Physics: Posters

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Browsing Physics: Posters by Author "Bienstock, Mollie"

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    Analysis of a Measurement of 12C(n,2n)11C Cross Sections
    (Houghton College, 2013-11-11) Hartshaw, Garrett; Love, Ian; Yuly, Mark; Padalino, Stephen; Russ, Megan; Bienstock, Mollie; Simone, Angela; Ellison, Drew; Desmitt, Holly; Massey, Thomas; Sangster, Craig
    In inertial confinement fusion (ICF), nuclear fusion reactions are initiated by bombarding a small fuel pellet with high power lasers. One ICF diagnostic tool involves placing graphite discs within the reaction chamber to determine the number of high-energy neutrons. This diagnostic requires accurate 12C(n,2n)11C cross sections, which have not been previously well measured. An experiment to measure this cross section was conducted at Ohio University, in which DT neutrons irradiated polyethylene and graphite targets. The neutron flux was determined by counting recoil protons from the polyethylene in a silicon dE-E detector telescope. Preliminary cross sections were calculated using the incident neutron flux and the number of 11C nuclei in the graphite and polyethylene targets determined by counting, in a separate counting station, the gamma rays resulting from the positron decay of 11C. This poster will present the data analysis techniques used to determine theses cross sections and the calculation of the corrections needed to account for the detector and target geometry. Funded in part by a LLE contract through the DOE.
    55th Annual Meeting of the APS Division of Plasma Physics, Denver, Colorado, November 11-15, 2013; Omega Laser Facility Users Group Workshop, Laboratory for Laser Energetics, Rochester, NY, April 23-25, 2014.
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    Coincidence Efficiency Measurement Using 11B(p,n)11C
    (Houghton College, 2012-10-24) Padalino, Stephen; Polsin, Danae; Russ, Megan; Krieger, Michael; Stillman, Collin; Simone, Angela; Bienstock, Mollie; Ellison, Drew; Yuly, Mark; Mann, Keith; Reynolds, Tyler; Sangster, Craig
    An attempt to measure the 12C(n,2n)11C cross section for high energy neutrons in the range of 20-30 MeV was conducted using Ohio University’s accelerator facility as a fast neutron source. The neutrons were incident on a graphite target and the β+ decay of the activated carbon-11 nuclei were observed in an on-axis gamma ray detector pair. To predetermine the efficiency of this gamma ray detector system, a boron-11 activation experiment was performed. Using SUNY Geneseo’s 1.7 MV tandem pelletron accelerator, 3.1 MeV protons were incident upon the 11B foil inducing the 11B(p,n)11C reaction to occur at a high rate of activation. The 11C decays via ?+ emission, then upon annihilation with an electron creates characteristic 511-511 keV photon pairs which were counted using coincidence methods. Since the 11B(p,n) cross section is well defined, a calculation was performed to determine the expected number of activations and later compared to the total number of decays observed in the counting system. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.
    2012 Fall Meeting of the APS Division of Nuclear Physics, Newport Beach, CA, October 24-27, 2012.
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    Coincidence Efficiency of Sodium Iodide Detectors for Positron Annihilation
    (Houghton College, 2014-10-27) Eckert, Thomas; Vincett, Laurel; Yuly, Mark; Stephen Padalino,; Russ, Megan; Bienstock, Mollie; Simone, Angela; Ellison, Drew; Desmitt, Holly; Sangster, Craig; Regan, Sean
    One possible diagnostic technique for characterizing inertial confinement fusion reactions involves tertiary neutron activation of 12C via the 12C(n,2n)11C reaction. Because the cross section for this reaction is not well measured in the energy range of interest, a new measurement was recently made at Ohio University. Part of this experiment involves counting the positron annihilation 511 keV gamma rays from the 11C decay using two sodium iodide detectors in coincidence. A new technique has been developed to measure the coincidence efficiency by detecting the positron prior to its annihilation, and requiring that the 1275 keV gamma ray also emitted by the 22Na be in the full-peak in another NaI(Tl) detector. Measurements and simulation results for the absolute coincidence full-peak efficiencies are presented.
    56th Annual Meeting of the APS Division of Plasma Physics, New Orleans, Lousiana, October 27-31, 2014; Penn-York Undergraduate Research Association Conference, Houghton College, Houghton, NY 14744. Nov. 1, 2104; XXXIV Annual Rochester Symposium for Physics Students, SUNY Oswego, Oswege, NY, April 11, 2015; Omega Laser User’s Group Meeting, Laboratory for Laser Energetics, Rochester, NY, April 22-24, 2015.
