Single-neutron structure of neutron-rich nuclei near 132 Sn Jolie A. Cizewski Department of Physics...

Single-neutron structure of neutron-rich nuclei near 132SnSingle-neutron structure of

neutron-rich nuclei near 132Sn

Jolie A. Cizewski

Department of Physics & Astronomy

Rutgers University

INPC Jun 2007CENTER OF EXCELLENCE FOR

RADIOACTIVE ION BEAM STUDIESFOR STEWARDSHIP SCIENCEUniversity Radioactive Ion Beam Consortium

CollaborationRIBENS/Center of Excellence

CollaborationRIBENS/Center of Excellence

Rutgers University J.A.C., R. Hatarik, P.O’Malley, Steve Pain, T. Swan

ORNL D.W. Bardayan, J.C. Blackmon, F. Liang, C.D. Nesaraja, D. Shapira, M.S. Smith

Univ. Tennessee K.Y. Chae, Kate L. Jones, Z. Ma, B.H. Moazen

Tennessee Tech Ray Kozub, J.Shriner, D.Sissom

ORAU C. Matei

University of Surrey J.S. Thomas

Colorado School of Mines K. Chipps, L. Erikson, R.J. Livesay

Ohio University A. Adekola

Warsaw W. Krolas

Funded in part by the U.S. DOE Office of Science & NNSA/SSAA and the National Science Foundation.



Fundamental Questions in Nuclear & Astro PhysicsFundamental Questions in Nuclear & Astro Physics

•Origin of elements•Limits of nuclear existence•Evolution of shell structure



Neutron magic-number nuclei at waiting points

N=82

HRIBF yields

Measuring (d,p) on Rare Isotopes near Shell ClosuresMeasuring (d,p) on Rare Isotopes near Shell ClosuresMeasuring (d,p) on Rare Isotopes near Shell ClosuresMeasuring (d,p) on Rare Isotopes near Shell Closures

Measure (d,p) reactions with unstable beams Measure single-neutron energies +

spectroscopic strengths Provide data to understand r process

nucleosynthesis

Transfer measurements around Transfer measurements around 132132SnSnTransfer measurements around Transfer measurements around 132132SnSn

124Sn

In

Sb

Te

130Te 131Sn133Sn

Sn Z = 50

N = 82

135Te

Stable Doubly magic

Double shell closure Z=50, N=82

132Sn(d,p)133Sn, 130Sn(d,p)131Sn and 134Te(d,p)135Te measurements completed



132Sn(d,p) kinematics @ 4.7 A-MeV132Sn(d,p) kinematics @ 4.7 A-MeV

Forward c-o-m ↔ backward lab

At backward lab cross section very small and Eproton very small.

At forward lab Eproton rises quickly with angle (dE/d is large).

Want to measure around 90o. 5

10

15

20

30 60 90 120 150

dd

(

mb/

sr)

lab (deg)

0

Ene

rgy

(MeV

)

Angle (deg)

ORRUBA: Oak Ridge Rutgers University Barrel ArrayORRUBA: Oak Ridge Rutgers University Barrel ArrayORRUBA: Oak Ridge Rutgers University Barrel ArrayORRUBA: Oak Ridge Rutgers University Barrel Array

• Flexible design for measuring ejectiles from transfer reactions in inverse kinematics

• Resistive and non-resistive Si detectors (1000m, 500m and 65m)

• ORRUBA gives ~80% coverage over the range 47° →132°

• 288 electronics channels (conventionally instrumented)



132Sn(d,p) detectors132Sn(d,p) detectors

Plan View Beam View

ORRUBA 1000μm

ORRUBA telescopes

Beam

Beam

SIDAR

ORRUBA telescopes

5x5cm2 telescopes

ORRUBA telescopes

ORRUBA 1000μm

6 x ORRUBA 1000μm

5x5cm2 telescope



132Sn(d,p) photo132Sn(d,p) photo

ORRUBA detectorstectors(back angles)

SIDAR detectorstectors(back angles)



1g7/2

2d5/2

3s1/2

2d3/2

1h11/2

1h9/2

2f7/2

2f5/2

3p3/2

3p1/2

1i13/2

82

Two neutron holes in 130Sn80(g.s.)

