The Superconducting ECR ion source SUSI for the coupled ...

The Superconducting ECR ion source SUSI for the
coupled cyclotron Facility (CCF) at NSCL/MSU
G.Machicoane C. Benatti, D.Cole, M.
Doleans, O. Kester, X. Wu, C. Zhang
(National Superconducting Cyclotron Laboratory)
Peter Zavodszky
(General Electric)
G. Machicoane ICIS09, 09/21/2009, Slide 1

Outline
3 rd Generation ion source for NSCL/MSU
Construction and Testing
Commissioning Results
Beam extraction studies
Collimation Channel
Installation for injection in the K500
G. Machicoane ICIS09, 09/21/2009, Slide 2

National Superconducting Cyclotron Laboratory
US user facility for Rare Isotope research
Isotope production by fast-beam fragmentation
and in-flight separation
education in nuclear science, astro-nuclear physics
and accelerator physics
SUSI Artemis
Ion Charge St at e Current (euA)
18 0 3+ 35
40 Ar 7+ 40
58 Ni 11+ 8
76 Ge 12+ 5
78 Kr 14+ 15
48 Ca 8+ 10
136 Xe 21+ 11
G. Machicoane ICIS09, 09/21/2009, Slide 3

Bright future in US for Rare Isotope Research
ReA3 & ReA12
Facility for Rare Ion Beam (DOE)
Talk by Stefan Schwarz (NSCL/MSU) Thursday 8:30 AM
“Opportunities and Challenges for the next Facility for Rare Isotope Beams”
G. Machicoane ICIS09, 09/21/2009, Slide 4

Increase Primary Beam Power from CCF
Snapshot of CCF Operation: 04/01/2008 to 03/29/2009 ~4450 hours scheduled to run
NSCL delivered rare isotope beams to 27 experiments:
Beam delivered within 24 hours of scheduled time
Beam availability > 90%
40 Ar
48 Ca
76 Ge
124 Xe
2007 1350 1200 625 425
2006 1350 950 625 225
2005 750 675 250 225
2004 725 400 175 125
Challenges
Improve beam brightness and Improve beam matching into K500
Minimize beam losses on deflectors
Improve stripper foil lifetime
K500 injection use 2 ECR ion sources (14.5 GHz & 6.4GHz)
Improve beam intensity from ion source (SUSI)
Off line diagnostics development (Artemis-B)
Develop collimation scheme and use of beam chopper
G. Machicoane ICIS09, 09/21/2009, Slide 5

The Superconducting Source for Ions (SuSI)
18 GHz operating frequency (possibly 24 GHz)
[BECR=0.643 Tesla]
Binj=2.5T; Bext=1.4T;Brad=1.5T
ne 2
RF
Al. Plasma chamber of 100 mm in
state)
Fully Superconducting coils
extraction up to 27kV
(medium charge
Specific Design features
6 solenoids coils
Movable injection baffle
G. Machicoane ICIS09, 09/21/2009, Slide 6

Engineering of SuSI used techniques developed for VENUS (LBNL)
Project started in 2003
Mechanical design started in early 2004
Coils winding completed in September 2005
Cryostat completed in September 2006
Source assembly completed in January 2007
First Plasma ignited in March 2007
Long period of training (Quenches) until October 2007
Reliable coils system but:
Need to ramp Solenoid and Hexapole together
Field not as flexible as intended
All design and
construction was
done at NSCL
G. Machicoane ICIS09, 09/21/2009, Slide 7

