ER@CEBAF: A test of 5-pass energy recovery at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, S. A.; Douglas, D.; Dubbe, C.

2016-06-06

Jefferson Lab personnel have broad expertise in the design, commissioning, and operation of multiple energy recovery linacs (ERLs): the CEBAF Front-End Test (early 1990s), CEBAF-ER (2003), the IR Free Electron Laser (FEL) Demo, the IR FEL Upgrade, and the UV FEL Driver (1997-2014). Continued development of this core competency has led to this collaborative proposal to explore the forefronts of ERL technology at high energy in a unique expansion of CEBAF capability to a 5-pass ERL with negligible switchover time and programmatic impact to the CEBAF physics program. Such a capability would enable world-class studies of open issues in high-energymore » ERL beam dynamics that are relevant to future facilities such as electron-ion colliders (EICs). This proposal requests support from the CEBAF Program Advisory Committee to seek funding for hardware installation, and a prospective 12 days of beam time circa Fall 2018 for commissioning this high-energy multi-pass ERL experiment in CEBAF.« less

Spin observables in charged pion photo-production from polarized neutrons in solid HD at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kageya, Tsuneo; Ho, Dao; Peng, Peng

E asymmetries have been extracted from double-polarizationexperiments in Hall-B of the Thomas Jefferson National Accelerator Facility (JLab). Results have been obtained from the E06-101 (g14) experiment, using circularly polarized photon beams, longitudinally polarized Deuterons in solid HD targets, and the CEBAF Large Acceptance Spectrometer (CLAS). The results cover a range inW from 1.48 to 2.32 GeV. Three independent analyses, using distinctly different methods, have been combined to obtain the final values, which have been published recently. Partial wave analyses (PWA), which have had to rely on a sparse neutron data base, havebeen significantly changed with the inclusion of these g14more » asymmetries.« less

Measurement of the polarized structure function σLT' for p(e→,e'p)π0 in the Δ(1232) resonance region

NASA Astrophysics Data System (ADS)

Joo, K.; Smith, L. C.; Burkert, V. D.; Minehart, R.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Audit, G.; Auger, T.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Ciciani, L.; Cole, P. L.; Coleman, A.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Desanctis, E.; Devita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Eckhause, M.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Forest, T. A.; Funsten, H.; Gaff, S. J.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Gordon, C. I.; Griffioen, K.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Heimberg, P.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ilieva, Y.; Ito, M. M.; Jenkins, D.; Kelley, J. H.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuang, Y.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Lawrence, D.; Li, Ji; Lima, A. C.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McNabb, J. W.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Morand, L.; Morrow, S. A.; Mozer, M. U.; Muccifora, V.; Mueller, J.; Murphy, L. Y.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Opper, A. K.; Osipenko, M.; Park, K.; Pasyuk, E.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Sabourov, K.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Sargsyan, M.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zhao, J.; Zhou, Z.

2003-09-01

The polarized longitudinal-transverse structure function σLT' has been measured in the Δ(1232) resonance region at Q2=0.40 and 0.65 GeV2. Data for the p(e→,e'p)π0 reaction were taken at Jefferson Lab with the CEBAF large acceptance spectrometer (CLAS) using longitudinally polarized electrons at an energy of 1.515 GeV. For the first time a complete angular distribution was measured, permitting the separation of different nonresonant amplitudes using a partial wave analysis. Comparison with previous beam asymmetry measurements at MAMI indicate a deviation from the predicted Q2 dependence of σLT' using recent phenomenological models.

Measurement of beam-spin asymmetries for π+ electroproduction above the baryon resonance region

NASA Astrophysics Data System (ADS)

Avakian, H.; Burkert, V. D.; Elouadrhiri, L.; Bianchi, N.; Adams, G.; Afanasev, A.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Armstrong, D. S.; Asavapibhop, B.; Audit, G.; Auger, T.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Ciciani, L.; Cole, P. L.; Coleman, A.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Desanctis, E.; Devita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Dharmawardane, K. V.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Eckhause, M.; Egiyan, H.; Egiyan, K. S.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Forest, T. A.; Funsten, H.; Gaff, S. J.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Gordon, C. I. O.; Griffioen, K.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Heimberg, P.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ilieva, Y.; Ito, M. M.; Jenkins, D.; Joo, K.; Kelley, J. H.; Kellie, J.; Khandaker, M.; Kim, D. H.; Kim, K. Y.; Kim, K.; Kim, M. S.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuang, Y.; Kubarovsky, V.; Kuhn, S. E.; Lachniet, J.; Laget, J. M.; Lawrence, D.; Livingston, K.; Li, Ji; Longhi, A.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Morand, L.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Opper, A. K.; Osipenko, M.; Park, K.; Pasyuk, E.; Peterson, G.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Sabourov, K.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Sargsyan, M.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zhang, B.; Zhao, J.; Zhou, Z.

2004-06-01

We report the first evidence for a nonzero beam-spin azimuthal asymmetry in the electroproduction of positive pions in the deep-inelastic kinematic region. Data for the reaction ep→e'π+X have been obtained using a polarized electron beam of 4.3 GeV with the CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Accelerator Facility. The amplitude of the sin φ modulation increases with the momentum of the pion relative to the virtual photon, z. In the range z=0.5 0.8 the average amplitude is 0.038±0.005±0.003 for a missing mass MX>1.1 GeV and 0.037±0.007±0.004 for MX>1.4 GeV.

Search for the Θ+ Pentaquark in the γd→ΛnK+ Reaction Measured with the CLAS Spectrometer

NASA Astrophysics Data System (ADS)

Niccolai, S.; Mirazita, M.; Rossi, P.; Baltzell, N. A.; Carman, D. S.; Hicks, K.; McKinnon, B.; Mibe, T.; Stepanyan, S.; Tedeschi, D. J.; Adams, G.; Ambrozewicz, P.; Anefalos Pereira, S.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Batourine, V.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Boiarinov, S.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carnahan, B.; Chen, S.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dashyan, N.; Degtyarenko, P. V.; de Masi, R.; Deppman, A.; de Sanctis, E.; Deur, A.; Devita, R.; Dharmawardane, K. V.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feldman, G.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gonenc, A.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hardie, J.; Hersman, F. W.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Livingston, K.; Lu, H.; MacCormick, M.; Markov, N.; Mecking, B. A.; Mellor, J.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Moteabbed, M.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; de Oliveira Echeimberg, J.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shvedunov, N. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Thoma, U.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z.

2006-07-01

For the first time, the reaction γd→ΛnK+ has been analyzed in order to search for the exotic pentaquark baryon Θ+(1540). The data were taken at Jefferson Laboratory, using the Hall-B tagged-photon beam of energy between 0.8 and 3.6 GeV and the CEBAF Large Acceptance Spectrometer (CLAS). No statistically significant structures were observed in the nK+ invariant-mass distribution. The upper limit on the γd→ΛΘ+ integrated cross section has been calculated and found to be between 5 and 25 nb, depending on the production model assumed. The upper limit on the differential cross section is also reported.

Spin Observables in h Meson Photoproduction on the Proton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tucker, Ross

2016-05-01

A series of experiments using a polarized beam incident on a polarized frozen spin target (FROST) was conducted at Jefferson Lab in 2010. Results presented here were taken during the second running period with the FROST target using the CEBAF Large Acceptance Spectrometer (CLAS) detector at Jefferson Lab, which used transversely-polarized protons in a butanol target and a circularly-polarized incident tagged photon beam with energies between 0:62 and 2:93 GeV. Data are presented for the F and T polarization observables for n meson photoproduction on the proton from W = 1:55 GeV to 1:80 GeV. The data presented here willmore » improve the world database and refine theoretical approaches of nucleon structure.« less

Helicity Asymmetry in gamma p -> pi+ n with FROST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steffen Strauch

2012-04-01

The main objective of the FROST experiment at Jefferson Lab is the study of baryon resonances. The polarization observable E for the reaction gamma p to pi+n has been measured as part of this program. A circularly polarized tagged photon beam with energies from 0.35 to 2.35 GeV was incident on a longitudinally polarized frozen-spin butanol target. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer. Preliminary polarization data agree fairly well with present SAID and MAID partial-wave analyses at low photon energies. In most of the covered energy range, however, significant deviations are observed. These discrepancies underlinemore » the crucial importance of polarization observables to further constrain these analyses.« less

Beam-Target Helicity Asymmetry for γ → n → → π - p in the N * Resonance Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, D.; Peng, P.; Bass, C.

2017-06-01

We report the first beam-target double-polarization asymmetries in the gamma+n(p)->pi(-)+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several gamma nN*more » resonance photocouplings.« less

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region.

PubMed

Ho, D; Peng, P; Bass, C; Collins, P; D'Angelo, A; Deur, A; Fleming, J; Hanretty, C; Kageya, T; Khandaker, M; Klein, F J; Klempt, E; Laine, V; Lowry, M M; Lu, H; Nepali, C; Nikonov, V A; O'Connell, T; Sandorfi, A M; Sarantsev, A V; Schumacher, R A; Strakovsky, I I; Švarc, A; Walford, N K; Wei, X; Whisnant, C S; Workman, R L; Zonta, I; Adhikari, K P; Adikaram, D; Akbar, Z; Amaryan, M J; Anefalos Pereira, S; Avakian, H; Ball, J; Bashkanov, M; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A; Briscoe, W J; Burkert, V D; Carman, D S; Celentano, A; Charles, G; Chetry, T; Ciullo, G; Clark, L; Colaneri, L; Cole, P L; Contalbrigo, M; Crede, V; Dashyan, N; De Sanctis, E; De Vita, R; Djalali, C; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Fersch, R; Filippi, A; Fradi, A; Ghandilyan, Y; Gilfoyle, G P; Girod, F X; Glazier, D I; Gleason, C; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hakobyan, H; Harrison, N; Hattawy, M; Hicks, K; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jenkins, D; Jiang, H; Jo, H S; Joo, K; Joosten, S; Keller, D; Khachatryan, G; Kim, A; Kim, W; Klein, A; Kubarovsky, V; Kuleshov, S V; Lanza, L; Lenisa, P; Livingston, K; MacGregor, I J D; Markov, N; McKinnon, B; Mineeva, T; Mokeev, V; Montgomery, R A; Movsisyan, A; Munoz Camacho, C; Murdoch, G; Niccolai, S; Niculescu, G; Osipenko, M; Paolone, M; Paremuzyan, R; Park, K; Pasyuk, E; Phelps, W; Pogorelko, O; Price, J W; Procureur, S; Protopopescu, D; Ripani, M; Riser, D; Ritchie, B G; Rizzo, A; Rosner, G; Sabatié, F; Salgado, C; Sharabian, Y G; Skorodumina, Iu; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Strauch, S; Tian, Ye; Torayev, B; Ungaro, M; Voskanyan, H; Voutier, E; Watts, D P; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W

2017-06-16

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.

Precise determination of the deuteron spin structure at low to moderate Q2 with CLAS and extraction of the neutron contribution

NASA Astrophysics Data System (ADS)

Guler, N.; Fersch, R. G.; Kuhn, S. E.; Bosted, P.; Griffioen, K. A.; Keith, C.; Minehart, R.; Prok, Y.; Adhikari, K. P.; Adikaram, D.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crabb, D.; Crede, V.; D'Angelo, A.; Dashyan, N.; Deur, A.; Djalali, C.; Dodge, G. E.; Dupre, R.; Alaoui, A. El; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Garillon, B.; Garçon, M.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Joosten, S.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Livingston, K.; Lu, H. Y.; Mayer, M.; MacGregor, I. J. D.; McKinnon, B.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Net, L. A.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Simonyan, A.; Skorodumina, Iu.; Sokhan, D.; Sparveris, N.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Voutier, E.; Walford, N. K.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2015-11-01

We present the final results for the deuteron spin structure functions obtained from the full data set collected in 2000-2001 with Jefferson Lab's continuous electron beam accelerator facility (CEBAF) using the CEBAF large acceptance spectrometer (CLAS). Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.8 GeV were scattered from deuteron (15ND3 ) targets, dynamically polarized along the beam direction, and detected with CLAS. From the measured double-spin asymmetry, the virtual photon absorption asymmetry A1d and the polarized structure function g1d were extracted over a wide kinematic range (0.05 GeV2

Applying AN Object-Oriented Database Model to a Scientific Database Problem: Managing Experimental Data at Cebaf.

NASA Astrophysics Data System (ADS)

Ehlmann, Bryon K.

Current scientific experiments are often characterized by massive amounts of very complex data and the need for complex data analysis software. Object-oriented database (OODB) systems have the potential of improving the description of the structure and semantics of this data and of integrating the analysis software with the data. This dissertation results from research to enhance OODB functionality and methodology to support scientific databases (SDBs) and, more specifically, to support a nuclear physics experiments database for the Continuous Electron Beam Accelerator Facility (CEBAF). This research to date has identified a number of problems related to the practical application of OODB technology to the conceptual design of the CEBAF experiments database and other SDBs: the lack of a generally accepted OODB design methodology, the lack of a standard OODB model, the lack of a clear conceptual level in existing OODB models, and the limited support in existing OODB systems for many common object relationships inherent in SDBs. To address these problems, the dissertation describes an Object-Relationship Diagram (ORD) and an Object-oriented Database Definition Language (ODDL) that provide tools that allow SDB design and development to proceed systematically and independently of existing OODB systems. These tools define multi-level, conceptual data models for SDB design, which incorporate a simple notation for describing common types of relationships that occur in SDBs. ODDL allows these relationships and other desirable SDB capabilities to be supported by an extended OODB system. A conceptual model of the CEBAF experiments database is presented in terms of ORDs and the ODDL to demonstrate their functionality and use and provide a foundation for future development of experimental nuclear physics software using an OODB approach.

Polarization observables in few nucleon systems with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zachariou, Nicholas

The CEBAF Large Acceptance Spectrometer (CLAS), housed in Hall-B at the Thomas Jefferson National Accelerator Facility provides us with the experimental tools to study strongly-interacting matter and its dynamics in the transition from hadronic to partonic degrees of freedom in nuclear interactions. In this paper we discuss the progress made in understanding the relevant degrees of freedom using polarisation observables of deuteron photodisintegration in the few-GeV photon-energy region. We also address progress made in studying the interaction between Hyperons and Nucleons via polarisation observables, utilising high-statistics experiments that provided us with the large data samples needed to study final-state interactions,more » as well as perform detailed studies on initial-state effects. The polarisation observables presented here provide us with unique experimental tools to study the underlying dynamics of both initial and final-state interactions, as well as the information needed to disentangle signal from background contributions.« less

Polarization observables in few nucleon systems with CLAS

DOE PAGES

Zachariou, Nicholas

2017-12-01

The CEBAF Large Acceptance Spectrometer (CLAS), housed in Hall-B at the Thomas Jefferson National Accelerator Facility provides us with the experimental tools to study strongly-interacting matter and its dynamics in the transition from hadronic to partonic degrees of freedom in nuclear interactions. In this paper we discuss the progress made in understanding the relevant degrees of freedom using polarisation observables of deuteron photodisintegration in the few-GeV photon-energy region. We also address progress made in studying the interaction between Hyperons and Nucleons via polarisation observables, utilising high-statistics experiments that provided us with the large data samples needed to study final-state interactions,more » as well as perform detailed studies on initial-state effects. The polarisation observables presented here provide us with unique experimental tools to study the underlying dynamics of both initial and final-state interactions, as well as the information needed to disentangle signal from background contributions.« less

TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Haipeng; Guo, Jiquan; Rimmer, Robert A.

2016-05-01

The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability.more » We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.« less

Qualification and cryogenic performance of cryomodule components at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heckman, J.; Macha, K.; Fischer, J.

1996-12-31

At CEBAF an electron beam is accelerated by superconducting resonant niobium cavities which are operated submerged in superfluid helium. The accelerator has 42 1/4 cryomodules, each containing eight cavities. The qualification and design of components for the cryomodules under went stringent testing and evaluation for acceptance. Indium wire seals are used between the cavity and helium vessel interface to make a superfluid helium leak tight seal. Each cavity is equipped with a mechanical tuner assembly designed to stretch and compress the cavities. Two rotary feedthroughs are used to operate each mechanical tuner assembly. Ceramic feedthroughs not designed for super-fluid weremore » qualified for tuner and cryogenic instrumentation. To ensure long term integrity of the machine special attention is required for material specifications and machine processes. The following is to share the qualification methods, design and performance of the cryogenic cryomodule components.« less

The CEBAF Element Database and Related Operational Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larrieu, Theodore; Slominski, Christopher; Keesee, Marie

The newly commissioned 12GeV CEBAF accelerator relies on a flexible, scalable and comprehensive database to define the accelerator. This database delivers the configuration for CEBAF operational tools, including hardware checkout, the downloadable optics model, control screens, and much more. The presentation will describe the flexible design of the CEBAF Element Database (CED), its features and assorted use case examples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, A.; Avakian, H.; Burkert, V.

The target and double spin asymmetries of the exclusive pseudoscalar channel e→p→→epπ0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, -t and Φ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs)more » provides the first insight on the chiral-odd GPDs H˜T and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and E¯T. These data provide a crucial input for parametrizations of essentially unknown chiral-odd GPDs and will strongly influence existing theoretical calculations based on the handbag formalism.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, A.; Avakian, H.; Burkert, V.

The target and double spin asymmetries of the exclusive pseudoscalar channelmore » $$\\vec e\\vec p\\to ep\\pi^0$$ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of $Q^2$, $$x_B$$, $-t$ and $$\\phi$$. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs $$\\tilde{H}_T$$ and $$E_T$$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $$H_T$$ and $$\\bar E_T$$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.« less

The extraction of Φ – N total cross section from d ( γ , p K + K - ) n

DOE PAGES

Qian, X.; Chen, W.; Gao, H.; ...

2009-10-01

We report on the first measurement of the differential cross section ofmore » $$\\phi$$-meson photoproduction for the $$d(\\gamma,pK^{+}K^{-})n$$ exclusive reaction channel. The experiment was performed using a \\textcolor{black}{tagged-photon} beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the $$d(\\gamma,pK^{+}K^{-})n$$ channel and those from a previous publication on coherent $$\\phi$$ production on the deuteron has been carried out to extract the $$\\phi-N$$ total cross section, $$\\sigma_{\\phi N}$$. The extracted $$\\phi-N$$ total cross section favors a value above 20 mb. This value is larger than the value extracted using vector-meson dominance models for $$\\phi$$ photoproduction on the proton.« less

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2 . I. e p →e π+n

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; De Vita, R.; Deur, A.; De Sanctis, E.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Forest, T.; Fradi, A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hakobyan, H.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Net, L. A.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V. I.; Montgomery, R. A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rosner, G.; Rossi, P.; Schumacher, R. A.; Seder, E.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-03-01

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π+ electroproduction reaction γ*p →n π+ . The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1

Root Causes of Field Emitters in SRF Cavities Placed in CEBAF Tunnel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Rongli

It has been suspected that appearance of new field emitters can occur in SRF cavities after their placement in accelerator tunnel for long term beam operation. This apparently has been the case for CEBAF. However, no physical evidence has been shown in the past. In this contribution, we will report on the recent results concerning the root cause of field emitters in SRF cavities placed in CEBAF tunnel. We will discuss these results in the context of high-reliability and low-cryogenic-loss operation of CEBAF.

Longitudinal target-spin asymmetries for deeply virtual compton scattering.

PubMed

Seder, E; Biselli, A; Pisano, S; Niccolai, S; Smith, G D; Joo, K; Adhikari, K; Amaryan, M J; Anderson, M D; Anefalos Pereira, S; Avakian, H; Battaglieri, M; Bedlinskiy, I; Bono, J; Boiarinov, S; Bosted, P; Briscoe, W; Brock, J; Brooks, W K; Bültmann, S; Burkert, V D; Carman, D S; Carlin, C; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Crabb, D; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Doughty, D; Dupre, R; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Fradi, A; Garillon, B; Garçon, M; Gevorgyan, N; Ghandilyan, Y; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Harrison, N; Hattawy, M; Hirlinger Saylor, N; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jo, H S; Joosten, S; Keith, C D; Keller, D; Khachatryan, G; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, F J; Koirala, S; Kubarovsky, V; Kuhn, S E; Lenisa, P; Livingston, K; Lu, H Y; MacGregor, I J D; Markov, N; Mayer, M; McKinnon, B; Meekins, D G; Mineeva, T; Mirazita, M; Mokeev, V; Montgomery, R; Moody, C I; Moutarde, H; Movsisyan, A; Munoz Camacho, C; Nadel-Turonski, P; Niculescu, I; Osipenko, M; Ostrovidov, A I; Paolone, M; Pappalardo, L L; Park, K; Park, S; Pasyuk, E; Peng, P; Phelps, W; Pogorelko, O; Price, J W; Prok, Y; Protopopescu, D; Puckett, A J R; Ripani, M; Rizzo, A; Rosner, G; Rossi, P; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Senderovich, I; Simonyan, A; Skorodumina, I; Sokhan, D; Sparveris, N; Stepanyan, S; Stoler, P; Strakovsky, I I; Strauch, S; Sytnik, V; Taiuti, M; Tang, W; Tian, Y; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zonta, I

2015-01-23

A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6 GeV electron beam, a longitudinally polarized proton target, and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for ep→e^{'}p^{'}γ events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in Q^{2}, x_{B}, t, and ϕ, for 166 four-dimensional bins. In the framework of generalized parton distributions, at leading twist the t dependence of these asymmetries provides insight into the spatial distribution of the axial charge of the proton, which appears to be concentrated in its center. These results also bring important and necessary constraints for the existing parametrizations of chiral-even generalized parton distributions.

Longitudinal Target-Spin Asymmetries for Deeply Virtual Compton Scattering

NASA Astrophysics Data System (ADS)

Seder, E.; Biselli, A.; Pisano, S.; Niccolai, S.; Smith, G. D.; Joo, K.; Adhikari, K.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Battaglieri, M.; Bedlinskiy, I.; Bono, J.; Boiarinov, S.; Bosted, P.; Briscoe, W.; Brock, J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Carlin, C.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crabb, D.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Garçon, M.; Gevorgyan, N.; Ghandilyan, Y.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hirlinger Saylor, N.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joosten, S.; Keith, C. D.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Meekins, D. G.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L. L.; Park, K.; Park, S.; Pasyuk, E.; Peng, P.; Phelps, W.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Senderovich, I.; Simonyan, A.; Skorodumina, I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tang, W.; Tian, Y.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.; CLAS Collaboration

2015-01-01

A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6 GeV electron beam, a longitudinally polarized proton target, and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for e p →e'p'γ events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in Q2 , xB, t , and ϕ , for 166 four-dimensional bins. In the framework of generalized parton distributions, at leading twist the t dependence of these asymmetries provides insight into the spatial distribution of the axial charge of the proton, which appears to be concentrated in its center. These results also bring important and necessary constraints for the existing parametrizations of chiral-even generalized parton distributions.

HDice, Highly-Polarized Low-Background Frozen-Spin HD Targets for CLAS experiments at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Xiangdong; Bass, Christopher; D'Angelo, Annalisa

2012-12-01

Large, portable frozen-spin HD (Deuterium-Hydride) targets have been developed for studying nucleon spin properties with low backgrounds. Protons and Deuterons in HD are polarized at low temperatures (~10mK) inside a vertical dilution refrigerator (Oxford Kelvinox-1000) containing a high magnetic field (up to 17T). The targets reach a frozen-spin state within a few months, after which they can be cold transferred to an In-Beam Cryostat (IBC). The IBC, a thin-walled dilution refrigerator operating either horizontally or vertically, is use with quasi-4{pi} detector systems in open geometries with minimal energy loss for exiting reaction products in nucleon structure experiments. The first applicationmore » of this advanced target system has been used for Spin Sum Rule experiments at the LEGS facility in Brookhaven National Laboratory. An improved target production and handling system has been developed at Jefferson Lab for experiments with the CEBAF Large Acceptance Spectrometer, CLAS.« less

First measurement of target and double spin asymmetries for e→p→→epπ0 in the nucleon resonance region above the Δ(1232)

NASA Astrophysics Data System (ADS)

Biselli, A. S.; Burkert, V. D.; Amaryan, M. J.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Bellis, M.; Benmouna, N.; Berman, B. L.; Blaszczyk, L.; Bookwalter, C.; Boiarinov, S.; Bosted, P.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Casey, L.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crede, V.; Dale, D.; Dashyan, N.; de Masi, R.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Deur, A.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dzyubak, O. P.; Egiyan, H.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feuerbach, R.; Fersch, R.; Forest, T. A.; Fradi, A.; Garçon, M.; Gavaliann, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Keller, D.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kossov, M.; Krahn, Z.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Livingston, K.; Lu, H. Y.; MacCormick, M.; Markov, N.; Mattione, P.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Park, S.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schott, D.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yurov, M.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2008-10-01

The exclusive channel p→(e→,e'p)π0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer. Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the π0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A1/2 and S1/2 for the Roper resonance N(1400)P11 and the N(1535)S11 and N(1520)D13 states.

Few-body physics with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

G.P. Gilfoyle

2011-05-01

The study of few-body, nuclear systems with electromagnetic probes is an essential piece of the scientific program at Jefferson Lab. Reactions using real photons and electrons (up to energies of 6 GeV) are measured using the CEBAF large acceptance spectrometer (CLAS) detector in Hall B, a nearly 4π magnetic spectrometer. We focus here on three areas. (1) Short-range correlations (SRCs) probe the high-momentum components of the nuclear wave function. Recent CLAS experiments map out their isospin character and reveal the importance of the tensor part of the nuclear force. (2) Three-body forces are an essential feature of nuclei. We willmore » show results using real photons and 3He and 4He targets that remain largely unexplained. (3) Evidence for the transition to a quark-gluon description of nuclei has been observed with photon beams in CLAS on deuterium and 3-He targets. Alternative explanations reveal the geography of the transition is complex.« less

Few body physics with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

G.P. Gilfoyle for the CLAS Collaboration

2011-02-01

The study of few-body, nuclear systems with electromagnetic probes is an essential piece of the scientific program at Jefferson Lab. Reactions using real photons and electrons (up to energies of 6 GeV) are measured using the CEBAF large acceptance spectrometer (CLAS) detector in Hall B, a nearly 4π magnetic spectrometer. We focus here on three areas. (1) Short-range correlations (SRCs) probe the high-momentum components of the nuclear wave function. Recent CLAS experiments map out their isospin character and reveal the importance of the tensor part of the nuclear force. (2) Three-body forces are an essential feature of nuclei. We willmore » show results using real photons and 3He and 4He targets that remain largely unexplained. (3) Evidence for the transition to a quark-gluon description of nuclei has been observed with photon beams in CLAS on deuterium and 3-He targets. Alternative explanations reveal the geography of the transition is complex.« less

Target and double spin asymmetries of deeply virtual π0 production with a longitudinally polarized proton target and CLAS

NASA Astrophysics Data System (ADS)

Kim, A.; Avakian, H.; Burkert, V.; Joo, K.; Kim, W.; Adhikari, K. P.; Akbar, Z.; Anefalos Pereira, S.; Badui, R. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Bosted, P.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garc con, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hanretty, C.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P.; McCracken, M. E.; McKinnon, B.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Salgado, C.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zana, L.; Zhang, J.

2017-05-01

The target and double spin asymmetries of the exclusive pseudoscalar channel e → p → → epπ0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, -t and ϕ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs H˜T and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and EbarT. These data provide a crucial input for parametrizations of essentially unknown chiral-odd GPDs and will strongly influence existing theoretical calculations based on the handbag formalism.

Target and double spin asymmetries of deeply virtual π 0 production with a longitudinally polarized proton target and CLAS

DOE PAGES

Kim, A.; Avakian, H.; Burkert, V.; ...

2017-02-22

The target and double spin asymmetries of the exclusive pseudoscalar channelmore » $$\\vec e\\vec p\\to ep\\pi^0$$ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of $Q^2$, $$x_B$$, $-t$ and $$\\phi$$. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs $$\\tilde{H}_T$$ and $$E_T$$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $$H_T$$ and $$\\bar E_T$$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.« less

Induced polarization of Λ (1116) in kaon electroproduction

NASA Astrophysics Data System (ADS)

Gabrielyan, M.; Raue, B. A.; Carman, D. S.; Park, K.; Adhikari, K. P.; Adikaram, D.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Baturin, V.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, T.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fleming, J. A.; Forest, T. A.; Garillon, B.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lenisa, P.; Levine, W. I.; Livingston, K.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Meyer, C. A.; Mestayer, M. D.; Mirazita, M.; Mokeev, V.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Pappalardo, L. L.; Paremuzyan, R.; Pasyuk, E.; Peng, P.; Phelps, W.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Rimal, D.; Ripani, M.; Rizzo, A.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Simonyan, A.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Tang, W.; Ungaro, M.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.; CLAS Collaboration

2014-09-01

We have measured. the induced polarization of the Λ(1116) in the reaction ep →e'K+Λ, detecting the scattered e' and K+ in the final state along with the proton from the decay Λ →pπ-. The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy W (1.6≤W≤2.7 GeV) and covered the full range of the kaon production angle at an average momentum transfer Q2=1.90GeV2. In this experiment a 5.50-GeV electron beam was incident upon an unpolarized liquid-hydrogen target. We have mapped out the W and kaon production angle dependencies of the induced polarization and found striking differences from photoproduction data over most of the kinematic range studied. However, we also found that the induced polarization is essentially Q2 independent in our kinematic domain, suggesting that somewhere below the Q2 covered here there must be a strong Q2 dependence. Along with previously published photo- and electroproduction cross sections and polarization observables, these data are needed for the development of models, such as effective field theories, and as input to coupled-channel analyses that can provide evidence of previously unobserved s-channel resonances.

