Low-energy M1 strength within the shell model R. Schwengner1, S. Frauendorf2, A. C. Larsen3 1

Institut f¨ur Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany 2

Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA 3

Department of Physics, University of Oslo, 0316 Oslo, Norway

Text optional: Institutsname
Prof. Dr. Hans Mustermann
www.fzd.de
Mitglied der Leibniz-Gemeinschaft Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Dipole strength in

94

Mo

Dipole strength function f1 = σγ /[3(π¯hc)2Eγ ] f1 = Γ ρ(Ex , J)/Eγ3

(γ, γ’) up to 4 MeV: N. Pietralla et al., PRL 83, 1303 (1999)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Dipole strength in

94

Mo

Dipole strength function f1 = σγ /[3(π¯hc)2Eγ ] f1 = Γ ρ(Ex , J)/Eγ3

(γ, γ’) from 4 MeV to Sn : G. Rusev et al., PRC 79, 061302 (2009)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Dipole strength in

3

94

Mo

94

( He,3He’) Mo, Oslo data, E&B2009 norm. -6

Mo(γ ,x)

E1 strength

-3

γ -ray strength function (MeV )

10

Dipole strength function f1 = σγ /[3(π¯hc)2Eγ ] f1 = Γ ρ(Ex , J)/Eγ3

94

M1 strength

10-7

Sum of E1 and M1

10-8

94

10-9

Mo(3He,3 He’):

M. Guttormsen et al., 0

2

4

6 8 10 12 14 γ -ray energy Eγ (MeV)

16

PRC 71, 044307 (2005)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Dipole strength in

95

Mo

Dipole strength function f1 = σγ /[3(π¯hc)2Eγ ] f1 = Γ ρ(Ex , J)/Eγ3

94

Mo(d,p)95 Mo:

M. Wiedeking et al., PRL 108, 162503 (2012)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Experimental B(M1) and B(E1) values in nuclei around A = 90

0.7 0.6

E1: 171 transitions

0.5

2

2

B(M1) (µN )

2

M1: 312 transitions

B(E1) (10 e fm )

< < 88 = A = 98

−2

0.4 0.3 0.2 0.1

Data taken from NNDC data base:

0

http://www.nndc.bnl.gov/nudat2/ 0

500

1000

1500

2000

Eγ (keV)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Shell-model calculations around N = 50 ◦ 94Mo/95Mo: Z = 40 + two 0g9/2 protons, N = 50 + two/three 1d5/2 neutrons. ◦ Shell-model calculations possible – calculation of M1 transition strengths. ◦ Up to now: Code RITSSCHIL used to describe M1 sequences at high spin in nuclides with N = 46 to 54. ◦ Present task: Calculation of B(M1) values of transitions between many states far from yrast, approaching the quasicontinuum. Determination of average B(M1) values in energy bins. ◦ Calculations for 94Mo, 95Mo and for the Z = 40, N = 50 nuclide 90Zr for comparison.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Shell-model calculations around N = 50 Configuration space SM1: π

Two-body matrix elements: ππ: empirical from fit to N=50 nuclei, 78Ni core; X. Ji, B.H. Wildenthal, PRC 37 (1988) 1256

ν 1d5/2

0g9/2

0g9/2

1p1/2

1p1/2

50

πν, νν (0g9/2 ,1p1/2 ): emp. from fit to N=48,49,50 nuclei, 88Sr core; R. Gross, A. Frenkel, NPA 267 (1976) 85 πν (π0f5/2,ν0g9/2 ): experimental from transfer reactions; P.C. Li et al., NPA 469 (1987) 393

1p3/2 0f 5/2

28

Core 66 28 Ni 38

Code: RITSSCHIL

νν (0g9/2,1d5/2 ): exp. from energies of the multiplet in 88Sr; P.C. Li, W.W. Daehnick, NPA 462 (1987) 26 remaining: MSDI; K. Muto et al., PLB 135 (1984) 349

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Shell-model calculations around N = 50 Configuration space SM2: π

Two-body matrix elements: ππ: empirical from fit to N=50 nuclei, 78Ni core; X. Ji, B.H. Wildenthal, PRC 37 (1988) 1256

ν 0g 7/2 1d5/2

1p1/2

πν, νν (0g9/2 ,1p1/2 ): emp. from fit to N=48,49,50 nuclei, 88Sr core; R. Gross, A. Frenkel, NPA 267 (1976) 85

1p3/2 0f

πν (π0f5/2,ν0g9/2 ): experimental from transfer reactions; P.C. Li et al., NPA 469 (1987) 393

0g9/2

0g9/2

50

5/2

28

Core 68 28 Ni 38

Code: RITSSCHIL

νν (0g9/2,1d5/2 ): exp. from energies of the multiplet in 88Sr; P.C. Li, W.W. Daehnick, NPA 462 (1987) 26 remaining: MSDI; K. Muto et al., PLB 135 (1984) 349

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Shell-model calculations around N = 50 Truncations in configuration space SM1: ◦

◦

90

Zr: – 4 protons may be lifted from the fp subshell to the 0g9/2 orbit. – 1 neutron may be excited from the 0g9/2 orbit to the 1d5/2 orbit.

