the gsi unilac upgrade program for fair requirements, l. dahl, hiat, venice, 12.6.2009 staff: 1,100...
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The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Staff: 1,100 (~ 50% permanent)Accelerators: UNILAC; SIS; ESRUser: 1100/yr (~1000 from outside)
Member of Helmholtz Community
The GSI UNILAC Upgrade Program for FAIR Requirements
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Unilac
SIS18
ESR
Present accelerators
UNILAC: Universal Linear Accelerator, 12.5 MeV/u
SIS: Heavy Ion Synchrotron, 1-2 GeV/u
ESR: Experimental Storage Ring
Accelerated Ions: p to U
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Primary beams
1012/s; 1.5-2 GeV/u; 238U28+
1011/s 238U73+
100-1000 fold intensities4x1013/s 30 GeV Protons
Sekundary beams
wide range of radioactive beamsup to 1.5 - 2 GeV/u; intensity gain of factor 10 000 Antiprotons 3 - 30 GeV
•Cooled beams•Fast ramped super conducting magnets
Key technologiesStorage and cooler rings
Radioactive beams
e – A(RIB) Collider
1011 stored and cooled 3 - 15 GeV pbars
SIS100/SIS300
HESR
NESRCR
SIS18
FAIR Beam Data
UNILAC
SFRS
p-linac
ESR
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
FAIR beam intensity and beam quality requirements
SIS space charge limit is reached by four 100 µs injections with each fifteen Multiturns. Uranium reference beam intensities:
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
High Current Injector Alvarez Single Gap Resonators
The UNILAC
11.4 MeV/u
1.4 MeV/u
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Example of three beam pulse-to-pulse operation
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Transverse emittance growth along the UNILAC
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Space charge forces along the UNILAC
Calculated by PARMILA and PARMTRA codes
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
MUCIS & MEVVA- Ion Sources
MUCIS(Multi Cusp Ion Source)
(Emission Current Density 150 mA/cm²)
MEVVA(MEtal Vacuum Vapor Arc Ion Source)
(Emission Current Density 150 mA/cm²)
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
0
2
4
6
8
10
12
14
16
18
20
beam
cu
rren
t [e
mA
]
LE
BT
HS
I
Ga
ss
trip
pe
r
Alv
are
z
Sin
gle
Ga
pR
es
on
ato
rs
Fo
il S
trip
pe
r
SIS
-In
jec
tio
n
Dez 01 Okt 02
Oct-03 Design
U4+ U28+ U73+
1.3 emA3.7 emA
Status of Uranium intensity in 2003
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Unilac measures since 2003
• Improvement of the Mevva high current ion source
•RFQ-Upgrade: exchange of RFQ minivanes, modified IRM
• Increased stripper gas density
•Matching to the Alvarez DTL under space charge conditions
• Increase of Alvarez DTL transverse phase advance
•High current beam diagnostics, measurement of long. emittance
•Machine investigations: frontend, Alvarez matching, transfer line long. and transv. emittance measurements
•New charge state separator in the transfer channel to SIS18 for U73+
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
RFQ-Upgrade: Modified Input Radial Matcher
30.000 mm X 15.000 mrad
30.000 Deg X 100.00 keV
10.000 mm X 100.000 mrad
30.000 Deg X 100.00 keV NP1= 1 NP2= 9 80.00 mm (Horiz) 30.0 Deg (Long.)
80.00 mm (Vert) Length= 2722.65mm
1
2 Q
3
4 Q
5
6 Q
7
8 Q
9
H A=-0.45000 B= 1.6300 V A= -2.2300 B= 5.6400
Z A= 1.00000E-04 B= 1.00000E+06
BEAM AT NEL1= 1 H A= 1.0500 B= 0.11301 V A= 1.0501 B= 0.11301
Z A= 3.09881E-04 B= 1.00000E+06
BEAM AT NEL2= 9 I= 0.0mA W= 0.1300 0.1300 MeV
FREQ= 36.16MHz WL=8290.73mm EMITI= 145.000 145.000 0.00 EMITO= 145.000 145.000 0.00
N1= 1 N2= 9 PRINTOUT VALUES PP PE VALUEMATCHING TYPE = 8
DESIRED VALUES (BEAMF) alpha beta x 1.0500 0.1130 y 1.0500 0.1130 MATCH VARIABLES (NC=4) MPP MPE VALUE 1 2 -2.62989 1 4 5.29843 1 6 -7.57860 1 8 9.22129
