light ion ecr sources state of the art for linacs
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| PAGE 1
LIGHT ION ECR SOURCES
STATE OF THE ART
FOR LINACS
SEPTEMBER 14, 2012
LINAC2012|
Raphaël GOBIN, N. CHAUVIN,
O. DELFERRIERE, O. TUSKE, O. URIOT
13 SEPTEMBRE 2012 CEA | 10 AVRIL 2012
OUTLINE
General assessments on light ion ECR sources
- General principle
- Several key points
- Pulsed beam and Space charge compensation
Worldwide overview
CEA involvement on IFMIF, Spiral 2 and FAIR projects
13 SEPTEMBRE 2012 | PAGE 2 LINAC 2012 R. GOBIN CEA | September 14, 2012
One of the main requests, especially for ADS is the reliability
ECR ion sources (no filament, no antenna)
Particles Intensity Pulse length Repetition Duty Factor Emittance
p/d/H- mA ms Hz % π mm.mad
LEDA H+ 100 CW - 100 0.25
IPHI* H+ 100 CW - 100 0.25
TRASCO H+ 30 CW - 100 0.2
SARAF H+, D+ 2 CW - 100 0.2
IFMIF* D+ 140 CW - 100 0.25
Spiral2* H+, D+ 5 CW - 100 0.25
PEFP H+ 20 2 8-20
MYRRHA H+ 10/25 CW - 100 0.25
Chinese ADS H+ 10 CW - 100
FAIR* H+ 100 1 4 0.4 0.3
ImPUF H+, D+ 5 CW - 100
ESS H+ 60/90 2.9 14 4 0.3
RISP H2+, D+ 1 - 5
NUMEROUS HPPA-LIKE PROJECTS AROUND THE WORD
Negative ion HPPA are not listed in this table
| PAGE 3 LINAC 2012 R. GOBIN - CEA | September 14, 2012
| PAGE 4 LINAC 2012 R. GOBIN - CEA | September 14, 2012
HIGH INTENSITY SOURCES
In the 90’s, CEA started the IPHI project with the SILHI source.
Goal : > 100 mA H+
and is now involved in several projects: IFMIF, SPIRAL2, FAIR, ESS, LINAC 4
RFQ
LEBT
Ion Source
MEBT
Low Energy
Linac
Target
Target High Energy Linac
HEBT
Schematic drawing of an HPPA
The ion source aim is to produce high intensity
light ion beams (pulsed or continuous)
for injection into a RFQ via a LEBT
Ion source + extraction system + LEBT
have to be considered as a whole. (S. Gammino at ICIS 2009)
| PAGE 5 LINAC 2012 R. GOBIN - CEA | September 14, 2012
GENERAL PRINCIPLE OF THE SOURCE
SILHI source at CEA/Saclay
ECR Source Resonance zone if = e B / m
2.45 GHz 875 Gauss
Magnetic field provided by coils or permanent magnets
Multi-electrode extraction system
, pulsation
e, electron charge
B, magnetic field
m, electron mass
| PAGE 6 LINAC 2012 R. GOBIN - CEA | September 14, 2012
-600
-100
400
900
1400
1900
-200 -150 -100 -50 0 50 100 150 200
m
Ga
us
s
-10
10
30
50
70
90
110
130
150
I1=63,I2=84,z1=80,z2=166
Bz = 875 Gauss
I1=57,I2=83.4,z1=82,z2=176
I1=61, I2=84, z1=82, z2=176
Objet1
Objet2
Electrodes
Série7
Several key points (1)
Protection of the window
Electron repeller
Ridged or tapered transition on RF chain
Ceramic disks to improve electron density
Resonance value at plasma chamber entrance
Negative Triple junction shielding
SILHI source at Saclay
J. Sherman, RSI 69, 1998
| PAGE 7 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Several key points (2)
Reduce LEBT length
Small amount of heavy gas in LEBT can improve SCC
R. Hollinger, Linac2006, TU3001
When HI beam interacts with residual gas, SCC occurs :
H+ + H2 H+ + H2+ + e-
Generally, electrons are confined in the beam
and secondary ions are repelled towards the walls.