High-power infrared and ultraviolet free electron lasers at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byung Yunn; Charles Sinclair; Christoph Leemann

1992-06-15

In response to requirements for national laboratory technology transfer, CEBAF has proposed an industrial R&D initiative: a Free Electron Laser(FEL) User Facility based on an infrared FEL and an ultraviolet FEL, with the injector and the north linac of the CEBAF superconducting,recirculating accelerator serving as drivers. The initiative is a collaborative effort with four U.S. corporate partners and capitalizes on CEBAF'ssuperconducting rf technology. The FELs will provide monochromatic, tunable (3.6 to 1.7 ¿m and 150 to 260 nm), high-average-power (-kW) lightfor technical applications and basic science studies. FEL capabilities will be competitive with those of similar initiatives worldwide. FEL operationmore » willnot impair beam delivered to CEBAF's nuclear physics experiments. Substational commitments are in hand from the industray partners and theCommonwealth of Virgina for cost-sharing the project with the Federal Government.« less

High-power infrared and ultraviolet free electron lasers at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dylla, H.F.; Bisognano, J.J.; Douglas, D.

1992-12-05

In response to requirements for national laboratory technology transfer, CEBAF has proposed an industrial R D initiative: a Free Electron Laser (FEL) User Facility based on an infrared FEL and an ultraviolet FEL, with the injector and the north linac of the CEBAF superconducting, recirculating accelerator serving as drivers. The initiative is a collaborative effort with four U.S. corporate partners and capitalizes on CEBAF's superconducting rf technology. The FELs will provide monochromatic, tunable (3.6 to 1.7 [mu]m and 150 to 260 nm), high-average-power (-kW) light for technical applications and basic science studies. FEL capabilities will be competitive with those ofmore » similar initiatives worldwide. FEL operation will not impair beam delivered to CEBAF's nuclear physics experiments. Substational commitments are in hand from the industray partners and the Commonwealth of Virgina for cost-sharing the project with the Federal Government.« less

First measurement of the polarization observable E in the p → (γ → ,π+) n reaction up to 2.25 GeV

NASA Astrophysics Data System (ADS)

Strauch, S.; Briscoe, W. J.; Döring, M.; Klempt, E.; Nikonov, V. A.; Pasyuk, E.; Rönchen, D.; Sarantsev, A. V.; Strakovsky, I.; Workman, R.; Adhikari, K. P.; Adikaram, D.; Anderson, M. D.; Anefalos Pereira, S.; Anisovich, A. V.; Badui, R. A.; Ball, J.; Batourine, V.; Battaglieri, M.; Bedlinskiy, I.; Benmouna, N.; Biselli, A. S.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Cao, T.; Carlin, C.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; Dashyan, N.; D'Angelo, A.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Gevorgyan, N.; Ghandilyan, Y.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Keith, C. D.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meekins, D. G.; Meyer, C. A.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; O'Rielly, G.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Peng, P.; Phelps, W.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seely, M. L.; Senderovich, I.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stoler, P.; Stepanyan, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Trivedi, A.; Tucker, R.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.

2015-11-01

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction γ → p → →π+ n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, Jülich-Bonn, and SAID groups.

Determination of the beam-spin asymmetry of deuteron photodisintegration in the energy region Eγ=1.1 -2.3 GeV

NASA Astrophysics Data System (ADS)

Zachariou, N.; Ilieva, Y.; Berman, B. L.; Ivanov, N. Ya.; Sargsian, M. M.; Avakian, R.; Feldman, G.; Nadel-Turonski, P.; Adhikari, K. P.; Adikaram, D.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Badui, R. A.; Baltzell, N. A.; Battaglieri, M.; Baturin, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; Alaoui, A. El; Fassi, L. El; Elouadrhiri, L.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hafidi, K.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hughes, S. M.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P. T.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeeev, V. I.; Montgomery, R. A.; Moutarde, H.; Camacho, C. Munoz; Net, L. A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Senderovich, I.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D.; Wei, X.; Wood, M. H.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2015-05-01

The beam-spin asymmetry, Σ , for the reaction γ d →p n has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins, between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, θc .m ., between 25∘ and 160∘. These are the first measurements of beam-spin asymmetries at θc .m .=90∘ for photon-beam energies above 1.6 GeV, and the first measurements for angles other than θc .m .=90∘ . The angular and energy dependence of Σ is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition region between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.

Beam asymmetry Σ for π+ and π0 photoproduction on the proton for photon energies from 1.102 to 1.862 GeV

NASA Astrophysics Data System (ADS)

Dugger, M.; Ritchie, B. G.; Collins, P.; Pasyuk, E.; Briscoe, W. J.; Strakovsky, I. I.; Workman, R. L.; Azimov, Y.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; Vita, R. De; Sanctis, E. De; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; Egiyan, H.; Alaoui, A. El; Fassi, L. El; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fleming, J. A.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuleshov, S. V.; Lewis, S.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Nepali, C. S.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Peng, P.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Rimal, D.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Senderovich, I.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strauch, S.; Taiuti, M.; Tang, W.; Tian, Ye; Tkachenko, S.; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D. P.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2013-12-01

Beam asymmetries for the reactions γp →pπ0 and γp →nπ+ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged, linearly polarized photon beam with energies from 1.102-1.862 GeV. A Fourier moment technique for extracting beam asymmetries from experimental data is described. The results reported here possess greater precision and finer energy resolution than previous measurements. Our data for both pion reactions appear to favor the SAID and Bonn-Gatchina scattering analyses over the older Mainz MAID predictions. After incorporating the present set of beam asymmetries into the world database, exploratory fits made with the SAID analysis indicate that the largest changes from previous fits are for properties of the Δ(1700)3/2- and Δ(1905)5/2+ states.

Deeply virtual Compton scattering with a positron beam

NASA Astrophysics Data System (ADS)

Girod, François-Xavier; Elouadrhiri, Latifa; Burkert, Volker D.

2018-05-01

The hard electroproduction of a photon off a hadron in the Bjorken regime, Deeply Virtual Compton Scattering, unravels three-dimensional information on the partonic structure of the hadron. The imaginary part of the amplitude is more particularly sensitive to the spatial distribution of quarks as functions of the light cone momentum fraction. On the other hand, the real part of the amplitude is less constrained experimentally, and provides access to the D-term. Here we present preliminary results for the extraction of the D-term from unpolarized cross-sections and beam spin asymmetries measured with the CEBAF Large Acceptance Spectrometer at 6 GeV. We discuss some aspects of the associated physics interpretation, and give prospects for future measurements. The availability of a Positron beam at Jefferson Lab will provide access to the Beam Charge Asymmetry for this reaction, which will crucially enable us to keep under control the systematical and model uncertainties in this framework.

Measurement of the generalized form factors near threshold via γ*p→nπ+ at high Q2

NASA Astrophysics Data System (ADS)

Park, K.; Gothe, R. W.; Adhikari, K. P.; Adikaram, D.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bookwalter, C.; Boiarinov, S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fradi, A.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Heddle, D.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Joo, K.; Kalantarians, N.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Kvaltine, N. D.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Mestayer, M. D.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, S.; Pereira, S. Anefalos; Phelps, E.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Ricco, G.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tian, Y.; Tkachenko, S.; Trivedi, A.; Ungaro, M.; Vernarsky, B.; Vlassov, A. V.; Voutier, E.; Watts, D. P.; Weygand, D. P.; Wood, M. H.; Zachariou, N.; Zhao, B.; Zhao, Z. W.

2012-03-01

We report the first extraction of the pion-nucleon multipoles near the production threshold for the nπ+ channel at relatively high momentum transfer (Q2 up to 4.2 GeV2). The dominance of the s-wave transverse multipole (E0+), expected in this region, allowed us to access the generalized form factor G1 within the light-cone sum-rule (LCSR) framework as well as the axial form factor GA. The data analyzed in this work were collected by the nearly 4π CEBAF Large Acceptance Spectrometer (CLAS) using a 5.754-GeV electron beam on a proton target. The differential cross section and the π-N multipole E0+/GD were measured using two different methods, the LCSR and a direct multipole fit. The results from the two methods are found to be consistent and almost Q2 independent.

Longitudinal target-spin asymmetries for deeply virtual Compton scattering

DOE PAGES

Seder, E.; Biselli, A.; Pisano, S.; ...

2015-01-22

A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6-GeV electron beam, a longitudinally polarized proton target and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for ep → e'p'y events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in Q 2, x B, t and Φ, for 166 four-dimensional bins. In the framework of Generalized Parton Distributions (GPDs), at leading twist the t dependence of these asymmetries provides insight on the spatial distribution ofmore » the axial charge of the proton, which appears to be concentrated in its center. In conclusion, these results bring important and necessary constraints for the existing parametrizations of chiral-even GPDs.« less

First measurement of the polarization observable E in the p →(y →π +)n reaction up to 2.25 GeV

DOE PAGES

Strauch, Steffen

2015-08-28

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E , for the reaction y →p →→π +n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have beenmore » included in new multipole analyses resulting in updated nucleon resonance parameters. Lastly, we report updated fits from the Bonn–Gatchina, Jülich–Bonn, and SAID groups.« less

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q 2 > 1 GeV 2 . I. e p → e π + n

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.

2017-03-20

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π+ electroproduction reaction γ*p → nπ +. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 < W < 3 GeV and 1 < Q 2 < 6GeV 2. Results were obtained for about 6000 bins in W, Q 2, cos(θ*), and Φ*. Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previousmore » data for W < 1.6 GeV, but very large differences are seen at higher values of W. Finally, a generalized parton distributions (GPD)-based model is in poor agreement with the data. When combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2, for resonances with masses as high as 2.4 GeV.« less

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q 2 > 1 GeV 2 . II. e p → e π 0 p

DOE PAGES

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.; ...

2017-03-20

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π + electroproduction reaction γ*p→nπ +. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 < W < 3 GeV and 1 < Q 2 < 6GeV 2. Results were obtained for about 6000 bins in W, Q 2, cos(θ*), and Φ*. Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previous datamore » for W < 1.6 GeV, but very large differences are seen at higher values of W. A generalized parton distributions (GPD)-based model is in poor agreement with the data. As a result, when combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2, for resonances with masses as high as 2.4 GeV.« less

Science Requirements and Conceptual Design for a Polarized Medium Energy Electron-Ion Collider at Jlab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abeyratne, S; Ahmed, S; Barber, D

2012-08-01

Researchers have envisioned an electron-ion collider with ion species up to heavy ions, high polarization of electrons and light ions, and a well-matched center-of-mass energy range as an ideal gluon microscope to explore new frontiers of nuclear science. In its most recent Long Range Plan, the Nuclear Science Advisory Committee (NSAC) of the US Department of Energy and the National Science Foundation endorsed such a collider in the form of a 'half-recommendation.' As a response to this science need, Jefferson Lab and its user community have been engaged in feasibility studies of a medium energy polarized electron-ion collider (MEIC), cost-effectivelymore » utilizing Jefferson Lab's already existing Continuous Electron Beam Accelerator Facility (CEBAF). In close collaboration, this community of nuclear physicists and accelerator scientists has rigorously explored the science case and design concept for this envisioned grand instrument of science. An electron-ion collider embodies the vision of reaching the next frontier in Quantum Chromodynamics - understanding the behavior of hadrons as complex bound states of quarks and gluons. Whereas the 12 GeV Upgrade of CEBAF will map the valence-quark components of the nucleon and nuclear wave functions in detail, an electron-ion collider will determine the largely unknown role sea quarks play and for the first time study the glue that binds all atomic nuclei. The MEIC will allow nuclear scientists to map the spin and spatial structure of quarks and gluons in nucleons, to discover the collective effects of gluons in nuclei, and to understand the emergence of hadrons from quarks and gluons. The proposed electron-ion collider at Jefferson Lab will collide a highly polarized electron beam originating from the CEBAF recirculating superconducting radiofrequency (SRF) linear accelerator (linac) with highly polarized light-ion beams or unpolarized light- to heavy-ion beams from a new ion accelerator and storage complex. Since the very beginning, the design studies at Jefferson Lab have focused on achieving high collider performance, particularly ultrahigh luminosities up to 10{sup 34} cm{sup -2}s{sup -1} per detector with large acceptance, while maintaining high polarization for both the electron and light-ion beams. These are the two key performance requirements of a future electron-ion collider facility as articulated by the NSAC Long Range Plan. In MEIC, a new ion complex is designed specifically to deliver ion beams that match the high bunch repetition and highly polarized electron beam from CEBAF. During the last two years, both development of the science case and optimization of the machine design point toward a medium-energy electron-ion collider as the topmost goal for Jefferson Lab. The MEIC, with relatively compact collider rings, can deliver a luminosity above 10{sup 34} cm{sup -2}s{sup -1} at a center-of-mass energy up to 65 GeV. It offers an electron energy up to 11 GeV, a proton energy up to 100 GeV, and corresponding energies per nucleon for heavy ions with the same magnetic rigidity. This design choice balances the scope of the science program, collider capabilities, accelerator technology innovation, and total project cost. An energy upgrade could be implemented in the future by adding two large collider rings housed in another large tunnel to push the center-of-mass energy up to or exceeding 140 GeV. After careful consideration of an alternative electron energy recovery linac on ion storage ring approach, a ring-ring collider scenario at high bunch repetition frequency was found to offer fully competitive performance while eliminating the uncertainties of challenging R&D on ampere-class polarized electron sources and many-pass energy-recovery linacs (ERLs). The essential new elements of an MEIC facility at Jefferson Lab are an electron storage ring and an entirely new, modern ion acceleration and storage complex. For the high-current electron collider ring, the upgraded 12 GeV CEBAF SRF linac will serve as a full-energy injector, and, if needed, provide top-off refilling. The CEBAF fixed-target nuclear physics program can be simultaneously operated since the filling time of the electron ring is very short. The ion complex for MEIC consists of sources for polarized light ions and unpolarized light to heavy ions, an SRF ion linac with proton energy up to 280 MeV, a 3 GeV prebooster synchrotron, a large booster synchrotron for proton energy up to 20 GeV, and a medium-energy collider ring with energy up to 100 GeV. The ion complex can accelerate other species of ions with corresponding energies at each accelerating stage. There are three collision points planned for MEIC. Two of them are for collisions with medium-energy ions; the third is for low energy ion beams stored in a dedicated low-energy compact storage ring, as a possible follow-on project.« less

Use of the CEBAF Accelerator for IR and UV Free Electron Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yunn, Byung; Sinclair, Charles; Leemann, Christoph

1992-08-01

The CEBAF superconducting linac is capable of accelerating electron beams suitable for driving high-power free-electron lasers. The 45 MeV injector linac with a 6 cm period wiggler can produce kilowatt output powers of infrared light (3.6-17 micrometer), while the 400 MeV north linac can produce ultraviolet light (~200 nm) at similar powers. The FELs require the addition of a high-peak intensity electron source (~ 60 A peak current) and extraction beam lines to wigglers with appropriate electron and photon optics. FEL operation is compatible with simultaneous baseline CEBAF nuclear physics operation. A design for a CEBAF-based FEL facility has beenmore » developed. The current status of the FEL project is reported.« less

First measurement of target and double spin asymmetries for e-vectorp-vector{yields}ep{pi}{sup 0} in the nucleon resonance region above the {delta}(1232)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biselli, A. S.; Burkert, V. D.; Avakian, H.

2008-10-15

The exclusive channel p-vectore-vector,e{sup '}p){pi}{sup 0} was studied in the first and second nucleon resonance regions in the Q{sup 2} range from 0.187 to 0.770 GeV{sup 2} at Jefferson Lab using the CEBAF Large Acceptance Spectrometer. Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the {pi}{sup 0} and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once includedmore » in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A{sub 1/2} and S{sub 1/2} for the Roper resonance N(1400)P{sub 11} and the N(1535)S{sub 11} and N(1520)D{sub 13} states.« less

Cross sections and beam asymmetries for e→p→enπ+ in the nucleon resonance region for 1.7⩽Q2⩽4.5 GeV2

NASA Astrophysics Data System (ADS)

Park, K.; Burkert, V. D.; Kim, W.; Aznauryan, I. G.; Minehart, R.; Smith, L. C.; Joo, K.; Elouadrhiri, L.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Blaszczyk, L.; Bonner, B. E.; Bookwalter, C.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Casey, L.; Cazes, A.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crede, V.; Cummings, J. P.; Dale, D.; Dashyan, N.; Masi, R. De; Vita, R. De; Sanctis, E. De; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dhamija, S.; Dharmawardane, K. V.; Dhuga, K. S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Fassi, L. El; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Forest, T. A.; Fradi, A.; Funsten, H.; Gabrielyan, M. Y.; Garçon, M.; Gavalian, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gonenc, A.; Gordon, C. I. O.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hafnaoui, K.; Hakobyan, H.; Hakobyan, R. S.; Hanretty, C.; Hardie, J.; Hassall, N.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Juengst, H. G.; Kalantarians, N.; Keller, D.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Lima, A. C. S.; Livingston, K.; Lu, H. Y.; Lukashin, K.; MacCormick, M.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Moreno, B.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, S.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schott, D.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shaw, J.; Shvedunov, N. V.; Skabelin, A. V.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.; Takeuchi, T.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Yurov, M.; Zana, L.; Zhang, B.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2008-01-01

The exclusive electroproduction process e→p→e'nπ+ was measured in the range of the photon virtuality Q2=1.7-4.5GeV2, and the invariant mass range for the nπ+ system of W=1.15-1.7GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive π+ production from protons with nearly full coverage in the azimuthal and polar angles of the nπ+ center-of-mass system. The nπ+ channel has particular sensitivity to the isospin ½ excited nucleon states, and together with the pπ0 final state will serve to determine the transition form factors of a large number of resonances. The largest discrepancy between these results and present modes was seen in the σLT' structure function. In this experiment, 31,295 cross section and 4,184 asymmetry data points were measured. Because of the large volume of data, only a reduced set of structure functions and Legendre polynomial moments can be presented that are obtained in model-independent fits to the differential cross sections.

Petabyte Class Storage at Jefferson Lab (CEBAF)

NASA Technical Reports Server (NTRS)

Chambers, Rita; Davis, Mark

1996-01-01

By 1997, the Thomas Jefferson National Accelerator Facility will collect over one Terabyte of raw information per day of Accelerator operation from three concurrently operating Experimental Halls. When post-processing is included, roughly 250 TB of raw and formatted experimental data will be generated each year. By the year 2000, a total of one Petabyte will be stored on-line. Critical to the experimental program at Jefferson Lab (JLab) is the networking and computational capability to collect, store, retrieve, and reconstruct data on this scale. The design criteria include support of a raw data stream of 10-12 MB/second from Experimental Hall B, which will operate the CEBAF (Continuous Electron Beam Accelerator Facility) Large Acceptance Spectrometer (CLAS). Keeping up with this data stream implies design strategies that provide storage guarantees during accelerator operation, minimize the number of times data is buffered allow seamless access to specific data sets for the researcher, synchronize data retrievals with the scheduling of postprocessing calculations on the data reconstruction CPU farms, as well as support the site capability to perform data reconstruction and reduction at the same overall rate at which new data is being collected. The current implementation employs state-of-the-art StorageTek Redwood tape drives and robotics library integrated with the Open Storage Manager (OSM) Hierarchical Storage Management software (Computer Associates, International), the use of Fibre Channel RAID disks dual-ported between Sun Microsystems SMP servers, and a network-based interface to a 10,000 SPECint92 data processing CPU farm. Issues of efficiency, scalability, and manageability will become critical to meet the year 2000 requirements for a Petabyte of near-line storage interfaced to over 30,000 SPECint92 of data processing power.

Generating Fiducial Cuts for CLAS E5

NASA Astrophysics Data System (ADS)

Greenholt, Kristen

2005-04-01

The Thomas Jefferson National Accelerator Facility, located in Newport News, Virginia, is home to CLAS (CEBAF Large Acceptance Spectrometer) which observes the scattering effects of high-energy collisions of an electron beam and a proton or deuteron target. When data are collected with CLAS, one of the properties measured is the cross-section, which is proportional to the number of events and the efficiency and inversely proportional to the solid angle. The efficiency, or acceptance of the detector, is the ratio between the data one expects to observe in an ideal detector and the data that we actually measure with the real CLAS detector. In outlying azimuthal regions, the efficiency is less clearly understood, which leads to measurements which are reliant on the conditions of the detector itself. In order to analyze data which fall in regions of stable and well-understood efficiency, we generated fiducial cuts on CLAS. Our fiducial cuts fit a function to the edges of regions of stable efficiency. These cuts enable us to focus on the data with good acceptance/efficiency. When examining at the fiducial cuts, we required stable efficiency, or flat regions, a good visual fit, a minimized chi squared, and a reasonable behavior in each in azimuthal versus polar angle plane for each electron-momentum bin. Generating these fiducial cuts enables us to focus on data from CLAS where the efficiency of the detector is well understood.

Jefferson Lab 12 GEV Cebaf Upgrade

NASA Astrophysics Data System (ADS)

Rode, C. H.

2010-04-01

The existing continuous electron beam accelerator facility (CEBAF) at Thomas Jefferson National Accelerator Facility (TJNAF) is a 5-pass, recirculating cw electron Linac operating at ˜6 GeV and is devoted to basic research in nuclear physics. The 12 GeV CEBAF Upgrade is a 310 M project, sponsored by the Department of Energy (DOE) Office of Nuclear Physics, that will expand its research capabilities substantially by doubling the maximum energy and adding major new experimental apparatus. The project received construction approval in September 2008 and has started the major procurement process. The cryogenic aspects of the 12 GeV CEBAF Upgrade includes: doubling the accelerating voltages of the Linacs by adding ten new high-performance, superconducting radiofrequency (SRF) cryomodules (CMs) to the existing 42 1/4 cryomodules; doubling of the 2 K cryogenics plant; and the addition of eight superconducting magnets.

Precision measurements of g1 of the proton and of the deuteron with 6 GeV electrons

NASA Astrophysics Data System (ADS)

Prok, Y.; Bosted, P.; Kvaltine, N.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Baghdasaryan, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Biselli, A. S.; Bono, J.; Briscoe, W. J.; Brock, J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carlin, C.; Carman, D. S.; Celentano, A.; Chandavar, S.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crabb, D.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Forest, T. A.; Garçon, M.; Garillon, B.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Giovanetti, K. L.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guler, N.; Hafidi, K.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S.; Jiang, X.; Jo, H. S.; Joo, K.; Kalantarians, N.; Keith, C.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Meekins, D.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Peng, P.; Phillips, J. J.; Pierce, J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Rimal, D.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Smith, C.; Smith, G.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tang, W.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2014-08-01

The inclusive polarized structure functions of the proton and deuteron, g1p and g1d, were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at laboratory angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual deep inelastic region kinematics, Q2>1 GeV2 and the final-state invariant mass W >2 GeV, the ratio of polarized to unpolarized structure functions g1/F1 is found to be nearly independent of Q2 at fixed x. Significant resonant structure is apparent at values of W up to 2.3 GeV. In the framework of perturbative quantum chromodynamics, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions.

Measurement of the generalized form factors near threshold via γ *p → nπ + at high Q 2

DOE PAGES

Park, K.; Adhikari, K. P.; Adikaram, D.; ...

2012-03-26

We report the first extraction of the pion-nucleon multipoles near the production threshold for the nπ + channel at relatively high momentum transfer (Q 2 up to 4.2 GeV 2). The dominance of the s-wave transverse multipole (E 0+), expected in this region, allowed us to access the generalized form factor G 1 within the light-cone sum rule (LCSR) framework as well as the axial form factor G A. The data analyzed in this work were collected by the nearly 4π CEBAF Large Acceptance Spectrometer (CLAS) using a 5.754-GeV electron beam on a proton target. The differential cross section andmore » the π-N multipole E 0+/G D were measured using two different methods, the LCSR and a direct multipole fit. The results from the two methods are found to be consistent and almost Q 2 independent.« less

Light vector mesons in the nuclear medium

NASA Astrophysics Data System (ADS)

Wood, M. H.; Nasseripour, R.; Weygand, D. P.; Djalali, C.; Tur, C.; Mosel, U.; Muehlich, P.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Blaszczyk, L.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Casey, L.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dickson, R.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Fradi, A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hanretty, C.; Hardie, J.; Hassall, N.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Livingston, K.; Lu, H. Y.; MacCormick, M.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Williams, M.; Wolin, E.; Yegneswaran, A.; Zana, L.; Zhang, B.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2008-07-01

The light vector mesons (ρ,ω, and ϕ) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the ρ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to e+e-. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The ρ-meson mass spectrum was extracted after the ω and ϕ signals were removed in a nearly model-independent way. Comparisons were made between the ρ mass spectra from the heavy targets (A>2) with the mass spectrum extracted from the deuterium target. With respect to the ρ-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion.

Measurement of the polarized structure function σL T' for p ( e→ , e' π+ ) n in the Δ ( 1232 ) resonance region

NASA Astrophysics Data System (ADS)

Joo, K.; Smith, L. C.; Aznauryan, I. G.; Burkert, V. D.; Minehart, R.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Benmouna, N.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Chen, S.; Ciciani, L.; Cole, P. L.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; de Sanctis, E.; Devita, R.; Degtyarenko, P. V.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fersch, R.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Gaff, S. J.; Garçon, M.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D.; Ito, M. M.; Jenkins, D.; Juengst, H. G.; Kellie, J. D.; Kelley, J. H.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Koubarovski, V.; Kramer, L. H.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McNabb, J. W.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Sabourov, K.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.

2004-10-01

The polarized longitudinal-transverse structure function σL T' has been measured using the p ( e→ , e' π+ ) n reaction in the Δ ( 1232 ) resonance region at Q2 =0.40 and 0.65 GeV2 . No previous σL T' data exist for this reaction channel. The kinematically complete experiment was performed at the Jefferson Lab with the CEBAF large acceptance spectrometer using longitudinally polarized electrons at an energy of 1.515 GeV . A partial-wave analysis of the data shows generally better agreement with recent phenomenological models of pion electroproduction compared to the previously measured π0 p channel. A fit to both π0 p and π+ n channels using a unitary isobar model suggests the unitarized Born terms provide a consistent description of the nonresonant background. The t -channel pion pole term is important in the π0 p channel through a rescattering correction, which could be model dependent.

First measurement of beam-recoil observables Cx and Cz in hyperon photoproduction

NASA Astrophysics Data System (ADS)

Bradford, R. K.; Schumacher, R. A.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Bianchi, N.; Biselli, A. S.; Bonner, B. E.; Bouchigny, S.; Boiarinov, S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Chen, S.; Cole, P. L.; Coleman, A.; Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Masi, R. De; Sanctis, E. De; Vita, R. De; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dickson, R.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Fassi, L. El; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gonenc, A.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hu, J.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lima, A. C. S.; Livingston, K.; Lu, H. Y.; Lukashin, K.; MacCormick, M.; Manak, J. J.; Marchand, C.; Markov, N.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Natasha, N.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Quinn, B. P.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Serov, V. S.; Shafi, A.; Sharabian, Y. G.; Shaw, J.; Shvedunov, N. V.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Spraker, M.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Watts, D. P.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2007-03-01

Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions γ→+p→K++Λ→ and γ→+p→K++Σ→0. The data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS) detector at the Jefferson Lab for center-of-mass energies W between 1.6 and 2.53 GeV, and for -0.85

Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target

NASA Astrophysics Data System (ADS)

Pisano, S.; Biselli, A.; Niccolai, S.; Seder, E.; Guidal, M.; Mirazita, M.; Adhikari, K. P.; Adikaram, D.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bosted, P.; Briscoe, B.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Carlin, C.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crabb, D. G.; Crede, V.; D'Angelo, A.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Garçon, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, X.; Jo, H. S.; Joo, K.; Joosten, S.; Keith, C. D.; Keller, D.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacCormick, M.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Meekins, D. G.; Meyer, C. A.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Munoz Camacho, C.; Nadel-Turonski, P.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Phelps, W.; Phillips, J. J.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Skorodumina, I.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Tian, Ye; Tkachenko, S.; Turisini, M.; Ungaro, M.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2015-03-01

Single-beam, single-target, and double spin asymmetries for hard exclusive electroproduction of a photon on the proton e →p →→e'p'γ are presented. The data were taken at Jefferson Lab using the CEBAF large acceptance spectrometer and a longitudinally polarized NH3 14 target. The three asymmetries were measured in 165 four-dimensional kinematic bins, covering the widest kinematic range ever explored simultaneously for beam and target-polarization observables in the valence quark region. The kinematic dependences of the obtained asymmetries are discussed and compared to the predictions of models of generalized parton distributions. The measurement of three DVCS spin observables at the same kinematic points allows a quasi-model-independent extraction of the imaginary parts of the H and H ˜ Compton form factors, which give insight into the electric and axial charge distributions of valence quarks in the proton.

