Browsing by Author "Ahmed, MW"

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    A segmented, enriched N-type germanium detector for neutrinoless double beta-decay experiments
    (Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014-01-01) Leviner, LE; Aalseth, CE; Ahmed, MW; Avignone, FT; Back, HO; Barabash, AS; Boswell, M; De Braeckeleer, L; Brudanin, VB; Chan, YD; Egorov, VG; Elliott, SR; Gehman, VM; Hossbach, TW; Kephart, JD; Kidd, MF; Konovalov, SI; Lesko, KT; Li, J; Mei, DM; Mikhailov, S; Miley, H; Radford, DC; Reeves, J; Sandukovsky, VG; Umatov, VI; Underwood, TA; Tornow, W; Wu, YK; Young, AR
    We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT6×2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the Majorana collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the Majorana resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM. © 2013 Elsevier B.V.
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    Compton scattering from 4He at 61 MeV
    (PRC, 2017-11-27) Sikora, MH; Ahmed, MW; Banu, A; Bartram, C; Crowe, B; Downie, EJ; Feldman, G; Gao, H; Grießhammer, HW; Hao, H; Howell, CR; Karwowski, HJ; Kendellen, DP; Kovash, MA; Li, X; Markoff, DM; Mikhailov, S; Popov, V; Pywell, RE; Silano, JA; Spraker, MC; Wallace, P; Weller, HR; Whisnant, CS; Wu, YK; Xiong, W; Yan, X; Zhao, ZW
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    Compton scattering from 4He at the TUNL HIγS facility
    (PRC, 2020-03-30) Li, X; Ahmed, MW; Banu, A; Bartram, C; Crowe, B; Downie, EJ; Emamian, M; Feldman, G; Gao, H; Godagama, D; Grießhammer, HW; Howell, CR; Karwowski, HJ; Kendellen, DP; Kovash, MA; Leung, KKH; Markoff, D; Mikhailov, S; Pywell, RE; Sikora, MH; Silano, JA; Sosa, RS; Spraker, MC; Swift, G; Wallace, P; Weller, HR; Whisnant, CS; Wu, YK; Zhao, ZW
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    Compton scattering from He 4 at the TUNL HIγ S facility
    (Physical Review C, 2020-03-01) Li, X; Ahmed, MW; Banu, A; Bartram, C; Crowe, B; Downie, EJ; Emamian, M; Feldman, G; Gao, H; Godagama, D; Grießhammer, HW; Howell, CR; Karwowski, HJ; Kendellen, DP; Kovash, MA; Leung, KKH; Markoff, D; Mikhailov, S; Pywell, RE; Sikora, MH; Silano, JA; Sosa, RS; Spraker, MC; Swift, G; Wallace, P; Weller, HR; Whisnant, CS; Wu, YK; Zhao, ZW
    © 2020 American Physical Society. Differential cross sections for elastic Compton scattering from He4 have been measured with high statistical precision at the High Intensity γ-ray Source at laboratory scattering angles of 55°, 90°, and 125° using a quasi-monoenergetic photon beam with a weighted mean energy value of 81.3 MeV. The results are compared to previous measurements and similar fore-aft asymmetry in the angular distribution of the differential cross sections is observed. This experimental work is expected to strongly motivate the development of effective-field-theory calculations of Compton scattering from He4 to fully interpret the data.
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    Parity assignments in 172,174Yb using polarized photons and the K quantum number in rare earth nuclei
    (Physical Review C - Nuclear Physics, 2005-03-01) Savran, D; Muller, S; Zilges, A; Babilon, M; Ahmed, MW; Kelley, JH; Tonchev, A; Tornow, kW; Weller, HR; Pietralla, N; Li, J; Pinayev, IV; Wu, YK
    The 100% polarized photon beam at the high intensity γ ray source (HIγS) at Duke University has been used to determine the parity of six dipole excitations between 2.9 and 3.6 MeV in the deformed nuclei 172,174Yb in photon scattering (γ →, γ′) experiments. The measured parities are compared with previous assignments based on the K quantum number that had been assigned in nuclear resonance fluorescence (NRF) experiments by using the Alaga rules. A systematic survey of the relation between γ-decay branching ratios and parity quantum numbers is given for the rare earth nuclei. © 2005 The American Physical Society.