O. Tengblad IEM-CSIC EUROGENESIS EUROGENESIS workshop on reactions of Astrophysical Interest April th IEM-CSIC Madrid N UCLEAR A THE A CCELERATOR

cmam Formation of 12 C and 7 Be Life of stars Death of stars Production of p-nuclei Study of 10 B( 3 He,p) 12 C* & 11 B( 3 He,d) 12 C* 197 Au(  n) 200 Tl reaction cross section 2 Study of 4 He( 3 He,  ) 7 Be & 3 He( 4 He,  ) 7 Be Mariano Carmona O. TENGBLAD EuroGENESIS workshop R&D

3 Nuclear Structure & Astrophysics – “Exact” A-body calculations possible for A  12 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. 12 C & The triple alpha process 4 He + 4 He ↔ 8 Be 8 Be + 4 He ↔ 12 C + γ MeV  clustering

12 C ≈10 (0,2 + ) g.s (2 - )  , , 2 -, 3 -, , Single-nucleon excitations to 1p 1/2,1d 5/2 and 2s 1/2 : 12 C* Excited states: Theory 1s 1/2  1p 3/2 1p 1/2 1d 5/2 2s 1/2 4 Recent theoretical papers discussing different cluster modules, that can reproduce rather well the states in 12 C: Bijker and Iachello, Ann. Phys. 298, 334 (2002). Kanada En’yo, Prog. Theo. Phys. 117 (2007) 65 O. TENGBLAD EuroGENESIS workshop

Excited states: Recent experiments 12 C g.s (2 - ) (0 + )  MeV Included in the NACRE compilation (theory) Nucl. Phys. A, 656,3, MeV 12 C(p,p’) 12 C* Nucl. Phys. A, 834, 621c, MeV 12 C( 12 C,3  ) Phys. Rev. C 76, , (also new 1 -, 3 - ) MeV 12 C( ,  ’) 12 C* Phys. Rev. C 68, , (3) MeV 12 C( ,  ’) 12 C* Nucl. Phys. A, 738, 268, 2004 ( and 15.4 MeV TUNL compilation Nucl. Phys. A, 506, 1, MeV MeV  -decay 12 N, 12 B Phys. Rev. C 81, , O. TENGBLAD EuroGENESIS workshop

4 He +4 He g.s Be 12 C (2 - ) ≈100 +  More questions: Decay mechanisms    12 C    8 Be Direct decay Sequential decay  How do the different states decay ? How is this related to the state structure ? 6 O. TENGBLAD EuroGENESIS workshop

7 12 C ISOLDE, JYFL & KVI Measured with high segmentation  decay mechanism / branching Measured with implantation method  total energy Experiment Experiment april 2006

How to produce the 12 C* CMAM A+a  C*  B*+b MeV 10 B 13 N * p 12 C * +  9B*9B*  OR MeV 11 B + d 12 C * + 8 O. TENGBLAD EuroGENESIS workshop

Targets: 18.9  g/cm 2 10 B enriched (90%) on 4  g/cm 2 C-backing 22.0  g/cm 2 11 B with 4  g/cm 2 C-backing Beam: and 8.5 MeV from 5 MV Tandetron The experiment: highly segmented  = 38% of 4  Reactions: 10 B( 3 He,p)  11 B( 3 He,d)  9 O. TENGBLAD EuroGENESIS workshop

Particle Identification 3 He + 11 B d + 12 C * EE E d 10 Reaction productsQ-Value (MeV) 14 N +  C + p C + d B +  C + n + p Li + 2  Be + p +  He + p + 2  B + 3 He C + t-2.00  p

Minimize Random Coincidences 11 B( 3 He,d  ) data 11 Reduce the acceptance window by gate in TDC 2.5  s ADC window (data taking) 0.1  s TDC gate (analysis) < 50 MeV/c < 1 MeV Energy & Momentum gates are independent 11 B( 3 He,p  )n TDC gate

12 E i (  ) (MeV) E sum (  ) (MeV) E sum =3/2*E MeV E 12C (MeV) Selecting proton channel: p +  +  +  coincidences  Excitation Energy in 12 C reconstructed 12 C *  8 Be(0 + )   EE O. TENGBLAD EuroGENESIS workshop

13 3 He + 11 B d + 12 C *  Partial branches O. TENGBLAD EuroGENESIS workshop

g.s Be 12 C 7.27 MeV (2 - ) ≈ B( 3 He,d  ) data O. TENGBLAD EuroGENESIS workshop Partial branches

