O. TengbladIEM-CSIC

EUROGENESIS workshop on reactions of Astrophysical Interest April 27-29th IEM-CSIC Madrid

NUCLEAR ASTROPHYSICS @ THE ACCELERATOR

Astrophysics @ cmam

Formation of 12C and 7Be

Life of stars

Death of starsProduction of p-nuclei

Study of 10B(3He,p)12C* & 11B(3He,d)12C*

197Au(a,n)200Tl reaction cross section2

Study of 4He(3He,g)7Be & 3He(4He,g)7BeMariano Carmona

O. TENGBLAD EuroGENESIS workshop

R&D

3

Nuclear Structure & Astrophysics

– “Exact” A-body calculations possible for A12 • Shell-model states• Molecular-cluster states

– We can cover from drip-line to drip-line– Break-up mechanism not fixed by kinematics

• Sequential?• Direct?

– Crucial for bridging the • A=5 and A=8 gaps in Big Bang and Stellar nuclear

synthesis.

12C & The triple alpha process4He + 4He ↔ 8Be 8Be + 4He ↔ 12C + γ + 7.367 MeV

a clustering

4

12C

12.71 1+

≈10 (0,2+)

4.44 2+

g.s. 0+

7.65 0+

9.64 3-

10.84 1-

11.83 2-

13.35 (2-)

14.08 4+

15.11 1+

aaa7.27

1+, 2+ 1-, 2-, 3-, 4- 1-, 2-

- Single-nucleon excitations to 1p1/2,1d5/2 and 2s1/2 :

12C*

Excited states: Theory

1s1/2pn

1p3/2

1p1/2

1d5/2

2s1/2

Recent theoretical papers discussing different cluster modules, that can reproduce rather well the states in 12C:

• Bijker and Iachello, Ann. Phys. 298, 334 (2002).• Kanada En’yo, Prog. Theo. Phys. 117 (2007) 65 O. TENGBLAD

EuroGENESIS workshop

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Excited states: Recent experiments

12C

4.44 2+

g.s. 0+

13.35 (2-)

15.11 1+

12.71 1+

10.3 (0+)

7.65 0+

aaa7.27

2+ @ 9.0 MeV Included in the NACRE compilation (theory)Nucl. Phys. A, 656,3,1999

2+ @ 9.6 MeV12C(p,p’)12C*Nucl. Phys. A, 834, 621c, 2010

2+ @ 11.16 MeV12C(12C,3a)Phys. Rev. C 76, 034320, 2007. (also new 1-, 3-)

2+ @ 11.5 MeV12C(a,a’)12C*Phys. Rev. C 68, 014305, 2003

2+ @ 9.9(3) MeV12C(a,a’)12C*Nucl. Phys. A, 738, 268, 2004

(2+) @ 11.2 and 15.4 MeVTUNL compilationNucl. Phys. A, 506, 1, 1990

2+ @ 11.1 MeV0+ @ 11.2 MeVb-decay 12N,12BPhys. Rev. C 81, 024303, 2010.

O. TENGBLAD EuroGENESIS

workshop

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4He+4He

7.65 0+

11.35 4+

3.03 2+

g.s. 0+ -0.092

8Be12C7.27

9.64 3-

10.84 1-

11.83 2-

12.71 1+

13.35 (2-)

14.08 4+

15.11 1+

16.11 2+

18.71

≈10 0+

a

More questions: Decay mechanisms

a

a

a

12C

a

a

a

12C 8Be

Direct decay

Sequential decay

a

• How do the different states decay ?• How is this related to the state structure ?