Precision measurements of g1 of the proton and the deuteron with 6 GeV electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prok, Yelena; Bosted, Peter; Kvaltine, Nicholas

2014-08-01

The inclusive polarized structure functions of the proton and deuteron, g1p and g1d, were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at lab angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual DIS kinematics, Q^2>1 GeV^2 and the final-state invariant mass W>2 GeV, the ratio of polarized to unpolarized structure functions g1/F1 is found to be nearly independent of Q^2 at fixed x. Significant resonant structure is apparent at values of W up tomore » 2.3 GeV. In the framework of perturbative QCD, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions.« less

Determination of the beam-spin asymmetry of deuteron photodisintegration in the energy region Eγ=1.1 –2.3 GeV

DOE PAGES

Zachariou, N.; Ilieva, Y.; Ivanov, N. Ya.; ...

2015-05-01

The beam-spin asymmetry, Σ, for the reaction γd→ΣΣpn has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins, between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, Θ c.m., between 25° and 160°. These are the first measurements of beam-spin asymmetries at Θ c.m.=90° for photon-beam energies above 1.6 GeV, and the first measurements for angles other than Θ c.m.=90°. The angular and energy dependence of Σ is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration inmore » the transition region between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.« less

Measurement of the helicity asymmetry E in ω → π + π - π 0 photoproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akbar, Z.; Roy, P.; Park, S.

The double-polarization observablemore » $E$ was studied for the reaction $$\\gamma p\\to p\\omega$$ using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally-polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, $$\\omega\\to\\pi^+\\pi^-\\pi^0$$, using a circularly-polarized tagged-photon beam with energies ranging from the $$\\omega$$ threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the $3/2^+$ partial wave near threshold, which is identified with the sub-threshold $$N(1720)\\,3/2^+$$ nucleon resonance. To describe the entire data set, which consisted of $$\\omega$$ differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. Here, with respect to non-resonant mechanisms, $$\\pi$$ exchange in the $t$-channel was found to remain small across the analyzed energy range, while pomeron $t$-channel exchange gradually grew from the reaction threshold to dominate all other contributions above $$W \\approx 2$$ GeV.« less

Measurement of the helicity asymmetry E in ω → π + π - π 0 photoproduction

DOE PAGES

Akbar, Z.; Roy, P.; Park, S.; ...

2017-12-28

The double-polarization observablemore » $E$ was studied for the reaction $$\\gamma p\\to p\\omega$$ using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally-polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, $$\\omega\\to\\pi^+\\pi^-\\pi^0$$, using a circularly-polarized tagged-photon beam with energies ranging from the $$\\omega$$ threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the $3/2^+$ partial wave near threshold, which is identified with the sub-threshold $$N(1720)\\,3/2^+$$ nucleon resonance. To describe the entire data set, which consisted of $$\\omega$$ differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. Here, with respect to non-resonant mechanisms, $$\\pi$$ exchange in the $t$-channel was found to remain small across the analyzed energy range, while pomeron $t$-channel exchange gradually grew from the reaction threshold to dominate all other contributions above $$W \\approx 2$$ GeV.« less

The Search for Exotic Mesons in gamma p -> pi+pi+pi-n with CLAS at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craig Bookwalter

2011-12-01

The {pi}{sub 1}(1600), a J{sup PC} = 1{sup {-+}} exotic meson has been observed by experiments using pion beams. Theorists predict that photon beams could produce gluonic hybrid mesons, of which the {pi}{sub 1}(1600) is a candidate, at enhanced levels relative to pion beams. The g12 rungroup at Jefferson Lab's CEBAF Large Acceptance Spectrometer (CLAS) has recently acquired a large photoproduction dataset, using a liquid hydrogen target and tagged photons from a 5.71 GeV electron beam. A partial-wave analysis of 502K {gamma}p {yields} {pi}{sup +}{pi}{sup +}{pi}{sup -}n events selected from the g12 dataset has been performed, and preliminary fit resultsmore » show strong evidence for well-known states such as the a{sub 1}(1260), a{sub 2}(1320), and {pi}{sub 2}(1670). However, we observe no evidence for the production of the {pi}{sub 1}(1600) in either the partial-wave intensities or the relative complex phase between the 1{sup {-+}} and the 2{sup {-+}} (corresponding to the {pi}{sub 2}) partial waves.« less

First measurement of target and double spin asymmetries for polarized e- polarized p --> e p pi0 in the nucleon resonance region above the Delta(1232)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biselli, Angela; Burkert, Volker; Amaryan, Moscov

2008-10-01

DOI: http://dx.doi.org/10.1103/PhysRevC.78.045204 The exclusive channel polarized proton(polarized e,e prime p)pi0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set,more » once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A_{1/2} and S_{1/2} for the Roper resonance N(1400)P11, and the N(1535)S11 and N(1520)D13 states.« less

Measurement of the helicity asymmetry E in ω →π+π-π0 photoproduction

NASA Astrophysics Data System (ADS)

Akbar, Z.; Roy, P.; Park, S.; Crede, V.; Anisovich, A. V.; Denisenko, I.; Klempt, E.; Nikonov, V. A.; Sarantsev, A. V.; Adhikari, K. P.; Adhikari, S.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Boiarinov, S.; Briscoe, W. J.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Cao, F. T.; Carlin, C.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; Egiyan, H.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fersch, R.; Filippi, A.; Fradi, A.; Garçon, M.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Hollis, G.; Holtrop, M.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Joosten, S.; Keith, C. D.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meekins, D. G.; Mineeva, T.; Mokeev, V.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

2017-12-01

The double-polarization observable E was studied for the reaction γ p →p ω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω →π+π-π0 , using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3 /2+ partial wave near threshold, which is identified with the subthreshold N (1720 ) 3 /2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t -channel exchange gradually grew from the reaction threshold to dominate all other contributions above W ≈2 GeV.

The Science and Experimental Equipment for the 12 GeV Upgrade of CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arrington, John; Bernstein, Aron; Brooks, William

2005-01-10

This Conceptual Design Report (CDR) presents the compelling scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab to 12 GeV. Such a facility will make profound contributions to the study of hadronic matter.

Status Report on the CEBAF IR and UV FELs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leemann, Christoph; Bisognano, Joseph; Douglas, David

1993-07-01

The CEBAF five pass recirculating, superconducting linac, being developed as a high power electron source for nuclear physics, is also an ideal FEL driver.The 45 MeV front end linac is presently operational with a CW (low peak current) nuclear physics gun and has met all CEBAF performance specifications including low emittance and energy spread (< 1 * 10^-4). Progress will be reported in commissioning.This experience leads to predictions of excellent FEL performance.Initial designs reported last year have been advanced.Using the output of a high charge DC photoemission gun under development with a 6 cm period wiggler produces kilowatt output powersmore » in the 3.6 to 17 micrometer range in the fundamental.Third harmonic operation extends IR performance down to 1.2 micrometer.Beam at energies up to 400 MeV from the first full CEBAF linac will interact in a similar but longer wiggler to yield kilowatt UV light production at wavelengths as short as 0.15 micrometers.Full power FEL« less

Target and beam-target spin asymmetries in exclusive π+ and π- electroproduction with 1.6- to 5.7-GeV electrons

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Biselli, A. S.; Careccia, S.; Dodge, G.; Fersch, R.; Guler, N.; Kuhn, S. E.; Pierce, J.; Prok, Y.; Zheng, X.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Boiarinov, S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Garçon, M.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Keller, D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Minehart, R.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sparveris, N.; Stankovic, Ivana; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2016-11-01

Beam-target double-spin asymmetries and target single-spin asymmetries in exclusive π+ and quasiexclusive π- electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for π+) and deuterons (for π-) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 1.5 GeV. Very large target-spin asymmetries are observed for W >1.6 GeV. When combined with cross-section measurements, the present results can provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q2, for resonances with masses as high as 2.3 GeV.

Numerical modelling of the CEBAF electron gun with EGUN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philippe Liger; Geoffrey Krafft

1990-09-10

The electron source used in the injector for the CEBAF accelerator is a Hermosa electron gun with a 2 mm diameter cathode and a control electrode. It produces a 100 keV electron beam to be focused on the first of two apertures which comprise an emittance filter. A normalized emittance of less than {pi} mm mrad at 1.2 mA is set by the requirements of the final beam from the CEBAF linac, since downstream of the filter, a system of two choppers and a third aperture removes 5/6 of the current. In addition, for RF test purposes a higher currentmore » of about 5 mA is needed, possibly at higher emittance. This paper presents a way of calculating the characteristics of the CEBAF electron gun with the gun design code EGUN, and the accuracy of the results is discussed. The transverse shape of the beam delivered by the gun has been observed, and its current measured. A halo around the beam has been seen, and the calculations can reproduce this effect.« less

Continuous wave superconducting radio frequency electron linac for nuclear physics research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reece, Charles E.

CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively serving the nuclear physics research community as a unique forefront international resource since 1995. This cw electron linear accelerator (linac) at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab) has continued to evolve as a precision tool for discerning the structure and dynamics within nuclei. Superconducting rf (SRF) technology has been the essential foundation for CEBAF, first as a 4 GeV machine, then 6 GeV, and currently capable of 12 GeV. Lastly, we review the development, implementation, and performance of SRF systems for CEBAF from itsmore » early beginnings to the commissioning of the 12 GeV era.« less

Beams-becoming enthusiastic about math and science - A Department of Energy research laboratory/school district partnership program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strozak, K.; Gagnon, S.

1994-12-31

BEAMS immerses fifth and sixth grade classes in CEBAF`s environment for a week of school. By exposing students and teachers to science`s excitement, challenges, and opportunities, BEAMS motivates students, enhances teachers, and involves parents, with the goal of improving scientific literacy and work force readiness. CEBAF and its school partners are extending BEAMS into a multi-year program, integrating educational partnerships active in the region. The planned focus emphasizes grades four through ten. A long-term evaluation model, incorporating measures of students attitudes, achievement, and academic course choices is being implemented. Three years of data on student attitudinal changes, referenced against controls,more » have been analyzed.« less

A Beat Frequency RF Modulator for Generation of Low Repetition Rate Electron Microbunches for the CEBAF Polarized Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Musson; Reza Kazimi; Benard Poelker

2007-06-25

Fiber-based drive lasers now produce all of the spin-polarized electron beams at CEBAF/Jefferson Lab. The flexibility of these drive lasers, combined with the existing three-beam CEBAF photoinjector Chopper, provides a means to implement a beat frequency technique to produce long time intervals between individual electron microbunches (tens of nanoseconds) by merely varying the nominal 499 MHz drive laser frequency by < 20%. This submission describes the RF Laser modulator that uses a divider and heterodyne scheme to maintain coherence with the accelerator Master Oscillator (MO), while providing delay resolution in increments of 2ns. Some possible uses for such a beammore » are discussed as well as intended future development.« less

Continuous wave superconducting radio frequency electron linac for nuclear physics research

DOE PAGES

Reece, Charles E.

2016-12-28

CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively serving the nuclear physics research community as a unique forefront international resource since 1995. This cw electron linear accelerator (linac) at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab) has continued to evolve as a precision tool for discerning the structure and dynamics within nuclei. Superconducting rf (SRF) technology has been the essential foundation for CEBAF, first as a 4 GeV machine, then 6 GeV, and currently capable of 12 GeV. Lastly, we review the development, implementation, and performance of SRF systems for CEBAF from itsmore » early beginnings to the commissioning of the 12 GeV era.« less

Polarization Observables T and F in the yp -> pi p Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Hao

The theory that describes the interaction of quarks is Quantum Chromodynamics (QCD), but how quarks are bound inside a nucleon is not yet well understood. Pion photoproduction experiments reveal important information about the nucleon excited states and the dynamics of the quarks within it and thus provide a useful tool to study QCD. Detailed information about this reaction can be obtained in experiments that utilize polarized photon beams and polarized targets. Pion photoproduction in the γρ -> π0ρ reaction has been measured in the FROST experiment at the Thomas Jefferson National Accelerator Facility. In this experiment circularly polarized photons withmore » electron-beam energies up to 3.082 GeV impinged on a transversely polarized frozen-spin target. Final-state protons were detected in the CEBAF Large Acceptance Spectrometer. Results of the polarization observables T and F have been extracted. The data generally agree with predictions of present partial wave analyses, but also show marked differences. The data will constrain further partial wave analyses and improve the extraction of proton resonance properties.« less

Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

NASA Astrophysics Data System (ADS)

Roy, P.; Akbar, Z.; Park, S.; Crede, V.; Anisovich, A. V.; Denisenko, I.; Klempt, E.; Nikonov, V. A.; Sarantsev, A. V.; Adhikari, K. P.; Adhikari, S.; Anefalos Pereira, S.; Ball, J.; Balossino, I.; Bashkanov, M.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Carlin, C.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clary, B. A.; Cole, P. L.; Contalbrigo, M.; D'Angelo, A.; Dashyan, N.; De Vita, R.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fradi, A.; Gavalian, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Joo, K.; Joosten, S.; Keith, C. D.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McCracken, M. E.; McKinnon, B.; Meekins, D. G.; Meyer, C. A.; Meziani, Z. E.; Mineeva, T.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, E.; Phelps, W.; Pierce, J. J.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Riser, D.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tan, J. A.; Torayev, B.; Ungaro, M.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

2018-05-01

The photoproduction of ω mesons off the proton has been studied in the reaction γ p →p ω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω →π+π-π0 , using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s -channel resonance production were found in addition to t -channel exchange processes.

Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

DOE PAGES

Roy, P.; Akbar, Z.; Park, S.; ...

2018-05-04

Here, the photoproduction ofmore » $$\\omega$$ mesons off the proton has been studied in the reaction $$\\gamma p\\to p\\,\\omega$$ using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target (FROST) in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry, $T$, has been measured in photoproduction from the decay $$\\omega\\to\\pi^+\\pi^-\\pi^0$$, using a transversely-polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant non-zero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry, $$\\Sigma$$, are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional $$\\omega$$-photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from $s$-channel resonance production were found in addition to $t$-channel exchange processes.« less

Moments of the spin structure functions g1p and g1d for 0.05

NASA Astrophysics Data System (ADS)

Clas Collaboration; Prok, Y.; Bosted, P.; Burkert, V. D.; Deur, A.; Dharmawardane, K. V.; Dodge, G. E.; Griffioen, K. A.; Kuhn, S. E.; Minehart, R.; Adams, G.; Amaryan, M. J.; Anghinolfi, M.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Blaszczyk, L.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Casey, L.; Cazes, A.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crede, V.; Cummings, J. P.; Dale, D.; Dashyan, N.; de Masi, R.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Dhuga, K. S.; Dickson, R.; Djalali, C.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feldman, G.; Fersh, R. G.; Feuerbach, R. J.; Forest, T. A.; Fradi, A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gothe, R. W.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hardie, J.; Hassall, N.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Keith, C. D.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klusman, M.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuleshov, S. V.; Kuznetsov, V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Lima, A. C. S.; Livingston, K.; Lu, H. Y.; Lukashin, K.; MacCormick, M.; Marchand, C.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Moreno, B.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Procureur, S.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Seely, M. L.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shaw, J.; Shvedunov, N. V.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2009-02-01

The spin structure functions g for the proton and the deuteron have been measured over a wide kinematic range in x and Q using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05

Exclusive &-circ; Electro-production from the Neutron in the Resonance Region

NASA Astrophysics Data System (ADS)

Zhang, Jixie

2008-10-01

The study of baryon resonances is crucial to our understanding of nucleon structure and dynamics. Although the excited states of the proton have been studied in great detail, there are very few data available for the neutron resonances because of the difficulty inherent in obtaining a free neutron target. To overcome this limitation, the spectator tagging technique was used in one of the CEBAF Large Acceptance Spectrometer(CLAS) collaboration experiments, Barely off-shell Nuclear Structure (BoNuS), in Hall-B at Jefferson Lab. We have constructed a radial time projection chamber (RTPC) based on the gaseous electron multiplier (GEM) technology to detect recoil protons with momenta from 70 to 200 MeV/c. Electron scattering data were taken in 2005 with beam energies of 2.1, 4.2 and 5.3 GeV using a 7 atm gaseous deuterium target in conjunction with the RTPC and CLAS detectors. We have analyzed exclusive D(e, e' &-circ;p) p events in which the proton was detected either in CLAS or in the RTPC. Preliminary cross sections will be presented for this reaction.

Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, P.; Akbar, Z.; Park, S.

Here, the photoproduction ofmore » $$\\omega$$ mesons off the proton has been studied in the reaction $$\\gamma p\\to p\\,\\omega$$ using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target (FROST) in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry, $T$, has been measured in photoproduction from the decay $$\\omega\\to\\pi^+\\pi^-\\pi^0$$, using a transversely-polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant non-zero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry, $$\\Sigma$$, are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional $$\\omega$$-photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from $s$-channel resonance production were found in addition to $t$-channel exchange processes.« less

Analysis of the polarization observables H and P for γ-> p -> ->π+ n

NASA Astrophysics Data System (ADS)

Lee, Robert J.; Ritchie, B. G.; Dugger, M.; CLAS Collaboration

2017-09-01

A search is underway to find baryon resonances that have been predicted, but yet remain unobserved. Nucleon resonances, due to their broad energy widths, overlap and must be disentangled in order to be identified. Meson photoproduction observables related to the orientation of the spin of the incoming photon and the spin of the target proton are useful tools to deconvolute the nucleon resonance spectrum. These observables are particularly sensitive to interference between phases of the complex amplitudes. A set of these observables has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab with linearly-polarized photons having energies from 725 to 2100 MeV with polar angle values of cos (θC . M .) between 1 and -0.8 and transversely-polarized protons in the Jefferson Lab FRozen Spin Target (FROST). By fitting π+ yields over azimuthal scattering angle, the observables H and P have been extracted. Preliminary results for these observables will be presented and compared with predictions provided by SAID Partial-Wave Analysis Facility. Work at ASU is supported by the U.S. National Science Foundation.

Single and double spin asymmetries for pion electro-production from the deuteron in the resonance region

NASA Astrophysics Data System (ADS)

Careccia, Sharon L.

The single and double spin asymmetries At and Aet have been measured in pi- electro-production off the deuteron using a longitudinally polarized electron beam and a polarized ND3 target. The electron beam was polarized using a strained GaAs cathode and the target was polarized using Dynamic Nuclear Polarization. The data were collected at beam energies of 1.6, 1.7, 2.5 and 4.2 GeV in Hall B at Jefferson Lab in the spring of 2001. The final state particles were detected in the CEBAF Large Acceptance Spectrometer (CLAS). The d(e,e'pi-p)p exclusive channel was identified using the missing mass technique and the asymmetries were extracted as a function of the momentum transfer Q2, invariant mass W, and center of mass pion angles cos(theta*) and φ*. The results are generally in agreement with the phenomenological model MAID at low energies, but there are discrepancies in the 2nd and 3rd resonance regions, as well as at forward angles.

Target and beam-target spin asymmetries in exclusive π + and π - electroproduction with 1.6- to 5.7-GeV electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosted, P. E.; Biselli, A. S.; Careccia, S.

Beam-target double-spin asymmetries and target single-spin asymmetries in exclusive pi(+) and quasiexclusive pi(-) electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for pi(+)) and deuterons (for pi(-)) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 < W < 2.6 GeV and 0.05 < Q(2) < 5 GeV2, with good angular coverage in the forward hemisphere. The asymmetry results were divided into approximately 40 000 kinematic bins for pi(+) from free protons and 15 000 bins for pi(-) production from bound nucleons in the deuteron.more » The present results are found to be in reasonable agreement with fits to previous world data for W < 1.7 GeV and Q(2) < 0.5 GeV2, with discrepancies increasing at higher values of Q(2), especially for W > 1.5 GeV. Very large target-spin asymmetries are observed for W > 1.6 GeV. When combined with cross-section measurements, the present results can provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q(2), for resonances with masses as high as 2.3 GeV.« less

Target and beam-target spin asymmetries in exclusive π + and π – electroproduction with 1.6- to 5.7-GeV electrons

DOE PAGES

Bosted, P. E.; Biselli, A. S.; Careccia, S.; ...

2016-11-01

Here, beam-target double-spin asymmetries and target single-spin asymmetries in exclusive π + and quasiexclusive π – electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for π +) and deuterons (for π –) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 < W < 2.6 GeV and 0.05 < Q 2 < 5GeV 2, with good angular coverage in the forward hemisphere. The asymmetry results were divided into approximately 40 000 kinematic bins for π + from free protons and 15 000 bins for πmore » – production from bound nucleons in the deuteron. The present results are found to be in reasonable agreement with fits to previous world data for W < 1.7 GeV and Q 2 < 0.5GeV 2, with discrepancies increasing at higher values of Q 2, especially for W > 1.5 GeV. Very large target-spin asymmetries are observed for W > 1.6 GeV. When combined with cross-section measurements, the present results can provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2, for resonances with masses as high as 2.3 GeV.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swapan Chattopadhyay

Hurricane Isabel was at category five--the most violent on the Saffir-Simpson scale of hurricane strength--when it began threatening the central Atlantic seaboard of the US. Over the course of several days, precautions against the extreme weather conditions were taken across the Jefferson Lab site in south-east Virginia. On 18 September 2003, when Isabel struck North Carolina's Outer Banks and moved northward, directly across the region around the laboratory, the storm was still quite destructive, albeit considerably reduced in strength. The flood surge and trees felled by wind substantially damaged or even devastated buildings and homes, including many belonging to Jeffersonmore » Lab staff members. For the laboratory itself, Isabel delivered an unplanned and severe challenge in another form: a power outage that lasted nearly three-and-a-half days, and which severely tested the robustness of Jefferson Lab's two superconducting machines, the Continuous Electron Beam Accelerator Facility (CEBAF) and the superconducting radiofrequency ''driver'' accelerator of the laboratory's free-electron laser. Robustness matters greatly for science at a time when microwave superconducting linear accelerators (linacs) are not only being considered, but in some cases already being built for projects such as neutron sources, rare-isotope accelerators, innovative light sources and TeV-scale electron-positron linear colliders. Hurricane Isabel interrupted a several-week-long maintenance shutdown of CEBAF, which serves nuclear and particle physics and represents the world's pioneering large-scale implementation of superconducting radiofrequency (SRF) technology. The racetrack-shaped machine is actually a pair of 500-600 MeV SRF linacs interconnected by recirculation arc beamlines. CEBAF delivers simultaneous beams at up to 6 GeV to three experimental halls. An imminent upgrade will double the energy to 12 GeV and add an extra hall for ''quark confinement'' studies. On a smaller scale, Jefferson Lab's original kilowatt-scale infrared free-electron laser (FEL) is ''driven'' by a high-current cousin of CEBAF, a 70 MeV SRF linac with a high-current injector. The FEL serves multidisciplinary science and technology as the world's highest-average-power source of tunable coherent infrared light. An upgrade to 10 kW is in commissioning--as it was when Isabel began threatening.« less

Test of New Readout Electronics for the BONuS12 Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ehrhart, Mathieu

For decades, electron-proton scattering experiments have been providing a large amount of data on the proton structure function. However, because of the instability of free neutrons, fewer experiments have been able to study the neutron structure function. The BONuS collaboration at Jefferson Laboratory addresses this challenge by scattering electrons off a deuterium target, using a RTPC capable of detecting the low-momentum spectator protons near the target. Events of electrons scattering on almost free neutrons are selected by constraining the spectator protons to very low momenta and very backward scattering angles. In 2005, BONuS successfully measured the neutron structure with scatteringmore » electrons of up to 5.3 GeV energy. An extension of this measurement has been approved using the newly upgraded 12 GeV electron beam and CLAS12 (CEBAF Large Acceptance Spectrometer). For this new set of measurements, a new RTPC detector using GEM trackers is being developed to allow measurements of spectator protons with momenta as low as 70 MeV/c. The new RTPC will use a new readout electronic system, which is also used by other trackers in CLAS12. This thesis will present the first tests of this electronics using a previously built RTPC of similar design.« less

Test of New Readout Electronics for the Bonus12 Experiment

NASA Astrophysics Data System (ADS)

Ehrhart, Mathieu

For decades, electron-proton scattering experiments have been providing a large amount of data on the proton structure function. However, because of the instability of free neutrons, fewer experiments have been able to study the neutron structure function. The BONuS collaboration at Jefferson Laboratory addresses this challenge by scattering electrons off a deuterium target, using a RTPC capable of detecting the low-momentum spectator protons near the target. Events of electrons scattering on almost free neutrons are selected by constraining the spectator protons to very low momenta and very backward scattering angles. In 2005, BONuS successfully measured the neutron structure with scattering electrons of up to 5.3 GeV energy. An extension of this measurement has been approved using the newly upgraded 12 GeV electron beam and CLAS12 (CEBAF Large Acceptance Spectrometer). For this new set of measurements, a new RTPC detector using GEM trackers is being developed to allow measurements of spectator protons with momenta as low as 70 MeV/c. The new RTPC will use a new readout electronic system, which is also used by other trackers in CLAS12. This thesis will present the first tests of this electronics using a previously built RTPC of similar design.

L-Band High Power Amplifiers for CEBAF Linac

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fugitt, Jock; Killion, Richard; Nelson, Richard

1990-09-01

The high power portion of the CEBAF RF system utilizes 340 5kW klystrons providing 339 separately controlled outputs. Modulating anodes have been included in the klystron design to provide for economically efficient operation. The design includes shunt regulator-type modulating anode power supplies running from the cathode power supply, and switching filament power supplies. Remotely programmable filament voltage allows maximum cathode life to be realized. Klystron operating setpoint and fast klystron protection logic are provided by individual external CEBAF RF control modules. A single cathode power supply powers a block of eight klystrons. The design includes circulators and custom extrusion andmore » hybrid waveguide components which have allowed reduced physical size and lower cost in the design of the WR-650 waveguide transmission system.« less

Asynchronous inputs and flip-flop metastability in the CLAS trigger at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doughty, D.C. Jr.; Lemon, S.; Bonneau, P.

1993-08-01

The impact of flip-flop metastability on the pipelined trigger for the CLAS detector at CEBAF has been studied. The authors find that the newest ECL flip-flops (ECLinPS) are much faster than older families (10H) at resolving the metastable condition. This will allow their use in systems with asynchronous inputs without an extra stage of synchronizing flip-flops.

A PARMELA model of the CEBAF injector valid over a wide range of beam parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuhong Zhang; Kevin Beard; Jay Benesch

A PARMELA model of the CEBAF injector valid over a wide range of beam parameters Yuhong Zhang, Kevin Beard, Jay Benesch, Yu-Chiu Chao, Arne Freyberger, Joseph Grames, Reza Kazimi, Geoff Krafft, Rui Li, Lia Merminga, Matt Poelker, Michael Tiefenback, Byung Yunn Thomas Jefferson National Accelerator Facility 12000 Jefferson Avenue, Newport News, VA 23606 USA An earlier PARMELA model of the Jefferson Lab CEBAF photoinjector was recently revised. The initial phase space distribution of an electron bunch was determined by measuring spot size and pulselength of the driver laser and by beam emittance measurements. The improved model has been used formore » simulations of the simultaneous delivery of the Hall A beam required for a hypernuclear experiment, and the Hall C beam required for the G0 parity violation experiment.« less

Magnetic field error measurement of the CEBAF (NIST) wiggler using the pulsed wire method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, Stephen; Colson, William; Neil, George

1993-07-01

The National Institute for Science and Technology (NIST) wiggler has been loaded to the Continuous Electron Beam Accelerator Facility (CEBAF). The pulsed wire method [R.W. Warren, Nucl. Instr. and Meth. A272 (1988) 267] has been used to measure the field errors of the entrance wiggler half, and the net path deflection was calculated to be Δx ≈ 5.2 m.

