Ion Source
Development at RAL
Dan Faircloth
Including the work of:
Scott Lawrie, Alan Letchford, Christoph Gabor, Phil Wise,
Mark Whitehead, Trevor Wood, Mike Perkins, Mick Bates,
David Findlay,
Juergen Pozimski, Simon Jolly, Pete Savage, David Lee
Dan Faircloth – Proton Meeting RAL Thursday 24th March
The ISIS Ion Source
• Penning H- ion source
• Surface plasma source (SPS)
• Dudnikov type
• 15 ml/min H2
• 3 g/month Cs
• 20 day average lifetime
Negative Ion
Beam
Penning Pole
Pieces
Slit
Aperture
Plate
Discharge Region
Hollow Anode
Source Body
Cathode
Air Cooling Channels
Ceramic Spacer
Mica
Mounting Flange
Water Cooling Channels
Extraction Electrode
Copper Spacer
10mm
+17 kV Extraction
Voltage
Negative Ion Beam
Caesium Vapour
Heated Transport
Line
50 A Discharge
Caesium
Oven
Hollow
Anode
10 mm
Piezo Hydrogen Valve
H2
+17 kV Extraction
Voltage
Negative Ion Beam
Caesium Vapour
Heated Transport
Line
50 A Discharge
Caesium
Oven
Source Runs
at 50 Hz
Rep Rate
Hollow
Anode
10 mm
Piezo Hydrogen Valve
H2
Timing
H2 Gas Pulse
~ 200 μs
~ 600 μs
~ 250 μs
Discharge Pulse
Extraction Voltage Pulse
H- Beam
Time
Source Runs
at 50 Hz
Rep Rate
Cathode
Hollow Anode
Heated Caesium
Transport Line
Hydrogen Feed
Air Cooling
Discharge
Power Feed
Source Body
Thermocouples
Aperture Plate
Extraction Mount
Support
Insulators
Caesium
Shields
Extraction
Electrode
3 Sources at ISIS
Operational Source
24 x 7 operation
20 day average lifetime
200-300 μs pulse length
50 Hz
35 keV
35 mA @ RFQ
Ion Source
Development Rig
FETS Source
Experimental sources
Pre-test operational
sources
High current
Problem solving
Long pulse
65 keV
FETS
65 kV high
voltage
platform
Ion Source
Diagnostics
Vessel
Laser
3 Solenoid
LEBT
Platform ground
18 kV Pulsed
extraction power
supply
+
Extraction
gap
-
65 kV
Platform DC
power supply
160 MΩ
Aperture plate
Extraction electrode
+
750 kΩ
P.S.
Protection
electrode
Extraction electrode,
coldbox and sector
magnet all pulsed
Laboratory
ground
Coldbox
H- beam
90 Sector
magnet
Toriod 1
Ground plane
Post extraction
acceleration gap
FETS Source Schematic
Suppression electrode
FETS Source
Dan Faircloth – ICIS 2009
1. Extend discharge duty cycle
Finite Element Modelling
Steady state
calculation
700
Cathode Surface
650
Temperature (C)
600
520
440
360
280
200
Transient Calculation
ΔT= 73 ºC
600
550
ΔT= 39 ºC
Anode Surface
500
450
0
0.005
0.01
0.015
0.02
0.025
0.03
Time (seconds)
Computational fluid
dynamic cooling
calculation
FETS source
modifications
2.2 ms discharge at
50 Hz achieved
with simple design
changes
1. Extend discharge duty cycle
2. Discharge current
Experiments
For each extraction condition
there is a range of discharge
currents that give minimum
beam divergence
14 kV extraction voltage
2.2 mm extraction gap
FETS source
modifications
1. Extend discharge duty cycle
3. Permanent magnet
Penning field
2. Discharge current
B
Nd2Fe14B Permanent Magnets
To allow different extraction
voltages the Penning field
must be decoupled from the
sector magnet field
Permanent magnets are
used to produce the produce
the 0.15 – 0.25 T required
for a stable discharge
FETS source
modifications
1. Extend discharge duty cycle
2. Discharge current
3. Permanent magnet
Penning field
4. Extraction
Voltage, Geometry and Meniscus
Increase voltage from 17 to 25 kV
Widen plasma electrode aperture
120
100
Ext V (kV)
Dis Cur (A)
80
H- (mA)
60
Child-Langmuir
40
20
3
2
V
IB  2
d
0
-100
0
-20
-40
-60
100
200
300
400
500
600
700
78 mA
-80
-100
Meniscus Studies
FETS source
modifications
Decrease extraction jaw separation
800
900
1000
1. Extend discharge duty cycle
Magnet Redesign
3. Permanent magnet
Beam expands under
space charge
Penning
field
Dipole has a focusing component
Exact degree of compensation unknown
2. Discharge current
R
Field gradient index n   e
Be
 dB 
 
 dR 
4. Optimum
Extraction
field gradient index n = 1.2
determined by experiment
Size of good field region increased
Field must be adequately terminated
0
Magnetic Field Gradient Index, n
Significant improvement
in emittance
5. Analysing magnet
FETS source
modifications
0.5T
55.0 mm PA Gap
2. Discharge current
9.2 mm PA Gap
4. Extraction
0
10
20
30
40
Electric Field [kV/mm]
Minimum emittance growth occurs for a
post acceleration field of 9 kVmm-1
Increasing Post Acceleration Gap Length
xx' emittance
yy' emittance
0.2 kVmm-
0.3 kVmm-
0.4 kVmm-
0.5 kVmm-
1
1
1
1
6. Post
acceleration
1.2 kVmm-
1.8 kVmm-
2.1 kVmm-
2.7 kVmm-
1
1
1
1
4.4 kVmm-
6.8 kVmm-
7.6 kVmm-
10 kVmm-
1
1
1
1
2.5 mm PA Gap
0.70
0.68
0.66
0.64
0.62
0.60
0.58
0.56
0.54
0.52
0.50
3. Permanent magnet
Penning field
2.0 mm PA Gap
norm. rms-emittance, 100%
1. Extend discharge duty cycle
Optimize Post Acceleration Gap
5.5 kVmm-1
8.5 kVmm-1
9.5 kVmm-1
1
11 kV PA Voltage
17 kV PA Voltage
19 kV PA Voltage
Increasing Post Acceleration Voltage
Constant 10 kV Extraction Voltage 23 mA H- Beam Current
Measured 355 mm from Ground Plane of PA Gap
5. Analysing magnet
FETS source
modifications
12.5 kVmm-
25 kV PA Voltage
Laser
Diagnostics
