1. October 23, 2006HRIBF Workshop, ORNL1/11 First Experimental Constraints on the interference of 3/2 + resonances in the 18 F(p,  ) 15 O reaction Kyung Yuk Chae University of Tennessee, Knoxville / ORNL

2. October 23, 2006HRIBF Workshop, ORNL2/11 18 F 18 F(p,  ) 15 O reaction 511 keV (and below) 17 O(p,  ) 17 F(p,  ) 18 Ne(e + e ) 18 F (p,  ) 15 O (p,  ) 19 Ne  ~ 2hrs, large production rate Important positron annihilation source INTEGRAL

3. October 23, 2006HRIBF Workshop, ORNL3/11 Previous Studies [Cos95, Reh96, Utk98, Bar00, Gra00, Bar01, Bar02, Bar04, deS05, Koz05] - (p,p) and (p,  ) reactions with stable and exotic beams - No study on interference effects among lower-lying 3/2 + resonances Séréville et. al. Measuring cross sections off resonance is required

4. October 23, 2006HRIBF Workshop, ORNL4/11 Experimental Setup - ~10 5 18 F/sec, 18 F/ 18 O ~0.04 - 70  g/cm 2 CH 2 - Energy steps of 1 MeV (E lab ) 29 o ≤  lab ≤ 73 o (SIDAR) 11.5 o ≤  lab ≤ 22.5 o (MINI) SIDAR MINI

5. October 23, 2006HRIBF Workshop, ORNL5/11 Particle Identification I Heavy Recoil Energy (arbitrary)  Energy (arbitrary) 18 O(p,  ) 15 N 18 F(p,  ) 15 O

6. October 23, 2006HRIBF Workshop, ORNL6/11 Particle Identification II Total Energy (arbitrary) SIDAR strip number 18 F/ 18 O 18 O 18 O(p,  ) 15 N 18 F(p,  ) 15 O Background

7. October 23, 2006HRIBF Workshop, ORNL7/11 Differential Cross Section E c.m. (keV)d  /d  mb/sr) 66338.3 ± 5.6 7178.4 ± 1.5 8771.7 ± 0.5 cross section E c.m. (keV)d  /d  mb/sr) 77017.3 8244.4 upper limit Christensen et. al.

8. October 23, 2006HRIBF Workshop, ORNL8/11 Results J  = 3/2 + levels : 8-, 38-, and 665-keV (eight possibilities) First experimental constraints on the interference Phys. Rev. C 74 012802(R) 4 out of 8 possibilities are ruled-out

9. October 23, 2006HRIBF Workshop, ORNL9/11 S-factors & Reaction Rates Measurements of the cross section between 330- and 665 keV uncertainty is reduced by up to 37% in nova temp.

10. October 23, 2006HRIBF Workshop, ORNL10/11 Conclusion - element synthesis calculations (Computational Infrastructure for Nuclear Astrophysics) - 169 isotopes up to 54 Cr - REACLIB database - 1.35 M sun ONeMg white dwarf - 28 zones Factor of 2 variation in 18 F abundance

11. October 23, 2006HRIBF Workshop, ORNL11/11 Thank You UTK/ORNL ORNL TTU ORAU CSM Rutgers K.Y. Chae, M.W. Gudiry, Z. Ma, C.D. Nesaraja D.W. Bardayan, J.C. Blackmon, M.S. Smith D. Gregory, R.L. Kozub, S. Paulauskas, J.F. Shriner Jr., N. Smith M.S. Johnson R.J. Livesay, M. Porter-Peden S.D. Pain, J.S. Thomas

12. 12 Appendix

13. October 23, 2006HRIBF Workshop, ORNL13/11 Novae &  -ray Nova Cygni 1992 model 511 keV line & continuum - Isotopic abundances - Expanding shell properties - Galactic distribution of novae - Mixing/Convection mechanisms - Abundant - Not absorbed

14. October 23, 2006HRIBF Workshop, ORNL14/11 18 F in novae Hot CNO cycle: 12 C(p,  ) 13 N(p,  ) 14 O(e + e ) 14 N(p,  ) 15 O(e + e ) 15 N(p,  ) 12 C T ~ 10 8 K 14 O( ,p) 17 F(p,  ) 18 Ne(e + e ) 18 F 16 O(p,  ) 17 F(p,  ) 18 Ne(e + e ) 18 F At higher temperatures OR cf. CNO cycle:

15. October 23, 2006HRIBF Workshop, ORNL15/11 Beam Production & Delivery

16. October 23, 2006HRIBF Workshop, ORNL16/11 Beam Current 18 O 18 F  E (channel) E (channel) counts E (channel) Ion Counter MINI elastic 18 F+ 18 O

17. October 23, 2006HRIBF Workshop, ORNL17/11 Resonance Parameters

18. October 23, 2006HRIBF Workshop, ORNL18/11 Summary 1 H( 18 F,  ) 15 O cross section measurements (E c.m. =663-887 keV) at ORNL HRIBF 1 H( 18 O,  ) 15 N measurements 4 out of 8 possibilities are ruled-out First experimental constraints on the interference effects Uncertainty in the reaction rate at nova temperature is reduced by up to 37% Element synthesis calculations (a factor of 2 variation in the amount of 18 F)