Asynchronous inputs and flip-flop metastability in the CLAS trigger at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dave Doughty; S. Lemon; P. Bonneau

1992-10-01

The impact of flip-flop metastability on the pipelined trigger for the CLAS detector at CEBAF (Continuous Electron Beam Accelerator Facility) has been studied. It is found that the newest ECL (emitter coupled logic) flip-flops (ECLinPS) are much faster than older families at resolving the metastable condition. This will allow their use in systems with asynchronous inputs without an extra stage of synchronizing flip-flops.

Research and Development for an Alternative RF Source Using Magnetrons in CEBAF

NASA Astrophysics Data System (ADS)

Jacobs, Andrew

2016-09-01

At Jefferson Lab, klystrons are currently used as a radiofrequency (RF) power source for the 1497 MHz Continuous Electron Beam Accelerator Facility (CEBAF) Continuous Wave (CW) system. A drop-in replacement for the klystrons in the form of a system of magnetrons is being developed. The klystron DC-RF efficiency at CEBAF is 35-51% while the estimated magnetron efficiency is 80-90%. Thus, the introduction of magnetrons to CEBAF will have enormous benefits in terms of electrical power saving. The primary focus of this project was to characterize a magnetron's frequency pushing and pulling curves at 2.45 GHz with stub tuner and anode current adjustments so that a Low Level RF controller for a new 1.497 GHz magnetron can be built. A Virtual Instrument was created in LabVIEW, and data was taken. The resulting data allowed for the creation of many constant lines of frequency and output power. Additionally, the results provided a characterization of magnetron oven temperature drift over the operation time and the relationship between anode current and frequency. Using these results, the control model of different variables and their feedback or feedforward that affect the frequency pushing and pulling of the magnetron is better developed. Department of Energy, Science Undergraduate Laboratory Internships, and Jefferson Lab.

Analog Techniques in CEBAF's RF Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hovater, J.; Fugitt, Jock

1988-01-01

Recent developments in high-speed analog technology have progressed into the areas of traditional RF technology.Diode-related devices are being replaced by analog IC's in the CEBAF RF control system.Complex phase modulators and attenuators have been successfully tested at 70 MHz.They have three advantages over existing technology: lower cost, less temperature sensitivity, and more linearity.RF signal conditioning components and how to implement the new analog IC's will be covered in this paper.

Single neutral pion electroproduction off the proton in the resonance region

NASA Astrophysics Data System (ADS)

Markov, Nikolay

We study a pi0 electroproduction off the proton in the invariant mass range for the ppi0 system of W = 1.1 -- 1.8 GeV in the broad range of the photon virtualities Q2 = 0.4 -- 1.0 GeV2. The experiment was conducted in the Hall B at the Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) detector which is uniquely suited for the spectroscopic measurements. The channel is identified by subsequent determination of the electron using information from the forward angle electromagnetic calorimeter and the drift chambers, and proton from the time of flight and drift chambers signals. Kinematical relations between the charged particles separate the single pion events. The detector efficiency and the geometrical acceptance are studied with the GEANT simulation of the CLAS. The exclusive channel radiative corrections are developed and applied. The full differential cross section of the pi0 electroproduction is measured with high statistical accuracy and small systematical error. The quality of the overall data analysis is checked against the firmly established benchmark reactions. The structure functions and Legendre multipoles are extracted and show the sensitivity of our measurements to the different resonance electroproduction amplitudes. The advanced phenomenological approach will be used to extract the Q2 evolution of the electromagnetic transition form factors of the different resonance states in the combined analysis of the major exclusive channels. This information will notably improve our understanding of the structure of the nucleon.

Measurement of target and double-spin asymmetries for the e ⃗p ⃗→e π+(n ) reaction in the nucleon resonance region at low Q2

NASA Astrophysics Data System (ADS)

Zheng, X.; Adhikari, K. P.; Bosted, P.; Deur, A.; Drozdov, V.; El Fassi, L.; Kang, Hyekoo; Kovacs, K.; Kuhn, S.; Long, E.; Phillips, S. K.; Ripani, M.; Slifer, K.; Smith, L. C.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chen, J.-P.; Chetry, T.; Choi, Seonho; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovach, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Peng, P.; Pisano, S.; Pogorelko, O.; Price, J. W.; Puckett, A. J. R.; Raue, B. A.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zonta, I.; CLAS Collaboration

2016-10-01

We report measurements of target- and double-spin asymmetries for the exclusive channel e ⃗p ⃗→e π+(n ) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35 (GeV/c ) 2 . The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6∘. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.

Characterization of Multianode Photomultiplier Tubes for a Cherenkov Detector

NASA Astrophysics Data System (ADS)

Benninghoff, Morgen; Turisini, Matteo; Kim, Andrey; Benmokhtar, Fatiha; Kubarovsky, Valery; Duquesne University Collaboration; Jefferson Lab Collaboration

2017-09-01

In the Fall of 2017, Jefferson Lab's CLAS12 (CEBAF Large Acceptance Spectrometer) detector is expecting the addition of a RICH (ring imaging Cherenkov) detector which will allow enhanced particle identification in the momentum range of 3 to 8 GeV/c. RICH detectors measure the velocity of charged particles through the detection of produced Cherenkov radiation and the reconstruction of the angle of emission. The emitted Cherenkov photons are detected by a triangular-shaped grid of 391 multianode photomultiplier tubes (MAPMTs) made by Hamamatsu. The custom readout electronics consist of MAROC (multianode read out chip) boards controlled by FPGA (Field Programmable Gate Array) boards, and adapters used to connect the MAROC boards and MAPMTs. The focus of this project is the characterization of the MAPMTs with the new front end electronics. To perform these tests, a black box setup with a picosecond diode laser was constructed with low and high voltage supplies. A highly automated procedure was developed to acquire data at different combinations of high voltage values, light intensities and readout electronics settings. Future work involves using the collected data in calibration procedures and analyzing that data to resolve the best location for each MAPMT. SULI, NSF.

Measurement of target and double-spin asymmetries for the e → p → → e π + ( n ) reaction in the nucleon resonance region at low Q 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, X.; Adhikari, K. P.; Bosted, P.

We repormore » t measurements of target- and double-spin asymmetries for the exclusive channel e → p → → e π + ( n ) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q 2 range from 0.0065 to 0.35 (GeV/c) 2. The Q 2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6 degrees. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.« less

Measurement of target and double-spin asymmetries for the $$\\vec e\\vec p\\to e\\pi^+ (n)$$ reaction in the nucleon resonance region at low $Q^2$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, X.; Adhikari, K. P.; Bosted, P.

We report measurements of target- and double-spin asymmetries for the exclusive channelmore » $$\\vec e\\vec p\\to e\\pi^+ (n)$$ in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH$$_3$$ target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3 and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low $Q^2$ range from $0.0065$ to $0.35$ (GeV$/c$)$^2$. The $Q^2$ access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as $$6^\\circ$$. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.« less

Measurement of target and double-spin asymmetries for the $$\\vec e\\vec p\\to e\\pi^+ (n)$$ reaction in the nucleon resonance region at low $Q^2$

DOE PAGES

Zheng, X.; Adhikari, K. P.; Bosted, P.; ...

2016-10-19

We report measurements of target- and double-spin asymmetries for the exclusive channelmore » $$\\vec e\\vec p\\to e\\pi^+ (n)$$ in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH$$_3$$ target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3 and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low $Q^2$ range from $0.0065$ to $0.35$ (GeV$/c$)$^2$. The $Q^2$ access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as $$6^\\circ$$. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.« less

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2. II. e p →e π0p

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Kim, A.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Badui, R. A.; Ball, J.; Balossino, I.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Glazier, D. I.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Hakobyan, H.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Hollis, G.; Holtrop, M.; Hughes, S. M.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, W.; Klei, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McCracken, M. E.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V. I.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Saini, M. S.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-03-01

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π0 electroproduction reaction γ*p →p π0 , expanding an analysis of the γ*p →n π+ reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1

Measurement of the deuteron structure function F2 in the resonance region and evaluation of its moments

NASA Astrophysics Data System (ADS)

Osipenko, M.; Ricco, G.; Simula, S.; Battaglieri, M.; Ripani, M.; Adams, G.; Ambrozewicz, P.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Biselli, A. S.; Bonner, B. E.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Cazes, A.; Chen, S.; Cole, P. L.; Coleman, A.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Cummings, J. P.; de Sanctis, E.; Devita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hu, J.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Lima, A. C. S.; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Nefedov, G.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strauch, S.; Suleiman, R.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, J.

2006-04-01

Inclusive electron scattering off the deuteron has been measured to extract the deuteron structure function F2 with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The measurement covers the entire resonance region from the quasielastic peak up to the invariant mass of the final-state hadronic system W≃2.7 GeV with four-momentum transfers Q2 from 0.4 to 6 (GeV/c)2. These data are complementary to previous measurements of the proton structure function F2 and cover a similar two-dimensional region of Q2 and Bjorken variable x. Determination of the deuteron F2 over a large x interval including the quasielastic peak as a function of Q2, together with the other world data, permit a direct evaluation of the structure function moments for the first time. By fitting the Q2 evolution of these moments with an OPE-based twist expansion we have obtained a separation of the leading twist and higher twist terms. The observed Q2 behavior of the higher twist contribution suggests a partial cancelation of different higher twists entering into the expansion with opposite signs. This cancelation, found also in the proton moments, is a manifestation of the “duality” phenomenon in the F2 structure function.

Summary Report for the C50 Cryomodule Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drury, Michael; Davis, G; Fischer, John

2011-03-01

The Thomas Jefferson National Accelerator Facility has recently completed the C50 cryomodule refurbishment project. The goal of this project was to enable robust 6 GeV, 5 pass operation of the Continuous Electron Beam Accelerator Facility (CEBAF). The scope of the project included removal, refurbishment and reinstallation of ten CEBAF cryomodules at a rate of three per year. The refurbishment process included reprocessing of SRF cavities to eliminate field emission and to increase the nominal gradient from the original 5 MV/m to 12.5 MV/m. New 'dogleg' couplers were installed between the cavity and helium vessel flanges to intercept secondary electrons thatmore » produce arcing in the fundamental Power Coupler (FPC). Other changes included new ceramic RF windows for the air to vacuum interface of the FPC and improvements to the mechanical tuner. Damaged or worn components were replaced as well. All ten of the refurbished cryomodules are now installed in CEBAF and are currently operational. This paper will summarize the performance of the cryomodules.« less

CEBAF Upgrade Cryomodule Component Testing in the Horizontal Test Bed (HTB)

DOE Office of Scientific and Technical Information (OSTI.GOV)

I.E. Campisi; B. Carpenter; G.K. Davis

2001-06-01

The planned upgrade of the CEBAF electron accelerator includes the development of an improved cryomodule. Several components differ substantially from the original CEBAF cryomodule; these include: the new 7-cell, 1.5 GHz cavities with integral helium vessel, a new, backlash-free cavity tuner, the waveguide coupler with its room-temperature ceramic window, and the HOM damping filters. In order to test the design features and performance of the new components, a horizontal cryostat (Horizontal Test Bed) has been constructed which allows testing with a turn around time of less than three weeks. This cryostat provides the environment for testing one or two cavities,more » with associated auxiliary components, in a condition similar to that of a real cryomodule. A series of tests has been performed on a prototype 7-cell cavity and the above-mentioned systems. In this paper the results of the tests on the cryostat, on the cavity performance, on its coupler, on the tuner characteristics, and on the microphonics behavior will be reported.« less

Software Tools for Emittance Measurement and Matching for 12 GeV CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, Dennis L.

2016-05-01

This paper discusses model-driven setup of the Continuous Electron Beam Accelerator Facility (CEBAF) for the 12GeV era, focusing on qsUtility. qsUtility is a set of software tools created to perform emittance measurements, analyze those measurements, and compute optics corrections based upon the measurements.qsUtility was developed as a toolset to facilitate reducing machine configuration time and reproducibility by way of an accurate accelerator model, and to provide Operations staff with tools to measure and correct machine optics with little or no assistance from optics experts.

Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stutzman, M L; Adderley, P; Brittian, J

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower partmore » of the UHV range. Measured NEG pump speed is high at pressures above 5×10 -11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.« less

The CEBAF RF Separator System Upgrade

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. Hovater; Mark Augustine; Al Guerra

2004-08-01

The CEBAF accelerator uses RF deflecting cavities operating at the third sub-harmonic (499 MHz) of the accelerating frequency (1497 MHz) to ''kick'' the electron beam to the experimental halls. The cavities operate in a TEM dipole mode incorporating mode enhancing rods to increase the cavity's transverse shunt impedance [1]. As the accelerators energy has increased from 4 GeV to 6 GeV the RF system, specifically the 1 kW solid-state amplifiers, have become problematic, operating in saturation because of the increased beam energy demands. Two years ago we began a study to look into replacement for the RF amplifiers and decidedmore » to use a commercial broadcast Inductive Output Tube (IOT) capable of 30 kW. The new RF system uses one IOT amplifier on multiple cavities as opposed to one amplifier per cavity as was originally used. In addition, the new RF system supports a proposed 12 GeV energy upgrade to CEBAF. We are currently halfway through the upgrade with three IOTs in operation and the remaining one nearly installed. This paper reports on the new RF system and the IOT performance.« less

Enhanced UV light detection using a p-terphenyl wavelength shifter

NASA Astrophysics Data System (ADS)

Joosten, S.; Kaczanowicz, E.; Ungaro, M.; Rehfuss, M.; Johnston, K.; Meziani, Z.-E.

2017-10-01

UV-glass photomultiplier tubes (PMTs) have poor photon detection efficiency for wavelengths below 300 nm due to the opaqueness of the window material. Costly quartz PMTs could be used to enhance the efficiency below 300 nm. A less expensive solution that dramatically improves this efficiency is the application of a thin film of a p-terphenyl (PT) wavelength shifter on UV-glass PMTs. This improvement was quantified for Photonis XP4500B PMTs for wavelengths between 200 nm and 400 nm. The gain factor ranges up to 5 . 4 ± 0 . 5 at a wavelength of 215 nm, with a material load of 110 ± 10 μg /cm2 (894 nm). The wavelength shifter was found to be fully transparent for wavelengths greater than 300 nm. The resulting gain in detection efficiency, when used in a typical C̆erenkov counter, was estimated to be of the order of 40%. Consistent coating quality was assured by a rapid gain testing procedure using narrow-band UV LEDs. Based on these results, 200 Photonis XP4500B PMTs were treated with PT for the upgraded low-threshold C̆erenkov counter (LTCC) to be used in the CEBAF Large Acceptance Spectrometer upgraded detector (CLAS12) at the Thomas Jefferson National Accelerator Facility.

Detector development for Jefferson Lab's 12GeV Upgrade

DOE PAGES

Qiang, Yi

2015-05-01

Jefferson Lab will soon finish its highly anticipated 12 GeV Upgrade. With doubled maximum energy, Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) will enable a new experimental program with substantial discovery potential, addressing important topics in nuclear, hadronic and electroweak physics. In order to take full advantage of the high energy, high luminosity beam, new detectors are being developed, designed and constructed to fit the needs of different physics topics. The paper will give an overview of various new detector technologies to be used for 12 GeV experiments. It will then focus on the development of two solenoid-based spectrometers,more » the GlueX and SoLID spectrometers. The GlueX experiment in Hall D will study the complex properties of gluons through exotic hybrid meson spectroscopy. The GlueX spectrometer, a hermetic detector package designed for spectroscopy and the associated partial wave analysis, is currently in the final stage of construction. Hall A, on the other hand, is developing the SoLID spectrometer to capture the 3D image of the nucleon from semi-inclusive processes and to study the intrinsic properties of quarks through mirror symmetry breaking. Such a spectrometer will have the capability to handle very high event rates while still maintaining a large acceptance in the forward region.« less

Resonance Search for a Heavy Photon in the 2015 Engineering Run Data of the Heavy Photon Search Experiment

NASA Astrophysics Data System (ADS)

Moreno, Omar; Heavy Photon Search Collaboration

2017-01-01

The Heavy Photon Search (HPS) experiment at Jefferson Lab is searching for a new U(1) vector boson (``heavy photon'',``dark photon'' or A') in the mass range of 20-500 MeV/c2. An A' in this mass range is theoretically favorable and may also mediate dark matter interactions. The A' couples to the ordinary photon through kinetic mixing, which induces their coupling to electric charge. Since heavy photons couple to electrons, they can be produced through a process analogous to bremsstrahlung, subsequently decaying to an e+e- , which can be observed as a narrow resonance above the dominant QED trident background. For suitably small couplings, heavy photons travel detectable distances before decaying, providing a second signature. Using the CEBAF electron beam at Jefferson Lab incident on a thin tungsten target, along with a compact, large acceptance forward spectrometer consisting of a silicon vertex tracker and lead tungstate electromagnetic calorimeter, HPS is accessing unexplored regions in the mass-coupling phase space. The HPS engineering run took place in spring of 2015 using a 1.056 GeV, 50 nA beam and collected 1165 nb-1 (7.29 mC) of data. This talk will present the results of a resonance search for a heavy photon using the engineering run data.

Measurement of two-photon exchange effect by comparing elastic e ± p cross sections

DOE PAGES

Rimal, D.; Adikaram, D.; Raue, B. A.; ...

2017-06-01

Here, the electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four momentum transfer (more » $$Q^{2}$$). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determine the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6 GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron/positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm long liquid hydrogen (LH$$_2$$) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented.« less

A proposal for antiparallel acceleration of positrons using CEBAF

NASA Astrophysics Data System (ADS)

Tiefenback, M.; Wojtsekhowski, B.

2018-05-01

We present a scheme for positron beam acceleration in CEBAF antiparallel to the normal electron path, requiring no change in polarity of the magnet systems. This feature is essential to the principal benefit: enabling extremely simple configuration changes between conventional (clockwise) e- acceleration and counter clockwise e+ acceleration. Additionally, it appears possible to configure the accelerating cavity phases to support concurrent acceleration of the electron and positron beams. The last mode also may enable use of the higher peak current electron beam for system diagnostics. The inherent penalty of the concurrent mode in acceleration efficiency and increased energy spread may render this a commissioning-only diagnostic option, but the possibility appears worthy of consideration.

RESULTS OF THE 2015 HELIUM PROCESSING OF CEBAF CRYOMODULES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drury, Michael A.; Humphry, Jr., Frank J.; King, Larry

2016-10-01

Many conference series have adopted the same The CEBAF accelerator at Jefferson Lab consists of an injec-tor and two linacs connected by arcs. Each linac contains 25 cryomodules that are designed to deliver an integrated energy of 2.2 GeV per pass to an electron beam in order to meet 12 GeV energy requirements. Helium processing is a processing technique that is used to reduce field emis-sion (FE) in SRF cavities. Helium processing of the 50 installed linac cryomodules was seen as necessary to support 12 GeV energy requirements. This paper will describe the processing procedure and summarize the results ofmore » this effort.« less

Enhanced UV light detection using a p-terphenyl wavelength shifter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joosten, Sylvester J.; Kaczanowicz, Ed; Ungaro, Maurizio

Here, UV-glass photomultiplier tubes (PMTs) have poor photon detection efficiency for wavelengths belowmore » $$300\\,\\text{nm}$$ due to the opaqueness of the window material. Costly quartz PMTs could be used to enhance the efficiency below $$300\\,\\text{nm}$$. A less expensive solution that dramatically improves this efficiency is the application of a thin film of a p-terphenyl (PT) wavelength shifter on UV-glass PMTs. This improvement was quantified for Photonis XP4500B PMTs for wavelengths between $$200\\,\\text{nm}$$ and $$400\\,\\text{nm}$$. The gain factor ranges up to 5.4 $$\\pm$$ 0.5 at a wavelength of $$215\\,\\text{nm}$$, with a material load of $$110\\pm10\\,\\mu\\text{g}/\\text{cm}^2$$ ($$894\\,\\text{nm}$$). The wavelength shifter was found to be fully transparent for wavelengths greater than $$300\\,\\text{nm}$$. The resulting gain in detection efficiency, when used in a typical Cherenkov counter, was estimated to be of the order of 40%. Consistent coating quality was assured by a rapid gain testing procedure using narrow-band UV LEDs. Based on these results, 200 Photonis XP4500B PMTs were treated with PT for the upgraded low-threshold Cherenkov counter (LTCC) to be used in the CEBAF Large Acceptance Spectrometer upgraded detector (CLAS12) at the Thomas Jefferson National Accelerator Facility.« less

Photon beam asymmetry Σ for η and η‧ photoproduction from the proton

NASA Astrophysics Data System (ADS)

Collins, P.; Ritchie, B. G.; Dugger, M.; Anisovich, A. V.; Döring, M.; Klempt, E.; Nikonov, V. A.; Rönchen, D.; Sadasivan, D.; Sarantsev, A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Balossino, I.; Bashkanov, M.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, Frank Thanh; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Zachariou, N.; Zhang, J.

2017-08-01

Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η‧ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp → ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp →η‧ p reaction. For γp → ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp →η‧ p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances - the N (1895) 1 /2-, N (1900) 3 /2+, N (2100) 1 /2+ and N (2120) 3 /2- resonances - which presently lack the ;four-star; status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.

A proposed U.S./China theoretical/experimental collaborative effort on baryon resonance extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

P.L. Cole

2009-12-01

In this paper we discuss the reasons for our work towards establishing a new collaboration between Jefferson Lab (JLab) and the Institute of High Energy Physics (IHEP) in Beijing. We seek to combine experimentalists and theorists into a dedicated group focused on better understanding the current and future data from JLab and from the Beijing Electron Positron Collider (BEPC). Recent JLab results on the extraction of single- and double-polarization observables in both the 1{pi}- and 2{pi}-channel show their high sensitivity to small production amplitudes and therefore their importance for the extraction of resonance parameters. The Beijing Electron Spectrometer (BES) atmore » the BEPC has collected high statistics data on J/{Psi} production. Its decay into baryon-antibaryon channels offers a unique and complementary way of probing nucleon resonances. The CEBAF Large Acceptance Spectrometer, CLAS, has access to N* form factors at high Q{sup 2}, which is advantageous for the study of dynamical properties of nucleon resonances, while the low-background BES results will be able to provide guidance for the search for less-dominant excited states at JLab. Moreover, with the recently approved experimental proposal Nucleon Resonance Studies with CLAS12 and the high-quality data streaming from BES-III and CLAS, the time has come for forging a new Trans-Pacific collaboration of theorists and experimentalists on NSTAR physics.« less

Photon beam asymmetry Σ for η and η' photoproduction from the proton

DOE PAGES

Collins, P.; Ritchie, B. G.; Dugger, M.; ...

2017-05-18

Measurements of the linearly-polarized photon beam asymmetrymore » $$\\Sigma$$ for photoproduction from the proton of $$\\eta$$ and $$\\eta^\\prime$$ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the $$\\gamma p \\to \\eta p$$ reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the $$\\gamma p \\to \\eta^\\prime p$$ reaction. For $$\\gamma p \\to \\eta p$$, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For $$\\gamma p \\to \\eta^\\prime p$$, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. In conclusion, initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances -- the $N(1895)1/2^-$, $N(1900)3/2^+$, $N(2100)1/2^+$ and $N(2120)3/2^-$ resonances -- which presently lack the "four-star" status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.« less

Photon beam asymmetry Σ for η and η' photoproduction from the proton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, P.; Ritchie, B. G.; Dugger, M.

Measurements of the linearly-polarized photon beam asymmetrymore » $$\\Sigma$$ for photoproduction from the proton of $$\\eta$$ and $$\\eta^\\prime$$ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the $$\\gamma p \\to \\eta p$$ reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the $$\\gamma p \\to \\eta^\\prime p$$ reaction. For $$\\gamma p \\to \\eta p$$, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For $$\\gamma p \\to \\eta^\\prime p$$, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. In conclusion, initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances -- the $N(1895)1/2^-$, $N(1900)3/2^+$, $N(2100)1/2^+$ and $N(2120)3/2^-$ resonances -- which presently lack the "four-star" status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.« less

Enhanced UV light detection using a p-terphenyl wavelength shifter

DOE PAGES

Joosten, Sylvester J.; Kaczanowicz, Ed; Ungaro, Maurizio; ...

2017-07-25

Here, UV-glass photomultiplier tubes (PMTs) have poor photon detection efficiency for wavelengths belowmore » $$300\\,\\text{nm}$$ due to the opaqueness of the window material. Costly quartz PMTs could be used to enhance the efficiency below $$300\\,\\text{nm}$$. A less expensive solution that dramatically improves this efficiency is the application of a thin film of a p-terphenyl (PT) wavelength shifter on UV-glass PMTs. This improvement was quantified for Photonis XP4500B PMTs for wavelengths between $$200\\,\\text{nm}$$ and $$400\\,\\text{nm}$$. The gain factor ranges up to 5.4 $$\\pm$$ 0.5 at a wavelength of $$215\\,\\text{nm}$$, with a material load of $$110\\pm10\\,\\mu\\text{g}/\\text{cm}^2$$ ($$894\\,\\text{nm}$$). The wavelength shifter was found to be fully transparent for wavelengths greater than $$300\\,\\text{nm}$$. The resulting gain in detection efficiency, when used in a typical Cherenkov counter, was estimated to be of the order of 40%. Consistent coating quality was assured by a rapid gain testing procedure using narrow-band UV LEDs. Based on these results, 200 Photonis XP4500B PMTs were treated with PT for the upgraded low-threshold Cherenkov counter (LTCC) to be used in the CEBAF Large Acceptance Spectrometer upgraded detector (CLAS12) at the Thomas Jefferson National Accelerator Facility.« less

Thomas Jefferson National Accelerator Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grames, Joseph; Higinbotham, Douglas; Montgomery, Hugh

The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. Themore » technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.« less

A proposal for antiparallel acceleration of positrons using CEBAF

DOE PAGES

Tiefenback, M.; Wojtsekhowski, B.

2018-05-01

Here, we present a scheme for positron beam acceleration in CEBAF antiparallel to the normal electron path, requiring no change in polarity of the magnet systems. This feature is essential to the principal benefit: enabling extremely simple configuration changes between conventional (clockwise) e - acceleration and counter clockwise e + acceleration. Additionally, it appears possible to configure the accelerating cavity phases to support concurrent acceleration of the electron and positron beams. The last mode also may enable use of the higher peak current electron beam for system diagnostics. The inherent penalty of the concurrent mode in acceleration efficiency and increasedmore » energy spread may render this a commissioning-only diagnostic option, but the possibility appears worthy of consideration.« less

A proposal for antiparallel acceleration of positrons using CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tiefenback, M.; Wojtsekhowski, B.

Here, we present a scheme for positron beam acceleration in CEBAF antiparallel to the normal electron path, requiring no change in polarity of the magnet systems. This feature is essential to the principal benefit: enabling extremely simple configuration changes between conventional (clockwise) e - acceleration and counter clockwise e + acceleration. Additionally, it appears possible to configure the accelerating cavity phases to support concurrent acceleration of the electron and positron beams. The last mode also may enable use of the higher peak current electron beam for system diagnostics. The inherent penalty of the concurrent mode in acceleration efficiency and increasedmore » energy spread may render this a commissioning-only diagnostic option, but the possibility appears worthy of consideration.« less

A High-Average-Power Free Electron Laser for Microfabrication and Surface Applications

NASA Technical Reports Server (NTRS)

Dylla, H. F.; Benson, S.; Bisognano, J.; Bohn, C. L.; Cardman, L.; Engwall, D.; Fugitt, J.; Jordan, K.; Kehne, D.; Li, Z.;

A high-average-power FEL for industrial applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dylla, H.F.; Benson, S.; Bisognano, J.

1995-12-31

CEBAF has developed a comprehensive conceptual design of an industrial user facility based on a kilowatt UV (150-1000 nm) and IR (2-25 micron) FEL driven by a recirculating, energy-recovering 200 MeV superconducting radio-frequency (SRF) accelerator. FEL users{endash}CEBAF`s partners in the Laser Processing Consortium, including AT&T, DuPont, IBM, Northrop-Grumman, 3M, and Xerox{endash}plan to develop applications such as polymer surface processing, metals and ceramics micromachining, and metal surface processing, with the overall effort leading to later scale-up to industrial systems at 50-100 kW. Representative applications are described. The proposed high-average-power FEL overcomes limitations of conventional laser sources in available power, cost-effectiveness, tunabilitymore » and pulse structure. 4 refs., 3 figs., 2 tabs.« less

Electron scattering from high-momentum neutrons in deuterium

NASA Astrophysics Data System (ADS)

Klimenko, A. V.; Kuhn, S. E.; Butuceanu, C.; Egiyan, K. S.; Griffioen, K. A.; Adams, G.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Biselli, A. S.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Cazes, A.; Chen, S.; Cole, P. L.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Cummings, J. P.; Dashyan, N. B.; Devita, R.; Sanctis, E. De; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Dharmawardane, K. V.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Elouadrhiri, L.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Fersch, R. G.; Feuerbach, R. J.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gonenc, A.; Gordon, C. I. O.; Gothe, R. W.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Livingston, K.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Thoma, U.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Zana, L.; Zhang, J.; Zhao, B.