94

Mo and 95Mo: – 4 protons may be lifted from the fp subshell to the 0g9/2 orbit. – 10 neutrons are in the 0g9/2 orbit and 2 in the 1d5/2 orbit.

Truncations in configuration space SM2: ◦

◦

90

Zr: – 2 protons may be lifted from the 1p1/2 orbit to the 0g9/2 orbit. – 1 neutron from the 0g9/2 orbit may be excited to the 1d5/2 orbit and 1 neutron to the 0g7/2 orbit or 2 neutrons from the 0g9/2 orbit may be excited to the 0g7/2 orbit.

94

Mo and 95Mo: – 2 protons may be lifted from the 1p1/2 orbit to the 0g9/2 orbit. – 1 neutron from the 0g9/2 orbit and 1 neutron from the 1d5/2 orbit may be excited to the 0g7/2 orbit or 1 neutron may be lifted from the 0g9/2 orbit to the 1d5/2 orbit and 1 neutron from the 1d5/2 orbit to the 0g7/2 orbit.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Level energies in

90

Zr

10

14 13

90

9

Zr shell model SM1 π=+

8

90

Zr shell model SM2

12

π=+

11 10

7

9

Ex (MeV)

Ex (MeV)

6 5 4

8 7 6 5

3

4 3

2

2

1

1 0

0 0

1

2

3

4

5

J

6

7

8

9

10 11

0

1

2

3

4

5

6

J

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Level energies in

94

Mo

7

10 9

94

Mo shell model SM2

π=+

π=+

8

5

7 6

Ex (MeV)

4

Ex (MeV)

94

Mo shell model SM1

6

3

5 4 3

2

2 1 1 0

0 0

1

2

3

4

5

J

6

7

8

9

10

0

1

2

3

4

5

6

J

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Level energies in

94

Mo and

90

Zr

10

14 13

9

94

Mo shell model SM2 π=+

8

90

Zr shell model SM2

12

π=+

11 10

7

9

Ex (MeV)

Ex (MeV)

6 5 4

8 7 6 5

3

4 3

2

2

1

1 0

0 0

1

2

3

J

4

5

6

0

1

2

3

4

5

6

J

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Level energies in

94

Mo and

95

Mo

10

10

9

9

94

95

Mo shell model SM2 π=+

8 7

7

6

6

5 4

5 4

3

3

2

2

1

1

0

0 0

1

2

3

J

π=+

8

Ex (MeV)

Ex (MeV)

Mo shell model SM2

4

5

6

0.5

1.5

2.5

3.5

4.5

5.5

6.5

J

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

94

Mo in SM1 and SM2

0.3

0.3 94

94

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

(π = +, 14276 transitions)

0.2

0.1

0

0

2000

4000

6000

(π = +, 14276 transitions)

0.2

(π = −, 14270 transitions)

2

B(M1) (µN )

(π = −, 14271 transitions)

2

B(M1) (µN )

Mo shell model SM1 J = 0i to 6i, i = 1 to 40

8000

0.1

0

0

Eγ (keV)

2000

4000

6000

8000

Eγ (keV)

◦ Average B(M1) values in bins of 100 keV of transition energy. ⇒ Enhancement of M1 strength toward very low transition energy in the two configuration spaces. ⇒ Large M1 strength around E γ = 7 MeV caused by 0 → 1 and 1 → 0 transitions with dominating 1 ν(0g−1 9/2 0g7/2 ) spin-flip configuration.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

90

Zr and

94

Mo

0.5

0.3 90

94

Zr shell model SM2 J = 0i to 6i, i = 1 to 40

0.4

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

B(M1) (µN )

(π = −, 14278 transitions)

0.3

(π = +, 14276 transitions)

0.2

(π = −, 14270 transitions)

2

2

B(M1) (µN )

(π = +, 14279 transitions)

0.2

0.1

0.1

0

0

2000

4000

Eγ (keV)

6000

8000

0

0

2000

4000

6000

8000

Eγ (keV)

⇒ Enhancement of M1 strength toward very low transition energy in the N = 50 nuclide

90

Zr as well.

