Nucleus-Nucleus 2012San Antonio (TX) 18 F+p  15 O + CRIB 1

Astrophysical motivations  Gamma-ray emission of energy 511 keV from novae is dominated by the positron annihilation following the   decay of unstable nuclei  18 F is especially important because  It is produced relatively abundantly  Its lifetime of ∼ 158 min is well matched to the timescale for nova ejecta to become transparent to  ray emission IT IS IMPORTANT TO STUDY THE REACTIONS PRODUCING AND DESTROYING 18 F as 18 F(p,  ) 15 O  The 18 F(p,  ) 15 O reaction influence the 15 O production considered as a key isotope for the escape from the hot- CNO cycle to the rp-process AXAX ++ (p,  ) (p,  ) 18 F Nucleus-Nucleus 2012San Antonio (TX) 2

18 F(p,  ) 15 O Astrophysical factor is dominated by several resonances in 19 Ne Nucleus-Nucleus 2012San Antonio (TX) Astrophysical motivations A. Coc, M. Hernanz, J. José, and J.-P. Thibaud Astron. Astrophys. 357, 561–571 (2000) 3

Nucleus-Nucleus 2012San Antonio (TX) State of Art ARGONNE LLN ORNL TRIUMF GANIL- SPIRAL RIKEN – CRIB TAMU Most recent references: D. J. Mountford et al PHYSICAL REVIEW C 85, (R) (2012) “Resonances in 19Ne with relevance to the astrophysically important 18F( p,α)15O reaction.” A. S. Adekola et al. PHYSICAL REVIEW C 83, (R) (2011) “First proton-transfer study of 18F + p resonances relevant for novae” C. E. Beer et al. PHYSICAL REVIEW C 83, (R) (2011) “Direct measurement of the 18F( p,α)15O reaction at nova temperatures” 4

5 Nucleus-Nucleus 2012San Antonio (TX) State of Art C. E. Beer et al. PHYSICAL REVIEW C 83, (R) (2011) D. J. Mountford et al PHYSICAL REVIEW C 85, (R) (2012) DIRECT EXPERIMENT A. S. Adekola et al. PHYSICAL REVIEW C 83, (R) (2011) TRANSFER REACTION

New CRIB by using the Trojan Horse Method d p n 18 F 15 O  Trojan Horse nucleus E BA > E C ECEC x S x x x S A=A= nuclear field E BA = A-B relative energy E C = A-B Coulomb Barrier B C D E Bx = E CD – Q 2Body (pcp) A (x+s) + B  C + D + S B + x  C + D 18 F + d  15 O +  + n 18 F + p  15 O +  Nucleus-Nucleus 2012San Antonio (TX) 6

In PWIA: TURNING THE IDEA INTO PRACTICE Assuming the QF mechanism is dominant the process can be represented in Feynman diagrams Three body reaction Virtual decay Virtual reaction Half off-shell (astrophysical process) Measured at high energy Calculated Deduced Need direct data for normalization ✚ 7 α

BEAM PRODUCTION 18 O MeV/A from AVF cyclotron gas target 2 H Double-achromatic magnetic separator 18 O(p,n) 18 F Scattering chamber Nucleus-Nucleus 2012San Antonio (TX) 8

Test fascio YearBTU type Prod.Target type Peak intensity 2006Beam devRoom temp.~ Thick target experiment Liquid N cooled5x Trojan Horse experiment Liquid N cooled> 10 6 Primary beam: 18 O 8+, MeVA Production target: H 2 Production reaction: 18 O(p,n) 18 F 18 F beam development BEAM PURITY > 98% E beam = 48.7 MeV  = 0.8 MeV Nucleus-Nucleus 2012San Antonio (TX) 9

188  g/cm 2 PPAC MCP CD2 2 TARGET DPSSD array Frontviewof DPSSDarray DSSSD  0.5 m  15 cm  28.7 cm Safety disk 2.4  10 6 pps MeV m EXPERIMENTAL SETUP (other than CRIB.....) ASTRHO: Array of Silicons for TRojan HOrse Nucleus-Nucleus 2012San Antonio (TX) 10

In order to allow for the optimization of the two experiments ASTRHO and the DSSSD were hosted in a mechanical system that allowed for easy movement of the detector holder plates Experimental setup 2 EXPERIMENTAL SETUP Nucleus-Nucleus 2012San Antonio (TX) 11

Experimental setup 3 How ASTRHO looks like in reality (before PPAC explosion...) EXPERIMENTAL SETUP Nucleus-Nucleus 2012San Antonio (TX) 12

BEAM TRACKER PPAC target MCP Beam track reconstruction event by event z x  mm y 11 22 DPSSD DSSiSD Nucleus-Nucleus 2012San Antonio (TX) 13

CUTS: Event multiplicity = 2 E1 > 20 MeV Q-VALUE SPECTRUM 18 F+d  15 N+  +p q = MeV 18 F+d  18 O+p+p q = MeV 18 F+d  18 F+p+n q = MeV Nucleus-Nucleus 2012San Antonio (TX) F+d  15 O+  +n q = MeV