2006-03-01

We report results from an experiment measuring the semiinclusive reaction H2(e,e'ps) in which the proton ps is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CEBAF large acceptance spectrometer. A reduced cross section was extracted for different values of final state missing mass W*, backward proton momentum p→s, and momentum transfer Q2. The data are compared to a simple plane wave impulse approximation (PWIA) spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. Within the framework of the simple spectator model, a “bound neutron structure function” F2neff was extracted as a function of W* and the scaling variable x* at extreme backward kinematics, where the effects of FSI appear to be smaller. For ps>0.4GeV/c, where the neutron is far off-shell, the model overestimates the value of F2neff in the region of x* between 0.25 and 0.6. A dependence of the bound neutron structure function on the neutron's “off-shell-ness” is one possible effect that can cause the observed deviation.

Studies of $$\\Lambda n$$ interaction through polarization observables for final-state interactions in exclusive $$\\Lambda$$ photoproduction off the deuteron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilieva, Yordanka; Cao, Tongtong; Zachariou, Nicholas

2016-06-01

Theoretical studies suggest that experimental observables for hyperon production reactions can place stringent constraints on the free parameters of hyperon-nucleon potentials, which are critical for the understanding of hypernuclear matter and neutron stars. Here we present preliminary experimental results for the polarization observables S, Py, Ox, Oz, Cx, and Cz for final-state interactions (FSI) in exclusive L photoproduction off the deuteron. The observables were obtained from data collected during the E06-103 (g13) experiment with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Lab. The g13 experiment ran with unpolarized deuteron target and circularly- and linearly-polarized photon beamsmore » with energies between 0.5 GeV and 2.5 GeV and collected about 51010 events with multiple charged particles in the final state. To select the reaction of interest, the K+ and the L decay products, a proton and a negative pion, were detected in the CLAS. The missing-mass technique was used to identify exclusive hyperon photoproduction events. Final-state interaction events were selected by requesting that the reconstructed neutron has a momentum larger than 200 MeV/c. The large statistics of E06-103 provided statistically meaningful FSI event samples, which allow for the extraction of one- and two-fold differential single- and double-polarization observables. Here we present preliminary results for a set of six observables for photon energies between 0.9 GeV and 2.3 GeV and for several kinematic variables in the Ln center-of-mass frame. Our results are the very first estimates of polarization observables for FSI in hyperon photoproduction and will be used to constrain the free parameters of hyperon-nucleon potentials.« less

Measurement of the x- and Q-dependence of the asymmetry A on the nucleon

NASA Astrophysics Data System (ADS)

Clas Collaboration; Dharmawardane, K. V.; Kuhn, S. E.; Bosted, P.; Prok, Y.; Adams, G.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Biselli, A. S.; Bonner, B. E.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Cazes, A.; Chen, S.; Cole, P. L.; Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; de Masi, R.; Devita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gonenc, A.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Keith, C.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Lima, A. C. S.; Livingston, K.; Lu, H.; Lukashin, K.; MacCormick, M.; Manak, J. J.; Markov, N.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Shvedunov, N. V.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z.

2006-09-01

We report results for the virtual photon asymmetry A on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton (NH315) and deuteron (ND315) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present Letter, we concentrate on our results for A(x,Q) and the related ratio g/F(x,Q) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q from 0.05 to 5.0GeV and in final-state invariant mass W up to about 3 GeV. Our data show detailed structure in the resonance region, which leads to a strong Q-dependence of A(x,Q) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A(x,Q) is not strictly Q-independent. We add significantly to the world data set at high x, up to x=0.6. Our data exceed the SU(6)-symmetric quark model expectation for both the proton and the deuteron while being consistent with a negative d-quark polarization up to our highest x. This data set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.

Numerical investigation of a laser gun injector at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byung Yunn; Charles Sinclair; David Neuffer

1993-08-23

A laser gun injector is being developed based on the superconducting rf technologies established at CEBAF. This injector will serve as a high charge cw source for a high power free electron laser. It consists of a dc laser gun, a buncher, a cryounit and a chicane. Its space-charge-dominated performance has been thoroughly investigated using the time-consuming but more appropriate point-by-point space charge calculation method in PARMELA. The notion of ``conditioning for final bunching'' will be introduced. This concept has been built into the code and has greatly facilitated the optimization of the whole system to achieve the highest possiblemore » peak current while maintaining low emittance and low energy spread. Extensive parameter variation studies have shown that the design will perform better than the specifications.« less

Design and Implementation of the CEBAF Element Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Theodore Larrieu, Christopher Slominski, Michele Joyce

2011-10-01

With inauguration of the CEBAF Element Database (CED) in Fall 2010, Jefferson Lab computer scientists have taken a first step toward the eventual goal of a model-driven accelerator. Once fully populated, the database will be the primary repository of information used for everything from generating lattice decks to booting front-end computers to building controls screens. A particular requirement influencing the CED design is that it must provide consistent access to not only present, but also future, and eventually past, configurations of the CEBAF accelerator. To accomplish this, an introspective database schema was designed that allows new elements, element types, andmore » element properties to be defined on-the-fly without changing table structure. When used in conjunction with the Oracle Workspace Manager, it allows users to seamlessly query data from any time in the database history with the exact same tools as they use for querying the present configuration. Users can also check-out workspaces and use them as staging areas for upcoming machine configurations. All Access to the CED is through a well-documented API that is translated automatically from original C++ into native libraries for script languages such as perl, php, and TCL making access to the CED easy and ubiquitous. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.« less

The founding of CEBAF, 1979 to 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. Westfall

1995-02-01

In early 1979 a group of physicists assembled at the University of Virginia (UVa) for a conference entitled ''Future Possibilities for Electron Accelerators.'' In the audience sat an organizer of the conference, UVa professor James McCarthy. While listening to talks by Gregory Loew of the Stanford Linear Accelerator Center (SLAC) and Roger Servranckx of the University of Saskatchewan, McCarthy got very excited. Both discussed new approaches to producing an almost continuous stream of electrons with improved designs for pulse stretcher rings that could be built within a reasonable budget. McCarthy saw the possibility of realizing a dream. This dream hadmore » its origins in the 1950s, when Robert Hofstadter, McCarthy's thesis advisor, made groundbreaking discoveries at Stanford's High Energy Physics Laboratory (HEPL) about the internal structure of nuclei and nucleons. For these experiments Hofstadter used Mark III, the most advanced in a series of electron accelerators designed by William Hansen, who pioneered methods of high frequency acceleration of electrons. The work by Hofstadter and Hansen led to two productive lines of inquiry. One group of researchers studied particle production using electrons at higher energies, which led to the construction in the 1960s of SLAC at Stanford. Another group of researchers, which included McCarthy, investigated nuclear structure with more modest increases in energy accompanied by increases in the duty factor of the electron beam. This line of inquiry, electro-nuclear physics, led in the 1960s and 1970s to a succession of accelerators, including a $7.2 million high duty factor 400 MeV linear accelerator (linac) completed in 1972 at the Bates Laboratory at the Massachusetts Institute of Technology (Bates-MIT), and ambitious attempts to develop untried technologies to further boost energy and duty factor, most notably the effort to develop superconducting radiofrequency (srf) accelerating technology at HEPL. By 1979 electro-nuclear physics had attracted a considerable following. The growing electro-nuclear physics community was eager to find a scheme to permit virtually continuous acceleration, which would greatly improve the capability of performing coincidence experiments. In the words of the UVa conference proceedings, this experimental capability promised to open entire new areas of nuclear physics. Convinced that he could be the one to design the necessary groundbreaking machine after hearing the ideas of Loew and Servranckx, McCarthy began gathering a small accelerator building team. Against all odds, McCarthy's pipe dream resulted in the construction of a major accelerator laboratory, the Continuous Electron Beam Accelerator Facility (CEBAF). The founding of CEBAF is a tale of luck, perseverance, the triumph of flexible amateurism over rigid professionalism, and ironically, the potential of amateurs when supported by a thoroughly professional international network with well-defined methods for organizing and building accelerators. The CEBAF tale also has a surprise ending, for at the last minute, McCarthy's pipe dream was radically transformed by Hermann Grunder, who would direct the construction of the project. The twists and turns of this tale reveal many lessons about what aids and what detracts from the success of a large, federally sponsored scientific project.« less

Generalized polarizabilities of the nucleon in baryon chiral perturbation theory

NASA Astrophysics Data System (ADS)

Lensky, Vadim; Pascalutsa, Vladimir; Vanderhaeghen, Marc

2017-02-01

The nucleon generalized polarizabilities (GPs), probed in virtual Compton scattering (VCS), describe the spatial distribution of the polarization density in a nucleon. They are accessed experimentally via the process of electron-proton bremsstrahlung (ep→ epγ ) at electron-beam facilities, such as MIT-Bates, CEBAF (Jefferson Lab), and MAMI (Mainz). We present the calculation of the nucleon GPs and VCS observables at next-to-leading order in baryon chiral perturbation theory (Bχ PT), and confront the results with the empirical information. At this order our results are predictions, in the sense that all the parameters are well known from elsewhere. Within the relatively large uncertainties of our calculation we find good agreement with the experimental observations of VCS and the empirical extractions of the GPs. We find large discrepancies with previous chiral calculations - all done in heavy-baryon χ PT (HBχ PT) - and discuss the differences between Bχ PT and HBχ PT responsible for these discrepancies.

Development of a BPM Lock-In Diagnostic System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard Dickson

2003-05-12

A system has been developed for the acquisition and analysis of high rate, time coherent BPM data across the Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF). This system will allow the acquisition of Beam Position Monitor (BPM) position and intensity information at a rate in excess 7 KHz for approximately 200 BPMs in a time synchronous manner. By inducing minute sinusoidal transverse beam motion in the CEBAF injector, with known phase relative to the synchronized BPM acquisition, it is possible to derive several types of useful information. Analysis of the BPM intensity data, which is proportional to beam current,more » by beating the signal with an in-phase sinusoidal representation of the transverse kick can localize beam scraping to a particular BPM. Similarly, real-time optics information may be deduced with an analysis of BPM position data. This paper will detail the frequency lock-in technique applied and present status.« less

Four Beam Generation for Simultaneous Four-Hall Operation at CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazimi, Reza; Grames, Joseph M.; Hansknecht, John C.

As part of the CEBAF 12 GeV upgrade at Jefferson Lab, a new experimental hall was added to the existing three halls. To deliver beam to all four halls simultaneous-ly, a new timing pattern for electron bunches is needed at the injector. This pattern change has consequences for the frequency of the lasers at the photogun, beam behavior in the chopping system, beam optics due to space charge, and setup procedures. We have successfully demonstrated this new pattern using the three existing drive lasers. The implementation of the full system will occur when the fourth laser is added and upgradesmore » to the Low Level RF (LLRF) are complete. In this paper we explain the new bunch pattern, the challenges for setting and measuring the pattern such as 180° RF phase ambiguity, addition of the fourth laser to the laser table and LLRF upgrade.« less

A High Peak Current Source for the CEBAF Injector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yunn, Byung; Sinclair, Charles; Krafft, Geoffrey

1992-07-01

The CEBAF accelerator can drive high power IR and UV FELs, if a high peak current source is added to the existing front end. We present a design for a high peak current injector which is compatible with simultaneous operation of the accelerator for cw nulear physics (NP) beam. The high peak current injector provides 60 A peak current in 2 psec long bunches carrying 120 pC charge at 7.485 MHz. At 10 MeV that beam is combined with 5 MeV NP beam (0.13pC, 2 psec long bunches at 1497 MHz) in an energy combination chicane for simultaneous acceleration inmore » the injector linac. The modifications to the low-energy NP transport are described. Results of optical and beam dynamics calculations for both high peak current and NP beams in combined operation are presented.« less

Deeply virtual and exclusive electroproduction of ω-mesons

NASA Astrophysics Data System (ADS)

Morand, L.; Doré, D.; Garçon, M.; Guidal, M.; Laget, J.-M.; Morrow, S.; Sabatié, F.; Smith, E.; Adams, G.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Ball, J.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Cazes, A.; Chen, S.; Cole, P. L.; Cords, D.; Corvisiero, P.; Crabb, D.; Cummings, J. P.; de Sanctis, E.; Devita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Eugenio, P.; Fatemi, R.; Feldman, G.; Fersch, R. G.; Feuerbach, R. J.; Funsten, H.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F.-X.; Goetz, J. T.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ito, M. M.; Jenkins, D.; Jo, H.-S.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Kubarovski, V.; Kramer, L. H.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Livingston, K.; Marchand, C.; Maximon, L. C.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Mueller, J.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rubin, P. D.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Skabelin, A. V.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Thoma, U.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Zana, L.

2005-06-01

The exclusive ω electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross-sections were measured up to large values of the four-momentum transfer (- t < 2.7 GeV2) to the proton. The contributions of the interference terms σ{TT} and σ{TL} to the cross-sections, as well as an analysis of the ω spin density matrix, indicate that helicity is not conserved in this process. The t-channel π0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction γ*p↦ωp, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross-sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.

The Differential Cross Section and Λ Recoil Polarization from γδ -> Κ0(ρ)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Compton, Nicholas; Thomas Jefferson National Accelerator Facility

2017-04-30

Presented is the analysis of the differential cross section and Λ recoil polarization from the reaction γδ -> Κ0(ρ). This work measured these observables over beam energies from 0.90 GeV to 3.0 GeV. These measurements are the first in this channel to cover such a wide range of energies. The data were taken using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory (JLAB) along with a tagged photon beam. This analysis was completed by identifying events of interest that decayed into the final state topology of π-π+,π-&rho'(ρ). Through conservation of energy and momentum, the Κ0, Λ and missing massmore » of the spectator proton were reconstructed. Utilizing the same analysis techniques, the observables were measured on two different experiments with good agreement. Photoproduction of strange mesons from the neutron are difficult to measure, consequently there are only a few measurements of this kind. Despite that, these reactions supply essential complementary data to those on the proton. The differential cross sections and the recoil polarization extracted, span the region where new nucleon resonances have been found from studies of the reaction γρ -> Κ+Λ. Comparisons between the Κ+Λ and Κ0Λ cross section demonstrate that possible interference terms near 1900 MeV are less pronounced in the latter. This unexpected result inspired a partial wave analyses (PWA) to be fitted to the data. The fit solution shows that this measurement fostered an improvement on the knowledge of observed resonance parameters, necessary to understanding these excited states. The study of nucleon resonances is a key motivating factor since the resonance masses can be calculated from the theory of the strong nuclear force, called quantum chromodynamics, or QCD.« less

Measurements of $$ep \\to e^\\prime π^+n$$ at W = 1.6 - 2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS

DOE PAGES

Park, Kijun; Aznauryan, I. G.; Burkert, V. D.; ...

2015-04-01

Differential cross sections of the exclusive processmore » $$e p \\to e^\\prime \\pi^+ n$$ were measured with good precision in the range of the photon virtuality $Q^2 = 1.8 - 4.5$ GeV$^2$, and the invariant mass range of the $$\\pi^+ n$$ final state W = 1.6 - 2.0 GeV using the CEBAF Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the $$n\\pi^+$$ center-of-mass system. More than 37,000 cross section points were measured. The contributions of the isospin $$I = {1\\over 2}$$ resonances $$N(1675){5\\over 2}^-$$, $$N(1680){5\\over 2}^+$$ and $$N(1710){1\\over 2}^+$$ were extracted at different values of $Q^2$ using a single-channel, energy-dependent resonance amplitude analysis. Two different approaches, the unitary isobar model and the fixed-$t$ dispersion relations, were employed in the analysis. We observe significant strength of the $$N(1675){5\\over 2}^-$$ in the $$A_{1/2}$$ amplitude, which is in strong disagreement with quark models that predict both transverse amplitudes to be strongly suppressed. For the $$N(1680){5\\over 2}^+$$ we observe a slow changeover from the dominance of the $$A_{3/2}$$ amplitude at the real photon point ($Q^2=0$) to a $Q^2$ where $$A_{1/2}$$ begins to dominate. The scalar amplitude $$S_{1/2}$$ drops rapidly with $Q^2$ consistent with quark model prediction. For the $$N(1710){1\\over 2}^+$$ resonance our analysis shows significant strength for the $$A_{1/2}$$ amplitude at $Q^2 < 2.5$ GeV$^2$.« less

Nb3Sn SRF Cavities for Nuclear Physics Applications

NASA Astrophysics Data System (ADS)

Eremeev, Grigory

2017-01-01

Nuclear physics experiments rely increasingly on accelerators, which employ superconducting RF (SRF) technology. CEBAF, SNS, FRIB, ESS, among others exploit the low surface resistance of SRF cavities to efficiently accelerate particle beams towards experimental targets. Niobium is the cavity material of choice for all current or planned SRF accelerators, but it has been long recognized that other superconductors with high superconducting transition temperatures have the potential to surpass niobium for SRF applications. Among the alternatives, Nb3Sn coated cavities are the most advanced on the path to practical applications: Nb3Sn coatings on R&D cavities have Tc consistently close the optimal 18 K, very low RF surface resistances, and very recently were shown to reach above Hc1 without anomalous RF surface resistance increase. In my talk I will discuss the prospects of Nb3Sn SRF cavities, the research efforts to realize Nb3Sn coatings on practical multi-cell accelerating structures, and the path toward possible inclusion in CEBAF. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics.

First attempt of at-cavity cryogenic X-ray detection in a CEBAF cryomodule for field emission monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Rongli; Daly, Edward; Drury, Michael

2015-09-01

We report on the first result of at-cavity X-ray detection in a CEBAF cryomodule for field emission monitoring. In the 8-cavity cryomodule F100, two silicon diodes were installed near the end flange of each cavity. Each cavity was individually tested during the cryomodule test in JLab’s cryomodule test facility. The behaviors of these at-cavity cryogenic X-ray detectors were compared with those of the standard ‘in air’ Geiger-Muller (G-M) tubes. Our initial experiments establish correlation between X-ray response of near diodes and the field emission source cavity in the 8-cavity string. For two out of these eight cavities, we also carriedmore » out at-cavity X-ray detection experiment during their vertical testing. The aim is to track field emission behavior uniquely from vertical cavity testing to horizontal cavity testing in the cryomodule. These preliminary results confirmed our expectation and warrant further effort toward the establishment of permanent at-cavity cryogenic X-ray detection for SRF development and operation.« less

Measurement of two-photon exchange effect by comparing elastic e ± p cross sections

DOE PAGES

Rimal, D.; Adikaram, D.; Raue, B. A.; ...

2017-06-01

Background: The electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments showa significant disagreement that grows with the squared four-momentum transfer (Q(2)). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. Purpose: We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determinemore » the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. Methods: We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6-GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron-positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm-long liquid hydrogen (LH2) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons, we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented. Results: We present previously unpublished results for the quantity R-2 gamma, the TPE correction to the elastic-scattering cross section, at Q(2) approximate to 0.85 and 1.45 GeV2 over a large range of virtual photon polarization epsilon. Conclusions: Our results, along with recently published results from VEPP-3, demonstrate a nonzero contribution from TPE effects and are in excellent agreement with the calculations that include TPE effects and largely reconcile the form-factor discrepancy up to Q(2) approximate to 2 GeV2. These data are consistent with an increase in R-2 gamma. with decreasing e at Q(2) approximate to 0.85 and 1.45 GeV2. There are indications of a slight increase in R-2 gamma with Q(2).« less

Measurement of two-photon exchange effect by comparing elastic e±p cross sections

NASA Astrophysics Data System (ADS)

Rimal, D.; Adikaram, D.; Raue, B. A.; Weinstein, L. B.; Arrington, J.; Brooks, W. K.; Ungaro, M.; Adhikari, K. P.; Afanasev, A. V.; Akbar, Z.; Pereira, S. Anefalos; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; Alaoui, A. El; Fassi, L. El; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Mestayer, M. D.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, Ivana; Stepanyan, S.; Strauch, S.; Sytnik, V.; Taiuti, M.; Torayev, B.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-06-01

Background: The electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four-momentum transfer (Q2). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. Purpose: We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determine the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. Methods: We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6-GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron-positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm-long liquid hydrogen (LH2) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons, we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented. Results: We present previously unpublished results for the quantity R2 γ, the TPE correction to the elastic-scattering cross section, at Q2≈0.85 and 1.45 GeV2 over a large range of virtual photon polarization ɛ . Conclusions: Our results, along with recently published results from VEPP-3, demonstrate a nonzero contribution from TPE effects and are in excellent agreement with the calculations that include TPE effects and largely reconcile the form-factor discrepancy up to Q2≈2 GeV2 . These data are consistent with an increase in R2 γ with decreasing ɛ at Q2≈0.85 and 1.45 GeV2. There are indications of a slight increase in R2 γ with Q2.

Experimental medium energy physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, P.D.

1991-01-01

This report discusses the following topics: Search for the H Dibaryon at the AGS; Hypernuclear Weak Decay Studies at the AGS; Relativistic Proton-Nucleus and Heavy Ion-Nucleus Collisions at the SPS; Hyperon-Antihyperon Production studies at LEAR; Hyperon Photoproduction at CEBAF; Double Lambda Hypernuclei; Weak Decay of Light Hypernuclei; and {pi}{sup 0}/{gamma}Detection with the CMU Scintillator Arrays.

Impact of remanent magnetic field on the heat load of original CEBAF cryomodule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ciovati, Gianluigi; Cheng, Guangfeng; Drury, Michael

The heat load of the original cryomodules for the CEBAF accelerator is ~50% higher than the target value of 100 W at 2.07 K for refurbished cavities operating at an accelerating gradient of 12.5 MV/m. This issue is due to the quality factor of the cavities being ~50% lower in the cryomodule than when tested in a vertical cryostat, even at low RF field. Previous studies were not conclusive about the origin of the additional losses. We present the results of a systematic study of the additional losses in a five-cell cavity from a decommissioned cryomodule after attaching components, whichmore » are part of the cryomodule, such as the cold tuner, the He tank and the cold magnetic shield, prior to cryogenic testing in a vertical cryostat. Flux-gate magnetometers and temperature sensors are used as diagnostic elements. Different cool-down procedures and tests in different residual magnetic fields were investigated during the study. Here, three flux-gate magnetometers attached to one of the cavities installed in the refurbished cryomodule C50-12 confirmed the hypothesis of high residual magnetic field as a major cause for the increased RF losses.« less

Impact of remanent magnetic field on the heat load of original CEBAF cryomodule

DOE PAGES

Ciovati, Gianluigi; Cheng, Guangfeng; Drury, Michael; ...

2016-11-22

The heat load of the original cryomodules for the CEBAF accelerator is ~50% higher than the target value of 100 W at 2.07 K for refurbished cavities operating at an accelerating gradient of 12.5 MV/m. This issue is due to the quality factor of the cavities being ~50% lower in the cryomodule than when tested in a vertical cryostat, even at low RF field. Previous studies were not conclusive about the origin of the additional losses. We present the results of a systematic study of the additional losses in a five-cell cavity from a decommissioned cryomodule after attaching components, whichmore » are part of the cryomodule, such as the cold tuner, the He tank and the cold magnetic shield, prior to cryogenic testing in a vertical cryostat. Flux-gate magnetometers and temperature sensors are used as diagnostic elements. Different cool-down procedures and tests in different residual magnetic fields were investigated during the study. Here, three flux-gate magnetometers attached to one of the cavities installed in the refurbished cryomodule C50-12 confirmed the hypothesis of high residual magnetic field as a major cause for the increased RF losses.« less

The Sidereal Time Variations of the Lorentz Force and Maximum Attainable Speed of Electrons

NASA Astrophysics Data System (ADS)

Nowak, Gabriel; Wojtsekhowski, Bogdan; Roblin, Yves; Schmookler, Barak

2016-09-01

The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab produces electrons that orbit through a known magnetic system. The electron beam's momentum can be determined through the radius of the beam's orbit. This project compares the beam orbit's radius while travelling in a transverse magnetic field with theoretical predictions from special relativity, which predict a constant beam orbit radius. Variations in the beam orbit's radius are found by comparing the beam's momentum entering and exiting a magnetic arc. Beam position monitors (BPMs) provide the information needed to calculate the beam momentum. Multiple BPM's are included in the analysis and fitted using the method of least squares to decrease statistical uncertainty. Preliminary results from data collected over a 24 hour period show that the relative momentum change was less than 10-4. Further study will be conducted including larger time spans and stricter cuts applied to the BPM data. The data from this analysis will be used in a larger experiment attempting to verify special relativity. While the project is not traditionally nuclear physics, it involves the same technology (the CEBAF accelerator) and the same methods (ROOT) as a nuclear physics experiment. DOE SULI Program.

The CEBAF Element Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Theodore Larrieu, Christopher Slominski, Michele Joyce

2011-03-01

With the inauguration of the CEBAF Element Database (CED) in Fall 2010, Jefferson Lab computer scientists have taken a step toward the eventual goal of a model-driven accelerator. Once fully populated, the database will be the primary repository of information used for everything from generating lattice decks to booting control computers to building controls screens. A requirement influencing the CED design is that it provide access to not only present, but also future and past configurations of the accelerator. To accomplish this, an introspective database schema was designed that allows new elements, types, and properties to be defined on-the-fly withmore » no changes to table structure. Used in conjunction with Oracle Workspace Manager, it allows users to query data from any time in the database history with the same tools used to query the present configuration. Users can also check-out workspaces to use as staging areas for upcoming machine configurations. All Access to the CED is through a well-documented Application Programming Interface (API) that is translated automatically from original C++ source code into native libraries for scripting languages such as perl, php, and TCL making access to the CED easy and ubiquitous.« less

Jefferson Lab Science: Present and Future

DOE PAGES

McKeown, Robert D.

2015-02-12

The Continuous Electron Beam Accelerator Facility (CEBAF) and associated experimental equipment at Jefferson Lab comprise a unique facility for experimental nuclear physics. Furthermore, this facility is presently being upgraded, which will enable a new experimental program with substantial discovery potential to address important topics in nuclear, hadronic, and electroweak physics. Further in the future, it is envisioned that the Laboratory will evolve into an electron-ion colliding beam facility.

Capture, acceleration and bunching rf systems for the MEIC booster and storage rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shaoheng; Guo, Jiquan; Lin, Fanglei

2015-09-01

The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. The electron collider ring accepts electrons from CEBAF at energies from 3 to 12 GeV. Protons and ions are delivered to a booster and captured in a long bunch before being ramped and transferred to the ion collider ring. The ion collider ring accelerates a small number of long ion bunches to colliding energy before they are re-bunched into a high frequency train of very short bunches for colliding. Two sets of low frequency RF systems are needed for the long ion bunch energymore » ramping in the booster and ion collider ring. Another two sets of high frequency RF cavities are needed for re-bunching in the ion collider ring and compensating synchrotron radiation energy loss in the electron collider ring. The requirements from energy ramping, ion beam bunching, electron beam energy compensation, collective effects, beam loading and feedback capability, RF power capability, etc. are presented. The preliminary designs of these RF systems are presented. Concepts for the baseline cavity and RF station configurations are described, as well as some options that may allow more flexible injection and acceleration schemes.« less

Electromagnetic properties of baryon resonances

NASA Astrophysics Data System (ADS)

Tiator, Lothar

2013-10-01

Longitudinal and transverse transition form factors for most of the four-star nucleon resonances have been obtained from high-quality cross section data and polarization observables measured at MAMI, ELSA, BATES, GRAAL and CEBAF. As an application, we further show how the transition form factors can be used to obtain empirical transverse charge densities. Contour plots of the thus derived densities are shown and compared for the Roper and S11 nucleon resonances.

Spectrum and Structure of Excited Baryons with CLAS

NASA Astrophysics Data System (ADS)

Burkert, Volker D.