90 ⇒ Total M1 strength of 1+ → 0+ 1 transitions around 8 MeV in Zr is in agreement with results of an experiment at HIγS [G. Rusev et al., PRL 110, 022503 (2013)].

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

95

Mo and

94

Mo

0.3

0.3 95

94

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

(π = +, 15057 transitions)

0.2

0.1

0

0

2000

4000

6000

(π = +, 14276 transitions)

0.2

(π = −, 14270 transitions)

2

B(M1) (µN )

(π = −, 15056 transitions)

2

B(M1) (µN )

Mo shell model SM2 J = 1/2i to 13/2i, i = 1 to 40

8000

0.1

0

0

2000

4000

Eγ (keV)

6000

8000

Eγ (keV)

◦ Average B(M1) values in bins of 100 keV of transition energy. ⇒ Enhancement of M1 strength toward very low transition energy in the two isotopes. 1 ⇒ ν(1d25/2 0g17/2) configuration preferred to ν(1d35/2 0g−1 9/2 0g7/2 ) configuration in

95

Mo.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

90

Zr and

94

Mo

1.2

1 90

(π = +, 14279

transitions)

(π = −, 14278

transitions)

0.6 0.4

(π = −, 14270 transitions)

0.6

0.4

0.2

0.2 0

(π = +, 14276 transitions) 2

2

0.8

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

0.8

B(M1) (µN )

1

B(M1) (µN )

94

Zr shell model SM2 J = 0i to 6i, i = 1 to 40

0

2000

4000

6000

8000

10000 12000

0

Ei (keV)

0

2000

4000

6000

8000

Ei (keV)

◦ Average B(M1) values in bins of 100 keV of excitation energy. ◦ ◦

90

Zr: Large peaks between about 5.9 and 7.5 MeV for π = – arise from states dominated by −1 1 1 the configuration π(1p−1 1/2 0g9/2 ) ν(0g9/2 1d5/2 ).

94

Mo: Large peaks between about 1.5 and 3.0 MeV for π = + and π = – arise from states dominated by 2 3 the configurations π(0g29/2) ν(1d25/2 ) and π(1p−1 1/2 0g9/2 ) ν(1d5/2 ), respectively.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

95

Mo and

94

Mo

1

1 95

94

Mo, shell model J = 1/2i to 13/2i, i = 1 to 40

0.8

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

0.8

(π = +, 14276 transitions)

(π = −, 15056 transitions)

2

0.6

B(M1) (µN )

2

B(M1) (µN )

(π = +, 15057 transitions)

0.4

0.2

0

(π = −, 14270 transitions)

0.6

0.4

0.2

0

2000

4000

6000

8000

0

Ei (keV)

0

2000

4000

6000

8000

Ei (keV)

◦ Average B(M1) values in bins of 100 keV of excitation energy. ◦ ◦

95

Mo: Large peaks between about 0.9 and 2.2 MeV for π = + and π = – arise from states dominated by 3 3 the configurations π(0g29/2) ν(1d35/2 ) and π(1p−1 1/2 0g9/2 ) ν(1d5/2 ), respectively.

94

Mo: Large peaks between about 1.5 and 3.0 MeV for π = + and π = – arise from states dominated by 2 3 the configurations π(0g29/2) ν(1d25/2 ) and π(1p−1 1/2 0g9/2 ) ν(1d5/2 ), respectively.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

90

Zr and

94

Mo

0.2

0.15 90

94

Zr shell model SM2 J = 0i to 6i, i = 1 to 40

0.15

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

(π = +, 14279 transitions)

(π = −, 14270 transitions)

2

B(M1) (µN )

2

B(M1) (µN )

(π = −, 14278 transitions)

(π = +, 14276 transitions)

0.1

0.1

0.05

0.05

0

0

1

2

3

4

5

Ji

6

0

0

1

2

3

4

5

6

Ji

◦ Average B(M1) values vs. initial spin. ◦

94

Mo: Staggering of the values for π = +. Large B(M1) values for transitions from states with the main configuration π(0g29/2 ) ν(1d25/2 ) and even spins.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Average M1 strengths in

95

Mo and

94

Mo

0.15

0.15 95

94

Mo shell model SM2 J = 0i to 6i, i = 1 to 40

(π = +, 15057 transitions)

0.1

0.05

0

0.5

1.5

2.5

3.5

4.5

(π = +, 14276 transitions)

0.1

(π = −, 14270 transitions)

2

B(M1) (µN )

(π = −, 15056 transitions)

2

B(M1) (µN )