Space charge can reach close to 100 % but non-linearity exists
(magnets, chamber size) and SCC can dramatically change.
At Saclay, ALISES
source developments
In PKU source and accel
column are located into
the vacuum chamber
just in front of Sol1.
How to limit the emittance growth?
t = 2 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 8
Pulsed beam and Space Charge
Compensation
| PAGE 8 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 9
Pulsed beam and Space Charge
Compensation
| PAGE 9 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 10
Pulsed beam and Space Charge
Compensation
| PAGE 10 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 11
Pulsed beam and Space Charge
Compensation
| PAGE 11 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 12
Pulsed beam and Space Charge
Compensation
| PAGE 12 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs t = 12 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 13
Pulsed beam and Space Charge
Compensation
| PAGE 13 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs t = 12 µs t = 14 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 14
Pulsed beam and Space Charge
Compensation
| PAGE 14 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs t = 12 µs t = 14 µs t = 16 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 15
Pulsed beam and Space Charge
Compensation
| PAGE 15 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs t = 12 µs t = 14 µs t = 16 µs t = 18 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 16
Pulsed beam and Space Charge
Compensation
| PAGE 16 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs t = 12 µs t = 14 µs t = 16 µs t = 18 µs t = 20 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 17
Pulsed beam and Space Charge
Compensation
| PAGE 17 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
t = 2 µs t = 4 µs t = 6 µs t = 8 µs t = 10 µs t = 12 µs t = 14 µs t = 16 µs t = 18 µs t = 20 µs
Dedicated code SOLMAXP (R. Duperrier et al.)
has been developed at Saclay
to take into account
the space charge compensation
evolution
| PAGE 18
Pulsed beam and Space Charge
Compensation
| PAGE 18 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Time is needed to reach SCC equilibrium
SOLMAXP gives the SC potential map
allowing calculation
of SC electric field map
| PAGE 19 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Pulsed beam and Space Charge
Compensation
i 1
i 2
Source
Sol. 1
Sol. 1
Pulse rise time depends on repetition rate and can reach 1 - 2 ms
With fast repetition, SCC rise time can be estimated
| PAGE 20 LINAC 2012 R. GOBIN - CEA | September 14, 2012
HPPA worldwide ion source activity
Chalk River 1st
Los Alamos
Indiana University
CEA/Saclay
INFN Catane
Bilbao
CIAE,
Peking University
IMP Lanzhou
CAT
BARC
And several companies in Europe, USA, Japan, …
Several groups develop ECR sources to produce high intensity light ion beams
SOREQ
Kanazawa Inst. Techn.
KAERI
| PAGE 21 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Pioneers…
Chalk River source with triode extr. system
(T. Taylor, J-F. Mouris)
Ion source developed by N. Sakudo for implanters
75keV LANL source with tetrode extr. system
(J. Sherman)
This source designed for LEDA allowed
75 mA accelerated beam behind 6.7 MeV RFQ
Very compact
permanent magnet
ion source
PKUNIFTY deuteron injector
| PAGE 22 LINAC 2012 R. GOBIN - CEA | September 14, 2012
ImPUF is a new project in
Peking University to produce
fast neutrons dedicated to
material research.
•CW accelerator
•H2+ beam operation for
commissioning
•D+ ~ 5 mA @ 3 - 40 MeV
•H+ ~ 5 mA @ 3 - 33 MeV
| PAGE 23 LINAC 2012 R. GOBIN - CEA | September 14, 2012
IMP Lanzhou
IMP Lanzhou is involved in Tsinghua University irradiation tool (CPHS) project and Chinese ADS
For CPHS, to limit spark rate in
extraction system, a 4th electrode
(grounded) has been added between
plasma electrode and repeller.
0 10 20 30 40 50 60 70 80 90
IGUN-7.074(C)R.Becker - RUN 08/07/12*036, file=9los.in
0
5
10
15
qinghua
6.20E-2 A, crossover at Z= 17, R=2.13 mesh units, Debye=2.52E-2 mesh units
0 V50000 V
0 V
-5000 V
Up=50015.9, Te=5.0 eV, Ui=5.0 eV, mass=1.0, Ti=0 eV, Usput=0 V
For CADS, IMP is in charge
of the design,
construction and studies
for both 35 keV injectors.
| PAGE 24 LINAC 2012 R. GOBIN - CEA | September 14, 2012
SARAF source in Israel
Source and LEBT designed and built by RI (former ACCEL).