O. TENGBLAD EuroGENESIS

workshop

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12C measured @ ISOLDE, JYFL & KVI

Measured with high segmentation decay mechanism / branching

Measured with implantation method total energy

Experiment 2002-2004

Experiment april 2006

How to produce the 12C* States @ CMAM

A+a C* B*+b

3He @ 4.9 MeV10B 13N*

p

12C*

+ a

a

a

9B*

a

OR3He @ 8.5 MeV

11B+ d 12C*+

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O. TENGBLAD EuroGENESIS workshop

O. TENGBLAD EuroGENESIS workshop

Targets:

18.9 mg/cm2 10B enriched (90%) on 4 mg/cm2 C-backing

22.0 mg/cm2 11B with 4 mg/cm2 C-backing

Beam: 3He @ 4.9 and 8.5 MeV from 5 MV Tandetron

The experiment: highly segmented

= 38% of 4p

Reactions: 10B(3He,p)aaa

11B(3He,d)aaa

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Particle Identification

3He + 11B d + 12C*

DE E

d

10

Reaction products Q-Value (MeV)14N + g 20.7413C + p 13.1912C + d 10.4610B + a 9.1212C + n + p 8.246Li + 2a 4.669Be + p + a 2.545He + p + 2a 0.0711B + 3He 0.0011C + t -2.00

a

p

Minimize Random Coincidences

11B(3He,daaa) data11

• Reduce the acceptance window by gate in TDC• 2.5 ms ADC window (data taking)• 0.1 ms TDC gate (analysis)

• < 50 MeV/c• < 1 MeV•Energy & Momentum gates are independent

11B(3He,paaa)n

E labtot E beam

Pi Pbeam

E labtot E beam

E labtot E beam

TDC gate

12

Ei(a) (MeV)

Esu

m(a

) (M

eV)

Esum=3/2*E1+0.092 MeV

E12

C (M

eV)

Selecting proton channel: p + a + a + a coincidences Excitation Energy in 12C reconstructed

12C* a1 8Be(0+)

a2 a3

SEa

O. TENGBLAD EuroGENESIS workshop

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3He + 11B d + 12C* aaa

Partial branches

O. TENGBLAD EuroGENESIS workshop

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7.65 0+

3.03 2+

g.s. 0+

8Be12C7.27 MeV

9.64 3-

10.84 1-

11.83 2-

12.71 1+

13.35 (2-)

≈10 0+

11B(3He,daaa) data

O. TENGBLAD EuroGENESIS workshop

Partial branches

15

7.65 0+

15.11 1+

Indirect Detection of g-decay

3He @ 4.5 MeV10B

p

12C*

17 mg/cm2

(+3 mg/cm2)

a a

a

g

12C*12.71 1+

≈10 0+

11.83 2-

12C

15.11 1+

7.65 0+

g

aaa

•The proton gives initial populated resonance in 12C• This state can emit g and populate a lower excited state•The 3alphas give resonance populated in 12C after g-decay

O. TENGBLAD EuroGENESIS workshop

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Excitation energy: calculated from p vs invariant mass of 3a

3He+11B d+3a

3He+11B n+p+3a

3He+10B p+3a

punch- throughs

M. Alcorta et al, NIM A605, 318 (2009). O. TENGBLAD EuroGENESIS workshop

Indirect Detection of g-decay

17O. Kirsebom et al, PLB 680, 44 (2009)

g-decay of 15.11 MeV

aaa

12.71 1+

≈10 0+

7.65 0+

11.83 2-

15.11 1+

12C

1.24.4 1.4 0.3

92.8% g width to bound states determined from p-12C coincidences

4.44 0+

0.0 0+

92.7

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p-process Studies

Production of most rare nuclei in the solar systemp-nuclei

Photon-disintegration reactions involved in the astrophysical p-process: (γ,n), (γ,p) & (γ,α)

(g,n)

b+

Photon-disintegration:p-process

(g,a)Experiments to improve knowledge

on α-nuclear potentials for

astrophysical applications

Nucleonsynthesis of the 35 stable p-rich nuclei, which cannot be reached in normal

n-capture process

Production & study of p-nuclei

19197Au(a,n)200Tl

D. Galaviz Redondo, Centro de Física Nuclear da Universidade de Lisboa

Radiative α-capture reactions (α,p), (α,n) & (α ,γ)

on proton-rich nuclei

Optimum energy for CMAMAstrophysical energy regionGamow-peak 6-12 MeV

first experiments on 92Mo, 130Ba & 162Er

α-beamEα = 5-15 MeV

Iα= 1µA

Au-Mo-Au

p

nγ

γ

αSi-detector

α-Intensity: 197Au(α,α)197Au 197Au(α,γ) reactions

10 h after end of activation

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O. TEN

GBLAD EuroGENESIS w

orkshop

372 keV40Ca(α,p)43Sc

367 keV200Tl

D. GalavizD. Galaviz Redondo, Centro de Física Nuclear da Universidade de Lisboa

197Au(a,n)200Tl

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Literature value: 26.1 (1) h