Mo, shell model J = 1/2i to 13/2i, i = 1 to 40

5.5

Ji

6.5

0.05

0

0

1

2

3

4

5

6

Ji

◦ Average B(M1) values vs. initial spin. ◦

94

Mo: Staggering of the values for π = +. Large B(M1) values for transitions from states with the main configuration π(0g29/2 ) ν(1d25/2 ) and even spins.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Shell-model calculations for

94

Mo

Configurations that generate large M1 transition strengths (active orbits with jπ 6= 0 and jν 6= 0): ν(1d25/2) ◦ π = +: π(0g29/2) 2 3 ) ν(1d 0g π = –: π(1p−1 5/2) 9/2 1/2 ν(1d15/2 0g17/2) ◦ π = +: π(0g29/2) 3 1 1 0g ) ν(1d π = –: π(1p−1 0g 9/2 5/2 7/2) 1/2 1 0g ν(1d25/2 0g−1 ◦ π = +: π(0g29/2) 7/2) 9/2 −1 3 1 2 0g 0g ) ν(1d π = –: π(1p−1 0g 9/2 7/2). 5/2 1/2 9/2

◦ π = +:

1 ν(1d25/2 0g−1 9/2 0g7/2)

⇒ “Mixed-symmetry” and spin-flip configurations.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Shell-model calculations for

90

Zr

Configurations that generate large M1 transition strengths (active orbits with jπ 6= 0 and jν 6= 0): −1 1 2 ◦ π = +: π(1p−2 1d ) ν(0g 0g 5/2) 9/2 9/2 1/2 −1 1 1 1d 0g ) ν(0g π = –: π(1p−1 5/2) 9/2 9/2 1/2 −1 1 2 ) ν(0g 0g ◦ π = +: π(1p−2 9/2 9/2 0g7/2) 1/2 −1 1 1 π = –: π(1p−1 1/2 0g9/2) ν(0g9/2 0g7/2)

◦ π = +:

1 0g ν(0g−1 7/2) 9/2

⇒ “Mixed-symmetry” and spin-flip configurations.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Generation of large M1 strengths

J+1 J Jπ

Jπ Jν Jν M1

~µ =

Z  X



glπ~lπ + gsπ~sπ +

N  X

glν~lν + gsν~sν



B(M 1, Ji → Jf ) = (2Ji + 1)−1 |hf kb µkii |2

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Generation of large M1 strengths

J+1 J Jπ

Jπ Jν Jν M1

⇒ Configurations including protons and neutrons in specific high-j orbits with large magnetic moments. ⇒ Coherent superposition of proton and neutron contributions for specific combinations of g π and g ν factors and relative phases (“mixed symmetry”). ⇒ Large M1 strengths appear between states with equal configurations by a recoupling of the proton and neutron spins.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Generation of large M1 strengths

Analogous “shears mechanism” in magnetic rotation

Examples near A = 90:

82

Rb,

84

Rb

H. Schnare et al., PRL 82, 4408 (1999).

B(M1) ∼ µ2⊥

R.S. et al., PRC 66, 024310 (2002).

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Dipole strength in

3

94

Mo

94

( He,3He’) Mo, Oslo data, E&B2009 norm. -6

Mo(γ ,x)

E1 strength

-3

γ -ray strength function (MeV )

10

Dipole strength function f1 = σγ /[3(π¯hc)2Eγ ] f1 = Γ ρ(Ex , J)/Eγ3

94

M1 strength

10-7

Sum of E1 and M1

10-8

94

10-9

Mo(3He,3 He’):

M. Guttormsen et al., 0

2

4

6 8 10 12 14 γ -ray energy Eγ (MeV)

16

PRC 71, 044307 (2005)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

M1 strength function in

94

Mo

Dipole strength function f1 = 11.5473 B(M1) ρ(Ex , J)

94

Mo shell model SM2 J = 0i to 6i, i = 1 to 40 3

3

( He, He’) data

−3

fM1 (10 MeV )

100

10

−9

M1 model

ρ(Ex , J) - level density of the shell-model states, includes π = +, π = −, all spins from 0 to 6.

