1. Absolute resonance strength measurements of the 22 Na(p,  ) reaction Chris Wrede Center for Experimental Nuclear Physics and Astrophysics University of Washington CAWONAPS TRIUMF, Vancouver, BC, Canada December 10 th, 2010

2. Outline Nucleosynthesis in ONe novae 22 Na as a potentially detectable cosmic  - ray emitter 22 Na(p,  ) 23 Mg background information 22 Na(p,  ) 23 Mg experiment 22 Na(p,  ) 23 Mg results 22 Na production in novae Conclusions

3. Classical novae Binary system: white-dwarf (WD) star accreting H from main-sequence star Slow accretion rate leads to electron-degenerate layer of H mixed with WD surface Temperature increases at constant pressure as hydrogen accreted At T ~ several MK, CNO hydrogen burning ignites thermonuclear runaway at surface Degeneracy lifted  expansion & ejection of envelope

4. Classical novae Rise time < 1 to 2 days E ~ 10 45 ergs L ~ 10 4 to 10 5 solar luminosities 10 -5 to 10 -4 solar masses ejected in 100-1000 s Peak temperatures up to 0.4 GK for ONe novae Can be recurrent (t ~10 to 100 ky) Galactic nova rate ~ 30 yr -1 (~5 yr -1 observed)

5. Nucleosynthesis in ONe novae Figure from J. Jose

6. Galactic 22 Na 22 Na (t 1/2 = 2.6 y) never observed from novae Observational upper limit of 2.7 x 10 -8 M solar of 22 Na from any ONe nova (COMPTEL, 1995) Hydrodynamic nova-model predictions of Jose and Hernanz (Barcelona, 1999) and Bishop et al. (TRIUMF, 2003) roughly one order of magnitude lower Currently searched for with INTEGRAL-SPI Iyudin et al., Astron. Astrophys. 300, 422 (2006) Jose and Hernanz, Astrophys. J., 520, 347 (1999) Bishop et al., Phys. Rev. Lett. 90, 162501 (2003)

7. Thermonuclear reaction rates for narrow, isolated (p,  ) resonances

8. 22 Na destruction via 22 Na(p,  ) 23 Mg Figure adapted from Jose and Hernanz, Ap.J. 520, 347 (1999)

9. 22 Na(p,  ) 23 Mg history Goerres et al. searched for resonances (Caltech, 1989) Seuthe et al. measured energies and strengths of resonances down to 288 keV (Bochum, 1990) Stegmueller et al. measured energy and strength of new resonance at 214 keV (Bochum, 1996) Goerres et al., Phys. Rev. C 39, 8 (1989) Seuthe et al., Nucl. Phys. A514, 471 (1990) Stegmueller et al., Nucl. Phys. A601, 168 (1996)

10. New resonance? Jenkins et al. measured 12 C( 12 C,n  ) 23 Mg (ANL, 2004) Discovered new 23 Mg level at E x = 7769 keV (E r = 198 keV) Strength of up to 4 meV Claim it could dominate 22 Na(p,  ) 23 Mg rate Need to measure 22 Na(p,  ) 23 Mg directly at 198 keV! Jenkins et al., Phys. Rev. Lett. 92, 031101 (2004)

11. 22 Na(p,  ) 23 Mg experiment proposal Caggiano et al. (TRIUMF, 2005) Search for 198-keV resonance Re-measure known 22 Na(p,  ) 23 Mg resonances Ion-implanted 22 Na targets from TRIUMF Test with 23 Na targets Measure 22 Na(p,  ) 23 Mg somewhere with intense low- energy proton beam: CENPA @ U. Washington Ph.D. thesis work of Anne Sallaska (University of Washington) Caggiano et al., TRIUMF Research Proposal (2005)

12. 22 Na targets Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted) Brown et al., NIM B 267, 3302 (2009)

13. 22 Na targets Based on 22,23 Na tests OFHC Cu substrate 30-keV 22 Na + beam 10-nA 22 Na + beam 22 Na beam rastered over 5-mm diameter collimator Two 300-  Ci targets Evaporated Cr layer Brown et al., NIM B 267, 3302 (2009) Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

