Hope College Department of Physics and Engineering
Research Experiences for Undergraduates
Summer 2004
Project Summary

 

Title : Investigating 6He Decay modes in the Reaction of 6He+209Bi near the Coulomb Barrier.
Name: Patrick J. Mears
Home Institution: Hope College
Research Advisor(s): Dr. P. A. DeYoung, Dr. G. F. Peaslee
Source of Support: NSF-RUI

The reaction of 6He+209Bi near the Coulomb barrier was studied to learn more about the properties of 6He, a rare Borromean nucleus. Recent studies found that the alpha- particle cross section in this reaction is higher than expected . The goal of this experiment was to gain insight into the significance of the three possible breakup modes of 6He; one-neutron transfer, two-neutron transfer and direct breakup. Previous work done by Hope student Joe Bychowski indicated that 20% of the total alpha cross section was due to one-neutron transfer.

A 23 MeV beam of 6He was created at Notre Dame's Nuclear Structure Lab, and then directed towards a thin 209Bi target, utilizing the TwinSol system. Neutrons created in the reaction were detected at angles ranging from 32-57 degrees relative to the 6He beam. Alpha particles were detected at +-90 and 120 degrees. Data was collected and analyzed using an Interactive Data Language program that was written by Hope College student Ben Hilldore.

Twice as many n-alpha coincidences were detected when neutrons and alphas at 90 degrees were on the same side as compared to alphas on the opposite side from the neutrons. A similar number of coincidence events were measured when alphas were detected at 120 degrees on the opposite side from the neutrons. These results indicate that two-neutron transfer is significant, since coincidence events on opposite sides must come from two-neutron transfer. They also indicate that breakup is significant because there are clearly more neutrons on the same side as the alphas. Current calculations indicate that 2-n transfer is responsible for 55 + 12% of the total alpha cross section at the “grazing peak.” More work is being done to understand what is happening at the forward angles.

