pierre delahaye, cern ep seminar, 2005/10/31 the physics requirements for advanced radioactive ion...
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Pierre Delahaye, CERN EP seminar, 2005/10/31
The Physics requirements for advanced radioactive ion beam manipulation
Pierre Delahaye
CERN - ISOLDE
Design Study
Pierre Delahaye, CERN EP seminar, 2005/10/31
The chart of the nuclidesAn open landscape for investigations
In…• Nuclear physicsStructure, magic numbers, deformations, haloes, Superheavy elements, nuclear equation of states…• Nuclear AstrophysicsNucleosynthesis, r and rp processes, supernovae explosions, X ray bursts…• Weak Interaction physics and fundamental symmetriesCVC, CKM Unitarity, Exotic interactions…• Solid State physics&• Medical Applications!
From the EURISOL reporthttp://www.ganil.fr/eurisol/Final_Report.html
Pierre Delahaye, CERN EP seminar, 2005/10/31
The EURISOL project
Design Study
More radioactive beams for more available energies!Beta-beam aspect
Beam preparation task
Advanced techniques for theRadioactive ion beam manipulation
Pierre Delahaye, CERN EP seminar, 2005/10/31
Outline of the talk
I) Inventory of devices and techniques
II) A few examples for beam preparation• The low energy stage of REX-ISOLDE post-accelerator• The Collaps experiment at ISOLDE
III) A few examples for precision measurements• The ISOLTRAP penning trap spectrometer• The beta –neutrino angular correlation measurements at LPC Caen, ISOLDE (WITCH) and at Triumf• The 6He charge radius measurement at ANL• The HITRAP project at GSI
Pierre Delahaye, CERN EP seminar, 2005/10/31
I - InventoryWhat devices for what purpose?
• A physics experiments usually requiresHigh intensityBeam purityBeam quality (radial and longitudinal emittances)A rich variety of available beamsA rich variety of accelerated beams
• Beam preparation• Also providing powerful tools to precision
measurements!
Pierre Delahaye, CERN EP seminar, 2005/10/31
• A mass separator
ISOLDE HRS upgradeTim Giles CERN AB-OP
R=m/m~4000 in best casesUpgradeR~10,000
Better … Beam purityHigh acceptance 100%
A mass separator
Pierre Delahaye, CERN EP seminar, 2005/10/31
A charge breeder• ECR booster vs EBIS – stripping foils
Singly charged ions n+ ions transformation• More post-accelerated beams available• More radioactive isotopes available• Better purity in some cases• Some applications for physics experiments of charge bred beams • Efficiency: 1 - 20% in one charge state depending on Z
Phoenix ECRIS14GHz
Test stand at ISOLDE
REX-EBIS
Operational at REX-ISOLDE
Molecular sidebands from the ISOLDE targets
Pierre Delahaye, CERN EP seminar, 2005/10/31
Ion coolers
• RFQ coolers vs Penning trap coolers
PhD thesis of Ivan Podadera, CERN
REXTRAP at REX-ISOLDEISCOOL in its commissioning phase
Electromagnetic traps filled by buffer gas: damping of the ion motion by collisions• Better beam quality – lower transversal emittance• Possibility of beam bunching: a few µs bunches• Penning trap: the mass selection is a-priori possible | R=105 at ISOLTRAP!• The transmission depends on space charge limits
Pierre Delahaye, CERN EP seminar, 2005/10/31
Electromagnetic traps
• Penning traps
• Paul traps
• MOT
z0
r0
Penning Traps
Electrostatic quadrupolar fieldMagnetic field (superconducting magnet)
Cylindrical trapz0
r0
Penning Traps
Electrostatic quadrupolar fieldMagnetic field (superconducting magnet)
Cylindrical trap
RFVRFV
Paul Traps
Radiofrequency quadrupolar electric field
Linear trap
RFVRFV
Paul Traps
Radiofrequency quadrupolar electric field
Linear trap
6 laser beamsWith a magnetic fieldAn atom trap
Pierre Delahaye, CERN EP seminar, 2005/10/31