Pulsed or continuous mode.
High reliability.
High molecular ion fraction.
Ingenious variable aperture is placed after the dipole.
Varying the aperture together with
Sol1 allows changing the beam
intensity by almost factor 100.
| PAGE 25 LINAC 2012 R. GOBIN - CEA | September 14, 2012
TRIPS, VIS and ESS source in Catania
Important work is done at INFN/LNS on magnetic configuration
TRIPS with 2 coils
and 80 kV DC break VIS with permanent
magnets + iron
ESS source
with 2 + 1 coils.
3rd coil to obtain
minimum B field
in Plasma Chamber
Courtesy L. Celona & S. Gammino
| PAGE 26 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Others…
In Bilbao
1st proton beam
has been extracted
July 2012 at 15 keV
with 25 mm gap.
Parameters
particle p
Energy 600 MeV
Current 4 mA
mode CW
MTBF > 250 h
In Belgium, Myrrha project is preparing a front end test stand in UCL
with an ECR ion source from Pantechnik.
Courtesy S. Djekic 2.7 GHz klystron operation
| PAGE 27 LINAC 2012 R. GOBIN - CEA | September 14, 2012
Spiral 2 in GANIL (France)
Ions Energy Current
H+ 20keV 8mA
D+ 40keV 6mA
Long beam line to allow injecting light
and heavy ions from 2 different sources
Permanent magnet source
5 electrode extraction system
Small HV platform
DC break
The whole Sp 2 injector has been
built and tested at Saclay before
transfer to GANIL in Caen
Spiral 2 Injector tested at Saclay
| PAGE 28 LINAC 2012 R. GOBIN - CEA | September 14, 2012
0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16 0,18
0
1000
2000
3000
4000
5000
H+
3
Inte
nsity o
n C
F1
2 (
µA
)
B field (T)
Intensity on CF12H+
H+
2 Unresolved Pollution
N2 O
2
CW PROTON BEAM
23-01-2012
• Nominal tuning : ~0.22 π.mm.mrad
ION Proportion
Ions 100%
H+ 81%
H2+ 14%
H3+ 1,7%
Heavy 3,4%
100 200 300 400 500 600 700 800 900
0
1000
2000
3000
4000
5000
6000
H+
3D
+
3
D+
2
D+ and H
+
2
Be
am
Du
mp
CF
12
(µ
A)
Hall Probe (mT)
Beam Dump CF 12
H+
CW DEUTERON BEAM Measurements ~0.18 π .mm.mrad
ION Proportion
Ions 100%
H+ 2,1%
H2+ 0,5%
D+ 83%
D2+ 9,7%
D3+ 1,2%
Heavy 3,5 %
Emittances measured
right after second dipole
Species measured after 1st dipole
Spiral 2 beam characterization
| PAGE 29 LINAC 2012 R. GOBIN - CEA | September 14, 2012
0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16 0,18
0
1000
2000
3000
4000
5000
H+
3
Inte
nsity o
n C
F1
2 (
µA
)
B field (T)
Intensity on CF12H+
H+
2 Unresolved Pollution
N2 O
2
CW PROTON BEAM
23-01-2012
• Nominal tuning : ~0.22 π.mm.mrad
ION Proportion
Ions 100%
H+ 81%
H2+ 14%
H3+ 1,7%
Heavy 3,4%
100 200 300 400 500 600 700 800 900
0
1000
2000
3000
4000
5000
6000
H+
3D
+
3
D+
2
D+ and H
+
2
Be
am
Du
mp
CF
12
(µ
A)
Hall Probe (mT)
Beam Dump CF 12
H+
CW DEUTERON BEAM Measurements ~0.18 π .mm.mrad
ION Proportion
Ions 100%
H+ 2,1%
H2+ 0,5%
D+ 83%
D2+ 9,7%
D3+ 1,2%
Heavy 3,5 %
Emittances measured
right after second dipole
Species measured after 1st dipole
Spiral 2 beam characterization
| PAGE 30 LINAC 2012 R. GOBIN - CEA | September 14, 2012
| PAGE 31 LINAC 2012 R. GOBIN - CEA | September 14, 2012
IFMIF Injector
Requirements Acceptance
criteria
Comment
Particle type D+ H+ for injector conditioning
Output energy
Energy stability
100 keV
± 100 eV
Fixed by the RFQ acceptance
Output D+ current 140 mA RFQ transmission ≥ 90%
Species fraction D+ ≥ 95 % At the output of the LEBT
Beam current noise ≤ 2 % rms At frequencies below ~1 MHz
rms norm. emittance ≤ 0.30 π mm mrad At the output of the LEBT
Duty factor CW Possibility of pulsed operation.