Should be strongest in N=82 (d,p)

( =1 and =3)

What should one expect to see?What should one expect to see?



N=83 SystematicsN=83 SystematicsOnly weak evidence for p1/2 state

Tentatively assigned f5/2;

other candidates at higher energies


RADIOACTIVE ION BEAM STUDIESFOR STEWARDSHIP SCIENCEUniversity Radioactive Ion Beam Consortium p (deg)

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Ep(M

eV)

14

12

10

8

6

4

2

60 70 80 90 100 110 120 130 1400

(d,p) to ground state

(7/2-)

(3/2-)

(9/2-)

(5/2-)

(11/2-)

(1/2-)

3700

2004.6

1560.9

853.7

0.0 1.45s

1655.7

(d,p) to 1st ex state

(d,p) to 5/2- state

(d,p) to 1/2- state ?

132Sn(d,p): “all” ORRUBA detectors132Sn(d,p): “all” ORRUBA detectors



133Sn Excitation Energy133Sn Excitation Energy

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Ex (channels)

g.s

ORRUBA detectorsC

ou

nts

Preliminary

Fit known levels: g.s., 853.7-keV and 2004.6 keV

(p1/2) candidate:Ex= 1390 (40) keV

90

80

70

60

50

40

30

20

10

00 20 40 60 80 100 120 140 160 180



134134Te(d,p): Q-value spectrumTe(d,p): Q-value spectrum134134Te(d,p): Q-value spectrumTe(d,p): Q-value spectrum

≈0.66 MeV (p3/2)

g.s. (f7/2)

≈1 MeV (p1/2)≈1.8 MeV

(f5/2 ?)

-3 -2 -1 10Q value (MeV)

5

10

15

20

25

30

35

-4

Cou

nts

PRELIMINARY: single stripPRELIMINARY: single strip

CoM resolution ≈250 keV (FWHM)



N=83 Single Particle EnergiesN=83 Single Particle Energies

Previously two (unhappy) alternatives:

• SPEs straight from experiment i.e. including the p1/2 at 1656 keV.

OR• Extract from states in other nuclei e.g.

Z=54, 56 isotonesSakar and Sakar Phys. Rev. C64 014312 (2001).

NOW correct SPE’s• Calculations of masses, other nuclear

properties• Nuclear astrophysics



130Sn(d,p)131Sn N=81Fwd ORRUBA #1, MCP coinc., narrow TAC window

130Sn(d,p)131Sn N=81Fwd ORRUBA #1, MCP coinc., narrow TAC window

0

10

20

30

40

-3000 -2000 -1000 0 1000 2000 3000 4000

4679(41) 4018(28) 3417(23) 2680(23) 131Sn* (keV)

Energies from 4-6 detectors

Calibrations: 132Sn(d,p)133Sn 130Te(d,p)131Te

Systematic error: 30 keVCou

nts

Q (keV)

(g.s.)

2H(132Sn,p)133Sn

PRELIMINARY



Summary:132Sn(d,p):

Confirm 3 previously measured states Populate (p1/2) state (for first time) at Ex=1390(40) keV Better agreement with systematics and theory

134Te(d,p): Candidate for f5/2 at ≈1.8 MeV

130Sn(d,p): States above N=82 gap: “Same” spectrum Ex>2.6 MeV as 133Sn

Work in progress:Analysis of all detectors, all experimentsAngular distributions

To support p1/2 assignment of 1390-keV state in 133Sn For all states populated in 133Sn, 135Te, 131Sn

Spectroscopic factorsElastic scattering in forward angle detectors



Thank youThank you

Single-neutron structure of neutron-rich nuclei near 132Sn

Work supported in part by the U.S. Department of Energy and

National Science Foundation

Single-neutron structure of neutron-rich nuclei near 132 Sn Jolie A. Cizewski Department of Physics...

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