II - Beam preparation
• The 1+ n+ scenario for the Physics with radioactive accelerated beams
• The case of REX-ISOLDE
• The requirements for charge bred beams
• The needs for cooled and bunched beams
• The Collaps experiment
Pierre Delahaye, CERN EP seminar, 2005/10/31
ISOL and In-flight facilities
From the EURISOL report
ISOLDE, GANIL/SPIRAL, TRIUMF, …
GSI (FAIR project), MSU, ANL…
Pierre Delahaye, CERN EP seminar, 2005/10/31
The 1+n+ scenarioat ISOL facilities
ECR breeder vs EBIS | stripping foilsStripping foils requires a pre-acceleratorUsually limited to small A/q
ISOL target 1+ ion source
1+ n+1+ separator A/q separator
Accelerator
Studied in the frame of the EURISOL and RIA projects
Pierre Delahaye, CERN EP seminar, 2005/10/31
Physics with accelerated beams at REX-ISOLDE
• The REX-ISOLDE post accelerator
ROBOT
RADIOACTIVELABORATORY
GPS
HRS
REX-ISOLDE
CONTROLROOM
1-1.4 GeV PROTONS
EXPERIMENTAL HALL
NEW EXTENSION
Pierre Delahaye, CERN EP seminar, 2005/10/31
The low energy stage
PENNING Trap
EBISA/q<4.5
ISOLDEbeam60 keV
HV platform60 kV
HV platform20-60 kV
Separator(q/A)/(q/A)= 1/150
tra
nsf
er
bea
m li
ne
cooled beam of singlycharged ions 60 keV
highly chargedions 5 keV/u
REXTRAP
REX EBIS
q/A-selector
breeding time (A/q < 4.5) 20 ms
beam intensities < 109 /s
ions in one charge state < 30%
injection efficiency into EBIS >80%
efficiency REXTRAP 50%
breeding time (A/q < 4.5) 20 ms
beam intensities < 109 /s
ions in one charge state < 30%
injection efficiency into EBIS >80%
efficiency REXTRAP 50%
Limited by space charge effects above 109 ions/ cycle
Pierre Delahaye, CERN EP seminar, 2005/10/31
Experiments by REX-ISOLDE
• Mainly nuclear spectroscopy experiments
• B(E2) measurements with MINIBALL transfer reactions and Coulomb excitations
CD detector
Miniball cluster
Pierre Delahaye, CERN EP seminar, 2005/10/31
Coulomb excitation of 70Se
Mass 70: contamination of 70Ge+ from the usual ZrO target Solution: molecular sidebands from the target 70SeCO
Measurement of the B(E2) of 70Se for validation of the shape coexistence in the mass 70 region
IS397 collaboration D. Jenkins, P.A. Butler
>50% efficiency for SeCO+ cooling
REXTRAP
REXEBIS>5% SeCO+Se19+
First run partly successful this year, should be renewed next year
Pierre Delahaye, CERN EP seminar, 2005/10/31
Different cooling schemes
~120 eV
80 eV
V
X
~30 eV
15 eV
V
X
Molecular break-up
SeCO molecule trapping
Time of flight out of REXTRAP
Pierre Delahaye, CERN EP seminar, 2005/10/31
Charge bred beams at ISOLDE
H. Haas AB-Note-2004-034-OP
Pierre Delahaye, CERN EP seminar, 2005/10/31
The needs for cooled and bunched beams
• Reduction of emittance for mass separators –ISCOOL for the HRS upgrade at ISOLDE
• Reduction of emittance and bunching for the EBIS charge breeders – REXTRAP at REX-ISOLDE
• Better transport to experiments• time reference, monochromatic beam, better
injection control into spectrometers – ISCOOL for Collaps
Pierre Delahaye, CERN EP seminar, 2005/10/31
The Collaps case
• Collinear laser spectroscopy and -NMR spectroscopy
• Measurement of nuclear moments, spin and charge radii of radioactive isotopes
Pierre Delahaye, CERN EP seminar, 2005/10/31
Experimental technique
courtesy of K. Flanagan COLLAPS collaboration
Pierre Delahaye, CERN EP seminar, 2005/10/31
A RFQ cooler
Expected ISCOOL transmission: 100% (less than 100nA)Radius: a few mmBunch time width: a few µs
Pierre Delahaye, CERN EP seminar, 2005/10/31
R
Current limiting factors for laser spectroscopy
• Background of scattered laser light detected by PMT ~2000/s.• Detection efficiency within the light collection region.• Broadening of lineshape due to voltage ripples.
