A new RFQ cooler: concept, simulations and status pped Radioactive Isotopes: icro-laboratories for Fundamental E. Traykov • TRIP project and facility • Our concept • Prototype tests • Our design • Simulations • Conclusion TRIP Group: G.P. Berg, U. Dammalapati, P.G. Dendooven, O. Dermois, G. Ebberink M.N. Harakeh, R. Hoekstra, L. Huisman, K. Jungmann, H. Kiewiet, R. Morgenstern, J. Mulder, G. Onderwater, A. Rogachevskiy, M. Sanchez-Vega, M. Sohani, M. Stokroos, R. Timmermans, E. Traykov, O. Versolato, L. Willmann and H.W. Wilschut Krakow, 3-6 June 2004
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A new RFQ cooler: concept, simulations and status Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics E. Traykov TRI P project.
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A new RFQ cooler: concept, simulations and status
Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics
TRIP Group:G.P. Berg, U. Dammalapati, P.G. Dendooven, O. Dermois, G. EbberinkM.N. Harakeh, R. Hoekstra, L. Huisman, K. Jungmann, H. Kiewiet, R. Morgenstern, J. Mulder, G. Onderwater, A. Rogachevskiy, M. Sanchez-Vega, M. Sohani, M. Stokroos, R. Timmermans, E. Traykov, O. Versolato, L. Willmann and H.W. Wilschut
Krakow, 3-6 June 2004
TRIP project and facility
IonCatcher
RFQCooler
MOT
Beyond the Standard Model
TeV Physics
Nu
clea
r P
hys
ics
Ato
mic
Ph
ysic
sP
arti
cle
Ph
ysic
s
ProductionTarget
MagneticSeparator
MeV
meV
keV
eV
neV
AGORcyclotron
AGOR cyclotronIon catcher (gas-cell or thermal ioniser)
Low energy beam line
RFQ cooler/buncher MOT
MOT
D
D
DD
Q
QQ
Q Q
QQ
Q
Magnetic separator
Production target
Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics
Wedge
Our RFQ cooler/buncher concept
Buffer gas pressure (He): ~10-1 mbar
RFQ ion cooler RFQ ion buncher10eV thermal
Trap position
U+Vcost
-(U+Vcost)
2 x 330 mm
Switching on end electrodes
• RF capacitive coupling• DC drag resistor chain
• Electronics designed for large range of isotopes• UHV compatible design and materials
• Standard vacuum parts (NW160)
~10-3 mbar
Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics
RFQ cooler prototype tests
• RFQ in vacuum• Transverse cooling• Velocity damping• With and without a drag voltage on the segments
133Cs+ beam, initial energy: 10eV
0
50
100
150
200
250
1.0E-03 1.0E-02 1.0E-01
Pressure [mbar]
Cu
rren
t [p
A]
.
Current through aperture Current on electrode Total current
Tests:
Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics
Our RFQ cooler/buncher design
Pressure
cooler
: ~10-
1 mbar
~10-3 m
bar He b
uffer g
asSeparate connections
for trap segments
Changeable separation electrodeswith different aperture diameters
Buffer gas: Helium for light ions (i.e. Na-21)(Heavier gas may be considered for Ra ions)
Kapton foil12.5m 120 pF
Stainless steel rods
OFHC copper
Preset frequencies:0.5MHz, 1 MHz, 1.5 MHz
RF amplitude:150 V (peak-to-peak)
UHV compatible resistors for drag voltage:Uncoated, 2.2 k
Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics
Simulations and calculation of E field
• Simulations• Real 3D geometry• Material properties • Geometry separated to smaller parts• Fine mesh and grid size• 3D electric field map (RF and DC)
RF electric potential DC drag potential
FEMLAB calculation examples:
Trapped Radioactive Isotopes: icro-laboratories for Fundamental Physics
Optimization using the simulations • Main goal: collect all ions• Confinement and transmission• Optimize parameters (regions of stable operation):
• pressure and type of gas• aperture diameters• beam settings at entrance• drag voltage step• potentials on separation electrodes • accumulation time (buncher)• trap potential depth and shape
• Questions:• phase dependence (cooler-buncher)• phase dependence (switching)• where do we loose ions (why?)
Exit RFQ guide
-2000
-1500
-1000
-500
0
500
1000
1500
2000
-0.002 -0.001 0 0.001 0.002
x, y [m]
Vx,
Vy
[m/s
] .
Velocity distribution at exit of RFQ1
0
50
100
150
200
225 1125 2025 2925 3825 4725 5625 6750
longitudinal velocities [m/s]
nu
mb
er o
f io
ns
. ~ 2 eVq=0.5p=0.025 mbardrag voltage=0.5V
Buffer gas pressureRF: 1500 kHz, 21Na+, 10 eV 950 m/s maximum transverse velocity0.5 V drag voltage step