350.00
300.00
250.00
200.00
150.00
100.00
50.00
0.00
Xe 27+
Commissioning Results from SUSI : 129 Xe
Xe 25+
Xe 20+
Xe 15+
120 130 140 150 160 170 180 190 200 210 220
129 Xe : optimized on Xe 20+ :335euA
1.7kW 18GHz
300W 14.5GHz
300.00
250.00
200.00
150.00
100.00
50.00
0.00
129 Xe : optimized on Xe 27+ :180euA
1.8kW 18GHz
500W 14.5GHz
Xe 30+
Xe 26+
Xe 27+
Xe 23+
115 125 135 145 155 165 175 185
G. Machicoane ICIS09, 09/21/2009, Slide 8

mpact of position of resonance zone on extracted currents for 84 Kr
Coils Polarity: + + - - + +
400.00
350.00
300.00
250.00
200.00
150.00
100.00
50.00
0.00
Kr14+ Kr16+ Kr 12+
Kr 10+
D=100mm
Id=3.8mA
80 100 120 140 160 180
400
350
300
250
200
150
100
Coils Polarity: + + + + - +
50
0
Kr 16+
Kr 14+ Kr 12+
Kr 11+
Kr 10+
D=11 mm
Id=5.5mA
90 110 130 150 170 190 210
G. Machicoane ICIS09, 09/21/2009, Slide 9

Commissioning Results from SUSI : 209 Bi
1.7kW (18GHz) +
300W (14.5GHz)
66 euA of Bi 33+
1.4kW (18GHz) +
300W (14.5GHz)
150 euA of Bi 28+
G. Machicoane ICIS09, 09/21/2009, Slide 10

180euA of Ni 17+
Current of Ni 12+
58 Ni development with inductive
Oven
200euA of Ni 12+
24h
Consumption: 410 mg
60euA 24 hrs
140euA 24 hrs
Average: 6.83mg/hr
G. Machicoane ICIS09, 09/21/2009, Slide 11

Challenges:
Beam extraction from SUSI
1. Extraction of “multicomponents” ion beam in
strong magnetic field
2. Optimize beam brightness
G. Machicoane ICIS09, 09/21/2009, Slide 12

3.
4.
5.
SUSI beam transport Setup
2.
1.
1. Ion Source
2. Extraction Box (puller)
3. 90 o Bending Magnet
4. Diag. Box: FC, KBr viewer, 4jaw slits
5. Allison Emittance Scanner
G. Machicoane ICIS09, 09/21/2009, Slide 13

3.
4.
5.
SUSI beam transport Initials Tests
1.
2.
HV=20-25kV
Transmission from source to 4. >80% for 1-2mA beam
~60-70 %>4mA
Bending Magnet was tested and showed a central region
(3”) with little to no aberrations
Tests with Negative HV (-30kV) to region from 2. to 4.
KE

3.
4.
5.
Current
Scan
100W
1.
2.
KBr viewer
Viewer
Image
Diagnostics
HV=20-25kV
400W
Faraday Cups
Allison ES:0.25mm 3mrad
4 Jaw collimators
1000W
G. Machicoane ICIS09, 09/21/2009, Slide 15

Kr 19+ Kr 17+
Kr 13+ Kr 11+ Kr 9+
Observations with 84 Kr
Kr 15+
Kr9+
Kr13+
Kr17+
G. Machicoane ICIS09, 09/21/2009, Slide 16

1500W (18GHz)
3mA
Gap:50mm
xy
xx’ yy’
Observations with 84 Kr (cont.)
900W (18GHz)
2.4mA
Gap: 55mm
Kr 13+ Kr 13+
xy
xx’ yy’
G. Machicoane ICIS09, 09/21/2009, Slide 17

Current Scan profile done with He 1+ and He 2+
He 1+
He 2+
1mA :
550 euA He 1+
300 euA He 2+
2mA :
1350 euA He 1+
500 euA He 2+
3mA :
1450 euA He 1+
600 euA He 2+
He 1+ more uniform than He 2+ for all extracted current
Not in Agreement with preliminary I-Gun calculations
G. Machicoane ICIS09, 09/21/2009, Slide 18

Summary on observations of intensity and phase space
distribution
High charge State beams extracted from ECR present
homogeneous distribution and little phase space distortion
Medium charge State have to be tuned carefully (i.e Kr13+)
Low charge state have been found systematically hollow
and present large phase space distortions
G. Machicoane ICIS09, 09/21/2009, Slide 19

