arduini, M. Chanel, K. Hanke, R. G. Arduini, M. Chanel, K. Hanke, R. Louwerse, J. Tuckmantel, U. WehrleLouwerse, J. Tuckmantel, U. Wehrle

PS-Booster, PS, and SPS operations PS-Booster, PS, and SPS operations crew and machine supervisors.crew and machine supervisors.

Beam instrumentation, power Beam instrumentation, power converter, kicker experts.converter, kicker experts.

Radioprotection experts.Radioprotection experts.


Results from the 2009 Beam Commissioning of the CERN Multi-Turn Extraction

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