© CERN
CERN’s Radioactive Ion Beam Facility
© CERN
ISOLDE at CERN
ISOLDE at CERN
◆ Isotope Separator OnLine DEvice
◆ First ISOL facility worldwide!
◆ Produces Radioactive Ion Beams (RIBs)
◆ Approved by the CERN council in 1964
◆ Initially used 600 MeV protons from SC
◆ Then used 1.0 GeV (later 1.4 GeV)
protons from the PSB
◆ A small facility with a big impact!
◆ ~0.1% of the CERN budget
◆ ~7% of the CERN scientists
◆ ~50% of the CERN protons
ISOLDE at CERN
ISOLDE
PSB
PS
LINAC2
◆ Operates ~8 months/year, 24/7 ◆ ~50 staff/students/fellows
◆ ~450 users for physics ◆ Maintain and operate the facility
◆ ~100 ongoing experiments
The nuclear playground
◆ ISOLDE is a radioactive ion beam facility where the nuclear
chart is our playground!
◆ We use high-energy protons to produce radioactive ions
◆ These radioactive isotopes are then sent to a variety of different
experiments
◆ There are 3 stages of preparation before the radioactive
isotopes are delivered to the experiments
◆ Production
◆ Ionization
◆ Separation
Number of
protons, Z
Number of neutrons, N
Production: Modern-day alchemy
◆ High energy (1.4 GeV) protons are impacted onto a thick target e.g. 238U
◆ The protons split up the heavy nucleus in one of three ways
◆ Fission
◆ Fragmentation
◆ Spallation
adioactive ion beam production
ck t arget s for a small projectile Spallation
238U
Proton beam
1.4 GeV
Proton beam
2 µA hits
up toFission the target
typical operation
from Easter until
Fragmentation
Ski Season
Production: Targets
Primary beam
Radioisotopes
Ions
*picture and animation courtesy of M. Delonca
◆ Over 120 materials have been tested and/or used as ISOL targets
◆ Choice of target material and ionizer dependent on radioactive beam of interest
◆ Target material and transfer tube heated to 1500 – 2000 degrees
◆ Operated by robots due to radiation
ISOLDE Robots
Ionization: The 3 options
◆ The radioactive products are the ionized in one of three ways
◆ Surface ionization – alkali metals, elements with low ionization potential
◆ Plasma ionization - gases
◆ Laser ionization (RILIS) – 48 elements and counting!
Surface Plasma Laser (RILIS)
Ionization: RILIS
◆ Resonance Ionization Laser Ion Source
◆ Uses lasers to selectively ionize a particular element (isotope/isomer)
Separation: the isotopes of interest
◆ All produced ions are extracted by electrostatic field
(up to 60kV)
◆ The radioactive products are then mass-separated
using a magnet
◆ The ions are bent by the magnetic field of the
magnet by the ratio (A/q)
◆ The heavier isotopes are bent less that the lighter ones
◆ So we can choose what mass (A) to study
Magnetic field
bends ions
Radioactive
isotopes
Too Too heavy
light
Selected mass
What is produced at ISOLDE?
◆ ~6000 isotopes predicted by theory
◆ ~3000 isotopes already discovered
◆ ~1000 isotopes produced by ISOLDE
◆ 74 different elements … ready to be studied!
◆ At ISOLDE we study:
◆ Nuclear physics
◆ Nuclear astrophysics
◆ Solid state physics
◆ Bio-physics
◆ Fundamental physics
◆ ISOLDE can produce isotopes that live between 1 ms and 1012 years
◆ Production rates range from < a few per hour to >109 a second
What is studied at ISOLDE?
Nuclear physics Material science
and and
atomic physics life sciences
Ion traps
Decay Laser
spectroscopy spectroscopy
decay
pattern
Transition mass
probability Spin,
parity e-m
half- moments
life radius
Nucleon- Beta-
transfer detected
reactions Coulomb NMR
excitation
Fundamental Nuclear
interactions astrophysics
The ISOLDE facility
Radioactive laboratory MEDICIS
Class A
HRS
High Resolution Separator
Target area
High Energy RIB
GPS
General Purpose Separator
Low energy RIB
Protons (1.4 GeV)
Low energy RIBs (up tp 60 keV)
High energy RIBs (up to 10 MeV/u)
◆ Pulse protons (1.2 s)
◆ 1.4 GeV
◆ 3.3 x 1013 protons per pulse
Experiments at ISOLDE
HRS GPS
TAS RILIS
REX-ISOLDE WISARD
HIE-ISOLDE
VITO
Scattering MINIBALL IDS Solid State
Chamber NICOLE CRIS
ISOLTRAP Physics
ISS COLLAPS
Separator area Travelling
Low energy experiments setups
High energy experiments
Studying nuclear structure
◆ The atomic hyperfine structure gives you information on:
◆ Nuclear spin
Ex
◆ Magnetic moment
◆ Quadrupole moment
◆ Relative charge radii GS
◆ Method: COLLAPS, CRIS (laser spectroscopy)
◆ The mass of the nucleus gives you information on:
◆ Binding energy
◆ Proton and neutron separation energy
◆ Method: ISOLTRAP (mass spectrometry)
◆ Spectroscopy of the nucleus gives you information on:
◆ Life time
◆ Decay mechanism
◆ Branching ratio
◆ Nuclear reactions, …
◆ Method: IDS, MINIBALL, ISS, SEC, TAS
A variety of experimental methods can provide
complementary information on the structure of the nucleus!
COLLAPS
◆ COLlinear LAser SPectroscopy
◆ Lasers overlapped with ion beam
◆ Atomic resonances: scan of ion energy
◆ Detection: fluorescence photons, beta particles, ions
electrostatic
deflection charge exchange cell (Na)
ion beam excitation &
Ekin~60 keV observation region
+ electrostatic lenses for
retardation
laser beam
fixed frequency +
+
o
◆ Fast beams: high-resolution
Photo
multiplier
◆ Bunched beams + gating of signal on bunch
◆ Background reduction by factor 10 000
COLLAPS
CRIS
Bunched Collinear Resonance Ionization (1) Count ions with MCP
ion beam Spectroscopy of atom
Laser light
IP
(2) Measure alpha decay
Neutralization
with silicon detectors
of ion bunch Ex
GS
(1) Study of the hyperfine (2) Identification of nuclear
structure with CRIS states with the DSS
◆ Collinear geometry allows for high-resolution laser spectroscopy
◆ Presence of DSS allows nuclear states to be identified
http://isolde-cris.web.cern.ch/
CRIS
Bunched Collinear Resonance Ionization (1) Count ions with MCP
ion beam Spectroscopy of atom
Laser light
IP
Neutralization
of ion bunch Ex
GS
(1) Study of the hyperfine
structure with CRIS
◆ Nuclear spin
◆ Magnetic moment
◆ Quadrupole moment
◆ Relative charge radii
◆ Collinear geometry allows for high-resolution laser spectroscopy
◆ Presence of DSS allows nuclear states to be identified
http://isolde-cris.web.cern.ch/
CRIS
Bunched Collinear Resonance Ionization
ion beam Spectroscopy of atom
Laser light
IP
(2) Measure alpha decay
Neutralization
with silicon detectors
of ion bunch Ex
GS
(2) Identification of nuclear
states with the DSS
◆ Collinear geometry allows for high-resolution laser spectroscopy
◆ Presence of DSS allows nuclear states to be identified
http://isolde-cris.web.cern.ch/
ISOLTRAP MCP
Precision
B U trap
Fm
50 – 2000 ms
Preparation
trap
50 – 200 ms
F. Herfurth et al., NIM A 469, 254 (2001).
R. N. Wolf et al., Int. J. Mass Spectrom 313, 8 (2012).
G. Savard et al., Phys. Lett. A 158, 247 (1991).
M. König et al., Int. J. Mass Spectrom. 142, 95 (1995).
ISOLTRAP MCP
Precision
trap
Measured by ISOLTRAP
50 – 2000 ms
Preparation
trap
50 – 200 ms
F. Herfurth et al., NIM A 469, 254 (2001).
R. N. Wolf et al., Int. J. Mass Spectrom 313, 8 (2012).
G. Savard et al., Phys. Lett. A 158, 247 (1991).
M. König et al., Int. J. Mass Spectrom. 142, 95 (1995).
ISOLTRAP
Great plains
Ridges
Faults
25
M. Wang et al., Chinese Physics C 36, 1603 (2012).
ISOLTRAP
Shells
Collectivity
Shell
closures
26
M. Wang et al., Chinese Physics C 36, 1603 (2012).
ISOLDE Decay Station
The ISOLDE Decay Station (IDS) aims to provide:
◆ Permanent setup for decay studies using RIB from
ISOLDE
◆ Flexible for several decay types or studies
◆ HPGe detectors (4 permanent clovers + extra)
◆ Ancillary detectors (LaBr3, plastic scintillator, silicon,
neutron)
◆ Tape station
◆ Collaboration to support and perform decay
studies at ISOLDE
http://isolde-ids.web.cern.ch/
ISOLDE Decay Station
http://isolde-ids.web.cern.ch/
Versatile Ion-polarized Technique Online
Spin-oriented
radioactive ion
beams
Interesting for:
◆ Nuclear physics
◆ Fundamental
interactions
◆ Chemistry and
biology
◆ Material science
Ingredients:
◆ Polarize nuclear ensemble: orient the nuclei in space
◆ Observe direction of radiation emission (beta particles, gamma rays) or
apply radiofrequency signals and perform Nuclear Magnetic Resonance
(NMR) studies
Versatile Ion-polarized Technique Online
◆ Lasers used to polarize atomic and nuclear spins
◆ Polarization observed in beta decay asymmetry in space
Observation of beta-decay asymmetry Laser spin Setting ions in resonance with laser
and beta-detected NMR polarization and (optional) neutralization of ions
Laser light
Ions from ISOLDE
M. Kowalska et al, accepted to JPhysG
Versatile Ion-polarized Technique Online
Towards beta-NMR in biology Na+ or K+ inside
DNA G-quadruplex structue
◆ Use radioactive nuclei to understand the role of
metal ions in biological systems
◆ Apply a technique which is a billion times more
sensitive than conventional approaches
Zn finger
WISARD
◆ Weak Interaction Studies with 32AR Decay
◆ Aim: search for a scalar current
contribution in the predominantly vector
current of beta decay via b-n correlation
◆ Tool: beta-p decay of 32Ar, Doppler effect
on proton energy
Vector current Scalar current
strong recoil: weak recoil:
strong Doppler effect weak Doppler effect
WISARD
◆ Positron-proton coincidence in supraconduction magnet
Proton and beta particle in same hemisphere
Vector Scalar
B
catcher
e+
beam
P Ep Ep
Proton and beta particle in opposite hemisphere
B
P
e+
Ep Ep
beam catcher
Doppler shift of proton energy
Detection set-up installed in magnet
Post-accelerated beams
◆ The low energy (<60 kV) beams can be accelerated for experiments that need
higher-energy ions
◆ Acceleration up to 3 MeV/u with REX-ISOLDE
◆ The new HIE-ISOLDE upgrade means beams can have energies of up to 10 MeV/u
HIE-ISOLDE upgrade
up to10 MeV/u
3 MeV/u
◆ High Intensity and Energy ISOLDE
◆ Energy upgrade: 10 MeV/u with construction of SC LINAC
◆ Intensity upgrade: 2 GeV protons with LINAC4 + PSB
◆ Increasing energy of REX-ISOLDE (3 MeV/u) to provide higher energy
radioactive ion beams
MINIBALL
◆ Coulomb excitation
◆ Inelastic scattering of nuclei with EM force only
◆ Nuclei never collide
◆ Miniball
◆ Si detectors for scattered particles
◆ High-purity Ge detectors for γ-ray decay
◆ Cross-section of
reaction depends on
the nuclear shape.
Oblate Prolate Octupole
e.g. pumpkin e.g. watermelon e.g. pear
ISOLDE Solenoid Spectrometer
◆ MRI magnet from Uni. Queensland, Australia
◆ Transfer reactions: adding or removing nucleons
◆ e.g. (d,p), (t,p), (α,p) etc.
◆ Outgoing charged particle follows helical orbit,
returning to axis after one orbit
◆ Position and energy detected in Si detectors
4T solenoid
Solid State Physics
◆ In addition to studying the radioactive ion beam produced by ISOLDE
◆ For nuclear (astro)physics, fundamental physics, etc.
◆ Use the radioactive ion as a probe to characterize different materials
Perturbed Angular Correlations (PAC)
Courtesy: J. Schell, A. Fenta and The 68mCu/68Cu isotope as a new probe
G. Correia for hyperfine studies: The nuclear moments
A. Fenta et al. EPL 115 (2016) 62002
Detectors
Cu beam
◆ PAC delivers local information on:
◆ Magnetic and electric hyperfine fields
◆ Chemical bonds
◆ Structural and electromagnetic phase
transitions
◆ Probe-atom lattice site location
◆ Probe-atoms diffusion on hosts… and much
more!
Material Science at ISOLDE contact: Juliana Schell juliana.schell@cern.ch
Emission Channeling (EC)
Courtesy: U. Wahl and L. Pereira Lattice Location of Mg in GaN:
A Fresh Look at Doping Limitations
U. Wahl et al. PRL 118 (2017) 095501
◆ Interstitial Mg fraction highest in p-
GaN:Mg
◆ EC delivers information on:
◆ Lowest in n-GaN:Si
◆ Precise probe atom lattice site
location as function of ◆ Site change interstitial →
implantation/annealing temperature substitutional MgGa
◆ Probe atom - defect interactions ◆ Activation energy for migration of
◆ Diffusion of probe atoms interstitial Mg: EM » 1.3 - 2.0 eV
◆ Annealing of implantation defects
Material Science at ISOLDE contact: Juliana Schell juliana.schell@cern.ch
MEDICIS
◆ MEDical Isotopes Collected from ISOLDE
◆ The new MEDICIS facility will provide beam for studies dedicated to medical
applications of radioisotopes
MEDICIS
◆ 80% of the proton beam goes through the
ISOLDE target unaffected
◆ MEDICIS makes use of these (free!) protons to
create more radioisotopes
◆ These radioisotopes are dedicated to medical
applications
◆ Pure samples can then be sent to hospitals for
further studies
◆ ‘Receptor-targeted’radiopharmaceuticals consist
of a radionuclide attached to a carrier that
selectively delivers it to tumour cells
◆ Used in 2 ways:
◆ Nuclear medical imaging
◆ Targeted radionuclide therapy
◆ Collections are performed on promising new
isotopes e.g. terbium
◆ Terbium is the ‘swiss-army knife of nuclear
medicine’ where different isotopes can be used for
the full range of medical procedures
Summary
◆ ISOLDE is the world’s first ISOL-type facility and is still providing radioactive ion
beams over 50 years later
◆ ISOLDE is host to a dozen permanent experiments (and many travelling setups)
studying:
◆ Nuclear physics
◆ Nuclear astrophysics
◆ Solid state physics
◆ Bio-physics
◆ Fundamental physics
◆ The new facility MEDICIS will produce radioactive isotopes dedicated to medical
applications
◆ The upgrade of HIE-ISOLDE will provide high-energy beams of up to 10 MeV/u
Enjoy your visit!
© CERN
Production: Modern-day alchemy
◆ High energy (1.4 GeV) protons are impacted onto a thick target e.g. 238U
◆ The protons split up the heavy nucleus in one of three ways
◆ Fission
◆ Fragmentation
◆ Spallation
Ionized
Proton beam
hits the target Radioactive
products produced
ISOLDE Frontend
Target station
Astatine: the rarest element on earth
◆ Last chemical element with unknown ionization potential (IP)
◆ Atomic fingerprint, determines chemical properties
◆ No stable isotope and < 1 g present naturally on earth
Ion current (pA)
IP(At) = 9.31751(8) eV
Wavenumber (cm-1)
S. Rothe et al., Nature
Comms. 4, 1835 (2013)
◆ IP determined with ISOLDE laser ion source (RILIS)
◆ Outlook: improved IP predictions for element 117
MINIBALL: Pear shape in 224Ra
◆ Pear shape - octupole deformation
◆ Very rare nuclear shape
◆ Coulomb excitation with MINIBALL
◆ Determine electric octupole transition strengths
(direct measure of octupole correlations)
◆ Pear shape shown for the 1st time experimentally
◆ Test of nuclear models
◆ Important in searches for permanent atomic
electric-dipole moments (EDMs)
Gamma rays following
Coulomb excitation of 224Ra
◆ L.P. Gaffney et al,
◆ Nature 497 (2013) 199
47
VITO: Beta-(detected) NMR
B
◆ Same principles as conventional
NMR
◆ Ingredients: b
◆ Radioactive (short-lived) NMR-active
atoms decaying via emission of beta
particles
◆ Beta particles emitted in spin
direction
◆ Detection of resonance: crystals
◆ Asymmetry in beta decay in space
◆ At resonance: decrease in
asymmetry
◆ Gain in NMR sensitivity: 1e5 orders
of magnitude
◆ When combined with spin
hyperpolarization:
=> Beta-NMR can be up to 1e10 more
sensitive than conventional NMR
plastic
scintilators RF-coil
magnet poles
VITO: Laser polarization & b-decay asymmetry
◆ Polarization of atomic spins with circularly polarized laser (DmF = +1 for s+
or -1 for s- light)
◆ Resulting polarization of nuclear spins via hyperfine interaction (PF->PI):
◆ Resulting beta-decay asymmetry Magnetic field (and path of ions)
3p 2P3/2 2
3
2
1
0 -2
DmF = +1 for s+ or -1 for s- light
3/2
29Na I =3/2
589 nm F 1/2
+1/2
D2-line s- -1/2
-3/2
2 2
3s 2S1/2 -2 mI mJ
mF
-1 -3/2
1 -1/2
Atomic 1/2 -1/2
polarization nuclear 49
polarization 3/2
The ISOLDE Facility
