Nuclear structure

Nuclear structure

~65% of Uk nuclear physics community is studying nuclear structure

Questions we address:

2007 nuclear physics strategy document

• 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 neutron-rich matter?

• Do symmetries seen in near-stable nuclei also appear far from stability and do we observe new symmetries?

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

SuperFRS

Future facility

Future facility

100 m

GSI todayGSI today

SIS 100/300

UNILAC

ESR

SIS 18

HESR

RESR

NESR

Rare isotope production target

UK is heavily involved in 3 “experiments” within NuSTAR

R3B : Reactions with Relativistic Radioactive Beams

HISPEC: High-resolution in-flight spectroscopy

DESPEC: Decay spectroscopy

One –nucleon knockout reactions measure the spectroscopic factors....how appropriate is a mean-field description for exotic nuclei?

R3B: Reactions with Relativistic Radioactive Beams: an example of

the physics…

n-rich p-rich

RIB from FRS

Light target e.g H2

R3B: Inverse kinematics

“Stripped „ beam carries on

Light particles are emitted here…. UK building a tracker to measure energy and direction

High energy IonsFrom this direction

Liquid Hydrogen TargetGold Foil surround (Not Shown)

3 Layers of Silicon

Vacuum Chamber

Calorimeter

R3B Si Tracker Layout WG leader: R. Lemmon, M. ChartierSTFC Daresbury Laboratory (+ STFC RAL for ASIC)

Universities of Birmingham, Edinburgh, Liverpool, Surrey

Nuclear Structure and Reactions within NUSTAR 8

High energy IonsFrom this direction

Liquid Hydrogen TargetGold Foil surround (Not Shown)

3 Layers of Silicon

Vacuum Chamber

Calorimeter

R3B Si Tracker Layout WG leader: R. Lemmon, M. ChartierSTFC Daresbury Laboratory (+ STFC RAL for ASIC)

Universities of Birmingham, Edinburgh, Liverpool, Surrey

Nuclear Structure and Reactions within NUSTAR 9

More information in Andy Bosto

n’s talk

Spectroscopy of proton drip-line nuclei

(a) How does the basic neutron-proton exchange symmetry evolve or break down at the drip-line

(b) Can we understand exotic particle decays from proton-rich nuclear matter?

(c) What is the structure of nuclei along the crucial rp process path?

58

65 r-processpath

rp-processpath

2028

50

82

8

8

20

28

50

82

126

m asses m easured at the FR S-ESR

stable nucle i

nuclides w ith know n m asses

W ill be m easured w ith SU PER -FR S-C R -N ESR

Proton drip-lin

e

HISPEC: High-resolution in-flight spectroscopy: an example of the physics…

In-flight spectroscopy

Produce proton drip-line nuclei.

RIB from FRS

Secondary target Identify products usingLYCCA Lund, York, Cologne calorimeter

The LYCCA Array: Lund-York-Cologne CAlorimeter

Secondary Target

Start Detector

Stop Detector

Si DSSSDs for ΔE and tracking

CsI scintillator for residual E

3.6 m

Si DSSSD for tracking

Slide from S.Milne, L.Scruton, University of York

The Experiment:Slide from S.Milne, L.Scruton, University of York

46V

Look for Tz dependencein B(E2) from first 2+

1 mm 1 mm

Slide from S.Milne, L.Scruton, University of York

Motivation: Isospin Mixing in 46V

Continuing the work at York on mirror pairs and Coulomb energy differences

P.J.Davies et al.,: Physical Review Letters 111 (2013) 072501

-decay

TAS

-b delayed neutron detector

β,n, g-decay of exotic (neutron-rich) nuclei...DESPEC is the most sensitive piece of equipment

Neutron spectrometer MONSTER

g-ray time measurements

DESPEC: Decay spectroscopy, what’s the physics?

g-ray time measurements

Precision tests of wavefunctions by measuring level lifetimes.

RIB from FRS

Stopper

b-decay

or isomeric

decay

g1

g2

• 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/

Active stopper…AIDA...Advanced Implantation Detector Array

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 @ Riken12 RISING clusters 18 LaBr3(Ce) detectors

BigRIPS separator at RIBF at RIKEN

Implant into WAS3ABI - 5 DSSD’swith 2 plastic scintillators

PID plot for 102Y setting, 5 x 105 102Y implants in 2.5 hours

102Y

b correlation time set at 5 t1/2

Cluster spectrum scaled by a factor of 0.06

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

Frequency (MHz)

102

101

100

99

98

96

94

93

92

95

97

Cheal et al., Phys.Letts B645 (2007) 133

Static deformation only

b rms=

0.43b rm

s=0.0

Ytrrium (Z=39) shapes measured with lasers

IGISOL IV

Slide from P.Campbell

First on-line laser spectroscopy experiment

104MoIGISOL 3July 2008

104MoIGISOL 4April 2013

107MoIGISOL 4April 2013 • First “commissioning run”

• Already seeing improvements• 107Mo now measured

Slide from P.Campbell

(p,f) 100 μA on 30 g/cm250kW 25MeV photon

Slide from P.Campbell

Delayed Gammas

Isomeric state

PROMPT gammas

Isomeric state

Trigger-less Data Acquisition System

JUROGAM, RITU, GREAT and the TDR.