Modulation
capability
1 ms – CW
@ 1-20 Hz
Typically
As shown on Tuesday, IFMIF is the machine
of all the challenges…
as soon as the exit of the source.
IFMIF Injector has been designed, built and under test
at Saclay before shipment to Rokkasho site in Japan
100 KeV, 175 mA total beam current, 1560 A/m² ( 12mm)
Plasma electrode
12mm 45° angle 100 kV
Intermediate electrode
12mm Adjustable 57 kV
e- screening electrode
12mm -9.8 kV
Grounded electrode
14mm 0 kV
(80% D+, 15% D2+,5% D3
+) (140mA D+, 26 mA D2+,9 mA D3
+)
IFMIF Extraction System
Preliminary tests at high energy showed high spark rate.
The installation of a 2nd grounded electrode (between puller and repeller) is underway.
| PAGE 33 LINAC 2012 R. GOBIN - CEA | September 14, 2012
IFMIF beam analysis
Green: current from HVPS
Blue: current on Beam Stop (w/o cone)
Electrode plasma Φ 10
I ext. = 81 mA
I BS = 42 mA (with cone)
CW 50 keV H+ beam.
Emittance:
- After Sol1, 81 mA, 0. 46 π.mm.mrad
- After cone, 42 mA, 0.29 π.mm.mrad
1st D+ beam: 100keV, I ext. 125 mA
1% dc
| PAGE 34 LINAC 2012 R. GOBIN - CEA | September 14, 2012
FAIR proton linac injector
FAIR p-linac injector
• SILHI-type ion source.
• The ion source is operating in pulsed mode.
• 5 electrode extraction system.
• LEBT with a 2 solenoids focusing scheme.
• LEBT design is based on IFMIF LEBT.
• Chopper system after the second solenoid.
First beam in CEA-Saclay: Mid-2013
Diagnostics:
• Allison scanner.
• Wien Filter
• Wire scanner
• Iris
• 2 ACCTs
• Pulsed beam (36µs-4Hz)
• Energy: 95 keV
• H+ : 100 mA at RFQ entrance
R. GOBIN CEA/Saclay DSM/IRFU/SACM/LEDA Meeting ESS Bilbao at Saclay APRIL 22, 2009 35
Several words from Bloomington:
“For the proton therapy system we have been operating
the ion source (20 keV – few mA into
CW RFQ).
6 months servicing for changing BN disks
Between 2006 and 2012 there have been no
failures of the ion source.”
In conclusion, such sources are very well adapted for HPPAs
Special thanks to: - L. Celona
- V. Derenchuk
- S. Djekic,
- S. Gammino,
- S. Peng,
- D. Vandeplassche,
- L. Weissman
- Z. Zhang
- H. Zhao
and to SPIRAL 2, IFMIF and
FAIR injector groups.
CONCLUSION
Direction Sciences de la Matière
Institut de Recherche sur les lois
Fondamentales de l’Univers
Service Accélérateur, Magnétisme et
Cryogénie
Commissariat à l’énergie atomique et aux énergies alternatives
Centre de Saclay | 91191 Gif-sur-Yvette Cedex
T. +33 (0)1 69 08 27 64| F. +33 (0)1 69 08 14 30
Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 019 13 SEPTEMBRE 2012
CEA | 10 AVRIL 2012
Thank you for your attention
| PAGE 36 LINAC 2012 R. GOBIN - CEA | September 14, 2012
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