14. 22 Na(p,  ) 23 Mg Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

15. 22 Na(p,  ) 23 Mg @ CENPA 22 Na target on water-cooled mount Proton beam magnetically rastered over target 2 HPGe’s at ±55 o 26 mm of Pb shielding to reduce 22 Na radiation Annular scintillator for cosmic-ray anticoincidence Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

16. Proton-beam density,  beam Measured 27 Al(p,  ) 28 Si Two thick Al targets -extended target -5-mm “coin” target Two energies Supplemented by Monte Carlo Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

17. Number of 22 Na target atoms, N T N T from in-situ measurement of 22 Na activity 22 Na target degradation minimal thanks to Cr coating Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

18. 22 Na(p,  ) 23 Mg efficiency 60 Co, 24 Na sources + 27 Al(p,  ) + PENELOPE Monte Carlo Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

19. 22 Na(p,  ) 23 Mg data Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

20. 22 Na(p,  ) 23 Mg results Resonance energies in good agreement with previous work Resonance strengths 2.4 to 3.2 times higher! Good limit for 198-keV resonance Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

21. Verification: 23 Na(p,  ) 24 Mg measurement Strength of 91.3 +/- 12.5 meV for 512-keV 23 Na(p,  ) resonance is a recommended standard Using an implanted 23 Na target, we measured the strength of this resonance to be 79 +/- 17 meV Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted) Iliadis et al. Ap.J.S.S. 134, 151 (2001)

22. 22 Na(p,  ) 23 Mg rate Re-evaluated thermonuclear 22 Na(p,  ) 23 Mg reaction rate Energies and strengths primarily from present work Monte-Carlo method to determine uncertainties Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted) Schmidt et al., Nucl. Phys. A521, 227 (1995)

23. 22 Na production in ONe novae Production of 22 Na reduced by factors of 1.5 to 2.0 in hydrodynamic models of ONe novae Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted) WD mass 22 Na (previous) 22 Na (present)factor 1.15 M solar 1.6 x 10 -4 M solar 7.8 x10 -5 M solar 2.0 1.25 M solar 1.9 x 10 -4 M solar 1.0 x10 -4 M solar 1.9 1.35 M solar 5.9 x 10 -4 M solar 3.8 x10 -4 M solar 1.5

24. 22 Na(p,  ) 23 Mg conclusions 198-keV resonance proposed by Jenkins et al. (ANL, 2004) does not dominate 213-keV and 288-keV resonances still dominate and are ~3x stronger than previously thought 22 Na production in ONe-nova models reduced by factors of 1.5 to 2.0 Sallaska et al., Phys. Rev. Lett. 105, 152501 (2010) Sallaska et al., Phys. Rev. C (submitted)

25. Thank You!

26. Papers and collaborations 1 CENPA, University of Washington, Seattle, Washington, USA 2 TRIUMF, Vancouver, British Columbia, Canada Properties of 23 Na implanted targets, NIM B 267, 3302 (2009) T.A.D. Brown, 1 K. Deryckx, 1 A. Garcia, 1 A. L. Sallaska, 1 K. A. Snover, 1 D. W. Storm, 1 C. Wrede 1 Direct measurements of 22 Na(p,  ) resonances and consequences for 22 Na production in classical novae, PRL 105, 152501 (2010) A. L. Sallaska, 1 C. Wrede, 1 A. Garcia, 1 D. W. Storm, 1 T. A. D. Brown, 1 C. Ruiz, 2 K. Snover, 1 D. F. Ottewell, 2 L. Buchmann, 2 C. Vockenhuber, 2 D. A. Hutcheon, 2 J. A. Caggiano 2 Absolute determination of the 22 Na(p,  ) reaction rate in novae, PRC (submitted) A. L. Sallaska, 1 C. Wrede, 1 A. Garcia, 1 D. W. Storm, 1 T. A. D. Brown, 1 C. Ruiz, 2 K. Snover, 1 D. F. Ottewell, 2 L. Buchmann, 2 C. Vockenhuber, 2 D. A. Hutcheon, 2 J. A. Caggiano 2 Ph.D thesis, University of Washington (defended December 6th, 2010) A. L. Sallaska, 1

27. 22 Na(p,  ) 23 Mg systematics

28. PDFs for upper limits

29. More excitation functions