Indirect Detection of  -decay MeV 10 B p 12 C * 17  g/cm 2 (+3  g/cm 2 )     12 C * ≈ C   The proton gives initial populated resonance in 12 C This state can emit  and populate a lower excited state The 3  alphas give resonance populated in 12 C after  -decay 15 O. TENGBLAD EuroGENESIS workshop

Excitation energy: calculated from p vs invariant mass of 3  3 He+ 11 B d+3  3 He+ 11 B n+p+3  3 He+ 10 B p+3  punch- throughs M. Alcorta et al, NIM A605, 318 (2009). 16 O. TENGBLAD EuroGENESIS workshop Indirect Detection of  -decay

O. Kirsebom et al, PLB 680, 44 (2009)  -decay of MeV  ≈ C %  width to bound states determined from p- 12 C coincidences

18 p-process Studies Production of most rare nuclei in the solar system p-nuclei Photon-disintegration reactions involved in the astrophysical p-process: (γ,n), (γ,p) & (γ,α) ( ,n) ++ Photon-disintegration: p-process (  ) 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 Au( ,n) 200 Tl 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 CMAM Astrophysical energy region Gamow-peak 6-12 MeV first experiments on 92 Mo, 130 Ba & 162 Er α-beam E α = 5-15 MeV I α = 1µA Au-Mo-Au p n γ γ α Si-detector α-Intensity: 197 Au(α,α) 197 Au 197 Au(α,γ) reactions

10 h after end of activation 20 O. TENGBLAD EuroGENESIS workshop 372 keV 40 Ca(α,p) 43 Sc 367 keV 200 Tl D. GalavizD. Galaviz Redondo, Centro de Física Nuclear da Universidade de Lisboa 197 Au( ,n) 200 Tl

21 Literature value: 26.1 (1) h 197 Au( ,n) 200 Tl D. GalavizD. Galaviz Redondo, Centro de Física Nuclear da Universidade de Lisboa

22 R&D for experiments

500  m N- Detector E 1  m N+ Detector  E Rear cathode 0.5  m  E (N+) Monolithic  E-E telescope

EE E FWHM 80 KeV Beams of 27 Al & 23 CMAM green  30 MeV blue  25 MeV red  20 MeV yellow  15 MeV dark blue  10 MeV 27 Al 23 Na

Detectors: DSSSD  monolithic Si telescope Detector area: 5x5 cm 2 64 pixel detectores á 3x3=9 mm electronic channels Solid angle 20% of the DSSSD and 4 times more electronics needed!! 5x5 cm 2 16x16 strips á 3mm 256 pixel detectors á 3x3=9 mm 2 32 electronic channels DSSSDMonolito

compact multiplexed readout 26 O. TENG BLAD FPA Area 64 x 3x3 mm 2,  E 1  m, E 400  m 128 ch electronics

compact multiplexed readout

256 channels multiplexed to MDI-2 via a 20 pin twisted pair cable 2x MTM channels MDI-2 Motorola power PC VME5055 Twisted pair 20 line

29 Materials Energy Resolution (at 662 keV) (%) Light yield (photons/k eV γ) Decay time (ns) λ emision LaBr nm LaCl nm LaBr 3 LaCl mm  Two crystals of different materials with a unique readout system?  Optically compatible E  E 1  E 2 Phoswich for high E Gamma and Proton detection

Phoswich: 1 st results  it works ENERGY SPECTRUM WITH GATE B FWHM 4 % PHOSWICH TEMPORAL SPECTRUM + 30 O. TENG BLAD FPA

LaCl 3 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 Flash ADC PMT LaBr 3 31 FWHM < 1%

Reactions study at CMAM 32 p( 17 0, 18 F) γ p( 17 0, 14 N)α } Difficult to compare previous results Uncertainties associated to thickness and composition of the target We will perform our expeiments in inverse kinematics 17 0(p, γ) 18 F 17 0(p, α) 14 N ISOLDE/JYFL Si-Ball: 36x4 quadrants of 1000 micron Si L.M. Fraile & J.Äystö, NIMA513 (2003) 28 LaBr 3 +LaCl 3 Phoswich 9x { 15x15 mm 2 x (40+60)mm } crystals 3-1% resolution, 40% photopeak efficiency 0-20 MeV

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. 33 O. TENGBLAD EuroGENESIS workshop

34 19 F(p,α  ) 16 O beam: protones de 1 MeV target: teflon “Gamma beam” test bench