EVENT SELECTION Red : 18 F + d  15 N +  + p Black: 18 F + d  15 O +  + n Blue: 18 F + d  18 F + p + n Green: 18 F + d  18 O + p + p “1”+“2”+“3” Nucleus-Nucleus 2012San Antonio (TX) 15

Correlation E 13 - E 12 Correlation E 1 -  1 Correlation E 13 - E 12 Correlation E 1 -  1 Q-VALUE SPECTRUM CUTS: Event multiplicity = 2 E1 > 20 MeV GOOD AGREEMENT with  q-value expected position (0.658 MeV)  and beam profile (exp. Sigma 0.8 MeV) Nucleus-Nucleus 2012San Antonio (TX) 16

HINTS FOR QF MECHANISM If the quasi-free mechanism is predominant N Hulten function Minumum of p s Nucleus-Nucleus 2012San Antonio (TX) 17

BARE NUCLEUS CROSS SECTION 38 keV Nucleus-Nucleus 2012San Antonio (TX) 18

 THM was successfully applied to radioactive ion beam induced reaction  the beam is tracked event by event and the kinematical variables were consequently reconstructed  the preliminary results showed the possibility to study the cross section of the 18 F(p,  ) 15 O reaction and extract complementary information on S(E) factor  (work in progress)  To do: Increase statistics and confirm the results with a second experimental run  Explore the possibility to measure the 18 F(n,  ) 15 N reaction Conclusions and Perspective Nucleus-Nucleus 2012San Antonio (TX) 19

S. Cherubini, M. Gulino, M. La Cognata, L. Lamia, G. G. Rapisarda, C. Spitaleri, S. Kubono, H. Yamaguchi, S. Hayakawa, Y. Wakabayashi,‡, N. Iwasa§, S. Kato ¶, H. Komatsubara k, T. Teranishi ††, A.Coc‡‡, N. De Séréville§§ and F. Hammache§§ Dipartimento di Fisica ed Astronomia, Università di Catania and INFN-LNS, Catania, Italy †INFN-LNS, Catania, Italy and UniKORE, Enna, Italy Center for Nuclear Study, The University of Tokyo, Japan ‡Present address KEK, Japan §Department of Physics, Tohoku University, Sendai, Japan ¶Department of Physics, Yamagata University, Yamagata, Japan kDepartment of Physics, Tsukuba University, Tsukuba, Japan ††Department of Physics, Kyushu University, Fukuoka, Japan ‡‡Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, IN2P3, F Orsay, France §§Institut de Physique Nucléaire, IN2P3, F Orsay, France 20 Nucleus-Nucleus 2012San Antonio (TX) THANK YOU FOR YOUR ATTENTION ! THANK YOU TO ALL THE COLLABORATION !

BARE NUCLEUS CROSS SECTION Nucleus-Nucleus 2012San Antonio (TX) 21

Trojan Horse for Resonance Reactions HALF OFF-SHELL ON-SHELL PENETRABILITY 22

BEAM position on PPAC and MCP 23

CUTS 24

State of Art Many experiments performed using 18F ARGONNE - ATLAS LLN ORNL TRIUMF GANIL- SPIRAL RIKEN – CRIB TAMU Direct measurements  thick target method Indirect measurement  (d,p) (d,n) stripping reaction Most recent references: D. J. Mountford et al PHYSICAL REVIEW C 85, (R) (2012) “Resonances in 19Ne with relevance to the astrophysically important 18F( p,α)15O reaction.” A. S. Adekola et al. PHYSICAL REVIEW C 83, (R) (2011) “First proton-transfer study of 18F + p resonances relevant for novae” C. E. Beer et al. PHYSICAL REVIEW C 83, (R) (2011) “Direct measurement of the 18F( p,α)15O reaction at nova temperatures” Nucleus-Nucleus 2012San Antonio (TX) 25

Summary  Astrophysical motivations & State of Art  Indirect measurement by Trojan Horse Method  Experimental set-up  new apparatus for RIB application  Data Analysis and preliminary results Nucleus-Nucleus 2012San Antonio (TX) 26

“Plus” of the TH methods 1)Typical QF process cross sections (mbarn/sr) though measuring astrophysical ones 2)The TH cross sections is the purely NUCLEAR one: no Coulomb barrier effects 3)No electron screening effects: an INDEPENDENT piece of information can be obtained on the electron screening potential Ue by comparison to direct data 4)Can be extended to use QFR for studying NEUTRON induced reactions (VNM Virtual Neutron Method) “Minus” of the TH methods 1) Competition between QF and other reaction mechanisms: identification of the convenient kinematical conditions may need more than one experiment run 2) Some dependence on theoretical models 3) Need of direct data at higher energies for normalization S. Cherubini et al., ApJ 457 (1996)