2017-01-01

In this contribution I discuss recent results in light quark baryon spectroscopy involving CLAS data and higher level analysis results from the partial wave analysis by the Bonn-Gatchina group. New baryon states were discovered largely based on the open strangeness production channels γp → K+Λ and γp → K+Σ0. The data illustrate the great potential of the kaon-hyperon channel in the discovery of higher mass baryon resonances in s-channel production. Other channels with discovery potential, such as γp → pω and γp → ϕp are also discussed. In the second part I will demonstrate on data the sensitivity of meson electroproduction to expose the active degrees of freedom underlying resonance transitions as a function of the probed distance scale. For several of the prominent excited states in the lower mass range the short distance behavior is described by a core of three dressed-quarks with running quark mass, and meson-baryon contributions make up significant parts of the excitation strength at large distances. Finally, I give an outlook of baryon resonance physics at the 12 GeV CEBAF electron accelerator. Talk presented at the CRC-16 Symposium, Bonn University, June 6-9, 2016.

Exploration of material removal rate of srf elliptical cavities as a function of media type and cavity shape on niobium and copper using centrifugal barrel polishing (cbp)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palczewski, Ari; Ciovati, Gianluigi; Li, Yongming

Centrifugal barrel polishing (cbp) for SRF application is becoming more wide spread as the technique for cavity surface preparation. CBP is now being used in some form at SRF laboratories around the world including in the US, Europe and Asia. Before the process can become as mature as wet chemistry like eletro-polishing (EP) and buffered chemical polishing (BCP) there are many questions which remain unanswered. One of these topics includes the uniformity of removal as a function of cavity shape and material type. In this presentation we show CBP removal rates for various media types on 1.3 GHz TESLA andmore » 1.5 GHz CEBAF large/fine grain niobium cavities, and 1.3GHz low surface field copper cavity. The data will also include calculated RF frequency shift modeling non-uniform removal as a function of cavity position and comparing them with CBP results.« less

Di-hadron production at Jefferson Laboratory

NASA Astrophysics Data System (ADS)

Anefalos Pereira, Sergio; CLAS Collaboration

2015-04-01

Semi-inclusive deep inelastic scattering (SIDIS) has been used extensively in recent years as an important testing ground for QCD. Studies so far have concentrated on better determination of parton distribution functions, distinguishing between the quark and antiquark contributions, and understanding the fragmentation of quarks into hadrons. Pair of hadrons (di-hadron) SIDIS provides information on the nucleon structure and hadronization dynamics that complements single-hadron SIDIS. The study of di-hadrons allow us to study higher twist distribution functions and Dihadron Fragmentation Functions (DiFF). Together with the twist-2 PDFs (f 1, g 1, h 1), the Higher Twist (HT) e and hL functions are very interesting because they offer insights into the physics of the largely unexplored quark-gluon correlations which provide direct and unique insights into the dynamics inside hadrons. The CLAS spectrometer, installed in Hall-B at Jefferson Lab, has collected data using the CEBAF 6 GeV longitudinally polarized electron beam on longitudinally polarized solid NH3 targets. Preliminary results on beam-, target- and double-spin asymmetries will be presented.

5 MeV Mott Polarimeter Development at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, J. S.; Sinclair, C. K.; Cardman, L. S.

1997-01-01

Low energy (E{sub k}=100 keV) Mott scattering polarimeters are ill- suited to support operations foreseen for the polarized electron injector at Jefferson Lab. One solution is to measure the polarization at 5 MeV where multiple and plural scattering are unimportant and precision beam monitoring is straightforward. The higher injector beam current offsets the lower cross-sections. Recent improvements in the CEBAF injector polarimeter scattering chamber have improved signal to noise.

Current experiments in elementary particle physics. Revision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galic, H.; Armstrong, F.E.; von Przewoski, B.

1994-08-01

This report contains summaries of 568 current and recent experiments in elementary particle physics. Experiments that finished taking data before 1988 are excluded. Included are experiments at BEPC (Beijing), BNL, CEBAF, CERN, CESR, DESY, FNAL, INS (Tokyo), ITEP (Moscow), IUCF (Bloomington), KEK, LAMPF, Novosibirsk, PNPI (St. Petersburg), PSI, Saclay, Serpukhov, SLAC, and TRIUMF, and also several underground and underwater experiments. Instructions are given for remote searching of the computer database (maintained under the SLAC/SPIRES system) that contains the summaries.

Neutron skyshine from end stations of the Continuous Electron Beam Accelerator Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Rai-Ko S.

1991-12-01

The MORSE{_}CG code from Oak Ridge National Laboratory was applied to the estimation of the neutron skyshine from three end stations of the Continuous Electron Beam Accelerator Facility (CEBAF), Newport News, VA. Calculations with other methods and an experiment had been directed at assessing the annual neutron dose equivalent at the site boundary. A comparison of results obtained with different methods is given, and the effect of different temperatures and humidities will be discussed.

Neutron skyshine from end stations of the Continuous Electron Beam Accelerator Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Rai-Ko S.

1991-12-01

The MORSE{ }CG code from Oak Ridge National Laboratory was applied to the estimation of the neutron skyshine from three end stations of the Continuous Electron Beam Accelerator Facility (CEBAF), Newport News, VA. Calculations with other methods and an experiment had been directed at assessing the annual neutron dose equivalent at the site boundary. A comparison of results obtained with different methods is given, and the effect of different temperatures and humidities will be discussed.

Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aznauryan, I. G.; Yerevan Physics Institute, 375036 Yerevan; Burkert, V. D.

2009-11-15

We present results on the electroexcitation of the low mass resonances {delta}(1232)P{sub 33}, N(1440)P{sub 11}, N(1520)D{sub 13}, and N(1535)S{sub 11} in a wide range of Q{sup 2}. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for {pi} electroproduction off the proton. The data were analyzed using two conceptually different approaches--fixed-t dispersion relations and a unitary isobar model--allowing us to draw conclusions on themore » model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the {delta}(1232)P{sub 33} show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q{sup 2}{<=}6 GeV{sup 2}. For the Roper resonance, N(1440)P{sub 11}, the data provide strong evidence that this state is a predominantly radial excitation of a three-quark (3q) ground state. Measured in pion electroproduction, the transverse helicity amplitude for the N(1535)S{sub 11} allowed us to obtain the branching ratios of this state to the {pi}N and {eta}N channels via comparison with the results extracted from {eta} electroproduction. The extensive CLAS data also enabled the extraction of the {gamma}*p{yields}N(1520)D{sub 13} and N(1535)S{sub 11} longitudinal helicity amplitudes with good precision. For the N(1535)S{sub 11}, these results became a challenge for quark models and may be indicative of large meson-cloud contributions or of representations of this state that differ from a 3q excitation. The transverse amplitudes for the N(1520)D{sub 13} clearly show the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q{sup 2}>1 GeV{sup 2}, confirming a long-standing prediction of the constituent quark model.« less

Current Experiments in Particle Physics. 1996 Edition.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galic, Hrvoje

2003-06-27

This report contains summaries of current and recent experiments in Particle Physics. Included are experiments at BEPC (Beijing), BNL, CEBAF, CERN, CESR, DESY, FNAL, Frascati, ITEP (Moscow), JINR (Dubna), KEK, LAMPF, Novosibirsk, PNPI (St. Petersburg), PSI, Saclay, Serpukhov, SLAC, and TRIUMF, and also several proton decay and solar neutrino experiments. Excluded are experiments that finished taking data before 1991. Instructions are given for the World Wide Web (WWW) searching of the computer database (maintained under the SLAC-SPIRES system) that contains the summaries.

Di-hadron production at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anefalos Pereira, Sergio; et. al.,

Semi-inclusive deep inelastic scattering (SIDIS) has been used extensively in recent years as an important testing ground for QCD. Studies so far have concentrated on better determination of parton distribution functions, distinguishing between the quark and antiquark contributions, and understanding the fragmentation of quarks into hadrons. Hadron pair (di-hadron) SIDIS provides information on the nucleon structure and hadronization dynamics that complement single hadron SIDIS. Di-hadrons allow the study of low- and high-twist distribution functions and Dihadron Fragmentation Functions (DiFF). Together with the twist-2 PDFs ( f1, g1, h1), the Higher Twist (HT) e and hL functions are very interesting becausemore » they offer insights into the physics of the largely unexplored quark-gluon correlations, which provide access into the dynamics inside hadrons. The CLAS spectrometer, installed in Hall-B at Jefferson Lab, has collected data using the CEBAF 6 GeV longitudinally polarized electron beam on longitudinally polarized solid NH3 targets. Preliminary results on di-hadron beam-, target- and double-spin asymmetries will be presented.« less

Does one need a 4.5 K screen in cryostats of superconducting accelerator devices operating in superfluid helium? lessons from the LHL

NASA Astrophysics Data System (ADS)

Lebrun, Philippe; Parma, Vittorio; Tavian, Laurent

2014-01-01

Superfluid helium is increasingly used as a coolant for superconducting devices in particle accelerators: the lower temperature enhances the performance of superconductors in high-field magnets and reduces BCS losses in RF acceleration cavities, while the excellent transport properties of superfluid helium can be put to work in efficient distributed cooling systems. The thermodynamic penalty of operating at lower temperature however requires careful management of the heat loads, achieved inter alia through proper design and construction of the cryostats. A recurrent question appears to be that of the need and practical feasibility of an additional screen cooled by normal helium at around 4.5 K surrounding the cold mass at about 2 K, in such cryostats equipped with a standard 80 K screen. We introduce the issue in terms of first principles applied to the configuration of the cryostats, discuss technical constraints and economical limitations, and illustrate the argumentation with examples taken from large projects confronted with this issue, i.e. CEBAF, SPL, ESS, LHC, TESLA, European X-FEL, ILC.

Exclusive QCD processes, quark-hadron duality, and the transition to perturbative QCD

NASA Astrophysics Data System (ADS)

Corianò, Claudio; Li, Hsiang-nan; Savkli, Cetin

1998-07-01

Experiments at CEBAF will scan the intermediate-energy region of the QCD dynamics for the nucleon form factors and for Compton Scattering. These experiments will definitely clarify the role of resummed perturbation theory and of quark-hadron duality (QCD sum rules) in this regime. With this perspective in mind, we review the factorization theorem of perturbative QCD for exclusive processes at intermediate energy scales, which embodies the transverse degrees of freedom of a parton and the Sudakov resummation of the corresponding large logarithms. We concentrate on the pion and proton electromagnetic form factors and on pion Compton scattering. New ingredients, such as the evolution of the pion wave function and the complete two-loop expression of the Sudakov factor, are included. The sensitivity of our predictions to the infrared cutoff for the Sudakov evolution is discussed. We also elaborate on QCD sum rule methods for Compton Scattering, which provide an alternative description of this process. We show that, by comparing the local duality analysis to resummed perturbation theory, it is possible to describe the transition of exclusive processes to perturbative QCD.

Design of the Trigger Interface and Distribution Board for CEBAF 12 GeV Upgrade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, Jianhui; Dong, Hai; Cuevas, R

The design of the Trigger Interface and Distribution (TID) board for the 12 GeV Upgrade at the Continuous Electron Beam Accelerator Facility (CEBAF) at TJNAL is described. The TID board distributes a low jitter system clock, synchronized trigger, and synchronized multi-purpose SYNC signal. The TID also initiates data acquisition for the crate. With the TID boards, a multi-crate system can be setup for experiment test and commissioning. The TID board can be selectively populated as a Trigger Interface (TI) board, or a Trigger Distribution (TD) board for the 12 GeV upgrade experiments. When the TID is populated as a TI,more » it can be located in the VXS crate and distribute the CLOCK/TRIGGER/SYNC through the VXS P0 connector; it can also be located in the standard VME64 crate, and distribute the CLOCK/TRIGGER/SYNC through the VME P2 connector or front panel. It initiates the data acquisition for the front crate where the TI is positioned in. When the TID is populated as a TD, it fans out the CLOCK/TRIGGER/SYNC from trigger supervisor to the front end crates through optical fibres. The TD monitors the trigger processing on the TIs, and gives feedback to the TS for trigger flow control. Field Programmable Gate Arrays (FPGA) is utilised on TID board to provide programmability. The TID boards were intensively tested on the bench, and various setups.« less

An improved equivalent circuit model of a four rod deflecting cavity

NASA Astrophysics Data System (ADS)

Apsimon, R.; Burt, G.

2017-03-01

In this paper we present an improved equivalent circuit model for a four rod deflecting cavity which calculates the frequencies of the first four modes of the cavity as well as the RT/Q for the deflecting mode. Equivalent circuit models of RF cavities give intuition and understanding about how the cavity operates and what changes can be made to modify the frequency, without the need for RF simulations, which can be time-consuming. We parameterise a generic four rod deflecting cavity into a geometry consisting of simple shapes. Equations are derived for the line impedance of the rods and the capacitance between the rods and these are used to calculate the resonant frequency of the deflecting dipole mode as well as the lower order mode and the model is bench-marked against two test cases; the CEBAF separator and the HL-LHC 4-rod LHC crab cavity. CST and the equivalent circuit model agree within 4% for both cavities with the LOM frequency and within 1% for the deflecting frequency. RT/Q differs between the model and CST by 37% for the CEBAF separator and 25% for the HL-LHC 4-rod crab cavity; however this is sufficient for understanding how to optimise the cavity design. The model has then been utilised to suggest a method of separating the modal frequencies in the HL-LHC crab cavity and to suggest design methodologies to optimise the cavity geometries.

Exclusive and Semi-Exclusive Reactions at a Higher Energy CEBAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carl Carlson

More energy at CEBAF provides more opportunity for studies of hadron and nuclear properties. Many of the experiments that could be done are extensions of things already done at lower energies. Others represent new initiatives that could not work or could not theoretically be interpreted at lower energies. The author concentrates on the new initiatives, but do not wish our thinking to neglect what can be learned from continuations of lower energy work. The author begins with a list of some things that should be continued into a new energy regime. (1) Baryon and meson spectroscopy of higher mass states.more » With 4 GeV incoming electron energy, strange mesons are limited to 1.8 GeV in mass and charm is not producible. (2) Exclusive reactions, including meson and baryon form factors and reactions on few nucleon systems. The latter includes deuteron photodisintegration, the A and B form factors of the deuteron, and the deuteron tensor polarization T{sub 20}. (And we should not forget T{sub 20} in inclusive scattering.) (3) Hadrons in the nuclear medium, with such topics as color transparency, electroproduction of {rho} mesons, virtual Compton scattering off nuclei, and backward hadrons from e-d reactions. The very last must be especially important, since it gives the logo used in the advertizing for this conference. In addition, there are new initiatives that this talk will call attention to, in particular: (1) semi-exclusive meson production; (2) duality in semi-exclusive reactions; and (3) new views of exclusive reactions and perturbative QCD (leading to ''off-forward parton distributions'').« less

Operation of a high-gradient superconducting radio-frequency cavity with a non-evaporable getter pump

DOE PAGES

Ciovati, G.; Geng, R.; Lushtak, Y.; ...

2016-10-28

The use of non-evaporable getter (NEG) pumps in particle accelerators has increased significantly over the past few years because of their large pumping speed, particularly for hydrogen, compared to the size of the pump. A concern about using such pumps in superconducting radio-frequency (SRF) accelerators is the possibility of shedding particulates which could then migrate into the SRF cavities and produce field emission, therefore degrading the cavity performance. One option to mitigate such issue is to use sintered getter materials which intrinsically offer superior mechanical and particle retention properties. In this article we present the results from cryogenic RF testsmore » of a high-gradient SRF cavity after being evacuated several times with an NEG pump equipped with sintered getter disks and placed in close proximity to the cavity. Here, the results showed that the cavity performance was not affected by the pump up to the quench gradient of 34 MV/m. As a result of this study, two such NEG pumps have been installed next to a cryomodule in the CEBAF accelerator to maintain ultra-high vacuum in the SRF cryomodule and two adjacent warm girder sections.« less

Testing of the new tuner design for the CEBAF 12 GeV upgrade SRF cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edward Daly; G. Davis; William Hicks

2005-05-01

The new tuner design for the 12 GeV Upgrade SRF cavities consists of a coarse mechanical tuner and a fine piezoelectric tuner. The mechanism provides a 30:1 mechanical advantage, is pre-loaded at room temperature and tunes the cavities in tension only. All of the components are located in the insulating vacuum space and attached to the helium vessel, including the motor, harmonic drive and piezoelectric actuators. The requirements and detailed design are presented. Measurements of range and resolution of the coarse tuner are presented and discussed.

Optimization of the RF cavity heat load and trip rates for CEBAF at 12 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, He; Roblin, Yves R.; Freyberger, Arne P.

2017-05-01

The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.

Results from the first single cell Nb 3Sn cavity coatings at JLab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eremeev, Grigory

2015-09-01

Nb 3Sn is a promising superconducting material for SRF applications and has the potential to exceed the limitations of niobium. We have used the recently commissioned Nb 3Sn coating system to investigate Nb 3Sn coatings on several single cell cavities by applying the same coating procedure on several different single cells with different history and pre-coating surface preparation. We report on our findings with four 1.5 GHz CEBAF-shape single cell and one 1.3 GHz ILC-shape single cavities that were coated, inspected, and tested.

Chapter in book "Many Body Structure of Strongly Interacting Systems, Refereed and Selected Contributions from the Symposium '20 Years of Physics at the Mainz Microtron MAMI,'" Part I, Editors: Arenhövel, H.; Backe, H.; Drechsel, D.; Friedrich, J.; Kaiser, K.-H.; Walcher, Th., p.7-17 (contribution entitled Physics at the Thomas Jefferson National Accelerator Facility)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence Cardman

2006-09-01

The Continuous Electron Accelerator Facility, CEBAF, located at the Thomas Jefferson National Accelerator Facility, is devoted to the investigation of the electromagnetic structure of mesons, nucleons, and nuclei using high energy, high duty-cycle electron and photon beams. Selected experimental results of particular interest to the MAMI community are presented.

Excited Nucleons and Hadron Structure - Proceedings of the Nstar 2000 Conference

NASA Astrophysics Data System (ADS)

Burkert, V. D.; Elouadrhiri, L.; Kelly, J. J.; Minehart, R. C.

The Table of Contents for the book is as follows: * Probing the Structure of Nucleons in the Resonance Region * Pion Photoproduction Results from MAMI * Pion Production and Compton Scattering at LEGS * Electroproduction Multipoles from ELSA * Baryon Resonance Production at Jefferson Lab at High Q2 * A Dynamical Model for the Resonant Multipoles and the Δ Structure * Relations between N and Δ Electromagnetic Form Factors * Measurement of the Recoil Polarization in the [p(ěc e ,{e^prime}ěc p ){π ^0}] Reaction at the Energy of the Δ(1232) Resonance * Electroproduction Results from CLAS * S11 (1535) Resonance Production at Jefferson Lab at High Q2 * η and η' Electro- and Photoproduction with the CEBAF Large Acceptance Spectrometer * η Production in Hadronic Interactions * Electromagnetic Production of η and η' Mesons * The Crystal Barrel Experiment at ELSA * Measurement of π-p → Neutrals Using the Crystal Ball * π+π0 and η Photoproduction at GRAAL * Partial Wave Analysis of Pion Photoproduction with Constraints from Fixed-t Dispersion Relations * N* Resonances in e+e- Collisions at BEPC * What is the Structure of the Roper Resonance? * Hybrid Baryon Signatures * Mixing Angles Determination via the Process γp → ηp * SU(6) Breaking Effects in the Nucleon Elastic Electromagnetic Form Factors * The Hypercentral Constituent Quark Model * Baryon Resonance Decays Within Constituent Quark Models * Pion Production Model - Connection between Dynamics and Quark Models * N* Investigation via Two Pion Electroproduction with the CLAS Detector at Jefferson Laboratory * Isobar Model for Studies of N* Excitation in Charged Double Pion Production by Real and Virtual Photons * Double Pion Photoproduction in the Second Resonance Region * CLAS Electroproduction of ω(783) Mesons * Electromagnetic Production of Vector Mesons at Low Energies * Polarized Target Developments for GRAAL and Prospects * Analytic Structure of a Multichannel Model * Missing Nucleon Resonances in Kaon Production with Pions and Photons * Hyperon Electroproduction with CLAS * From Bjorken to Drell-Hearn-Gerasimov Sum Rules * GDH Measurements at Mainz * Double Polarization Measurements in Inclusive Inelastic e - p Scattering * Measurement of Inclusive Spin Asymmetries and Sum Rules on 3He and the Neutron * Polarization and Out-of-Plane Responses in Pion and ETA Electroproduction * Polarization Observables in π+ Electroproduction with CLAS * Pion Electroproduction on the Nucleon and the Generalized GDH Sum Rule * Virtual Compton Scattering in the Resonance Region * What We Know about the Theoretical Foundation of Duality in Electron Scattering * Hadron Structure in Lattice QCD: Exploring the Gluon Wave Functional * N* Spectrum in Lattice QCD * Baryon Spectrum in the Large Nc Limit * Deeply Virtual Photon and Meson Electroproduction * Why N*'s are Important * Participant List

Framing Innovation: Does an Instructional Vision Help Superintendents Gain Acceptance for a Large-Scale Technology Initiative?

ERIC Educational Resources Information Center

Flanagan, Gina E.

2014-01-01

There is limited research that outlines how a superintendent's instructional vision can help to gain acceptance of a large-scale technology initiative. This study explored how superintendents gain acceptance for a large-scale technology initiative (specifically a 1:1 device program) through various leadership actions. The role of the instructional…

Outreach programs in physics at Hampton University

NASA Astrophysics Data System (ADS)

Pittman, Carlane J.; Temple, Doyle A.

1996-07-01

The Department of Physics at Hampton University generates over 4.5 M dollars of external research funding annually and operates three research centers, the Nuclear High Energy Physics Research Center, the Research Center for Optical Physics, and the Center for Fusion Training and Research. An integral component of these centers is an active outreach and recruitment program led by the Associate Director for Outreach. This program includes summer internships and research mentorships, both at Hampton University and at national laboratories such as CEBAF and NASA Langley. Faculty presentations ar local area elementary schools, middle schools and high schools are also under the auspices of this program.

A design study for a compact two stage in-flight separator with a high mass resolution and large acceptance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Ji-Gwang; Kim, Eun-San, E-mail: eskim1@knu.ac.kr; Hatanaka, Kichiji

2015-03-15

The rare isotope beam separator with a large angular acceptance and energy acceptance is essential for examining the characteristics of unstable nuclei and exotic nuclear reactions. Careful design, however, is required to compensate for the effects of high order aberrations induced by large aperture magnets, which are used to collect rare isotopes obtained from a high energy primary heavy-ion beam hitting a target. In order to minimize the effect of the high order aberration, the optics was based on the mirror symmetry optics, which provides smaller high order aberrations, for the separation of {sup 132}Sn produced by a fission reactionmore » between the primary beam of {sup 238}U and a relatively thick Pb target. The designed optics provides energy acceptance (full), horizontal angular acceptance, and vertical acceptance of approximately 8%, 60 mrad, and 130 mrad, respectively.« less

A design study for a compact two stage in-flight separator with a high mass resolution and large acceptance.

PubMed

Hwang, Ji-Gwang; Kim, Eun-San; Hatanaka, Kichiji

2015-03-01

The rare isotope beam separator with a large angular acceptance and energy acceptance is essential for examining the characteristics of unstable nuclei and exotic nuclear reactions. Careful design, however, is required to compensate for the effects of high order aberrations induced by large aperture magnets, which are used to collect rare isotopes obtained from a high energy primary heavy-ion beam hitting a target. In order to minimize the effect of the high order aberration, the optics was based on the mirror symmetry optics, which provides smaller high order aberrations, for the separation of (132)Sn produced by a fission reaction between the primary beam of (238)U and a relatively thick Pb target. The designed optics provides energy acceptance (full), horizontal angular acceptance, and vertical acceptance of approximately 8%, 60 mrad, and 130 mrad, respectively.

A design study for a compact two stage in-flight separator with a high mass resolution and large acceptance

NASA Astrophysics Data System (ADS)

Hwang, Ji-Gwang; Kim, Eun-San; Hatanaka, Kichiji

2015-03-01

The rare isotope beam separator with a large angular acceptance and energy acceptance is essential for examining the characteristics of unstable nuclei and exotic nuclear reactions. Careful design, however, is required to compensate for the effects of high order aberrations induced by large aperture magnets, which are used to collect rare isotopes obtained from a high energy primary heavy-ion beam hitting a target. In order to minimize the effect of the high order aberration, the optics was based on the mirror symmetry optics, which provides smaller high order aberrations, for the separation of 132Sn produced by a fission reaction between the primary beam of 238U and a relatively thick Pb target. The designed optics provides energy acceptance (full), horizontal angular acceptance, and vertical acceptance of approximately 8%, 60 mrad, and 130 mrad, respectively.

Field Emission in Superconducting Accelerators: Instrumented Measurements for Its Understanding and Mitigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Rongli; Freyberger, Arne P.; Legg, Robert A.

Several new accelerator projects are adopting superconducting accelerator technology. When accelerating cavities maintain high RF gradients, field emission, the emission of electrons from cavity walls, can occur and may impact operational cavity gradient, radiological environment via activated components, and reliability. In this talk, we will discuss instrumented measurements of field emission from the two 1.1 GeV superconducting continuous wave (CW) linacs in CEBAF. The goal is to improve the understanding of field emission sources originating from cryomodule production, installation and operation. Such basic knowledge is needed in guiding field emission control, mitigation, and reduction toward high gradient and reliable operationmore » of superconducting accelerators.« less

Framing Innovation: The Impact of the Superintendent's Technology Infrastructure Decisions on the Acceptance of Large-Scale Technology Initiatives

ERIC Educational Resources Information Center

Arnold, Erik P.

2014-01-01

A multiple-case qualitative study of five school districts that had implemented various large-scale technology initiatives was conducted to describe what superintendents do to gain acceptance of those initiatives. The large-scale technology initiatives in the five participating districts included 1:1 District-Provided Device laptop and tablet…

The GlueX Experiment: First Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanelli, Cristiano

GlueX is a nuclear physics experiment located at the Thomas Jefferson National Accelerator Facility designed to study and understand the nature of confinement in QCD by mapping the spectrum of exotic mesons. The experiment will be able to probe new areas by using photoproduction, i.e. the scattering on nucleon of ~9 GeV linearly polarized photons derived from the recently upgraded CEBAF with a 12 GeV electron beam. Spring 2016 has been characterized by a continued detector commissioning and initial running at the full design energy. The current status of the GlueX detector performance and data collection will be discussed, withmore » a brief overview of first physics results, future run plans, and long term upgrades.« less

Investigations on Absorber Materials at Cryogenic Temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marhauser, Frank; Elliott, Thomas; Rimmer, Robert

2009-05-01

In the framework of the 12 GeV upgrade project for the Continuous Electron Beam Accelerator Facility (CEBAF) improvements are being made to refurbish cryomodules housing Thomas Jefferson National Accelerator Facility's (JLab) original 5-cell cavities. Recently we have started to look into a possible simplification of the existing Higher Order Mode (HOM) absorber design combined with the aim to find alternative material candidates. The absorbers are implemented in two HOM-waveguides immersed in the helium bath and operate at 2 K temperature. We have built a cryogenic setup to perform measurements on sample load materials to investigate their lossy characteristics and variationsmore » from room temperature down to 2 K. Initial results are presented in this paper.« less

Search for hybrid baryons with CLAS12 experimental setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanza, Lucille

It is crucial to study the meson electroproduction in the kinematic region dominated by the formation of resonances. CLAS12 setup in Hall B at Jefferson Lab is particularly suitable for this task, since it is able to detect scattered electrons at low polar angles thanks to the Forward Tagger (FT) component. The process that we propose to study is ep → e'K +Λ, where the electron beam will be provided by the CEBAF accelerator with energies of 6.6, 8.8, and 11 GeV. This thesis work describes the setup and calibration of the FT calorimeter and the studies related to themore » search of hybrid baryons through the measurement of the K + Λ electroproduction cross section.« less

A small-angle large-acceptance detection system for hadrons

NASA Astrophysics Data System (ADS)

Kalantar-Nayestanaki, N.; Bacelar, J. C. S.; Brandenburg, S.; Huisman, H.; Messchendorp, J. G.; Mul, F. A.; Schadmand, S.; van der Schaaf, K.; Schippers, J. M.; Volkerts, M.

2000-04-01

The performance of a segmented large-acceptance detector, capable of measuring particles at small forward angles, is presented. The Small-Angle Large-Acceptance Detector (SALAD), was built to handle very high rates of particles impinging on the detector. Particles down to a few MeV can be detected with it. The position of charged particles is measured by two Multi-Wire Proportional Chambers while scintillator blocks are used to measure the energy of the detected particle. A stack of thin scintillators placed behind the energy detectors allows for a hardware rejection (veto) of high-energy particles going through the scintillator blocks.

Mare Orientale: Widely Accepted Large Impact or a Regular Tectonic Depression?

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2018-04-01

Mare Orientale is one of the critical features on Moon surface explaining its tectonics. The impact origin of it is widely accepted, but an attentive examination shows that this large Mare is a part of endogenous tectonic structure, not a random impact.

