Plan for the extension of 12 month for JRA03
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Oliver KesterI3 EURONSPlan for the extension of 12
month for JRA03
* Double frequency operation of PHOENIX at LPSC (chamber is now available, simpler setup than 28 GHz operation)
* Further exploration of charge state manipulation and comparison with the new simulation tool CBSIM.
* Efficiency exploration with BNL EBIS (can only be done in 2008)
* Continuation of molecule break up and capture of decay products, which opens new possible beam development
Oliver KesterI3 EURONSTask 4: High-frequency exploration of ECRIS
4.1 Improving of breeding time of ECRISalready seen, to be measured systematically before interpratation4.2 High frequency (14-28 GHz) exploration28 GHz might be difficult before end 20084.3 Influence of ECRIS plasma volumeDouble frequency (14+18 GHz will be a good test)
Modifications of the booster under fabrication, will installed by the end of September 2007
Present PHOENI X Breeder Magnetic plug, Higher Binj, Less dissymmetry
UHV tech. and moveable grounded tubeTwo f requency plasma chamber
Oliver KesterI3 EURONSECRIS charge breeders pulsed
LPSCECR charge breeding time
0 2 4 6 8 10 12Time (ms)
Inte
nsit
y (m A
) Ar3+
Ar4+
Ar6+
Ar7+
Ar8+
Ar9+
Ar2+ Microwave pulse
0
800
Steady state Ar9+: 5 ms
Preglow
Afterglow
18 GHz, 950 W 28 GHz, 3600 W
Steady states reached at 3 ms for all charges !!
0 2 4 6 8 10 12Time (ms)
Inte
nsit
y (m A
) Ar3+
Ar4+
Ar6+
Ar7+
Ar8+
Ar9+
Ar2+Microwave pulse
300
0T. Thuillier et al., ICIS’07
In ECR Charge state increase can be very fast ! -> But trapping very long !
0
200
400
600
-800 -600 -400 -200 0
Time (ms)
IRb
15+
(nA
)
End of Rb1+ injection
RF power cancellationRF Power
RB1+ injection Rb15+ Afterglow
Here 520 ms for Rb15+
N. Chauvin et al., Nucl. Instrum. Meth. A, Vol 419, nb. 1, 1998
Charge breeding time is a result of the ECRIS compromise, RF, B, Gas
Oliver KesterI3 EURONSShift of the charge state spectra to
higher charge states
* In Bari rf-excitation (BRIC)* MAXEBIS reduced barrier* Uni Frankfurt fast variation of electron beam current
Can be done by fast removalof hot low charged ions cooling effect
Oliver KesterI3 EURONSCharge state manipulation
methods?
Using atomic shell structure: Beneficial only for heavy ions until now (REXEBIS) Very high abundance in on charge states in EBIT, but at the expense of low efficiency
Using DR resonances: In principle possible (shown at Heidelberg EBIT), but efficiency spoiled by energy spread of the electron beam.
Cooling of highly charged ions: Works for medium heavy and heavy elements survey required
Oliver KesterI3 EURONS Simulation tool: CBSIM
Included so far:
Collision physics:
Stepwise ionisation,charge exchange, RR
Collision and trap physics:
electron-ion-heating,ion-ion cooling
Without charge exchange and recombination, but ion losses
With charge exchange and recombination
Included so far:
Trap physics:
space charge neutralisation andion losses
Soon: atomic data tables
Oliver KesterI3 EURONS
TOF out of the REXTRAP for stable SeCO beam injected
* Molecular sideband beams from ISOLDE to avoid isobaric contamination* e.g. 70SeCO to avoid 70Ge* Keep molecules inside trap, break them in EBIS (or break inside trap with different trap potential settings)
Results
* ~50% SeCO out of trap* 6.5% SeCO+ to Se19+ in EBIS (58 ms breeding time)
* Problems inside the EBIS: ions with high electro-negative values escape the electron beam
* Also tried SrF, BaF, AlF (>16% total efficiency for Al7+)
Molecule breakup (EBIS)
Oliver KesterI3 EURONS 61Mn trapping and ejection
Measurement cycle:
1. RF on, plasma ignited
2. 61Mn injected into the ECR
3. RF is kept on for a time that can be varied (0s, 800ms…)
4. Ejection of the ions as a pulse
0.71s
5.98m
1.65hFrom TOI, R.B. Firestone
Gamma spectrum, 800ms trapping, 61Mn12+ and 61Fe12+ extracted
FeMn
Fe FeMn
Fe Fe Fe
Energy (keV)
cnts
Oliver KesterI3 EURONS Emittance measurements ECRIS
Two 1+ and two n+ identical emittancemeters are setup in the beamLine of LPSC and are working RMS emittances absolute (20 kV*q)
Xplane: 84Kr15+ Y plane: 84Kr15+ Xplane: 84Kr1+ Y plane: 84Kr1+
norm. ~0.015 mm mrad norm ~0.06 mm mrad