Currently the minimum ion beam diameter reached is ~6mm
Within the light collection region the ion beam should have zero divergence (parallel beam)
In order to maximize the detection efficiency good overlap between laser and ion beams is necessary
This results in a high background level from scattered lightK. Flanagan COLLAPS collaboration
Cold and bunched beams for Collaps
Pierre Delahaye, CERN EP seminar, 2005/10/31
Cold and bunched beams for Collaps
• A reduction in the ion beam diameter will allow the laser to be reduced in diameter (and therefore power) with no detrimental effect on the detection efficiency.• Immediate consequences for the detected background
Bunching ions in the RFQ cooler
Trap and accumulates ions – typically for 300 ms
Releases ions in a 15 µs bunch
Background suppression equal to the ratio of the trapping time to the bunch width 300ms/15 µs ~ 104
K. Flanagan COLLAPS collaboration
Pierre Delahaye, CERN EP seminar, 2005/10/31
JYFL experiment
8000 ions/sec
5.3 hours
Data from work at Jyvaskyla JYFL J.Billowes
Photons from laser-excitation of radioactive 88Zr
Laser frequency
200
100
30
0
BEFORE
AFTER
(Photon-ion coincidence
method)
2000 ions/sec
48 minutes
For optical measurements the minimum
ion beam intensity is 106/s
Compare to COLLAPS
K. Flanagan COLLAPS collaboration
Pierre Delahaye, CERN EP seminar, 2005/10/31
III - Precision measurements
• The ISOLTRAP penning trap spectrometer
• The beta –neutrino angular correlation measurements at LPC Caen, ISOLDE (WITCH) and at Triumf
• The 6He charge radius measurement at ANL
• The HITRAP project at GSIElectromagnetic traps as a precision measurement tool
Pierre Delahaye, CERN EP seminar, 2005/10/31
The ISOLTRAP mass spectrometer
Stable alkali reference ion
source
ISOLDE beam60 keV
Carbon cluster ion source
RFQ cooler buncher
Cooling Penning trap
Precision Penning trap
MCP1
MCP3
MCP5
2.8 keV ion bunches
Precision trap
Precision measurement of c=qB/m
Pierre Delahaye, CERN EP seminar, 2005/10/31
Ion motion manipulation
Magnetron excitation:
Cyclotron excitation: +
1071195 1071200 1071205 1071210 1071215 1071220 1071225
200
220
240
260
280
300
320
340
Measurement Theoretical Fit
85Rb
Tim
e-of
-flig
ht [
s]
Excitation frequency [Hz]
TOF vs. excitation frequency
c = Bqm
Sca
n Q
P-e
xcita
tion
freq
. r
f a
bout
c
Quadrupolar excitation rf
TOF resonance
Radial energy axial energy
Magnetron excitation
Relative accuracy: (m/m) 10-7
Pierre Delahaye, CERN EP seminar, 2005/10/31
• The mass as a fundamental quantity for– Reactions (Q values)– Nuclear models
– Nuclear Structure (S2n)– shell closure, magic numbers, deformations, IMME…
– Astrophysics - waiting points, decay rates– Weak interaction physics - Tests of CVC and
the unitarity of the CKM matrix
The physical aims
Pierre Delahaye, CERN EP seminar, 2005/10/31
FT value measurements
Superallowed transitions: 0+ -> 0+
Comparative half-life
corrected ft
Is constant in the CVC hypothesis
R radiative correctionC isospin symmetry-breaking correctionR
V nucleus independent radiative correction
f~Q5
Pierre Delahaye, CERN EP seminar, 2005/10/31
CVC test
22Mg
74Rb
F. Herfurth et al., Eur. Phys. J. A 15, 17 (2002)A. Kellerbauer et al., Phys. Rev. Lett.93, 072502 (2004)M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004)