Jefferson Lab Experimental Hall C

NASA Astrophysics Data System (ADS)

Carlini, Roger D.

1996-10-01

Jefferson Lab's Hall C went into initial operation in November 1995. The hall has a short orbit spectrometer (SOS) for short-lived particles such as pions and kaons and a high-momentum spectrometer (HMS) usually used for electrons. The SOS can also be used for protons. The HMS can range to 7 GeV/c. Both the SOS and HMS have typical resolutions of (10-3). Experiments for this hall range from measuring the neutron electric form factor, to color transparency, to creating strange nuclei. This paper will present the optical capabilities of the spectrometers, the parameters of the detection systems, and the overall beam line characteristics of the hall as determined from the results from the recent physics experiments along with the upcoming experimental schedule. Additional information is available at URL http://www.cebaf.gov/hallc.html.

Framing Innovation: The Role of Distributed Leadership in Gaining Acceptance of Large-Scale Technology Initiatives

ERIC Educational Resources Information Center

Turner, Henry J.

2014-01-01

This dissertation of practice utilized a multiple case-study approach to examine distributed leadership within five school districts that were attempting to gain acceptance of a large-scale 1:1 technology initiative. Using frame theory and distributed leadership theory as theoretical frameworks, this study interviewed each district's…

The Saskatchewan-Alberta large acceptance detector for photonuclear physics

NASA Astrophysics Data System (ADS)

Cairns, E. B.; Cameron, J.; Choi, W. C.; Fielding, H. W.; Green, P. W.; Greeniaus, L. G.; Hackett, E. D.; Holm, L.; Kolb, N. R.; Korkmaz, E.; Langill, P. P.; McDonald, W. J.; Mack, D.; Olsen, W. C.; Peterson, B. A.; Rodning, N. L.; Soukup, J.; Zhu, J.; Hutcheon, D.; Caplan, H. S.; Pywell, R. E.; Skopik, D. M.; Vogt, J. M.; van Heerden, I. J.

1992-09-01

The Saskatchewan-Alberta Large Acceptance Detector (SALAD) is a 4 π detector designed and built for studies of photonuclear reactions with a tagged photon beam. The design and performance of the detector are described. Its characteristics have been studied by examining p-p elastic scattering with a proton beam at TRIUMF.

Divergent Perceptions: Parental Acceptance and Adolescents' Psychosocial Adjustment.

ERIC Educational Resources Information Center

Eguia, Maria E.

This study examined whether divergent parent-adolescent perceptions regarding parental acceptance predicted adolescent adjustment when the level of parental acceptance (as perceived by the adolescent) was held constant, a methodological and theoretical issue largely ignored by previous research. Subjects were 192 intact, primarily dual-earner…

Retiree health benefits: availability from employers and participation by employees.

PubMed

Loprest, P

1998-12-01

Data from the September 1994 Current Population Survey are used to examine the factors associated with early retirees' access to offers of retiree health insurance (RHI) and their likelihood of accepting these offers. I find large differences in offer rates, with those with pensions and from large firms much more likely to receive an offer, and women and non-Whites less likely. Even among those with an offer of RHI, more than a quarter do not accept the offer. Early retirees who have lower incomes and lack pensions are significantly less likely to accept an offer of RHI, suggesting that policies that increase offers are not sufficient to increase coverage for early retirees. Barriers to accepting offers need to be considered.

A 100 MV cryomodule for CW operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charles Reece

2005-07-10

A cryomodule designed for high-gradient CW operation has been built at Jefferson Lab. The Renascence cryomodule is the final prototype of a design for use in the 12 GeV CEBAF upgrade. The module uses eight 7-cell 1497 MHz cavities to be individually powered by 13 kW klystrons. Specifications call for providing >109 MV CW with < 250 W of dynamic heat at 2.07 K. The module incorporates a new generation of tuners and higher power input waveguides. A mixture of the new HG and LL cavity shapes are used. A new high thermal conductivity RF feedthrough has been developed andmore » used on the 32 HOM coupler probes of Renascence. The cryomodule assembly is complete. Testing is to begin late June. Design features and initial test data will be presented.« less

Radiation Damage From Mono-energetic Electrons Up to 200 keV On Biological Systems

NASA Astrophysics Data System (ADS)

Prilepskiy, Yuriy

2006-03-01

The electron gun of the CEBAF machine at Jefferson lab (Newport News, VA) is capable of delivering electrons with energies up to 200 keV with a resolution of about 10-5. This 1.5 GHz beam permits to generate cellular radiation damage within minutes. We have performed irradiation of cancer cells with different energies and different currents to investigate their biological responses. This study will permit to address the physical processes involved in the RBE and LET at a level that supersedes current data listed in the literature by orders of magnitude. We will discuss the experimental setup and results of the first stage of data collected with this novel system. This research is part of a global program to provide detailed information for the understanding of radiation based cancer treatments.

Acceptance and usability of a home-based monitoring tool of health indicators in children of people with dementia: a Proof of Principle (POP) study.

PubMed

Boessen, April Bcg; Vermeulen, Joan; de Witte, Luc P

2017-01-01

Large-scale cohort studies are needed to confirm the relation between dementia and its possible risk factors. The inclusion of people with dementia in research is a challenge, however, children of people with dementia are at risk and are highly motivated to participate in dementia research. For technologies to support home-based data collection during large-scale studies, participants should be able and willing to use technology for a longer period of time. This study investigated acceptance and usability of iVitality, a research platform for home-based monitoring of dementia health indicators, in 151 children of people with dementia and investigated which frequency of measurements is acceptable for them. Participants were randomized to fortnightly or monthly measurements. At baseline and after 3 months, participants completed an online questionnaire regarding the acceptance (Technology Acceptance Model; 38 items) and usability (Post-Study System Usability Questionnaire; 24 items) of iVitality. Items were rated from 1 (I totally disagree) to 7 (I totally agree). Participants were also invited to take part in an online focus group (OFG) after 3 months of follow-up. Descriptive statistics and both two-sample/independent and paired t -tests were used to analyze the online questionnaires and a directed content analysis was used to analyze the OFGs. Children of people with dementia accept iVitality after long-term use and evaluate iVitality as a user-friendly, useful, and trusted technology, despite some suggestions for improvement. Overall, mean scores on acceptance and usability were higher than 5 (I somewhat agree), although the acceptance subscales "social influence" and "time" were rated somewhat lower. No significant differences in acceptance and usability were found between both protocol groups. Over time, "affect" significantly increased among participants measuring blood pressure fortnightly. iVitality has the potential to be used in large-scale studies for home-based monitoring of health indicators related to the development of dementia.

The GAENE--Generalized Acceptance of EvolutioN Evaluation: Development of a New Measure of Evolution Acceptance

ERIC Educational Resources Information Center

Smith, Mike U.; Snyder, Scott W.; Devereaux, Randolph S.

2016-01-01

The present study reports the development of a brief, quantitative, web-based, psychometrically sound measure--the Generalized Acceptance of EvolutioN Evaluation (GAENE, pronounced "gene") in a format that is useful in large and small groups, in research, and in classroom settings. The measure was designed to measure only evolution…

Mindfulness and Acceptance-Based Group Therapy for Social Anxiety Disorder: An Open Trial

ERIC Educational Resources Information Center

Kocovski, Nancy L.; Fleming, Jan E.; Rector, Neil A.

2009-01-01

Mindfulness and Acceptance-Based Group Therapy (MAGT) for Social Anxiety Disorder (SAD) is based largely on Acceptance and Commitment Therapy (ACT; Hayes et al., 1999), with enhanced mindfulness mostly from Mindfulness-Based Cognitive Therapy (MBCT; Segal et al., 2002). The purpose of this study was to assess the feasibility and initial…

Different shades of green: a case study of support for wind farms in the rural midwest.

PubMed

Mulvaney, Kate K; Woodson, Patrick; Prokopy, Linda Stalker

2013-05-01

Benton County, in north-central Indiana, USA has successfully sited more than 500 turbines. To understand Benton County's acceptance of wind farms, a holistic case study was conducted that included a document review, a survey of local residents and interviews with key stakeholders. Survey questionnaires were sent to 750 residents asking questions about attitudes toward the wind farms, perceived benefits and impacts from the wind farms, environmental attitudes, and demographic information. Key stakeholders were also interviewed for a deeper understanding of the historical timeline and community acceptance of the wind farm development. While there is limited opposition to the turbines, on the whole the community presents a front of acceptance. Financial, rather than environmental, benefits are the main reason for the acceptance. Although significant in other case studies, transparency and participation do not play a large role in Benton County's acceptance. Most residents are not concerned with either visual impacts or noise from the wind turbines. More concrete benefits to the community, such as reduced energy bills for county residents, could help to extend acceptance even further within the community. Although there are concerns about the acceptance of wind farms and the impacts of those farms on local residents in both peer-reviewed literature and popular media, we found little evidence of those concerns in Benton County. Instead, we found Benton County to be a community largely accepting of wind farms.

Different Shades of Green: A Case Study of Support for Wind Farms in the Rural Midwest

NASA Astrophysics Data System (ADS)

Mulvaney, Kate K.; Woodson, Patrick; Prokopy, Linda Stalker

2013-05-01

Benton County, in north-central Indiana, USA has successfully sited more than 500 turbines. To understand Benton County's acceptance of wind farms, a holistic case study was conducted that included a document review, a survey of local residents and interviews with key stakeholders. Survey questionnaires were sent to 750 residents asking questions about attitudes toward the wind farms, perceived benefits and impacts from the wind farms, environmental attitudes, and demographic information. Key stakeholders were also interviewed for a deeper understanding of the historical timeline and community acceptance of the wind farm development. While there is limited opposition to the turbines, on the whole the community presents a front of acceptance. Financial, rather than environmental, benefits are the main reason for the acceptance. Although significant in other case studies, transparency and participation do not play a large role in Benton County's acceptance. Most residents are not concerned with either visual impacts or noise from the wind turbines. More concrete benefits to the community, such as reduced energy bills for county residents, could help to extend acceptance even further within the community. Although there are concerns about the acceptance of wind farms and the impacts of those farms on local residents in both peer-reviewed literature and popular media, we found little evidence of those concerns in Benton County. Instead, we found Benton County to be a community largely accepting of wind farms.

CEBAF Superconducting Cavity RF Drive System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fugitt, Jock; Moore, Thomas

1987-03-01

The CEBAR RF system consists of 418 individual RF amplifier chains. Each superconducting cavity is phase locked to the master drive reference line to within 1 degree, and the cavity field gradient is regulated to within 1 part in 10 by a state-of-the-art RF control module. Precision, continuously adjustable, modulo 360 phase shifters are used to generate the individual phase references, and a compensated RF detector is used for level feedback. The close coupled digital system enhances system accuracy, provides self-calibration, and continuously checks the system for malfunction. Calibration curves, the operating program, and system history are stored in anmore » on board EEPROM. The RF power is generated by a 5Kw, water cooled, permanent magnet focused klystorn. The klystons are clustered in groups of 8 and powered from a common supply. RF power is transmitted to the accelerator sections by semiflexible waveguide.« less

RF System Requirements for a Medium-Energy Electron-Ion Collider (MEIC) at JLab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rimmer, Robert A; Hannon, Fay E; Guo, Jiquan

2015-09-01

JLab is studying options for a medium energy electron-ion collider that could fit on the JLab site and use CEBAF as a full-energy electron injector. A new ion source, linac and booster would be required, together with collider storage rings for the ions and electrons. In order to achieve the maximum luminosity these will be high-current storage rings with many bunches. We present the high-level RF system requirements for the storage rings, ion booster ring and high-energy ion beam cooling system, and describe the technology options under consideration to meet them. We also present options for staging that might reducemore » the initial capital cost while providing a smooth upgrade path to a higher final energy. The technologies under consideration may also be useful for other proposed storage ring colliders or ultimate light sources.« less

Integrated numerical modeling of a laser gun injector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, H.; Benson, S.; Bisognano, J.

1993-06-01

CEBAF is planning to incorporate a laser gun injector into the linac front end as a high-charge cw source for a high-power free electron laser and nuclear physics. This injector consists of a DC laser gun, a buncher, a cryounit and a chicane. The performance of the injector is predicted based on integrated numerical modeling using POISSON, SUPERFISH and PARMELA. The point-by-point method incorporated into PARMELA by McDonald is chosen for space charge treatment. The concept of ``conditioning for final bunching`` is employed to vary several crucial parameters of the system for achieving highest peak current while maintaining low emittancemore » and low energy spread. Extensive parameter variation studies show that the design will perform beyond the specifications for FEL operations aimed at industrial applications and fundamental scientific research. The calculation also shows that the injector will perform as an extremely bright cw electron source.« less

Parity Violation in Deep Inelastic Scattering in Hall C at JLab

NASA Astrophysics Data System (ADS)

Dalton, Mark Macrae; Keppel, Cynthia; Paschke, Kent

2017-09-01

The measurement of parity-violation in inclusive electron deep inelastic scattering (DIS) from a proton or deuteron target can be used to study the flavor structure of the nucleon. While valence quark parton distribution functions (PDF) can be probed in high- x measurements such as with the proposed SoLID spectrometer, complementary measurements are possible at moderate x 0.1 where the sea quarks may still play a significant role. In particular, such measurements would provide a cleanly interpretable measurement of the strange quark PDF. These measurements are possible with the upgraded CEBAF accelerator at JLab and do not require significant new experimental hardware. The prospects and potential impacts of such a measurement will be presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC05-06OR23177 and DE-FG02-07ER41522.

Study of Electron Polarization Dynamics in the JLEIC at Jlab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Fanglei; Derbenev, Yaroslav; Morozov, Vasiliy

The design of an electron polarization scheme in the Jefferson Lab Electron-Ion Collider (JLEIC) aims to attain a high longitudinal electron polarization (over 70%) at collision points as required by the nuclear physics program. Comprehensive strategies for achieving this goal have been considered and developed including injection of highly polarized electrons from CEBAF, mechanisms for manipulation and preservation of the polarization in the JLEIC collider ring and measurement of the electron polarization. In particular, maintaining a sufficiently long polarization lifetime is crucial for accumulation of adequate experimental statistics. The chosen electron polarization configuration, based on the unique figure-8 geometry ofmore » the ring, removes the electron spin-tune energy dependence. This significantly simplifies the control of the electron polarization and suppresses the synchrotron sideband resonances. This paper reports recent studies and simulations of the electron polarization dynamics in the JLEIC electron collider ring.« less

A greater focus on metals in biomedicine and neuroscience is needed.

PubMed

White, Anthony R

2016-11-05

Metals have many essential functions in the brain and a large body of evidence supports important roles for altered metal stasis in many brain disorders. However, despite this evidence, acceptance of metals as key mediators of brain dysfunction is largely lacking in mainstream biomedicine. This editorial will outline the possible reasons for this and suggest potential means to improve the acceptance of metals as central players in brain disease.

Cleanliness for the NIF 1ω Laser Amplifiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spaeth, M. L.; Manes, K. R.; Honig, J.

During the years before the National Ignition Facility (NIF) laser system, a set of generally accepted cleaning procedures had been developed for the large 1ω amplifiers of an inertial confinement fusion laser, and up until 1999 similar procedures were planned for NIF. Several parallel sets of test results were obtained from 1992 to 1999 for large amplifiers using these accepted cleaning procedures in the Beamlet physics test bed and in the Amplifier Module Prototype Laboratory (AMPLAB), a four-slab-high prototype large amplifier structure. Both of these showed damage to their slab surfaces that, if projected to operating conditions for NIF, wouldmore » lead to higher than acceptable slab-refurbishment rates. Finally, this study tracks the search for the smoking gun origin of this damage and describes the solution employed in NIF for avoiding flashlamp-induced aerosol damage to its 1ω amplifier slabs.« less

Cleanliness for the NIF 1ω Laser Amplifiers

DOE PAGES

Spaeth, M. L.; Manes, K. R.; Honig, J.

2017-03-23

During the years before the National Ignition Facility (NIF) laser system, a set of generally accepted cleaning procedures had been developed for the large 1ω amplifiers of an inertial confinement fusion laser, and up until 1999 similar procedures were planned for NIF. Several parallel sets of test results were obtained from 1992 to 1999 for large amplifiers using these accepted cleaning procedures in the Beamlet physics test bed and in the Amplifier Module Prototype Laboratory (AMPLAB), a four-slab-high prototype large amplifier structure. Both of these showed damage to their slab surfaces that, if projected to operating conditions for NIF, wouldmore » lead to higher than acceptable slab-refurbishment rates. Finally, this study tracks the search for the smoking gun origin of this damage and describes the solution employed in NIF for avoiding flashlamp-induced aerosol damage to its 1ω amplifier slabs.« less

Geo-spatial aspects of acceptance of illegal hunting of large carnivores in Scandinavia.

PubMed

Gangaas, Kristin E; Kaltenborn, Bjørn P; Andreassen, Harry P

2013-01-01

Human-carnivore conflicts are complex and are influenced by: the spatial distribution of the conflict species; the organisation and intensity of management measures such as zoning; historical experience with wildlife; land use patterns; and local cultural traditions. We have used a geographically stratified sampling of social values and attitudes to provide a novel perspective to the human - wildlife conflict. We have focused on acceptance by and disagreements between residents (measured as Potential Conflict Index; PCI) towards illegal hunting of four species of large carnivores (bear, lynx, wolf, wolverine). The study is based on surveys of residents in every municipality in Sweden and Norway who were asked their opinion on illegal hunting. Our results show how certain social values are associated with acceptance of poaching, and how these values differ geographically independent of carnivore abundance. Our approach differs from traditional survey designs, which are often biased towards urban areas. Although these traditional designs intend to be representative of a region (i.e. a random sample from a country), they tend to receive relatively few respondents from rural areas that experience the majority of conflict with carnivores. Acceptance of poaching differed significantly between Norway (12.7-15.7% of respondents) and Sweden (3.3-4.1% of respondents). We found the highest acceptance of illegal hunting in rural areas with free-ranging sheep and strong hunting traditions. Disagreements between residents (as measured by PCI) were highest in areas with intermediate population density. There was no correlation between carnivore density and either acceptance of illegal hunting or PCI. A strong positive correlation between acceptance of illegal hunting and PCI showed that areas with high acceptance of illegal hunting are areas with high potential conflict between people. Our results show that spatially-stratified surveys are required to reveal the large scale patterns in social dynamics of human-wildlife conflicts.

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.

Background: The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multi-nucleon system and as an ``effective neutron target''. Quasi-elastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. Purpose: The experimental data presented here test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on the limits of the Impulse Approximation (IA) picture andmore » put the interpretation of spin structure measurements with deuterium on a firmer footing. Information on this reaction can also be used to improve the determination of the deuteron polarization through quasi-elastic electron scattering. Method: We measured the beam-target double spin asymmetry (A||) for quasi-elastic electron scattering off the deuteron at several beam energies (1.6-1.7 GeV, 2.5 GeV, 4.2 GeV and 5.6-5.8 GeV), using the CEBAF Large Acceptance Spectrometer (CLAS) at Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double spin asymmetries were measured as a function of photon virtuality Q2 (0.13-3.17 (GeV/c)2), missing momentum (pm = 0.0 - 0.5 GeV/c), and the angle between the (inferred) ``spectator'' neutron and the momentum transfer direction (θnq). Results: The results are compared with a recent model that includes Final State Interactions (FSI) using a complete parameterization of nucleon-nucleon scattering, as well as a simplified model using the Plane Wave Impulse Approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low to medium missing momenta (pm ≤ 0.25 GeV/c), including the change of the asymmetry due to the contribution of the deuteron D-state at higher momenta. At the highest missing momenta, our data clearly agree better with the calculations including FSI. Conclusions: Final state interactions seem to play a lesser role for polarization observables in deuteron two-body electro-disintegration than for absolute cross sections. Our data, while limited in statistical power, indicate that PWIA models work reasonably well to understand the asymmetries at lower missing momenta. In turn, this information can be used to extract the product of beam and target polarization (PbPt) from quasi-elastic electron-deuteron scattering, which is useful for measurements of spin observables in electron-neutron inelastic scattering. However, at the highest missing (neutron) momenta, FSI effects become important and must be accounted for.« less

Rejection and Acceptance across Contexts: Parents and Peers as Risks and Buffers for Early Adolescent Psychopathology. The TRAILS Study

ERIC Educational Resources Information Center

Sentse, Miranda; Lindenberg, Siegwart; Omvlee, Annelies; Ormel, Johan; Veenstra, Rene

2010-01-01

In a large sample of early adolescents (T2: n = 1023; M age = 13.51; 55.5% girls) it was investigated whether the effects of parental and peer acceptance and rejection on psychopathology (externalizing and internalizing problems) remain when taking into account both contexts simultaneously. Moreover, we examined whether acceptance in one context…

Acceptance and usability of a home-based monitoring tool of health indicators in children of people with dementia: a Proof of Principle (POP) study

PubMed Central

Boessen, April BCG; Vermeulen, Joan; de Witte, Luc P

2017-01-01

Background Large-scale cohort studies are needed to confirm the relation between dementia and its possible risk factors. The inclusion of people with dementia in research is a challenge, however, children of people with dementia are at risk and are highly motivated to participate in dementia research. For technologies to support home-based data collection during large-scale studies, participants should be able and willing to use technology for a longer period of time. Objective This study investigated acceptance and usability of iVitality, a research platform for home-based monitoring of dementia health indicators, in 151 children of people with dementia and investigated which frequency of measurements is acceptable for them. Methods Participants were randomized to fortnightly or monthly measurements. At baseline and after 3 months, participants completed an online questionnaire regarding the acceptance (Technology Acceptance Model; 38 items) and usability (Post-Study System Usability Questionnaire; 24 items) of iVitality. Items were rated from 1 (I totally disagree) to 7 (I totally agree). Participants were also invited to take part in an online focus group (OFG) after 3 months of follow-up. Descriptive statistics and both two-sample/independent and paired t-tests were used to analyze the online questionnaires and a directed content analysis was used to analyze the OFGs. Results Children of people with dementia accept iVitality after long-term use and evaluate iVitality as a user-friendly, useful, and trusted technology, despite some suggestions for improvement. Overall, mean scores on acceptance and usability were higher than 5 (I somewhat agree), although the acceptance subscales “social influence” and “time” were rated somewhat lower. No significant differences in acceptance and usability were found between both protocol groups. Over time, “affect” significantly increased among participants measuring blood pressure fortnightly. Conclusion iVitality has the potential to be used in large-scale studies for home-based monitoring of health indicators related to the development of dementia. PMID:28814839

Reaction mechanisms in 12C(γ,pp) near 200 MeV

NASA Astrophysics Data System (ADS)

Hackett, E. D.; McDonald, W. J.; Opper, A. K.; Quraan, M. A.; Rodning, N. L.; Rozon, F. M.; Feldman, G.; Kolb, N. R.; Pywell, R. E.; Skopik, D. M.; Tiller, D. E.; Vogt, J. M.; Korkmaz, E.; O'rielly, G. V.

1996-03-01

Inclusive 12C(γ,pp) cross sections have been measured with tagged photons in the range Eγ=187-227 MeV using the Saskatchewan-Alberta Large Acceptance Detector (SALAD). The large angular acceptance allowed the measurement of noncoplanar pp emission. The cross sections were compared to a Monte Carlo intranuclear cascade calculation. Agreement was reasonable for the shapes of the cross sections but the calculated total cross section was 3.9 times larger than the data.

A pilot study to understand feasibility and acceptability of stool and cord blood sample collection for a large-scale longitudinal birth cohort.

PubMed

Bailey, S R; Townsend, C L; Dent, H; Mallet, C; Tsaliki, E; Riley, E M; Noursadeghi, M; Lawley, T D; Rodger, A J; Brocklehurst, P; Field, N

2017-12-28

Few data are available to guide biological sample collection around the time of birth for large-scale birth cohorts. We are designing a large UK birth cohort to investigate the role of infection and the developing immune system in determining future health and disease. We undertook a pilot to develop methodology for the main study, gain practical experience of collecting samples, and understand the acceptability of sample collection to women in late pregnancy. Between February-July 2014, we piloted the feasibility and acceptability of collecting maternal stool, baby stool and cord blood samples from participants recruited at prolonged pregnancy and planned pre-labour caesarean section clinics at University College London Hospital. Participating women were asked to complete acceptability questionnaires. Overall, 265 women were approached and 171 (65%) participated, with ≥1 sample collected from 113 women or their baby (66%). Women had a mean age of 34 years, were primarily of white ethnicity (130/166, 78%), and half were nulliparous (86/169, 51%). Women undergoing planned pre-labour caesarean section were more likely than those who delivered vaginally to provide ≥1 sample (98% vs 54%), but less likely to provide maternal stool (10% vs 43%). Pre-sample questionnaires were completed by 110/171 women (64%). Most women reported feeling comfortable with samples being collected from their baby (<10% uncomfortable), but were less comfortable about their own stool (19% uncomfortable) or a vaginal swab (24% uncomfortable). It is possible to collect a range of biological samples from women around the time of delivery, and this was acceptable for most women. These data inform study design and protocol development for large-scale birth cohorts.

Examining the relationship between male rape myth acceptance, female rape myth acceptance, victim blame, homophobia, gender roles, and ambivalent sexism.

PubMed

Davies, Michelle; Gilston, Jennifer; Rogers, Paul

2012-09-01

The relationship between male rape myth acceptance, female rape myth acceptance, attitudes toward gay men, a series of gender role and sexism measures, victim blame and assault severity were investigated. It was predicted that men would display more negative, stereotypical attitudes than women and that male rape myth endorsement would be related to, and predicted by, the other attitude and attribution scales. Respondents comprised 323 undergraduates (146 males and 177 females) from a large University in the Northwest of England. Results broadly conformed to predictions, with men generally more negative than women, and male rape myth acceptance significantly related to female rape myth acceptance, negative attitudes about gay men, gender role attitudes, and victim blame. Furthermore, male rape myth acceptance was predicted by female rape myth acceptance, gender attitudes, and victim blame. Methodological issues and implications for future work and those working with victims are discussed.

The process of accepting breast cancer among Chinese women: A grounded theory study.

PubMed

Chen, Shuang-Qin; Liu, Jun-E; Li, Zhi; Su, Ya-Li

2017-06-01

To describe the process by which Chinese women accept living with breast cancer. Individual interviews were conducted with 18 Chinese women who completed breast cancer treatment. Data were collected from September 2014 to January 2015 at a large tertiary teaching hospital in Beijing, China. In this grounded theory study, data were analyzed using constant comparative and coding analysis methods. In order to explain the process of accepting having breast cancer among women in China through the grounded theory study, a model that includes 5 axial categories was developed. Cognitive reconstruction emerged as the core category. The extent to which the women with breast cancer accepted having the disease was found to increase with the treatment stage and as their treatment stage progressed with time. The accepting process included five stages: non-acceptance, passive acceptance, willingness to accept, behavioral acceptance, and transcendence of acceptance. Our study using grounded theory study develops a model describing the process by which women accept having breast cancer. The model provides some intervention opportunities at every point of the process. Copyright © 2017. Published by Elsevier Ltd.

Design and Performance Tests of Ultra-Compact Calorimeters for High Energy Astrophysics

NASA Technical Reports Server (NTRS)

Salgado, Carlos W.

2003-01-01

This R&D project had two goals: a) the study of general-application ultra-compact calorimetry technologies for use in High Energy Astrophysics and, b) contribute to the design of an efficient calorimeter for the ACCESS mission. The direct measurement of galactic cosmic ray fluxes is performed from space or from balloon-borne detectors. Detectors used in those studies are limited in size and, specially, in weight. Since galactic cosmic ray fluxes are very small, detectors with high geometrical acceptances and long exposures are usually required for collecting enough statistics. We have studied calorimeter techniques that could produce large geometrical acceptance per unit of mass (G/w) and that may be used to study galactic cosmic rays at intermediate energies (knee energies).-The most important asset for detection of primary cosmic rays at and about the knee is large acceptance. To construct a large acceptance calorimeter (this term is used here in its most general accepted meaning of calorimeter as a device to measure particle energies ) the detector needs to be verv liaht or verv shallow . We studied two possible technologies to built compact calorimeters: the use of lead-tungstate crystals (PWO) and the use of sampling calorimetry using scintillating fibers embedded in a matrix of powder tungsten. For a very light detector, we considered the possibility of using Optical Transition Radiation (OTR) to measure the energy (and perhaps also direction and identity) of VHE cosmic rays.

Results from VDOT's pilot project using volumetric properties and asphalt content for acceptance of asphalt concrete.

DOT National Transportation Integrated Search

1995-01-01

In 1994 the Virginia Department of Transportation (VDOT) developed a specification for the acceptance of asphalt concrete based largely on Marshall compacted volumetric properties of the mix. A copy of the Special Provision is shown in the Appendix. ...