Ap.1
Sol.1
Ap.2
Sol.2
Ap.3
Sol.3
Ap.4
Collimation Chanel
Multiple-stage collimation with phase-space rotation in between
Possible to use solenoid lenses to do the phase space rotation
Design using 3 cells (3 solenoids –4 apertures)
- Building block (cell): drift-solenoid-drift
S = Length of the cell
L = Length of the solenoid (with L 90 degrees (115 deg in SuSI
channel)
-Odd numbers of solenoids leads to a preferred tune using 90 degrees accumulated XY
rotation (exchange X-Y phase spaces)
σ
β
B
2Bρ
S
σ
SL
2Bρ
B
L/S
G. Machicoane ICIS09, 09/21/2009, Slide 20

Simulations for an eigen ellipse
200 pi-mm-mrad beam full emittance
6-D waterbag input distribution
Used-Beam with eigen twiss parameters (α=0
β=1.05 m)-
5k particles (blue dots) run through-Beam
envelope (dashed ellipses) ran also showing the
beam without collimation for comparison
Four circular apertures of 15 mm diameters were
used for proof of collimation (final emittancesare ~
50 pi-mm-mardin this case)-
Beam xx’-yy’-xy spaces shown at the entrance and
after the four successive collimators
G. Machicoane ICIS09, 09/21/2009, Slide 21

Channel tuning recipe
• All solenoids set at same field (scaled with magnetic rigidity of beam)
• All apertures set at same width
Desired
beamemittance
Channelacceptance
(aperture width)
4β
channel
G. Machicoane ICIS09, 09/21/2009, Slide 22
2

FC:
SuSI - Argon Beam Collimation
625 . m 156 . m 56 . m 25 . m
150 e A 96 e A 43 e A 17 e A
G. Machicoane ICIS09, 09/21/2009, Slide 23

FC:
Krypton Beam Collimation
625 . m 156 . m 56 . m 25 . m
138 e A 100 e A 55 e A 19 e A
G. Machicoane ICIS09, 09/21/2009, Slide 24

Krypton 10+
• The medium charge Kr10+ phase space is more distorted by space
charge forces – But, the filtering action of the channel is similar to Kr14+
100 e A 18 e A
G. Machicoane ICIS09, 09/21/2009, Slide 25

Use channel to optimize SuSI-ECR tune (example)
• Started to use the channel as a tuning guide for SuSI-ECR parameters
• Set the channel at a given acceptance, modify source parameter and
record current after the channel
Beam current (normalized)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
drain current Ar7+ at 17FC
-50 -40 -30 -20 -10 0 10 20 30 40 50
baffle position (mm)
G. Machicoane ICIS09, 09/21/2009, Slide 26

Connection of SuSI to the Coupled Cyclotron
Large Planning effort during the last year
Project started in July 2009
Upgrade of Lead Shielding
Moved in August to ECR area
Cryogenics installed and Ion source cold by
last week of August
Field established the first week of September
Only 1 Quench before reaching Field for 18GHz
operation
Established Field for 24 GHz
Beam Line has been completed
Ion source and Beam Line are under vacuum
ARR scheduled for this week
Commissioning in the new area is scheduled to start next week
First Beam for CCF operation with SuSI to be delivered next month
G. Machicoane ICIS09, 09/21/2009, Slide 27

Accelerator
M.Doleans, O.Kester,
F. Marti, X. Wu,
Q. Zhao
Students
C. Benatti, G.Gasquet,
C. Zhang
Fabrication and assembly
J. Pline, J.Wagner,
Electricians,Machinist
NSCL Support
Operation
All Cyclotron operators, D. Cole, G.
Humenik, P. Miller, D. Poe,
J.Stetson, L.Tobos
P. Zavodzsky
Mechanical Design
B.Arend, R. Fontus,
D.Lawton, J. Ottarson
Electronics
K. Davidson, K.Holland,
G.Mujtaba,C.Supangco,
J.Vincent
Facilities
S. Chouhan, J. DeKamp, S.
Hitchcock, J. Yurkon, A. Zeller
G. Machicoane ICIS09, 09/21/2009, Slide 28