[I.S. Towner & J.C. Hardy, Phys. Rev. C 71, 055501 (2005)]
34Ar
T. Eronen et al., to be published (2005)G. Savard et al., Phys. Rev. Lett. 95, 102501 (2005)
Limit from QEC(38Ca)
62GaJYFLTRAP
LEBIT38Ca
CPT46V
66As
ISOLTRAP mass measurements 22Mg → 22Na : Q=0.28 keV, 34Ar → 34Cl : Q=0.41 keV, 74Rb → 74Kr : Q=4.5 keV
CVC hypothesis confirmed in this mass region
From Klaus Blaum, NUPAC meeting at ISOLDE 2005/10/11
Pierre Delahaye, CERN EP seminar, 2005/10/31
The angular correlation in nuclear decay
• Test of the V-A theory
• Sensitive to exotic interactions S,T• Pure Fermi transitions • Pure Gamow Teller transitions
V-A aF=1 V-A aGT=-1/3Johnson et al. (1963!)Adelberger et al. (1999)
32Ar 6He
& if & if
Pierre Delahaye, CERN EP seminar, 2005/10/31
46V
er=180°
er=0°
a
• Fermi transition (J=0)
6He
er=180°
er=0°
• Gamow-Teller transition (J=0±1)
decay spectrum
The - angular correlation in nuclear decay
Pierre Delahaye, CERN EP seminar, 2005/10/31
A Paul trap as the center of the detection setup
particle Recoil ion
Beta telescopeSilicone stripped detector
+ Scintillator
- Transparent Paul trap, UHV- Ions confined in the middle of the device, nearly at rest- In coincidence detection of the electron and the recoil ion
In coincidence measurement of: the time of flight of the recoil ion tR
the beta particle energy E
the angle between these two particles er
E, tstarttstop
er
Pierre Delahaye et al., Hyp. Int. 132(2001)479
MCPDelay lines anode
LPCTRAP collaboration, at GANIL
Pierre Delahaye, CERN EP seminar, 2005/10/31
Experimental setup
DSSD +scintillator
MCP +DL anode
MonitorMCP
"Ring"trap
RFQ cooler
buncher
pulse down
Paul trapchamber
SPIRAL beam
HT
20 cm
LPCTRAP collaboration
Pierre Delahaye, CERN EP seminar, 2005/10/31
First TOF spectrum
(V-A theory)• conditioned spectrum
Oscar Naviliat, Scientific council of GANIL, June 2005
LPCTRAP collaboration, at GANIL
Pierre Delahaye, CERN EP seminar, 2005/10/31
The WITCH retardation spectrometer
D. Beck NIM A 503(2003)567
Recoil ion energy spectrum
35Ar decaySearch for scalar interaction
The WITCH experiment IKS Leuven at ISOLDE
Pierre Delahaye, CERN EP seminar, 2005/10/31
The TRINAT experiment at TRIUMF
J. Behr et al, Phys. Rev. Lett. 79, 375
A MOT as the center of the detection setup
From Dan Melconian, PhD, Triumf
A. Gorelov et al, Phys. Rev. Lett. 94, 142501
e- shakeoff
6He - Single Atom Spectroscopy
Photoncounter
Zeemanslower
MOT
Transversecooling
389 nm 1083 nm
Atom Trapping of 6He
6Hetrapping rate
~ 2 / min
0 5 10 15 200.0
0.2
0.4
0.6
0.8
1.0
1.2
Ph
oto
n c
ou
ntr
ate
/ kH
z
Time (s)-8 -6 -4 -2 0 2 4 6 8
50
100
150
200
250
300
Frequency (MHz)
Ph
oto
n c
ou
nts
Single atom signal
One 6He atom
6He spectroscopy
~150 6He in 1 hr
RF -Discharge
Krcarrier
gas
He*
Spectroscopy389 nm
2 3S1
1 1S0
2 3P2
3 3P2
Trap1083 nm
He level scheme
Courtesy of Peter Müller, Argonne Nat. Lab
6He
7Li3+
60 MeV
6He Production @ ATLAS
Graphite
~ 1106 / s
6He - Nuclear Charge RadiusIsotope shift
(23S1 - 33P2, 6He – 4He)
43 194.772(56) MHz
6He rms charge radius
2.054(14) fm (0.7%)
L.-B. Wang et al.,PRL 93, 142501 (2004)
1.7 1.8 1.9 2.0 2.1 Point-Proton Radius of He-6 (fm)
He-6
Reaction collision
Elastic collision
Atomic isotope shift
Cluster models
No-core shell model
Quantum MC
Modelindependent!