CODE: TRACE3D v61L FILE: Quadruplet_uran.t3d DATE: 06/18/2004 TIME: 12:57:09
30.000 mm X 15.000 mrad
30.000 Deg X 100.00 keV
10.000 mm X 100.000 mrad
30.000 Deg X 100.00 keV NP1= 1 NP2= 9 80.00 mm (Horiz) 30.0 Deg (Long.)
80.00 mm (Vert) Length= 2722.65mm
1
2 Q
3
4 Q
5
6 Q
7
8 Q
9
H A=-0.45000 B= 1.6300 V A= -2.2300 B= 5.6400
Z A= 1.00000E-04 B= 1.00000E+06
BEAM AT NEL1= 1 H A= 0.75310 B= 5.26217E-02 V A= 0.72360 B= 5.50181E-02
Z A= 3.09881E-04 B= 1.00000E+06
BEAM AT NEL2= 9 I= 0.0mA W= 0.1300 0.1300 MeV
FREQ= 36.16MHz WL=8290.73mm EMITI= 145.000 145.000 0.00 EMITO= 145.000 145.000 0.00
N1= 1 N2= 9 PRINTOUT VALUES PP PE VALUEMATCHING TYPE = 8
DESIRED VALUES (BEAMF) alpha beta x 0.9000 0.0538 y 0.9000 0.0538 MATCH VARIABLES (NC=4) MPP MPE VALUE 1 2 0.00000 1 4 3.17745 1 6 -7.69094 1 8 11.28580
CODE: TRACE3D v61L FILE: Quadruplet_uran.t3d DATE: 06/18/2004 TIME: 12:51:12
Matching 1999
Matching 2004
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
LEBT emittance measurements with U4+ beam of 8 emA
horizontal vertical
1999
2004
Emittance Growth: -19 % (3 %)
Transmission: 70 % (84 %)
beforeQuadrupole
Quartet
2006: Mevva ion source: 37 emA of U4+ and 18 emA of U3+ beam
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
RFQ-upgrade: new RFQ-rods in 2004
After 5 years of operation
New RFQ-rods
After copper- plating
February 2003
Inp
ut
rf-P
ow
er [
kW
]
December2001
Commissioning 1999
rf-voltage [V]
Two reasons: improved input matching (Stepan Yaramishev)
high power consumption , dark currents
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
HSI RFQ commissioning (7/2004)
I = 16 emA, (Ar1+)
10
20
30
40
50
60
3,0 4,0 5,0 6,0 7,0
RFQ-Amplitude [V]
RF
Q-T
ran
smis
sio
n [
%]
April 2004
July 2004
wo
rkin
g p
oin
t
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
GSI Nitrogen gas stripper section at 1.4 MeV/u
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Increase of pressure and pumping capacity
• Hugh roots pump and four 1,000 l/s turbo pumps
• 50 % gas density increase
• approx. 1 µg/cm2 gas density
• 4,500 mbar at nozzle
• 50 % enlarged beam aperture
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Charge-Spectrum(after stripping of 238U4+)
0.0
0.2
0.4
0.6
0.8
1.0
B*l [Tm]
Inte
ns
ity
[%
]
28+ 27+26+
25+
24+
29+
30+
31+
32+
33+
Charge state spectrum of an Uranium beam
14 % of particles within charge state 28+
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Alvarez-Matching
Periodicity FDDF, interrupted by the intertank sections
Emittance Measurementbefore DTL, 3.5emA U28+
Betafunction (before Matching)
Betafunction (afterMatching)
Alvarez DTL-Transmission:92% (before)99%. (after)
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Experimental Set-up for Alvarez DTL matching
• set beam current to 7.1 mA of 40Ar10+ (equiv. to FAIR design of 15 mA of 238U28+)
• measure hor., ver. emittance and long. rms-bunch length at DTL entrance
• set DTL transverse phase advance to values from 35° to 90°
• tune depression varied from 21% (90°) to 43% (35°)
• measure transmission, hor., and ver. rms-emittance at DTL exit
rms-bunch length measurement
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Transverse emittance growth in Alvarez DTL
40Ar10+ beam, 7.1 emA, equivalent to 15 emA U28+ beam
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
• The achieved ratio current / rms-emittance at DTL exit is too low for FAIR
• Design: 15.5 mA / 0.25 µm; Achieved: 4.4 mA / 0.43 µm
• One measure of improvement → reduction of emittance growth along DTL
• Exp. and simulation: possible by increasing DTL quad strengths
0,3
0,4
0,5
0,6
0,7
30 40 50 60 70 80 90
Transverse Phase Advance (zero current) [deg]
No
rm. t
ran
sv
. rm
s-E
mit
tan
ce
[m
m*m
rad
]
7.1 mA 40Ar10+ ≙ 15.5 mA 238U27+
meas. transv. emittance @ DTL exit
todays PS current limit
New Power Supplies for the Alvarez dc-Magnets
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Present Uranium beam intensity
0
2
4
6
8
10
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16
18
20
beam
cu
rren
t [e
mA
]
LE
BT
HS
I
Ga
ss
trip
pe
r
Alv
are
z
Sin
gle
Ga
p
Re
so
na
tors
Fo
il S
trip
pe
r
SIS
-In
jec
tio
n
Dez 01 Okt 02
Oct-03 June_07
Design
U4+ U28+ U73+
2.7 emA
5.7 emA
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Normalized emittances along the UNILAC
0.0
0.5
1.0
1.5
2.0
2.5
3.0
LEBT HSI Gasstripper Alvarez Single GapResonators
Foil Stripper
90
%-t
ot.
