Browsing by Author "Runge, Jay"

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    Measurement of Proton Quenching in a Plastic Scintillator Detector
    (Journal of Instrumentation, 2020-11-22) Awe, Connor; Barbeau, Phillip; Haghighat, Alireza; Hedges, Sam; Johnson, Tyler; Li, Shengchao; Link, Jonathan M; Mascolino, Valerio; Runge, Jay; Steenis, Jacob; Subedi, Tulasi; Walkup, Keegan
    The non-linear energy response of the plastic scintillator EJ-260 is measured with the MicroCHANDLER detector, using neutron beams of energy 5 to 27 MeV at the Triangle Universities Nuclear Laboratory. The first and second order Birks' constants are extracted from the data, and found to be $k_B = (8.70 \pm 0.93)\times 10^{-3}\ {\rm g/cm^2/MeV}$ and $k_C = (1.42 \pm 1.00) \times 10^{-5}\ {\rm (g/cm^2/MeV)^2}$. This result covers a unique energy range that is of direct relevance for fast neutron backgrounds in reactor inverse beta decay detectors. These measurements will improve the energy non-linearity modeling of plastic scintillator detectors. In particular, the updated energy response model will lead to an improvement of fast neutron modeling for detectors based on the CHANDLER reactor neutrino detector technology.
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    Pair Transfer Reactions and Nuclear Matrix Elements for Neutrinoless Double Beta Decay
    (2024) Runge, Jay

    We test the validity of using the Quasiparticle Random Phase Approximation incalculating the nuclear matrix elements for neutrinoless double beta decay of 136Xe. The approximation is tested by measuring the transition strengths to the ground state and to excited 0` states in the residual nucleus via the (3He, n) two proton dropoff reaction. In this thesis, we describe the experimental techniques and data analysis methods developed and used to perform cross-section measurements of the (3He, n) reaction on 134Xe and 136Xe. We report our cross-section results as a differential cross section at a 3He lab energy of 26 MeV and a neutron scattering angle of 0 degrees. The cross section for the reaction on 134Xe was measured to be 355 ̆ 33 μb/sr, and the cross section for the reaction on 136Xe was measured to be 205 ̆ 19 μb/sr. In both reactions, strong transitions to 0` excited states were observed, though these transitions were much stronger for 136Xe. These results indicate a failure of the BCS approximation (commonly used as part of the QRPA) to describe the ground state of the 136Xe isotope and a possible failure for the 134Xe isotope as well.