Exp
erim
ent
The
ory
Tanihata ‘92
Alkhazov ‘97
This work
Csoto ‘93
Funada ‘94
Varga ‘94
Wurzer ‘97
Esbensen ‘97
Navratil ‘01
Pieper ’05priv. comm.
P. Delahaye
EXPERIMENTS WITH HIGHLY CHARGED IONS AT EXTREMELY LOW ENERGIES:
stable and radioactive isotopes
collisions at very low velocities, surface studies
laser and x-ray spectroscopy
g-factor measurements of the bound electron
fundamental constants
mass measurements of extreme accuracy
polarization of radionuclides, decay spectroscopy of
highly charged radionuclides
EXPERIMENTS WITH HIGHLY CHARGED IONS AT EXTREMELY LOW ENERGIES:
stable and radioactive isotopes
collisions at very low velocities, surface studies
laser and x-ray spectroscopy
g-factor measurements of the bound electron
fundamental constants
mass measurements of extreme accuracy
polarization of radionuclides, decay spectroscopy of
highly charged radionuclides
strippertarget
ESR
electron coolingand deceleration down to 4 MeV/u
U73+
U92+
4
00
MeV
/u
UNILAC
coolerPenning
trap
experiments with particles at rest or
at low energies
U92+
post-decelerator SIS
The HITRAP Project for Highly Charged IonsGSI Darmstadt
Courtesy of W. Quint and the HITRAP collaboration
P. Delahaye
Precisiontrap
Other experimental setups(beam line height: 1.25 m)
Re-injection channel
5 keV*q
MAX-EBIS
LEBT
verticalbeam line
Operational Parameters:
Deceleration from 4 MeV/u to keV/u
HCI with M/q 3
Beam intensity: some
105 ions/pulse for U92+
Repetition time: 10 s
Operational Parameters:
Deceleration from 4 MeV/u to keV/u
HCI with M/q 3
Beam intensity: some
105 ions/pulse for U92+
Repetition time: 10 s
HITRAP at the Experimental Storage Ring ESRCourtesy of W. Quint and the HITRAP collaboration
P. Delahaye
GSI Future Project FAIR:FLAIR - Facility for Low-Energy Antiproton and Ion Research
• NESR– Pbar & ions– 30 – 400 MeV
• LSR:– Standard ring– Min. 300 keV (CRYRING)
• USR– Electrostatic– Min 20 keV (MPI KP HD)
• HITRAP– Pbars and ions– Stopped & extracted @ 5 keV– (under construction for ESR)
energy range: 400 MeV – 1 meV
Pierre Delahaye, CERN EP seminar, 2005/10/31
Conclusion• Intensive studies of Mass separators, charge
breeders and ion coolers for the next generation facilities are going on
• Electromagnetic traps are particularly suited for precision experiments
• The advanced techniques for radioactive ion beam manipulation: a field in effervescence!
Thank you for your attention!
Pierre Delahaye, CERN EP seminar, 2005/10/31
Thanks to my colleagues
REX- ISOLDE
REX-ISOLDE
R. Savreux, T. Sieber, F. Wenander, D. Voulot, P. Delahaye and the REX-ISOLDE collaboration
The IS397 collaboration
C. J. Barton, K. Connell,T. Fritioff, O. Kester, T. Lamy, M. Lindroos, M. Marie-Jeanne, P.
Sortais, P. Suominen, G. Tranströmer, F. Wenander, P. Delahaye, …ISOLTRAP
G.Audi, K. Blaum, G. Bollen, D.Beck, C. Guénaut, F. Herfurth, A. Herlert, A. Kellerbauer, H.-J. Kluge, D. Lunney, S. Schwarz, L. Schweikhard, C. Weber, C. Yazidijan , P.
Delahaye ..., the ISOLTRAP and ISOLDE collaborationLPC CAEN (LPCtrap collaboration)
Gilles Ban, Guillaume Darius, Dominique Durand, Xavier Flechard, Mustapha Herbane, Marc Labalme, Etienne Lienard, François Mauger, Alain Mery, Oscar Naviliat, Pierre Delahaye