1

0

94

0

2000

4000

6000

Eγ (keV)

8000

10000

Mo(3He,3 He’):

M. Guttormsen et al., PRC 71, 044307 (2005)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Summary • Calculation of a large number of M1 transition strengths between the lowest 40 states each with spins 0 to 6 in 90Zr, 94Mo and spins 1/2 to 13/2 in 95Mo. • The calculations show an enhancement of the average B(M1) values toward very low transition energy. • Enhanced M1 strength at low energy is generated by transitions between closely lying states of all considered spins. • Large M1 strengths result from a recoupling of the spins of specific proton and neutron orbits. • Large M1 strengths at about 8 MeV are generated by the spin-flip configuration −1 0g17/2). ν(0g9/2 • A dipole strength function deduced from the average calculated B(M1) values in 94Mo is in agreement with a strength function deduced from a (3He,3He’) experiment.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Simulations of γ-ray cascades Monte Carlo simulations of γ-ray cascades from groups of levels in 100 keV bins (G. Rusev, dissertation)

Γ Γ0 Γ1 Γ2

E J π

⇒ Level scheme of J = |J0 ± 1, 2| states constructed by using: ◦ Backshifted Fermi-Gas Model with level-density parameters from T. v. Egidy, D. Bucurescu, PRC 80, 054310 (2009) ◦ Wigner level-spacing distributions ⇒ Partial decay widths calculated by using: ◦ Photon strength functions approximated by Lorentz curves (www-nds.iaea.org/RIPL-2). E 1: parameters from fit to (γ,n) data M1: global parametrisation of spin-flip resonances E 2: global parametrisation of isoscalar resonances ◦ Porter-Thomas distributions of decay widths. ⇒ Feeding intensities subtracted and intensities of g.s. transitions corrected with calculated branching ra0 tios Γ0/Γ .

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Simulations of γ-ray cascades

1.0 86

1.0

Ground−state transitions

Iγ (arb. units)

Iγ (arb. units)

Kr

0.5 Branching transitions

139

La

Ground−state transitions

0.5

Branching transitions

0.0

0

1

2

3

4

5

6

7

8

9

10

Eγ (MeV)

0.0

2

3

4

5

6

7

8

9

10

Eγ (MeV)

Simulated intensity distribution of transitions depopulating levels in a 100 keV bin around 9 MeV. ⇒ Subtraction of intensities of branching transitions.

86

Kr data: R.S. et al., PRC 87, 024306 (2013). 139 La data: A. Makinaga et al., PRC 82, 024314 (2010). Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Simulations of γ-ray cascades

100 100 86

139

Kr

La

80

b0 (%)

60

60

∆

∆

b0 (%)

80

40

20

20 0

40

4

5

6

7

8

9

10

Ex (MeV)

0

2

3

4

5

6

7

8

9

10

Ex (MeV)

Distribution of branching ratios b0 = Γ0/Γ versus the excitation energy as obtained from the simulations of γ-ray cascades. ⇒ Estimate of Γ0 and σγ . 86

Kr data: R.S. et al., PRC 87, 024306 (2013). 139 La data: A. Makinaga et al., PRC 82, 024314 (2010). Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Branching ratios in

136

Ba from measurements at HIγS

Response-corrected spectra. Simulated spectra of γ rays scattered by atomic processes. Subtracted spectra contain bunches of transitions to the ground state and to excited states.

R. Massarczyk et al., PRC 86, 014319 (2012).

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Test of simulated branching ratios - measurements at HIγS 100

Red circles: 136

with monoenergetic γ rays at HIγS (∆E ≈ 200 keV).

60

∆

b0 (%)

Branching ratios deduced from measurements

Ba

80

Black squares:

40

Distribution of branching ratios b0 = Γ0/Γ versus the excitation energy as obtained from

20

simulations of γ-ray cascades 0

(values of 10 realizations). 4

5

6

7

8

9

Ex (MeV)

R. Massarczyk et al., PRC 86, 014319 (2012).

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Absorption cross section of

136

Ba,

138

Ba

3

10

136

Ba

2

σγ (mb)

10

(γ,γ’) 1

10

Sn 0

10

4

6

8

10

12

14

16

18

Ex (MeV)

ELBE data for 136Ba R. Massarczyk et al., PRC 86, 014319 (2012)

HIGS data for 138Ba A. Tonchev et al., PRL 104, 072501 (2010)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Absorption cross section of

139

La,

138

Ba

La (γ,n)

100

(γ,γ’)corr

σγ (mb)

139

(γ,n)

10

(γ,γ’)uncorr 1

Sn 5

6

7

8

9 10 11 12 13 14 15 16 17 18

Ex (MeV)

ELBE data for 139La R. Makinaga et al., PRC 82, 024314 (2010)

HIGS data for 138Ba A. Tonchev et al., PRL 104, 072501 (2010)

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de

Announcement

The Fifteenth International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (CGS15) will take place in Dresden, Germany, from August 25 to August 29, 2014. We are looking forward to seeing you there.

Ronald Schwengner | Institut für Strahlenphysik | http://www.hzdr.de