Toroid 1
2000 Ls-1 Turbo Pump
Slit-slit scanners
400 Ls-1 turbo
pump
Solenoid 3
Solenoid 2
7×10-6 mBar
5×10-6 mBar
Camer
a
1×10-4 mBar
6×10-5 mBar
Isolating
Column
4 × 800
&
1 x 400 Ls-1
Turbo Pumps
Ls-1
Toroid 2
Solenoid 1
Differential pumping
and laser profile
vessel
Toroid3
Retractable
Faraday Cup
Toroid 4
Beam
shutter
Pepper pot or profile
scintillator head
Diagnostics
vessel
Short Pulse Operation <1ms
For pulse lengths shorter than 1 ms:
80 mA at the ground plane
60 mA at the entrance of the RFQ
0.3 πmm.mrads r.m.s normalised
Results that follow are for 2 ms pulse lengths…
Vary Discharge Current- 20 to 50 A
Discharge Current
Discharge Voltage
H- Beam Current
Discharge Power
Discharge Impedance
Possible Explanation of Droop:
1. Increased Plasma Density
• Increased H+ and Cs+ bombardment
sputters Cs from cathode surface.
• More H- are stripped on their way to
the extraction region.
2. Electrode Surface Temperature Rise
Discharge Power
Transient 3D FEA
calculations of electrode
surface temperature
Higher discharge currents
↓
Greater surface temperature rise during the pulse
↓
Surface Cs coverage pushed away from optimum
Vary Discharge Rep Rate
Vary Discharge Rep Rate
Vary Discharge Rep Rate
Lower repetition rate
↓
More time between pulses
↓
Longer time for Cs coverage to build up
Time Variation of Emittance:
25 Hz 50 A discharge
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
0 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
53 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
105 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
158 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
210 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
263 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
315 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
368 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
420 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
473 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
525 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
578 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
630 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
683 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
735 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
788 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
840 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
893 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
945 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
998 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1050 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1103 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1155 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1208 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1260 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1313 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1365 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1418 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1470 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1523 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1575 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1628 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1680 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1733 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1785 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1838 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1890 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1943 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
1995 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Current
(μA)
500
300
450
270
400
240
350
210
300
180
250
150
200
120
150
90
100
60
50
30
0
0
2048 µs
Beam Current
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
Vertical
Normalised RMS Emittance (π mm mrad)
Horizontal
Normalised RMS Emittance (π mm mrad)
Current
(μA)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
500
1000
1500
Time (µs)
2000
VERTICAL
HORIZONTAL
Time variation of Emittance Parameters for different conditions:
Normalised RMS Emittance
Phase space rotation caused by
decompensation of the beam
Twiss Alpha
Twiss Beta
Beam Brightness =
IB
8π2εHεV
ISIS Source around the World
Chinese Spallation Neutron Source
ESS Bilbao
CERN SLHC-pp Source
DESY
Linac4
LP-SPL
HP-SPL
H- current (mA)
40
80
80
80
RF peak power (kW)
30
100
100
100
RF frequency (MHz)
2
2
2
2
Repetition rate (Hz)
3
2
2
50
0.15
0.4
1.2
0.4 - 1.2
0.045
0.08
0.24
2–6
13.5
80
240
2000 - 6000
Pulse length (ms)
duty factor (%)
Average RF power (W)
THE CHALLENGE:
Over 3 times increase in power
Over 100 times increase in d.f.
Modelling and Prototyping
1.2 ms pulse length at 50 Hz
50 kW plasma stable
The Future
• Up-rated power supplies
• Better understanding of the plasma
- PhD research project with JAI
- Optical spectroscopy
- Plasma modelling
• Scaled source
• Understand lifetime limitations
Thank you for your attention
Questions, Comments?