I NSTITUTE FOR S TRUCTURE AND N UCLEAR A STROPHYSICS N UCLEAR S CIENCE L ABORATORY. Direct reaction measurements of astrophysical.

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1 I NSTITUTE FOR S TRUCTURE AND N UCLEAR A STROPHYSICS N UCLEAR S CIENCE L ABORATORY Direct reaction measurements of astrophysical interest using the JENSA gas jet target Dan Bardayan

2 I NSTITUTE FOR S TRUCTURE AND N UCLEAR A STROPHYSICS N UCLEAR S CIENCE L ABORATORY Nova Explosions Very common. ~30/year in the Milky Way Galaxy. Most are first observed by amateur astronomers. Still many open questions [How much mass ejected?, How much contribute to 26 Al?, Is there a relationship to Type Ia Supernovae (standard candles)?, etc ] Nova Cygni 1975

3 Incredible I NSTITUTE Advances FOR in Novae S TRUCTURE Observations AND N UCLEAR and Simulations A STROPHYSICS N UCLEAR S CIENCE L ABORATORY S. Mohamed et al., Proc. Int. Astron. Union 7, 195 (2013)

4 Institute for Structure and Nuclear Astrophysics Nuclear Science Laboratory Accretion driven phenomena

5 ReA3 Beams of Astrophysical Interest Nova Nucleosynthesis Good overlap between ReA3 beams and exotic nuclei produced in novae Not yet intense enough to measure proton-capture rates directly Need a localized gas target to study transfer reactions such ( 3 He,d), (d,p), etc. reactions on these beams ReA3

6 17 F(p, ) 18 Ne I NSTITUTE FOR S TRUCTURE AND N UCLEAR A STROPHYSICS N UCLEAR S CIENCE L ABORATORY 17 F(p, ) 18 Ne strongly affected by unmeasured DC rate Nova temperatures 3 + (mb) DC unmeasured strength from ORNL measurement Direct capt ure Total E (kev) Need C 2 S to calculate DC rate. Can use the 17 F( 3 He,d) reaction to measure the needed spectroscopic strengths.

7 JENSA Measurements at ReA3 17 F(p, ) 18 Ne strongly affected by unmeasured DC rate Nova temperatures 3 + DC can be determined from spectroscopic study of 17 F( 3 He,d) 18 Ne. (mb) DC unmeasured strength from ORNL measurement Direct capt ure Total E (kev) Monte Carlo simulation of 17 F( 3 He,d) 18 Ne with JENSA and SuperORRUBA Must measure the energy and angular distribution of reaction ejectiles. Need combination of a localized gas target + highly-efficient granular silicon array. Jet Experiments in Nuclear Structure and Astrophysics (Colorado School of Mines, ORNL, ND, LSU, NSCL, JINA, UT, etc )

8 gas receiver large-area Si detector array HRIBF beam DRS turbo turbo turbo turbo turbo turbo high pressure laval nozzle (~75 m 3 /hr at STP)

9 JENSA Constructed at ORNL ~100 m 3 /h gas flow handled by combination of roots blowers, turbo pumps, and multistage dry pumps. Final compression performed by industrial compressor. beam jet Targets densities of atoms/cm 2 = factor of 10 greater than previous targets achieved.

10 Initial JENSA tests Nitrogen gas Energy 244 Cm source 1-Dimensional Position Sensitive ORRUBA (Oak Ridge Rutgers University Barrel Array) Nitrogen Gas Counts Position 80 kev Energy Loss ~5 x N/cm 2 Energy

11 Initial JENSA tests Helium gas Inlet P=200 psi Inlet P=300 psi Inlet P=400 psi Energy loss indicates design goal met of He/cm 2 FWHM was about 4 5 mm at the jet depending on the nozzle size. Figures submitted to NIM

12 20 Ne(p,d) 19 Ne To Determine Spins of Astrophyiscally important 19 Ne levels 30 MeV protons from the Holifield Tandem 20 Ne target SIDAR Silicon Detector Array E 1 E 1 + E 2

13 Implanted 20 Ne target made things difficult P. D. O Malley, Ph. D. Thesis, Rutgers University (2011) ~5 g/cm 220 Ne in 20 g/cm 2 C foil

14 Deuteron Energy Spectrum Natural Neon Gas 3x10 18 atoms/cm mm wide 3 na of 30 MeV 1 H h shifts Counts 6290 kev 2792 kev kev g.s degrees Energy (5 kev/channel) Expected deuteron energies to populate known 19 Ne states Data taken August 2013 still under analysis.

15 Experiments at Oak Ridge 20 Ne(p,d) 19 Ne for 18 F(p, ) 15 O 20 Ne(p,t) 18 Ne 20 Ne(p,t) 18 Ne for 14 O(,p) 17 F Paul Thompson (UTK) 14 N(p,t) 12 N Kelly Chipps (ORNL) 4 He( 15 N, ) 15 N for 15 N( ) 19 F Antonios Kontos (NSCL)

16 After construction of JENSA at ORNL, it was moved to the new reaccelerated beam facility (ReA3) at Michigan State University

17 JENSA now installed at ReA3

18 3 mm 4 mm

19 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

20 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

21 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

22 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

23 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

24 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

25 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

26 6.00E E+11 Proton Yield (arb. units) 4.00E E E E E Steerer Current (A)

27 Possibilities to combine JENSA with Hagrid and VANDLE Use HAGRID array to measure -rays after transfer reactions [e.g., ( 3 He,d ),(d,p ), etc ] Use VANDLE array to measure neutrons from reactions such as ( 3 He,n) and (,n). Neutron energies determined via time of flight.

28 While we are putting much effort into advanced exotic beam facilities, we cannot neglect the target development that is crucial to their success. We have developed (the highest density) gas jet target JENSA for use at exotic beam facilities. First experiments were performed at ORNL, and it is now installed at NSCL. Near term future will be to study transfer reactions. Ultimately, will be target of (p, ) studies on exotic beams at FRIB. Enjoying the partnership with the NNSA Center of Excellence to push the boundaries of exotic beam physics.

29 Acknowledgements Some of The JENSA Collaboration: K.A. Chipps (ORNL/UTK, formerly CSM), U. Greife (CSM), D.W. Bardayan (ND, formerly ORNL), J.C. Blackmon (LSU), A. Kontos (MSU/NSCL/JINA), L.E. Linhardt (LSU), M. Matos (IAEA, formerly ORNL/UTK), S.D. Pain (ORNL), S.T. Pittman (LSU, formerly UTK), H. Schatz (MSU/NSCL), K.T. Schmitt (ORTEC, formerly UTK), M.S. Smith (ORNL), F. Montes (MSU/NSCL), J. Browne (MSU/NSCL), Z. Meisel (MSU/NSCL), P. D. O Malley (ND) Also: K. Jones (UTK), T. Ahn (MSU/NSCL, formerly ORNL/UTK), B. Manning (Rutgers) and Bill Peters (ORNL)

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