focusing of intense heavy ion beams with plasma lensesionenstrahlen und nichtneutrale plasmen...
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![Page 1: Focusing of Intense Heavy Ion Beams with Plasma LensesIonenstrahlen und Nichtneutrale Plasmen Author: nnp Created Date: 7/31/2012 4:06:07 PM](https://reader036.vdocument.in/reader036/viewer/2022071412/61084410e12a8f3c3a2d82da/html5/thumbnails/1.jpg)
NNP Non Neutral Plasma
Physics Group
Focusing of Intense Heavy Ion Beams
with Plasma Lenses
Oliver Meusel
12th Heavy Ion Accelerator Technology Conference
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NNP Non Neutral Plasma
Physics Group
Historical Remarks
Proposal of a SCL by Gabor, July 1947
Electrical & Electronic
Engineering Department,
Imperial College London
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NNP Non Neutral Plasma
Physics Group
Space Charge Lenses
high field Gabor lens for beam energies up to 500keV
lens properties:
FA,max = 6.5kV
Bz,max = 48mT
lens properties :
FA,max = 65kV
Bz,max = 220mT
Gabor lens for beam energies up to 50 keV
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NNP Non Neutral Plasma
Physics Group
Radial Confinement
m v
reE ev B
e e,
2
r e, z
e
e,v
r
pe
22
e
0 e
e n
m
ez
e
eB
m
plasma frequency
cyclotron frequency
angle velocity
Er given by Poisson equation:
1
r rrE
en (r)r
e
0
integration for 0 < r < Rp :
E1
2en rr
0
e
e
pe
e e
2
2
2
radial force balance equation
![Page 5: Focusing of Intense Heavy Ion Beams with Plasma LensesIonenstrahlen und Nichtneutrale Plasmen Author: nnp Created Date: 7/31/2012 4:06:07 PM](https://reader036.vdocument.in/reader036/viewer/2022071412/61084410e12a8f3c3a2d82da/html5/thumbnails/5.jpg)
NNP Non Neutral Plasma
Physics Group
Radial Confinement
maximum density by a trapping efficiency of
2
1
2
2
)2
1(12 e
peee
solution:
e
ze
e
pe
rm
Bn
21
2 2
0
2
2
r 1
e ee
2
r 1
e
pe
2
r
z
e e2
E
rB ;
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NNP Non Neutral Plasma
Physics Group
Longitudinal Confinement
Freen r
2
04
1 2
2
0r r r
en rr r e
F F ( )
integrated for 0 < r <Rp
maximum density at F Fanode r
Fr is determined from Poisson‘s equation:
2
04
ern A
e
F
longitudinal potential well
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NNP Non Neutral Plasma
Physics Group
Numerical Simulation
e
zA
m
Ber
8
22
F
y
x z
pz
GabLensM2
• kinetic description
• dynamic processes
• 3D-Particle-In-Cell Simulation
GaborM
• fluid description
• steady state
two different simulation methods
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NNP Non Neutral Plasma
Physics Group
Focusing Strength
mv
qgk
mv
qBk
2
2mv
qgk
time
comparison of focusing strengthes
MSQ / ESQ
strong
focusing/defocusing
SCL
strong focusing
Solenoid
weak focusing
be
z
Wm
qeBk
8
2
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NNP Non Neutral Plasma
Physics Group
Comparison of Focussing Strengthes
e
i
ii
be
z
m
m
vm
qBk
Wm
Bqk
2
8
22
Filling degree depends on:
• electron temperature
• loss and production rates
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NNP Non Neutral Plasma
Physics Group
Beam Transport Experiments
Preasure measurement
& control
Gabor lens
Faraday Cup
Beam dump
500 L/s Turbo Pump
Emittance Scanner
focussing of micro bunches passing a
Gabor lens @ 108MHz, Df = 60°
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NNP Non Neutral Plasma
Physics Group
Experiments Using Ion Beams
measurement of the electron density
using an ion beam
1
40
2
0f
x
xk l
en l
W
e
b
D ' ,exp
r
e
e theo
n
n
.exp
,
beam properties:
Wb = 110 keV/u
I = 1.2 mA
He+
p = 10-7 hPa
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NNP Non Neutral Plasma
Physics Group
Beam Emittance Growth
rms x x xx 2 2 2' '
D
rms
rms out
rms in
,
,
characterisation of lens aberration by
estimation of emittance growth
beam properties:
Wb = 110 keV/u
I = 1.2 mA
He+
p = 10-7 hPa
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NNP Non Neutral Plasma
Physics Group
Planned Experiments
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NNP Non Neutral Plasma
Physics Group
High Field Gabor Lens
HF-GL prototype for HSI upgrade
lens properties
ranode : 85mm
Bmax : 50mT
Fmax : 50kV
• ceramic insulator
• HV-contacting
• UH vacuum sealing
DN CF 160
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NNP Non Neutral Plasma
Physics Group
Performance Test of the HF-GL
emitted bremsstrahlung spectra
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NNP Non Neutral Plasma
Physics Group
Electron Clouds under XHV Conditions
loss and production rates at preasures below 10-12 mbar
Is it possible to use a Gabor - lens in a cryogenic interior?
SC-CH Cavity SC-Gabor lens SC-Gabor lens
Cryostat
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NNP Non Neutral Plasma
Physics Group
Thank you for your attention.
NNP Group
http://nnp.physik.uni-frankfurt.de
http://hicforfair.de