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
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 22
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)
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 44
Implementation of MTEImplementation of MTE
Sext/oct
Sext/oct
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 55
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
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 66
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
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 77
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
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 88
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
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 1010
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
1111IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010Massimo GiovannozziMassimo Giovannozzi
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
1212IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010Massimo GiovannozziMassimo Giovannozzi
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
1313IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010Massimo GiovannozziMassimo Giovannozzi
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.
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 1414
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.
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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
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 1616
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.
Massimo GiovannozziMassimo Giovannozzi IPAC'10 - May 27th 2010IPAC'10 - May 27th 2010 1717
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