197Au(a,n)200Tl

D. GalavizD. Galaviz Redondo, Centro de Física Nuclear da Universidade de Lisboa

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R&Dfor experiments

Front cathode0.5 µm

500 mm N- Detector E

1 mm N+ Detector DE

Rear cathode0.5 mm

E detector (N-)

DE (N+)

Monolithic DE-E telescope

DEEFWHM 80 KeV

Beams of 27Al & 23Na @ CMAMgreen 30 MeVblue 25 MeVred 20 MeVyellow 15 MeVdark blue 10 MeV

27Al

23Na

Detectors: DSSSD monolithic Si telescope

Detector area: 5x5 cm2

64 pixel detectores á 3x3=9 mm2

128 electronic channels

Solid angle 20% of the DSSSD and4 times more electronics needed!!

5x5 cm2 16x16 strips á 3mm

256 pixel detectors á 3x3=9 mm2

32 electronic channels

DSSSD Monolito

O. TENGBLAD FPA2009-07387

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compact multiplexed readout

Area 64 x 3x3 mm2, DE 1mm, E 400 mm128 ch electronics

compact multiplexed readout

256 channels multiplexed to MDI-2 via a 20 pin twisted pair cable

2x MTM-64128 channels

MDI-2

Motorola power PCVME5055

Twisted pair20 line

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MaterialsEnergy

Resolution (at 662 keV)

(%)

Light yield (photons/k

eV γ)

Decay time (ns) λemision

LaBr3 2.9 63 16 380 nm

LaCl3 3.8 49 28 350 nm

LaBr3 LaCl3

30 50 mm

Two crystals of different materials with a unique readout system? Optically compatible

EDE1 DE2

Phoswich for high E Gamma and Proton detection

O. TENGBLAD FPA2009-07387

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Phoswich: 1st results it works

ENERGY SPECTRUM WITH GATE B

FWHM 4 %

PHOSWICH TEMPORAL SPECTRUM

+

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LaCl3

PMT

Phoswich response to 180 mev protons

Proton slowed down in the two crystals

Proton escaping leaving part of energy

Proton scattered out from LaBr

Proton stopped in 1st crystal

Pile up & noise

Proton entered from the side to 2nd crystal

Phoswich detector response to 150 & 180 MeV protons

totdel IaI

Flash ADC

PMT

LaBr3

FWHM < 1%

Reactions study at CMAM

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p(170,18F)γ

p(170,14N)α

}Difficult to compare previous results

Uncertainties associated to thickness and composition of the target

We will perform our expeiments in inverse kinematics

170(p, γ)18F 170(p, α)14N

ISOLDE/JYFL Si-Ball: 36x4 quadrants of 1000 micron SiL.M. Fraile & J.Äystö, NIMA513 (2003) 28

LaBr3+LaCl3 Phoswich9x { 15x15 mm2 x (40+60)mm } crystals3-1% resolution, 40% photopeak efficiency 0-20 MeV

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Collaborators• H.O.U. Fynbo, O. Kirsebom, S. Hyldegaard, K. Riisager Århus University, Denmark

• B. Jonson, T. Nilsson, G. Nyman Chalmers Univ. of Technology, Göteborg, Sweden

• M. Alcorta, M.J.G. Borge, J-A Briz, M. Carmona, M. Cubero, E. Nacher, A. Perea, O. Tengblad, IEM-CSIC, Madrid, Spain

• B. R. Fulton, C. Aa Diget, N S Bondili University of York, United Kingdom.

O. TENGBLAD EuroGENESIS workshop