Advanced CB

1
Advanced charge state breeding
ObjectivesTo optimize the charge breeding
process by increasing thebreeding efficiency,
improving the beam quality and the beampurity.
Investigation of charge breeding process and
breedingof intense primary beams.
Issues to be addressed Injection into the high
charge state ion source (Continuous or pulsed,
emittance matching) Breeding and cooling of
highly charges ions (manipulation of abundance
in a single charge state) Extraction and
separation of n ions (beam emittance, molecule
break up, decay products)
2
Charge state breeder setup
Extraction and beam purification
Charge state development
Beam preparation and injection
3
Available setups
ISOLDE / CERN / REXTRAP REXEBIS
combinationDaresbury PHOENIX test bench at
ISOLDELPSC Grenoble 1 ? n test beam
lineGSI / LMU München MAXEBIS
(Frankfurt)MPI-K Heidelberg Heidelberg
EBITINFN-Bari BRIC charge state breeder
Charge state breeder outside Europe TRIUMF
PHOENIX ECRIS Booster (Canada) TITAN EBIT
(Penning trap mass measurements) ANL
(USA) ECRIS charge state breeder (CARIBU
project) MSU (USA) EBIT base charge state
breeder for post acceleration project (in
design state) KEK (Japan) ECRIS charge state
breeder
4
EBIS charge breeders survey
REX-ISOLDE
Plasma Surface Laser
25 target materials
F. Wenander et al.
5
The constant quest for efficiency
50 lost in trap gt gt26 in EBIS Global
efficiency for EBIS close to 100
From 6Li to 238U with total efficiencies of at
least 4 11Li (T1/28.5 ms) charge bred to 2
and 3 with tbreed of 5 and 9 ms - Light ions
(Alt10) still difficult to breed 5 total
efficiency - Problems with He ltgt charge
exchange processes in REXTRAP
Sometimes lower efficiency for radioactive
elements scaling problematic / no time for
tuning not visible intensities Have to speak
about time efficiency as well!
6
ECRIS charge breeders survey
IS397 Experiment at ISOLDE and experiments at LPSC
Efficiencies Decreasing with A/Q
P. Delahaye, T. Lamy et al.
Injection of molecules 13C16O ? 13C4 0.5
139LO ? 139L23 2.5 Preliminary
tests in Afterglow mode 86K13 ? 86K13
1 132Xe18 ? 132Xe18 2.2 85Rb1 ?
85Rb15 2.5 Trapping and breeding of daughter
nuclides (qualitative results) Injection of 61Mn
T1/2 670 ms decays to 61Fe T1/2 5.98 min
7
cw injection / pulsed extraction
EBIS ? accu mode Using EBIS capacity instead
of cooler storage capacity Short-lived ions
(lt20 ms)
EBIS potential settings and ion energy for
continuous injection
Efficiency (REXEBIS) K9 ltgt 4 for
tbreed9.5 ms Total efficiency for K10 in
pulsed mode at this moment gt7.5 CSD one
peak lower
8
ECRIS charge breeders pulsed
ECR charge breeding time
LPSC
28 GHz, 3600 W
18 GHz, 950 W
T. Thuillier et al., ICIS07
Steady states reached at 3 ms for all charges !!
9
Shift of the charge state spectra to higher
charge states
Can be done by fast removalof hot low charged
ions ? cooling effect
In Bari ? rf-excitation (BRIC) MAXEBIS ?
reduced barrier Uni Frankfurt ? fast variation
of electron beam current
10
Charge 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

11
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
12
Molecule breakup (EBIS)
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 (gt16 total
efficiency for Al7)
13
Molecule breakup (ECRIS)
420 nA injected Background subtracted
139LaO molecule breakup

0,1 23
up to 2.7 for 139La23A/q6.04
Injection of molecules 13CO ? 13C4 0.5
139LO ? 139L23 2.5
14
Trapping of daughter nuclides
Can the charge breeding with the ECR give access
to more beams ?
15
61Mn trapping and ejection

• Measurement cycle
• RF on, plasma ignited

• 61Mn injected into the ECR

• RF is kept on for a time that can be varied (0s,
  800ms)

• Ejection of the ions as a pulse

16
RHIC test EBIS setup
E. Beebe et al.
17
Pepperpot Analysis of a87kVq Ar-beam
Shot to shot output Profiles (left) Horz. and
Vert. emittances (below)
18
Emittance measurements ECRIS
Two 1 and two n identical emittancemeters are
setup in the beam Line of LPSC and are working ?
RMS emittances absolute (20 kVq)
Xplane 84Kr15
Y plane 84Kr15
Xplane 84Kr1
Y plane 84Kr1
norm 0.06 mm mrad
norm. 0.015 mm mrad
19
Variable pulse length from EBIS
Beam pulse can be extended from 50 us to gt400us
FWHM using a different extraction scheme
Normal extraction 90 of the beam within 80
ms Longer beam pulse desirable for experiments
(dead-time in DAQ)
20
Beam purification by charge breeding
FC/scanner3
before the ECRIS
3AXe3
102o doubly focusing magnet
2AKr2
AAr
tape station detectors
qnorm
after the ECRIS
ECRIS
AArn
lens steerer
2AKr2n
FC/scanner2
3AXe3n
FC/scanner1
qnorm
AArn
after the 102o magnet
2AKr2n
GPS switchyard
3AXe3n
1 m
qnorm
21
Conclusions and outlook
Efficiency survey for EBIS and ECRIS gt 4
for all isotopes, max. 18 for EBIS cooler
combination with optimized cooler
efficiencies gt 30 become possible for EBIS
Pulsed and continuous schemes are investigated
for both breeder setups ECRIS breeding times
are faster than assumed ? trapping time is the
restriction! Molecule break-up, breeding of
isotope cocktails and using daughter nuclei of
decay in the ion source plasma -gt development new
beams Emittance investigations of breeder
for intense primary beams Manipulation of
charge state distribution in principle possible,
but less boost of efficiency than expected
22
(No Transcript)
23
Emittance scanner used
Slit-foil scanner
Pepper pot scanner
24
Emittance measurements with He-beam

• He2-beam, 130 keV, created by a 6 A / 13 keV
  electron beam
• rms beam emittance gt 0.3 mm mrad
• He2 can be created, even if the ions do not stay
  all the time in the
• electron beam (larger beam radius)