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    Cross Section of the (n, 2n) Reaction in 12C in the Energy Interval 20-30 MeV
    (Houghton College, 2012-10-24) Padalino, Stephen; Polsin, Danae; Russ, Megan; Krieger, Michael; Stillman, Collin; Simone, Angela; Bienstock, Mollie; Ellison, Drew; Yuly, Mark; Mann, Keith; Reynolds, Tyler; Sangster, Craig
    The behavior of the (n, 2n) reaction in 12C and other light nuclei is known with much less certainty than for heavy nuclei. The published cross section data for the 12C(n, 2n)11C reaction is bifurcated in the energy range of 20-30 MeV. An experiment to measure the 12 C(n,2n)11C cross section for these neutron energies has been performed using the Ohio University Tandem Accelerator. Deuterons from the accelerator struck a tritium foil releasing neutrons via the T(d, n)4He reaction. Deuteron bombarding energies between 3.3-8.7 MeV resulted in neutrons with energies between 20-26 MeV. The geometry of the experiment was chosen so that the incident neutron energy would not vary by more than 0.5 MeV across the graphite target. After neutron bombardment, the decay of the 11C nuclei by positron emission was measured with an array of NaI detectors to determine the activity of the carbon sample. The neutron fluence through the carbon was measured using a particle telescope to detect protons from the 1H(n, p) reac9on in a polyethylene target, allowing the absolute cross section for the 12C(n, 2n)11C reaction to be determined. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.
    2012 Fall Meeting of the APS Division of Nuclear Physics, Newport Beach, CA, October 24-27, 2012.
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    Efficiency Calibration for Measuring the 12C(n, 2n)11C Cross Section
    (Houghton College, 2015-11-16) Eckert, Thomas; Gula, August; Vincett, Laurel; Yuly, Mark; Padalino, Stephen; Russ, Megan; Bienstock, Mollie; Simone, Angela; Ellison, Drew; Desmitt, Holly; Fitzgerald, Ryan; Sangster, Craig; Regan, Sean
    One possible inertial confinement fusion diagnostic involves tertiary neutron activation via the 12C(n, 2n)11C reaction. A recent experiment to measure this cross section involved coincidence counting annihilation gamma rays produced by the positron decay of 11C. This requires an accurate value for the full-peak coincidence efficiency of the NaI detector system. The GEANT 4 toolkit was used to develop a Monte-Carlo simulation of the detector system which can be used to calculate the required efficiencies. For validation, simulation predictions have been compared with the results of three experiments. In the first, full-peak coincidence positron annihilation efficiencies were measured for 22Na positrons that annihilate in a small plastic scintillator. In the second and third, NIST-calibrated 22Na and 68Ge sources were placed between copper and graphite disks. A comparison of calculated with measured efficiencies, as well as 12C(n, 2n)11C cross sections, are presented.
    57th Annual Meeting of the APS Division of Plasma Physics, Savannah, GA, Nov. 16-20, 2015; XXXV Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 2, 2016; Omega Laser User’s Group Meeting, Laboratory for Laser Energetics, Rochester, NY, April 27-29, 2016; 2015 APS Division of Plasma Physics Outstanding Undergraduate Poster Award.
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    In Situ Calibration of a Proton Particle Telescope using the SUNY Geneseo 1.7 MV Tandem Pelletron Accelerator
    (Houghton College, 2012-10-24) Padalino, Stephen; Polsin, Danae; Russ, Megan; Krieger, Michael; Stillman, Collin; Simone, Angela; Bienstock, Mollie; Ellison, Drew; Yuly, Mark; Mann, Keith; Reynolds, Tyler; Sangster, Craig
    The particle telescope was constructed for an experiment in progress at Ohio University’s Edward’s Accelerator Laboratory. The experiment seeks to measure the 12C(n, 2n) reaction cross section for neutron energies between 16 ? 26 MeV.
    2012 Fall Meeting of the APS Division of Nuclear Physics, Newport Beach, CA, October 24-27, 2012.
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    Measuring the Cross Section of the 12C(n,2n)11C Reaction for the 20-30MeV Energy Interval
    (Houghton College, 2013-04-06) Hartshaw, Garrett; Mann, Keith; Reynolds, Tyler; Yuly, Mark; Padalino, Stephen; Polsin, Danae; Russ, Megan; Krieger, Michael; Stillman, Collin; Simone, Angela; Bienstock, Mollie; Ellison, Drew; Sangster, Craig
    The behavior of the (n, 2n) reaction in 12C and other light nuclei is known with much less certainty than for heavy nuclei. The published cross section data for the 12C(n, 2n)11C reaction is bifurcated in the energy range of 20-30 MeV. An experiment to measure the 12C(n,2n)11C cross section for these neutron energies has been performed using the Ohio University Tandem Accelerator. Deuterons from the accelerator struck a tritium foil releasing neutrons via the T(d, n)4He reaction. Deuteron bombarding energies between 3.3- 8.7 MeV resulted in neutrons with energies between 20-26 MeV. The geometry of the experiment was chosen so that the incident neutron energy would not vary by more than 0.5 MeV across the graphite target. After neutron bombardment, the decay of the 11C nuclei by positron emission was measured with an array of NaI detectors to determine the activity of the carbon sample. The neutron fluence through the carbon was measured using a particle telescope to detect protons from the 1H(n, p) reaction in a polyethylene target, allowing the absolute cross section for the 12C(n, 2n)11C reaction to be determined. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.
    XXXII Annual Rochester Symposium for Physics Students, University of Rochester, Rochester, NY., April 6, 2013.