b delayed g decay measurements to probe thermonuclear astrophysical explosions Chris Wrede Michigan State University and NSCL for the NSCL E10034, E12028 & E14066 collaborations NIC XIII, Debrecen, Hungary July 9 th, 2014
Outline Nova contribution to Galactic 26 Al? Exp t 1: b-g decay of 26 P to probe 25 Al(p,g) 26 Si Are pre-solar nova grains from novae? Exp t 2: b-g decay of 31 Cl to probe 30 P(p,g) 31 S Conditions for CNO-cycle breakout in type I x-ray bursts? Exp t 3: b-g decay of 20 Mg to probe 15 O(a,g) 19 Ne C. Wrede - Slide 2
Radioactive 26 Al across Milky Way Data from COMPTEL & INTEGRAL-SPI Figure credit: MPE Garching / Roland Diehl C. Wrede - Slide 3
Classical novae Nova Cygni 1992 (in 1994) NASA, ESA, HST S. Starrfield et al., (1971, 1972) J. Jose et al., Nucl. Phys A777, 550 (2006) C. Wrede - Slide 4
Nucleosynthesis in ONe novae J. Jose, Proc. Sci., NIC XI 050 (2011) C. Wrede - Slide 5
25 Al(p,g) 26 Si reaction in novae Largest nuclear-physics uncertainty affecting 26 Al production Dominated by a J p = 3 +, ~412 kev resonance Need resonance strength... J. Jose et al., Astrophys. J. 520, 347 (1999); J.-C. Thomas et al., Eur. Phys. J. A 21, 419 (2004); D. W. Bardayan et al., Phys. Rev. C 74 045804 (2006); C. Wrede, Phys. Rev. C 79, 035803 (2009); K. Chipps et al., Phys. Rev. C 82, 045803 (2010); W. A. Richter et al., Phys. Rev. C 83, 065803 (2011) C. Wrede - Slide 6
Measuring key 3 + 25 Al(p,g) 26 Si resonance strength with 26 P decay g = (2J tgt (2Jr 1) 1)(2J p 1) G G p p G g G g Know J x and G p Measure G g /G p M. B. Bennett et al., Phys. Rev. Lett. 111, 232503 (2013) C. Wrede et al., approved NSCL PAC35 proposal E10034 J.-C. Thomas et al., Eur. Phys. J. A 21, 419 (2004) P. N Peplowski et al., Phys.Rev. C 79, 032801(R) (2009) C. Wrede - Slide 7
Pre-solar nova grain candidates Andrew M. Davis, Proc. Nat. Acad. Sci. U. S. A. 108, 19142 (2011) C. Wrede - Slide 8
Pre-solar nova grain candidates Andrew M. Davis, Proc. Nat. Acad. Sci. U. S. A. 108, 19142 (2011) C. Wrede - Slide 9
What should a SiC nova grain look like? Near solar 29 Si/ 28 Si High 30 Si/ 28 Si (?) depends strongly on 30 P(p,g) 31 S reaction rate J. Jose et al. Astrophys. J. 612, 414 (2004) C. Wrede - Slide 10
Status of 30 P(p,g) 31 S reaction rate Many (~10) indirect experiments: E r known but g unknown g = (2J tgt (2Jr 1) 1)(2J 1) NIC XIII satellite workshop Classical Novae in the Cosmos (July 5-6, 2014 at ATOMKI) aims to evaluate 30 P(p,g) 31 S reaction rate & quantify uncertainty in special issue of Eur. Phys. J. Plus p G G p p G g G g More experiments needed to reduce uncertainty C. Wrede, AIP Advances 4, 041004 (2014) C. Wrede - Slide 11
Populating L = 0 30 P(p,g) 31 S resonances with 31 Cl decay M. B. Bennett, Ph.D. thesis (in progress) C. Wrede et al., approved NSCL PAC37 proposal E12028 A. Kankainen, Eur. Phys. J. 27, 67 (2006) B. A. Brown, W. A. Richter, C. Wrede, Phys. Rev. C 89, 062801 (2014) C. Wrede - Slide 12
Production of 31 Cl at NSCL 150 MeV/u, 75 pna 36 Ar beam, 1.6 mg/cm 2 Be target Nearly 100% pure beam of >6,000 31 Cl ions per second M. B. Bennett, Ph.D. thesis (in progress) C. Wrede et al., approved NSCL PAC37 proposal E12028 C. Wrede - Slide 13
CloverShare HPGe array M. B. Bennett, Ph.D. thesis (in progress) C. Wrede et al., approved NSCL PAC37 proposal E12028 C. Wrede - Slide 14
31 Cl(b g): 4% of statistics (preliminary) M. B. Bennett, Ph.D. thesis (in progress) C. Wrede et al., approved NSCL PAC37 proposal E12028 C. Wrede - Slide 15
b decay of 20 Mg to probe 15 O(a,g) 19 Ne B. Glassman, Ph.D. thesis (in progress) C. Wrede et al., approved NSCL PAC38 proposal E14066 Decay scheme modified from TUNL A=20 evaluation Piechaczek et al., Nucl. Phys. A 594, 509 (1995) C. Wrede - Slide 16
Summary Experiment E10034: 26 P b-g decay experiment to constrain 26 Al production in novae via 25 Al(p,g) 26 Si reaction rate (published 2013) Experiment E12028: 31 Cl b-g decay experiment to help ID of candidate pre-solar nova grains via 30 P(p,g) 31 S reaction rate (ran 2014) Experiment E14066: 20 Mg b-p-g decay to investigate CNO-cycle break out via in type I x-ray bursts (upcoming run 2015) C. Wrede - Slide 17
Thank you for your attention! Collaborating institutions: Colorado School of Mines Joint Institute for Nuclear Astrophysics McMaster University Michigan State University National Superconducting Cyclotron Laboratory University of Notre Dame Oak Ridge National Laboratory Universitat Politècnica de Catalunya University of Southern Indiana University of Tennessee Texas A&M University University of Washington Yale University Special acknowledgments, in particular, to: Mike Bennett (MSU/NSCL), Sean Liddick (MSU/NSCL) C. Wrede - Slide 18