em
itta
nc
e [
mm
*mra
d]
Horizontal Vertikal
U4+
U28+
U73+
horizontal SIS-Acceptance
vertical SIS-acceptance
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Front-end upgrade (2009-2011)
• Test bench for the investigation of high current ion sources and
acceleration gap.
Optimization of extraction and gap geometry for highest beam
brilliance.
•New RFQ minivane design for enlarged acceptance and higher beam
brilliance.
•Dedicated high intensity beam LEBT (Compact LEBT) to transport
37 emA of U4+ beam into the RFQ.
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Old and new design of RFQ minivanes
New DesignExisting
Design
Voltage, kV 155.0 125.0
Average radius, cm 0.6 0.52-0.77
Electrode width, cm 0.84 0.9-1.08
Maximum field, kV/cm 312.0 318.5
Modulation 1.012-1.93 1.012-2.09
Synch. Phase, degree -90 to -28 -90 to -34
Aperture, cm 0.41 0.38
Min. transverse phase advance, rad
0.56 0.45
Norm. transverse acceptance, cm mrad 0.086 0.73
Output energy, MeV/u 0.120
Electrode length, mm 9208.4
Designed by
Andrej Kolomiets
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Advantages of new RFQ minivanes
• Higher transverse acceptance and phase advance
• New input radial matcher design improved beam matching
• Improved beam dynamics for gentle buncher, optimized for rapid and uniform separatrix filling
• Resonant frequency shift with increased average radius and reduced electrode thickness can easily be compensated
• Beam dynamics studied with DYNAMION& PARMTEQ-M
• Beam intensity at HSI-RFQ output (18 mA of U4+ ions) meets the FAIR requirement
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Compact LEBT
HSI-LEBT
Pre investigations
- High current test bench measurements
Upgrade I
- Switching magnet with increased aperture
- Quadrupole quartet with increased apertures (proper matching to the RFQ)
Upgrade II (Compact LEBT)
- sc solenoids for straight line
injection of 37 emA of U4+ beam
into the RFQ
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Summary
• An extended upgrade program at the UNILAC resulted in a Uranium beam intensity of up to
5.7 emA (28+) for the injection into the synchrotron SIS18.
• High current UNILAC-upgrade measures: improved ion source performance, increase of
stripper gas density, improved Alvarez-DTL-matching, increased phase advance in the DTL,
compact charge state separator behind the foil stripper.
• The UNILAC-upgrade will be continued with a new front end comprising a compact LEBT,
a new RFQ minivane design, and beam diagnostics devices, sufficient for the operation with
megawatt heavy ion beams (until 2011). Thus the FAIR requirements will be approached.
• BUT: The UNILAC is in operation since 35 years. In long term perspective the substitution
of the Alvarez DTL by more efficient high current heavy ion accelerators for low frequent
beam pulses for FAIR injection is necessary.
• AND: The UNILAC experimental program should be decoupled from the FAIR injection
linac by a new independent sc cw-linac up to 7.5 MeV/u.
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Longterm plans for Alvarez DTL substitution
SIS 100
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
New cw linac up to 7.5 MeV/u
1.4 MeV/u 7.3 MeV/u
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Prototyp of a sc CH-cavity
CH-prototype cavity, 19 cells,
IAP University of Frankfurt
1.4 MeV/u 7.3 MeV/u
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
New charge state separator behind foil stripper
Beam Energy 11.4 MeV/u
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Beam dynamics
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Foil stripping modes
high current beamno stripping
low current beam
quadrupole
foil deposit
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Commissioning with Uranium beam
horizontal vertical
Uranium charge states
71 - 75+
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Carbon foils 200 – 600 µg/cm2
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
Fish eye view of the charge state separator
The GSI UNILAC Upgrade Program for FAIR Requirements, L. Dahl, HIAT, Venice, 12.6.2009
co-workers
Winfried Barth
Gianluigi Clemente
Peter Gerhard
Lars Groening
Michael Kaiser
Michael Maier
Sascha Mickat
Anna Orzhekhovskaya
Bernhard Schlitt
Hartmut Vormann
Stepan Yaramishev
Ludwig Dahl
LINAC group of the GSI accelerator division: