Alison Bruce

Report
Nuclear structure
~65% of Uk nuclear physics community
is studying nuclear structure
Questions we address:
•
What are the limits of nuclear existence? What is the heaviest element we
can make and where does the nuclear dripline lie?
•
Do new forms of collective motion occur far from the valley of nuclear
stability?
•
Are there new forms of nuclear matter in very loosely bound nuclear
systems?
•
How does the ordering of quantum states alter in highly dilute or neutronrich matter?
•
Do symmetries seen in near-stable nuclei also appear far from stability and
do we observe new symmetries?
2007 nuclear physics strategy document
Major investments in time and
money at
GSI/FAIR
University of Jyvaskyla
CERN/ISOLDE (to a lesser extent)
…will focus on these three but
mention other highlights
Future FAIR facility
SIS 100/300
Future
facility
SIS 18
GSI today
Rare isotope
production
target
UNILAC
ESR
HESR
Super
FRS
100 m
RESR
NESR
UK is heavily involved in 3
“experiments” within NuSTAR
R3B
:
Reactions with Relativistic Radioactive Beams
HISPEC: High-resolution in-flight spectroscopy
DESPEC: Decay spectroscopy
3
R B: Reactions with Relativistic Radioactive
Beams: an example of the physics…
n-rich
p-rich
One –nucleon knockout reactions measure the
spectroscopic factors....how appropriate is a
mean-field description for exotic nuclei?
R3B: Inverse kinematics
Light target e.g H2
Light particles are
emitted here….
UK building a tracker to
measure energy and
direction
RIB from FRS
„
“Stripped
beam carries on
R3B Si Tracker Layout
WG leader: R. Lemmon, M. Chartier
STFC Daresbury Laboratory (+ STFC RAL for ASIC)
Universities of Birmingham, Edinburgh, Liverpool, Surrey
Calorimeter
Vacuum
Chamber
High energy Ions
From this direction
Nuclear Structure and Reactions within NUSTAR
3 Layers of Silicon
Liquid Hydrogen Target
Gold Foil surround (Not
Shown)
8
R3B Si Tracker Layout
WG leader: R. Lemmon, M. Chartier
STFC Daresbury Laboratory (+ STFC RAL for ASIC)
Universities of Birmingham, Edinburgh, Liverpool, Surrey
Calorimete
r
Vacuum
Chamber
High energy Ions
From this direction
Nuclear Structure and Reactions within NUSTAR
3 Layers of Silicon
Liquid Hydrogen Target
Gold Foil surround (Not
Shown)
9
HISPEC: High-resolution
in-flight spectroscopy: an
example of the physics…
Spectroscopy of proton drip-line nuclei
82
masses measured at the
FRS-ESR
(a) How does the basic neutron-proton exchange
symmetry evolve or break down at the drip-line
65
(b) Can we understand exotic particle decays from
proton-rich nuclear matter?
50
(c) What is the structure of nuclei along the
crucial rp process path?
rp-process
path
82
28
50
20
8
28
20
8
nuclides with
known masses
stable nuclei
In-flight spectroscopy
Secondary target
RIB from FRS
Produce proton drip-line nuclei.
Identify
products using
LYCCA Lund,
York, Cologne
calorimeter
The LYCCA Array: Lund-York-Cologne CAlorimeter
Secondary
Target
Start
Detector
Stop
Detector
CsI scintillator
for residual E
3.6 m
Si DSSSD
for tracking
Slide from S.Milne, L.Scruton, University of York
Si DSSSDs for ΔE
and tracking
The Experiment:
Slide from S.Milne, L.Scruton, University of York
Motivation: Isospin Mixing in 46V
46V
Look for Tz dependence
in B(E2) from first 2+
1 mm
1 mm
Slide from S.Milne, L.Scruton, University of York
Continuing the work at
York on mirror pairs
and Coulomb energy
differences
P.J.Davies et al.,: Physical Review Letters 111 (2013) 072501
DESPEC: Decay spectroscopy,
what’s the physics?
-decay
TAS
Neutron spectrometer
MONSTER
-delayed
neutron
detector
g-ray time
measurements
β,n, g-decay of exotic (neutronrich) nuclei...
DESPEC is the most sensitive
piece of equipment
g-ray time measurements
Stopper
RIB from FRS
g1
g2
Precision tests of wavefunctions by measuring level lifetimes.
Active stopper…
AIDA...Advanced Implantation Detector Array
• Uses 12 x 8cm x 8cm DSSSD
• Compatible with BELEN, MONSTER, TAS…..
• Measures position of implant
• Fast overload recovery (~ms}
• Time stamping
http://www2.ph.ed.ac.uk/~td/DSSD/
Design by University of Liverpool and STFC Daresbury Laboratory
ROSPHERE @ Bucharest

15 HPGe detectors (A/C) were
used to detect gamma rays;




10 x HPGe detectors placed @ 37o
1 x HPGe detector placed @ 64o
4 x HPGe detectors placed @ 90o
11 LaBr3(Ce) detectors were
also used:



ø2”x2” @ 90 and 64o (three)
(Cylindrical)
ø1.5”x1.5” @ 90 (six) (Cylindrical)
ø1”x1.5” @ 64o (two) (Conical)
EURICA @ Riken
12 RISING clusters
18 LaBr3(Ce) detectors
BigRIPS separator at RIBF at RIKEN
Implant into WAS3ABI - 5 DSSD’s
with 2 plastic scintillators
PID plot for 102Y setting,
5 x 105 102Y implants in 2.5 hours
102Y
Cluster spectrum scaled by a factor of 0.06
 correlation time set at 5 t1/2
Time between the beta (measured in the
plastic) and the gamma-ray in the LaBr.
Measured t1/2 = 2.0 (2) and 2.0 (3) ns, in
agreement with literature values
Motivation here is shape evolution towards more
neutron rich
Calculated using Grodzin’s formula
Ytrrium (Z=39) shapes measured with lasers
102
101
100
99
98
97
96
95
94
Static deformation only
9
3
92
Frequency (MHz)
Cheal et al., Phys.Letts B645 (2007) 133
IGISOL IV
Slide from P.Campbell
First on-line laser spectroscopy experiment
104Mo
104Mo
IGISOL 3
July 2008
IGISOL 4
April 2013
107Mo
IGISOL 4
April 2013
• First “commissioning run”
• Already seeing improvements
• 107Mo now measured
Slide from P.Campbell
(p,f) 100 μA on 30 g/cm2
50kW 25MeV photon
Slide from P.Campbell
JUROGAM, RITU, GREAT and the TDR.
PROMPT
gammas
Isomeric state
Isomeric state
Delayed
Gammas
Trigger-less Data Acquisition System
D.M. Cullen, Physics with Large Arrays of Novel Scintillators, Dublin, Jan 2014
Multiparticle spin trap 19- isomer
Isomeric states (from fragmentation)
*
*
■
■
■
A. Gottardo et al.
■
■ PRL109(2012)162502
210Hg:
PLB 725 (2013)292
208Hg,209Tl
N. Aldahan et al.,
PRC80,
061302(R) (2009).
M.Reed et al., PRL 105 (2010) 172501, PRC 86 (2012) 054321
(ESR storage ring)
*
Isomeric state
RISING: isomeric decays
S. Steer et al., Phys. Rev. C 84 (2011) 044313
Slide from Zs.Podolyak
π
ν
f7/2
j15/2
i13/2
i11/2
h9/2
g9/2
Z=82
N=126
s1/2
p1/2
d3/2
f5/2
h11/2
p3/2
d5/2
i13/2
Core-excited states around 208Pb
1.4 1.4
1.9
Slide from Zs.Podolyak
In box: E(4+)/E(2+) ratio
Pb
Isomeric states (from fragmentation)
*
*
■
■
■
A. Gottardo et al.
■
■ PRL109(2012)162502
210Hg:
PLB 725 (2013)292
208Hg,209Tl
N. Aldahan et al.,
PRC80,
061302(R) (2009).
M.Reed et al., PRL 105 (2010) 172501, PRC 86 (2012) 054321
(ESR storage ring)
*
Isomeric state
RISING: isomeric decays
S. Steer et al., Phys. Rev. C 84 (2011) 044313
Slide from Zs.Podolyak
GSI accelerator complex
SIS
UNILAC
9Be
target
Experimental Storage Ring (ESR)
Slide from P.M.Walker
Stored ions: high-K isomers in n-rich 184Hf
bare
(single ions)
197Au
fragmentation
Schottky mass spectrometry
A = 184, q = 72+
2.5 MeV
0e 1e
m2
g Ta
0
Hf
time (minutes)
10-second snapshots
● first observation of m2 isomer
● long-lived β-decaying isomer
2.5 MeV
10
T1/2 ≈ 12 min
20
frequency
Reed et al., Phys. Rev. Lett. 105 (2010) 172501
Slide from P.M.Walker
Spectroscopy Data
Slide from R.-D.Herzberg
Internal Conversion
Slide from R.-D.Herzberg
Overview
Slide from R.-D.Herzberg
SAGE campaigns
1st Campaign (2012)
• 251-Md
• 253-No
• 255-Lr
• 186-Hg
• 152-Sm
2nd Campaign (now)
 254-No
 249-Md



Slide from R.-D.Herzberg
186-Pb
179-Au
222-Th
Identification Problem Z > 112
Separation and implantation of fusion-evaporation products
Energy, position, and time correlation of implantation and decay
Alpha-decay chains into known isotopes
120
Z
Lv
Fl
114
108
Bh
Hs
Mt
Ds
Rg
Z=115
Cn
S.G. Nilsson et al.
NPA131, 1 (1969)
End points fission!
100
IUPAC & IUPAP:
direct measurement of atomic number Z !
152
Slide from R.-D.Herzberg
D. Rudolph, Lund University
162
SF
184
a
 + EC
N
-
Föreningen Rydbergs minne, Lund, November 2013
The TASISpec / TASCA E115 Collaboration
111, 112502 (2013)
Special thanks to …
UNILAC
ENSAR
Slide from R.-D.Herzberg
D. Rudolph, Lund University
Föreningen Rydbergs minne, Lund, November 2013
Other highlights:fission mechanism
Beta-delayed fission : ISOLDE/SHIP/GARIS
Fusion fission : JAEA, Tokai, Japan
A Andreyev, M.Huyse and P. Van Duppen: Reviews of Modern Physics 85 (2013) 1541
Other highlights:pear-shaped nuclei
Used Coulex of radioactive
220Rn and 224Ra beams to
measure octupole transition
strengths. Conclude stronger
octupole deformation in
224Ra than in 220Rn.
Gaffney, Butler at al.,: Nature 497 (2013) 1541
Other highlights: Carbon-12 caught
in a triangle
Mentioned specifically because
it used the Birmingham cyclotron…
…a UK facility!
Observed a 5- state in 12C
at 22.4 MeV which is
interpreted as built on
a triangular configuration.
Contradicts ab initio
calculations which indicate
a linear chain of three
alpha clusters.
D.J.Marin-Lambarri et al., : Physical Review Letters 113 (2014) 1541
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