E.F. Augilera, et. al ., Phys Rev. Lett. 84 ,5058 (200)
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Publications and Presentations:
“Comparison of Glass Fragments Using Particle Induced X-Ray Emission (PIXE) Spectrometry.” P.A. DeYoung, P.J. Mears*, C.C. Hall*, D.J. Padilla*, R.A. Sampson*, and G.F. Peaslee. Scheduled for publication in the Journal of Forensic Sciences, (2011).
“Forensic Analysis of Tempered Sheet Glass by Particle Induced X Ray Emission (PIXE)” L. J. Jisonna, P. A. DeYoung, J. Ferens*, C. Hall*, J. M. Lunderberg*, P. Mears*, D. Padilla*, G. F. Peaslee, and R. Sampson*. Nucl. Instr. And Meth. B, Nucl. Instr. And Meth. B (2011)
“Hindrance of Complete Fusion in the 8Li+208Pb System at Above-Barrier Energies.” E.F. Aguilera, E. Martinez-Quiroz, P. Rosales, J.J. Kolata, P.A. DeYoung, P.J. Mears*, C. Guess*, F.D. Becchetti, J.H. Lupton, and Yu Chen. Phys. Rev. C 80, 044605 (2009).
“Proton-halo effects in the 8B+58Ni reaction near the Coulomb barrier.” E.F. Aguilera, E. Martinez-Quiroz, P. Rosales, D. Lizcano, A. Gomez-Camacho, J.J. Kolata, L.O. Lamm, V. Guimaraes, R. Lichtenthaler, O. Camargo, F.D. Becchtti, H. Jing, P.A. DeYoung, P.J. Mears*, and T.L. Belyaeva. Revista Mexicana de Fisica 55, 1 (2009).
“Reaction Cross Sections for 8B, 7Be, and 6Li+58Ni Near the Coulomb Barrier: Proton-halo Effects.” E.F. Aguilera, E. Martinez-Quiroz, D. Lizcano, A. Gomez-Camacho, J.J. Kolata, L.O. Lamm, V. Guimaraes, R. Lichtenthaler, O. Camargo, F.D. Becchetti, H. Jiang, P.A. DeYoung, P,.J. Mears*, and T.L. Belyaeva. Phys. Rev. C 79, 021601(R) (2009).
“Development of an Ion Beam Analysis Method for Forensic Analysis of Glass.” Richard Sampson*, Graham F. Peaslee, Paul A. DeYoung, Christopher Hall*, Derek Padilla*, and Patrick Mears*. American Academy of Forensic Sciences 2008 Annual Meeting, Washington D.C. 2008.
“Neutron-Decay Spectroscopy of Neutron-Rich Oxygen Isotopes.” M.Thoennessen, C.R. Hoffman, T. Baumann, D. Bazin, J. Brown, G. Christian, P.A. DeYoung, J.E. Finck, N. Frank, J. Hinnefeld, R.Howes, P. Mears*, E.Mosby, S. Mosby, J. Reith*, B. Rizzo*, W.F. Rogers, G. Peaslee, W.A. Peters, A. Schiller, M.J. Scott, S.L. Tabor, P.J. Voss, and T. Williams. ENAM08, book of abstracts page 30, (2008).
“Elastic Scattering of a Proton-Halo Nucleus: 8B+58Ni.” E.F. Aguilera, E. Martinez-Quiroz, P. Rosales, D. Lizcano, A. Gomez-Comacho, J.J. Kolata, L.O. Lamm, V. Guimaraes, R. Lichtenthaler, O. Camargo, F.D. Becchetti, H. Jiang, P.A. DeYoung, and P.J. Mears*. Revista Mexicana de Fisica 54, 1 (2008).
“Determination of the N = 16 shell closure at the oxygen drip line.” C.R. Hoffman, T. Baumann, D. Bazin, J. Brown, G. Christian, P.A. DeYoung, J.E. Finck, N. Frank, J. Hinnefeld, R. Howes, P. Mears*, E. Mosby*, S. Mosby*, J. Reith*, B. Rizzo*, W.F. Rogers, G. Peaslee, W.A. Peters, A. Schiller, M.J. Scott*, S.L. Tabor, M. Thoennessen, P.J. Voss*, and T. Williams. Phys. Rev. Lett. 100, 152502 (2008).
“Breakup of 6He Incident on 209Bi near the Coulomb Barrier.” J.J. Kolata, H. Amro, F.D. Becchetti, J.A. Brown, P.A. DeYoung, M. Hencheck, J.D. Hinnefeld, G.F. Peaslee, A.S. Fritsch, C. Hall*, U. Khadka*, Patrick J. Mears*, P. O’Rourke, D. Padilla*, J. Reith*, Tabatha Spencer, and T. Williams. Phys. Rev. C 75, 031302 (2007).
7Be-Induced alpha-Transfer Reaction on 12C.” H. Amro, F.D. Becchetti, Yu Chen, Hao Jiang, M. Ojaruega, M.J. Golobish, H.C. Griffin, J.J. Kolata, B. Skorodumov, G. Peaslee, P.A. DeYoung, P. Mears*, D. Denby*, J. Brown, J.D. Hinnefeld, and A.M. Moro. Euro. Phys. Jour. 150, 1 (2007).
“Elastic Scattering of for the System 7Be+58Ni at Energies Near the coulomb Barrier.” D. Lizcano, EF. Aguilera, H. Garcia0-Martinez, E. Martinez-Quiroz, J.J. Kolata, H.A. Amro, L.O. Lamm, H. jiang, F.D. Becchetti, V. Guimaraes, R. Lichtenthaler, O. Camargo, P.A. DeYoung, and P.J. Mears*. XXIX Symposium on Nuclear Physics. Cocoyoc, Mexico, January 3-6, 2006.
“Elastic Scattering of 6Li on 58>Ni at Engeries Around the Coulomb Barrier.” H. Garcia-Martinez, E.F. Aguilera, D. Lizcano, E. Martinez-Quiroz, J.J. Kolata, H.A. Amro, L.O. Lamm, H. Jiang, F.D. Becchetti, V. Guimaraes, R. Lichtenhaler, O. Camargo, P.A. DeYoung, and P.J. Mears*. XXIX Symposium on Nuclear Physics. Cocoyoc, Mexico, January 3-6, 2006.
“Protons from 8B+58Ni.” E.f. Aguilera, E. Martinez-Quiroz, H. Garcia-martinez, D. Lizcano, J.J. Kolato, L.O. Lamm, G. Rogachev, P.A. DeYoung, C. Guess*, U. Khadka*, P.J. Mears*, F.D. Becchetti, Y. Chen, H. Jiang, J.D. Hinnefeld, and G.F. Peaslee. Revista Mexicana de Fisica 52, 41 (2006).
“Two-neutron Transfer in the 6He + 209Bi Reaction Near the Coulomb Barrier.” Patrick J. Mears*, P.A. DeYoung, G.F. Peaslee, J.J. Kolata, E.F. Aguilera, and F.D. Becchetti. Poster FR.00067. 2nd Joint Meeting of the Nuclear Physics Division of the APS and The Physical Society of Japan. Maui HI September 2005.
“Two-neutron Transfer in the 6He+209Bi Reaction Near the Coulomb Barrier.” P.A. DeYoung, P.J. Mears*, J.J. Kolata, E.F. Aguilera, F.D. Beccetti, Y. Chen, M. Cloughesy, H. Griffin, C. Guess*, J.D. Hinnefeld, H. Jiang, Scott R. Jones, U. Khadka*, D. Lizcano, E. Martinez-Quiroz, M. Ojaniega, G.F. Peaslee, A. Peña*, S. VanDenDrieddshe, and J. Zimmerman. Phys. Rev. C 71, 051601 (2005).
“Structure of Heavy Helium Isotopes via the Isobaric Analog States in Lithium.” G.V. Rogachev, A. Aprahamian, P. Boutachkov, M. Quinn, J.J. Kolata, B. Skorodumov, A. Woehr, V.Z. Goldberg, G. Chubarian, A. Fomichev, M.S. Golovkiv, Yu.Ts. Oganessian, A. Rodin, R.S. Slepnev, G. Ter-Akopian, R. Wolski, W.H. Trzaska, D.V. Aleksandrov, P.A. DeYoung, G.F. Peaslee, P.J. Mears*, F.D. Becchetti, and Y. Chen. Paper CE.006. Division of Nuclear Physics Fall Meeting. Tucson, AZ, October 2003.