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
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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
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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
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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