D.M. Cullen, Physics with Large Arrays of Novel Scintillators, Dublin, Jan 2014

Multiparticle spin trap 19- isomer

Isomeric states (from fragmentation)

208Hg,209TlN. Aldahan et al., PRC80, 061302(R) (2009).

Isomeric stateRISING: isomeric decays

S. Steer et al., Phys. Rev. C 84 (2011) 044313

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■

*

A. Gottardo et al.PRL109(2012)162502210Hg:PLB 725 (2013)292

M.Reed et al., PRL 105 (2010) 172501, PRC 86 (2012) 054321 (ESR storage ring)

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■

* *

Slide from Zs.Podolyak

In box: E(4+)/E(2+) ratio

Pb

π νf7/2 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

1.9

1.4 1.4

Core-excited states around 208Pb

Slide from Zs.Podolyak

Isomeric states (from fragmentation)

208Hg,209TlN. Aldahan et al., PRC80, 061302(R) (2009).

Isomeric stateRISING: isomeric decays

S. Steer et al., Phys. Rev. C 84 (2011) 044313

■

■

*

A. Gottardo et al.PRL109(2012)162502210Hg:PLB 725 (2013)292

M.Reed et al., PRL 105 (2010) 172501, PRC 86 (2012) 054321 (ESR storage ring)

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* *

Slide from Zs.Podolyak

GSI accelerator complex

UNILAC

ES

RF

RS

SIS

9Be target

Experimental Storage Ring (ESR)Slide from P.M.Walker

10-s

econ

d sn

apsh

ots

197Au fragmentation

A = 184, q = 72+

2.5 MeV

bare(single ions)

Reed et al., Phys. Rev. Lett. 105 (2010) 172501

0

tim

e (m

inut

es)

20

10

m2 g Ta 0e 1e

2.5 MeV

Hf

frequency

Stored ions: high-K isomers in n-rich 184Hf

Schottky mass spectrometry● first observation of m2 isomer● long-lived β-decaying isomer

T1/2 ≈ 12 min

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

186-Pb 179-Au 222-Th

Slide from R.-D.Herzberg

Identification Problem Z > 112

100

120

114

162

184

108

152

GSI Elements

Z = 107-112Cn

N

Z

DsMt

HsBh

a

b+ EC

SF

b-

Rg

End points fission!

FlLv

IUPAC & IUPAP: direct measurement of atomic number Z !

Z=115

Separation and implantation of fusion-evaporation productsEnergy, position, and time correlation of implantation and decayAlpha-decay chains into known isotopes

JINR H

ot Fusion

48 Ca +

Actinides

Z = 113-11

8

S.G. Nilsson et al.NPA131, 1 (1969)

D. Rudolph, Lund University Föreningen Rydbergs minne, Lund, November 2013

Slide from R.-D.Herzberg

Special thanks to …

The TASISpec / TASCA E115 Collaboration

D. Rudolph, Lund University Föreningen Rydbergs minne, Lund, November 2013

111, 112502 (2013)

ENSARUNILAC

Slide from R.-D.Herzberg

Other highlights:fission mechanism

A Andreyev, M.Huyse and P. Van Duppen: Reviews of Modern Physics 85 (2013) 1541

Beta-delayed fission : ISOLDE/SHIP/GARISFusion fission : JAEA, Tokai, Japan

Other highlights:pear-shaped nuclei

Gaffney, Butler at al.,: Nature 497 (2013) 1541

Used Coulex of radioactive 220Rn and 224Ra beams to measure octupole transition strengths. Conclude stronger octupole deformation in 224Ra than in 220Rn.

D.J.Marin-Lambarri et al., : Physical Review Letters 113 (2014) 1541

Other highlights: Carbon-12 caught in a triangle

Observed a 5- state in 12C at 22.4 MeV which is interpreted as built ona triangular configuration. Contradicts ab initio calculations which indicate a linear chain of three alpha clusters.

Mentioned specifically becauseit used the Birmingham cyclotron……a UK facility!

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