Acceptance of homosexuality through education? Investigating the role of education, family background and individual characteristics in the United Kingdom.

PubMed

la Roi, Chaïm; Mandemakers, Jornt J

2018-03-01

Higher educated people tend to be more accepting of homosexuality than lower educated people. This has inspired claims that education leads to a higher acceptance of homosexuality. Alternatively, the association between education and acceptance of homosexuality could be confounded by (un)observed family background and stable individual characteristics. This study investigated the association between education and acceptance of homosexuality and the role of potential confounders in a unique longitudinal sample of British siblings. Multilevel and fixed effects analyses show that both perspectives apply. A large part of the association between education and acceptance of homosexuality could be attributed to family background and observed individual characteristics (one third), as well as unobserved individual characteristics (an additional third), but the positive association remains. Findings are discussed in light of existing explanations regarding the effect of education on the acceptance of homosexuality. Copyright © 2017 Elsevier Inc. All rights reserved.

Exploring Students' Technology Acceptance in College Developmental Mathematics

ERIC Educational Resources Information Center

Williams, Handan

2012-01-01

Technology has become a large component of teaching and learning in mathematics education. Gaining insight into students' technology acceptance factors is a crucial step in understanding instructional design and implementation of technology-based learning programs. Despite the widespread use of technology in education, few research efforts…

Educational Data Mining Acceptance among Undergraduate Students

ERIC Educational Resources Information Center

Wook, Muslihah; Yusof, Zawiyah M.; Nazri, Mohd Zakree Ahmad

2017-01-01

The acceptance of Educational Data Mining (EDM) technology is on the rise due to, its ability to extract new knowledge from large amounts of students' data. This knowledge is important for educational stakeholders, such as policy makers, educators, and students themselves to enhance efficiency and achievements. However, previous studies on EDM…

The Heavy Photon Search test detector

DOE PAGES

Battaglieri, M.; Boyarinov, S.; Bueltmann, S.; ...

2014-12-17

The Heavy Photon Search (HPS), an experiment to search for a hidden sector photon in fixed target electroproduction, is preparing for installation at the Thomas Jefferson National Accelerator Facility (JLab) in the Fall of 2014. As the first stage of this project, the HPS Test Run apparatus was constructed and operated in 2012 to demonstrate the experiment's technical feasibility and to confirm that the trigger rates and occupancies are as expected. This paper describes the HPS Test Run apparatus and readout electronics and its performance. In this setting, a heavy photon can be identified as a narrow peak in themore » e⁺e⁻invariant mass spectrum above the trident background or as a narrow invariant mass peak with a decay vertex displaced from the production target, so charged particle tracking and vertexing are needed for its detection. In the HPS Test Run, charged particles are measured with a compact forward silicon microstrip tracker inside a dipole magnet. Electromagnetic showers are detected in a PbW0 4 crystal calorimeter situated behind the magnet, and are used to trigger the experiment and identify electrons and positrons. Both detectors are placed close to the beam line and split top-bottom. This arrangement provides sensitivity to low-mass heavy photons, allows clear passage of the unscattered beam, and avoids the spray of degraded electrons coming from the target. The discrimination between prompt and displaced e⁺e⁻ pairs requires the first layer of silicon sensors be placed only 10 cm downstream of the target. The expected signal is small, and the trident background huge, so the experiment requires very large statistics. In addition, the HPS Test Run utilizes high-rate readout and data acquisition electronics and a fast trigger to exploit the essentially 100% duty cycle of the CEBAF accelerator at JLab.« less

An Empirical Analysis of Citizens' Acceptance Decisions of Electronic-Government Services: A Modification of the Unified Theory of Acceptance and Use of Technology (UTAUT) Model to Include Trust as a Basis for Investigation

ERIC Educational Resources Information Center

Awuah, Lawrence J.

2012-01-01

Understanding citizens' adoption of electronic-government (e-government) is an important topic, as the use of e-government has become an integral part of governance. Success of such initiatives depends largely on the efficient use of e-government services. The unified theory of acceptance and use of technology (UTAUT) model has provided a…

When accepting a gift can be professional misconduct and theft.

PubMed

Griffith, Richard

2016-07-01

Gifts are often given as tokens of gratitude by grateful patients to district nurses. However, there are circumstances where the Nursing and Midwifery Council (NMC), as the professional regulator, and the courts, have held that accepting gifts, large or small, from vulnerable adults is dishonest and amounts to professional misconduct and even theft. Richard Griffith discusses the circumstances where a district nurse who accepts a gift can face a fitness-to-practise investigation and an allegation of theft.

High current polarized electron source

NASA Astrophysics Data System (ADS)

Suleiman, R.; Adderley, P.; Grames, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.

2018-05-01

Jefferson Lab operates two DC high voltage GaAs photoguns with compact inverted insulators. One photogun provides the polarized electron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) up to 200 µA. The other gun is used for high average current photocathode lifetime studies at a dedicated test facility up to 4 mA of polarized beam and 10 mA of un-polarized beam. GaAs-based photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed facilities that must operate in excess of tens of mA of polarized average current. This contribution describes techniques to maintain good vacuum while delivering high beam currents, and techniques that minimize damage due to ion bombardment, the dominant mechanism that reduces photocathode yield. Advantages of higher DC voltage include reduced space-charge emittance growth and the potential for better photocathode lifetime. Highlights of R&D to improve the performance of polarized electron sources and prolong the lifetime of strained-superlattice GaAs are presented.

The PEPPo method for polarized positrons and PEPPo II

DOE PAGES

Cardman, Lawrence S.

2018-05-01

The Polarized Electrons for Polarized Positrons (PEPPo) experiment at the injector of the Continuous Electron Beam Accelerator Facility demonstrated for the first time the efficient transfer of polarization from electrons to positrons via a two-step process: polarized bremsstrahlung radiation is induced by a polarized electron beam in a high-Z target; then the polarized bremsstrahlung produces polarized positrons via the pair-production process in the same target. Positron polarization up to 82% was measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization of 85%. This technique extends polarized positron capabilities from GeV to MeVmore » electron beams, and opens access to polarized positron beam physics to a wide community. We present the results of the PEPPo experiment and outline tentative plans for a follow-up experiment that would investigate key aspects of an approach based on PEPPo as a polarized positron source for the 12 GeV Upgrade of CEBAF.« less

Beamline Insertions Manager at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Michael C.

2015-09-01

The beam viewer system at Jefferson Lab provides operators and beam physicists with qualitative and quantitative information on the transverse electron beam properties. There are over 140 beam viewers installed on the 12 GeV CEBAF accelerator. This paper describes an upgrade consisting of replacing the EPICS-based system tasked with managing all viewers with a mixed system utilizing EPICS and high-level software. Most devices, particularly the beam viewers, cannot be safely inserted into the beam line during high-current beam operations. Software is partly responsible for protecting the machine from untimely insertions. The multiplicity of beam-blocking and beam-vulnerable devices motivates us tomore » try a data-driven approach. The beamline insertions application components are centrally managed and configured through an object-oriented software framework created for this purpose. A rules-based engine tracks the configuration and status of every device, along with the beam status of the machine segment containing the device. The application uses this information to decide on which device actions are allowed at any given time.« less

Linac cryogenic distribution system maintenance and upgrades at JLab

NASA Astrophysics Data System (ADS)

Dixon, K.; Wright, M.; Ganni, V.

2014-01-01

The Central Helium Liquefier (CHL) distribution system to the CEBAF and FEL linacs at Jefferson Lab (JLab) experienced a planned warm up during the late summer and fall of 2012 for the first time after its commissioning in 1991. Various maintenance and modifications were performed to support high beam availability to the experimental users, meet 10 CFR 851 requirements for pressure systems, address operational issues, and prepare the cryogenic interfaces for the high-gradient cryomodules needed for the 12 GeV upgrade. Cryogenic maintenance and installation work had to be coordinated with other activities in the linacs and compete for manpower from other department installation activities. With less than a quarter of the gas storage capacity available to handle the boil-off from the more than 40 cryomodules, 35,000 Nm3 of helium was re-liquefied and shipped to a vendor via a liquid tanker trailer. Nearly 200 u-tubes had to be removed and stored while seals were replaced on related equipment such as vacuum pump outs, bayonet isolation and process valves.

Workshop on Pion-Kaon Interactions (PKI2018) Mini-Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amaryan, M; Pal, Bilas

This volume is a short summary of talks given at the PKI2018 Workshop organized to discuss current status and future prospects of pi -K interactions. The precise data on pi K interaction will have a strong impact on strange meson spectroscopy and form factors that are important ingredients in the Dalitz plot analysis of a decays of heavy mesons as well as precision measurement of Vus matrix element and therefore on a test of unitarity in the first raw of the CKM matrix. The workshop has combined the efforts of experimentalists, Lattice QCD, and phenomenology communities. Experimental data relevant tomore » the topic of the workshop were presented from the broad range of different collaborations like CLAS, GlueX, COMPASS, BaBar, BELLE, BESIII, VEPP-2000, and LHCb. One of the main goals of this workshop was to outline a need for a new high intensity and high precision secondary KL beam facility at JLab produced with the 12 GeV electron beam of CEBAF accelerator.« less

Gender-Blind Sexism and Rape Myth Acceptance.

PubMed

Stoll, Laurie Cooper; Lilley, Terry Glenn; Pinter, Kelly

2017-01-01

The purpose of this article is to explore whether gender-blind sexism, as an extension of Bonilla-Silva's racialized social system theory, is an appropriate theoretical framework for understanding the creation and continued prevalence of rape myth acceptance. Specifically, we hypothesize that individuals who hold attitudes consistent with the frames of gender-blind sexism are more likely to accept common rape myths. Data for this article come from an online survey administered to the entire undergraduate student body at a large Midwestern institution (N = 1,401). Regression analysis showed strong support for the effects of gender-blind sexism on rape myth acceptance. © The Author(s) 2016.

Acceptability of School-Based Health Centers for Human Papillomavirus Vaccination Visits: A Mixed-Methods Study

ERIC Educational Resources Information Center

Hansen, Caitlin E.; Okoloko, Edirin; Ogunbajo, Adedotun; North, Anna; Niccolai, Linda M.

2017-01-01

Background: Countries with high human papillomavirus (HPV) vaccination rates have achieved this success largely through school-based vaccination. Using school-based health centers (SBHCs) in the United States, where HPV vaccine remains underutilized, could improve uptake. In this mixed-methods study, we examined acceptability, facilitators, and…

Examining the Antecedents of Social Networking Sites Use among CEGEP Students

ERIC Educational Resources Information Center

Doleck, Tenzin; Bazelais, Paul; Lemay, David John

2017-01-01

Investigations in technology acceptance in education has largely overlooked certain unique populations like students from the "Collège d'enseignement général et professionnel" (CEGEP) system. In studies examining CEGEP students' use of technology, the Technology Acceptance Model (TAM) perspective has not been taken into account, nor have…

29 CFR 2550.404c-5 - Fiduciary relief for investments in qualified default investment alternatives.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., liquidation or exchange fees, redemption fees and similar expenses charged in connection with the liquidation... accepted investment theories, is diversified so as to minimize the risk of large losses and that is... portfolio that applies generally accepted investment theories, is diversified so as to minimize the risk of...

29 CFR 2550.404c-5 - Fiduciary relief for investments in qualified default investment alternatives.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., liquidation or exchange fees, redemption fees and similar expenses charged in connection with the liquidation... accepted investment theories, is diversified so as to minimize the risk of large losses and that is... portfolio that applies generally accepted investment theories, is diversified so as to minimize the risk of...

29 CFR 2550.404c-5 - Fiduciary relief for investments in qualified default investment alternatives.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., liquidation or exchange fees, redemption fees and similar expenses charged in connection with the liquidation... accepted investment theories, is diversified so as to minimize the risk of large losses and that is... portfolio that applies generally accepted investment theories, is diversified so as to minimize the risk of...

Sibling Family Practices: Guidelines for Healthy Boundaries

ERIC Educational Resources Information Center

Johnson, Toni Cavanagh; Huang, Bevan Emma; Simpson, Pippa M.

2009-01-01

A questionnaire was given to 500 mental health and child welfare professionals asking for maximum acceptable ages for siblings to engage jointly in certain family practices related to hygiene, affection, and privacy. A large proportion of respondents felt it was never acceptable for siblings to take showers together (40%), kiss on the mouth (37%),…

An acceptable role for computers in the aircraft design process

NASA Technical Reports Server (NTRS)

Gregory, T. J.; Roberts, L.

1980-01-01

Some of the reasons why the computerization trend is not wholly accepted are explored for two typical cases: computer use in the technical specialties and computer use in aircraft synthesis. The factors that limit acceptance are traced in part, to the large resources needed to understand the details of computer programs, the inability to include measured data as input to many of the theoretical programs, and the presentation of final results without supporting intermediate answers. Other factors are due solely to technical issues such as limited detail in aircraft synthesis and major simplifying assumptions in the technical specialties. These factors and others can be influenced by the technical specialist and aircraft designer. Some of these factors may become less significant as the computerization process evolves, but some issues, such as understanding large integrated systems, may remain issues in the future. Suggestions for improved acceptance include publishing computer programs so that they may be reviewed, edited, and read. Other mechanisms include extensive modularization of programs and ways to include measured information as part of the input to theoretical approaches.

"Unspoken Agreements": Perceived Acceptability of Couples HIV Testing and Counseling (CHTC) Among Cisgender Men with Transgender Women Partners.

PubMed

Reisner, Sari L; Menino, David; Leung, Kingsley; Gamarel, Kristi E

2018-06-23

Transgender women (TW) are one of the highest risk groups for HIV infection globally; however, the HIV testing needs of their cisgender (non-transgender) male partners remain largely unknown. This study sought to examine the perceived acceptability of couples HIV testing and counseling (CHTC) for TW-male dyads from the perspective of cisgender men who partner with TW. Between September 2016 and June 2017, 19 cisgender men (mean age = 40.1, SD = 12.8) who currently have, or have ever had a TW partner completed an in-depth semi-structured phone interview and brief survey to gather data on acceptability of CHTC, as well as perceived barriers and facilitators to CHTC for TW-male couples. Qualitative data were thematically analyzed and integrated with survey data. Acceptability of CHTC was high in the sample (89.5%) but was complex and largely contingent on: (1) monogamy and commitment as critical precursors to CHTC acceptability; (2) risk perception and level of comfort with CHTC; (3) understandings of sexual agreements; and (4) personal relationships versus other TW-male relationships. Findings have implications for culturally-adapting and implementing CHTC in real-world settings for TW-male couples, as well as for meeting the individual HIV testing needs of cisgender men who partner with TW.

Large Aperture "Photon Bucket" Optical Receiver Performance in High Background Environments

NASA Technical Reports Server (NTRS)

Vilnrotter, Victor A.; Hoppe, D.

2011-01-01

The potential development of large aperture groundbased "photon bucket" optical receivers for deep space communications, with acceptable performance even when pointing close to the sun, is receiving considerable attention. Sunlight scattered by the atmosphere becomes significant at micron wavelengths when pointing to a few degrees from the sun, even with the narrowest bandwidth optical filters. In addition, high quality optical apertures in the 10-30 meter range are costly and difficult to build with accurate surfaces to ensure narrow fields-of-view (FOV). One approach currently under consideration is to polish the aluminum reflector panels of large 34-meter microwave antennas to high reflectance, and accept the relatively large FOV generated by state-of-the-art polished aluminum panels with rms surface accuracies on the order of a few microns, corresponding to several-hundred micro-radian FOV, hence generating centimeter-diameter focused spots at the Cassegrain focus of 34-meter antennas. Assuming pulse-position modulation (PPM) and Poisson-distributed photon-counting detection, a "polished panel" photon-bucket receiver with large FOV will collect hundreds of background photons per PPM slot, along with comparable signal photons due to its large aperture. It is demonstrated that communications performance in terms of PPM symbol-error probability in high-background high-signal environments depends more strongly on signal than on background photons, implying that large increases in background energy can be compensated by a disproportionally small increase in signal energy. This surprising result suggests that large optical apertures with relatively poor surface quality may nevertheless provide acceptable performance for deep-space optical communications, potentially enabling the construction of cost-effective hybrid RF/optical receivers in the future.

Rural Clinician Scarcity and Job Preferences of Doctors and Nurses in India: A Discrete Choice Experiment

PubMed Central

Rao, Krishna D.; Ryan, Mandy; Shroff, Zubin; Vujicic, Marko; Ramani, Sudha; Berman, Peter

2013-01-01

The scarcity of rural doctors has undermined the ability of health systems in low and middle-income countries like India to provide quality services to rural populations. This study examines job preferences of doctors and nurses to inform what works in terms of rural recruitment strategies. Job acceptance of different strategies was compared to identify policy options for increasing the availability of clinical providers in rural areas. In 2010 a Discrete Choice Experiment was conducted in India. The study sample included final year medical and nursing students, and in-service doctors and nurses serving at Primary Health Centers. Eight job attributes were identified and a D-efficient fractional factorial design was used to construct pairs of job choices. Respondent acceptance of job choices was analyzed using multi-level logistic regression. Location mattered; jobs in areas offering urban amenities had a high likelihood of being accepted. Higher salary had small effect on doctor, but large effect on nurse, acceptance of rural jobs. At five times current salary levels, 13% (31%) of medical students (doctors) were willing to accept rural jobs. At half this level, 61% (52%) of nursing students (nurses) accepted a rural job. The strategy of reserving seats for specialist training in exchange for rural service had a large effect on job acceptance among doctors, nurses and nursing students. For doctors and nurses, properly staffed and equipped health facilities, and housing had small effects on job acceptance. Rural upbringing was not associated with rural job acceptance. Incentivizing doctors for rural service is expensive. A broader strategy of substantial salary increases with improved living, working environment, and education incentives is necessary. For both doctors and nurses, the usual strategies of moderate salary increases, good facility infrastructure, and housing will not be effective. Non-physician clinicians like nurse-practitioners offer an affordable alternative for delivering rural health care. PMID:24376621

International Conference on Large Meteorite Impacts and Planetary Evolution

NASA Technical Reports Server (NTRS)

1992-01-01

The papers that were accepted for the International Conference on Large Meteorite Impacts and Planetary Evolution, 31 Aug. - 2 Sep. 1992, are presented. One of the major paper topics was the Sudbury project.

Large-acceptance diamond planar refractive lenses manufactured by laser cutting.

PubMed

Polikarpov, Maxim; Snigireva, Irina; Morse, John; Yunkin, Vyacheslav; Kuznetsov, Sergey; Snigirev, Anatoly

2015-01-01

For the first time, single-crystal diamond planar refractive lenses have been fabricated by laser micromachining in 300 µm-thick diamond plates which were grown by chemical vapour deposition. Linear lenses with apertures up to 1 mm and parabola apex radii up to 500 µm were manufactured and tested at the ESRF ID06 beamline. The large acceptance of these lenses allows them to be used as beam-conditioning elements. Owing to the unsurpassed thermal properties of single-crystal diamond, these lenses should be suitable to withstand the extreme flux densities expected at the planned fourth-generation X-ray sources.

Researching Instructional Use and the Technology Acceptation of Learning Management Systems by Secondary School Teachers

ERIC Educational Resources Information Center

De Smet, Cindy; Bourgonjon, Jeroen; De Wever, Bram; Schellens, Tammy; Valcke, Martin

2012-01-01

The aim of this large-scale study was to understand the technology acceptation of learning management systems (LMS) by secondary school teachers and to investigate the instructional use of LMS, distinguishing between informational use and communicational use. The predictive model further includes: perceived usefulness, perceived ease of use,…

Technical Adequacy and Acceptability of Curriculum-Based Measurement and the Measures of Academic Progress

ERIC Educational Resources Information Center

January, Stacy-Ann A.; Ardoin, Scott P.

2015-01-01

Curriculum-based measurement in reading (CBM-R) and the Measures of Academic Progress (MAP) are assessment tools widely employed for universal screening in schools. Although a large body of research supports the validity of CBM-R, limited empirical evidence exists supporting the technical adequacy of MAP or the acceptability of either measure for…

Teachers Left Behind: Acceptance and Use of Technology in Lebanese Public High Schools

ERIC Educational Resources Information Center

Baytiyeh, Hoda

2014-01-01

Nowadays, the use of computers in education is increasing worldwide. Information technology is deemed essential for the digital generation's classrooms. However, the adoption of technology in teaching and learning largely depends on the culture and social context. The aim of this research study is to evaluate the acceptance and use of technology…

The Relationship Between Television Sports Exposure and Rape Myth Acceptance: The Mediating Role of Sexism and Sexual Objectification of Women.

PubMed

Custers, Kathleen; McNallie, Jenna

2016-06-30

Rape affects a large proportion of women in the United States but is one of the most underreported crimes. It is believed that rape myth acceptance contributes to low reporting rates. We tested whether television sports exposure was indirectly related to higher acceptance of rape myth beliefs. An online survey involving 465 undergraduate students showed that viewing TV sports was positively related to hostile sexism, benevolent sexism, and sexual objectification of women. Through these variables, TV sports was indirectly and positively associated with rape myth acceptance. These results suggest that sports programming contributes to the perpetuation of rape myths in society. © The Author(s) 2016.

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.

The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system and as an effective neutron target. Quasielastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground statemore » (due to the D-state admixture) and on the limits of the impulse approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. Information on this reaction can also be used to reduce systematic uncertainties on the determination of neutron form factors or deuteron polarization through quasielastic polarized electron scattering. Furthermore, we measured the beam-target double-spin asymmetry (A ||) for quasielastic electron scattering off the deuteron at several beam energies (1.6–1.7, 2.5, 4.2, and 5.6–5.8GeV), using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double-spin asymmetries were measured as a function of photon virtuality Q 2 (0.13–3.17(GeV/c) 2), missing momentum (p m=0.0–0.5GeV/c), and the angle between the (inferred) spectator neutron and the momentum transfer direction (θ nq). We compare our results with a recent model that includes final-state interactions (FSI) using a complete parametrization of nucleon-nucleon scattering, as well as a simplified model using the plane wave impulse approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low to medium missing momenta (p m≤0.25GeV/c), including the change of the asymmetry due to the contribution of the deuteron D state at higher momenta. At the highest missing momenta, our data clearly agree better with the calculations including FSI. Final-state interactions seem to play a lesser role for polarization observables in deuteron two-body electrodisintegration than for absolute cross sections. Our data, while limited in statistical power, indicate that PWIA models work reasonably well to understand the asymmetries at lower missing momenta. In turn, this information can be used to extract the product of beam and target polarization (P bP t) from quasielastic electron-deuteron scattering, which is useful for measurements of spin observables in electron-neutron inelastic scattering. But, at the highest missing (neutron) momenta, FSI effects become important and must be accounted for.« less

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

DOE PAGES

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.; ...

2017-02-24

The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system and as an effective neutron target. Quasielastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground statemore » (due to the D-state admixture) and on the limits of the impulse approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. Information on this reaction can also be used to reduce systematic uncertainties on the determination of neutron form factors or deuteron polarization through quasielastic polarized electron scattering. Furthermore, we measured the beam-target double-spin asymmetry (A ||) for quasielastic electron scattering off the deuteron at several beam energies (1.6–1.7, 2.5, 4.2, and 5.6–5.8GeV), using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double-spin asymmetries were measured as a function of photon virtuality Q 2 (0.13–3.17(GeV/c) 2), missing momentum (p m=0.0–0.5GeV/c), and the angle between the (inferred) spectator neutron and the momentum transfer direction (θ nq). We compare our results with a recent model that includes final-state interactions (FSI) using a complete parametrization of nucleon-nucleon scattering, as well as a simplified model using the plane wave impulse approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low to medium missing momenta (p m≤0.25GeV/c), including the change of the asymmetry due to the contribution of the deuteron D state at higher momenta. At the highest missing momenta, our data clearly agree better with the calculations including FSI. Final-state interactions seem to play a lesser role for polarization observables in deuteron two-body electrodisintegration than for absolute cross sections. Our data, while limited in statistical power, indicate that PWIA models work reasonably well to understand the asymmetries at lower missing momenta. In turn, this information can be used to extract the product of beam and target polarization (P bP t) from quasielastic electron-deuteron scattering, which is useful for measurements of spin observables in electron-neutron inelastic scattering. But, at the highest missing (neutron) momenta, FSI effects become important and must be accounted for.« less

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

NASA Astrophysics Data System (ADS)

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.; Akbar, Z.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Bosted, P.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Keith, C.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; McKinnon, B.; Meekins, D.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Net, L. A.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zonta, I.; CLAS Collaboration

2017-02-01

Background: The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system and as an effective neutron target. Quasielastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. Purpose: The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground state (due to the D -state admixture) and on the limits of the impulse approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. Information on this reaction can also be used to reduce systematic uncertainties on the determination of neutron form factors or deuteron polarization through quasielastic polarized electron scattering. Method: We measured the beam-target double-spin asymmetry (A||) for quasielastic electron scattering off the deuteron at several beam energies (1.6 -1.7 , 2.5, 4.2, and 5.6 -5.8 GeV ), using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double-spin asymmetries were measured as a function of photon virtuality Q2(0.13 -3.17 (GeV/c ) 2) , missing momentum (pm=0.0 -0.5 GeV /c ), and the angle between the (inferred) spectator neutron and the momentum transfer direction (θn q). Results: The results are compared with a recent model that includes final-state interactions (FSI) using a complete parametrization of nucleon-nucleon scattering, as well as a simplified model using the plane wave impulse approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low to medium missing momenta (pm≤0.25 GeV /c ), including the change of the asymmetry due to the contribution of the deuteron D state at higher momenta. At the highest missing momenta, our data clearly agree better with the calculations including FSI. Conclusions: Final-state interactions seem to play a lesser role for polarization observables in deuteron two-body electrodisintegration than for absolute cross sections. Our data, while limited in statistical power, indicate that PWIA models work reasonably well to understand the asymmetries at lower missing momenta. In turn, this information can be used to extract the product of beam and target polarization (PbPt ) from quasielastic electron-deuteron scattering, which is useful for measurements of spin observables in electron-neutron inelastic scattering. However, at the highest missing (neutron) momenta, FSI effects become important and must be accounted for.

Walla Walla District History. Part 3. 1975-80

DTIC Science & Technology

1980-01-01

1 to acceptance of the project by fishery agencies, the local people, and the State of , I daho . II By 1980 i nsta 11 ati on of all three new units...the I daho water plan II that the future growth and quality of life in Idaho depends, in large measure, upon the acceptance and adoption of a...funds was deferred. 32 Nonetheless, the states of Washington and I daho began the comp 1 i cated process of se 1 ect i ng a site acceptable to both

Healthcare professionals and the ethics of healthcare marketing.

PubMed

Hammond, Kevin L; Jurkus, Anthony F

1993-01-01

The article explores marketing ethics considerations in the application of marketing to healthcare. While we realize that acceptance of healthcare marketing by all stakeholders is important for successful marketing, we emphasize its level of acceptance by healthcare professionals. The high levels of resistance to advertising and other forms of healthcare marketing by healthcare professionals has been largely based on the grounds that the practices are unethical. The nature of the resistance thus invites this exploration of healthcare marketing (and the marketing concept), marketing ethics, and the acceptance (rejection) by healthcare professionals of healthcare marketing.

[Analysis the relationship between the found ways and first diagnosis age for large vestibular aqueduct children].

PubMed

Yang, Yali; Huang, Lihui; Cheng, Xiaohua; Fu, Xinxing; Liu, Jiaxing; Ni, Tingting

2014-11-01

To explore the found ways and first diagnosis age of children with large vestibular aqueduct, and their relations with hearing loss. Medical histories of 122 cases of children diagnosed with large vestibular aqueduct by HRCT or MRI had been collected from January 2009 to April 2014 in our hospital children's hearing diagnosis center clinic. Found ways comprise of accepting universal newborn hearing screening (UNHS) group and unaccepting UNHS group. Accepting UNHS children were divided into two ears unpassing group, single ear unpassing group and passing group. The patients in unaccepting UNHS group were divided into not sensitive to sounds, speech stunting, sudden hearing loss, and other group. Analysis the relationship between the found ways and first diagnosis age and their relations with hearing loss. There are 84 cases (68.85%) accepting UNHS, the average age of first diagnosis was (17.24 ± 17.08) months; 37 cases (31.15%) are not accepting UNHS. The average age of first diagnosis was (30.92 ± 18.21) months. The average first diagnosis age of accepting UNHS group was more earlier than the unaccepting UNHS group. The difference was statistically signif- icant (P < 0.01). There were 57 cases (67.85%) whose two ears not pass UNHS; 15 cases (17.86%) single ear not pass; namely the referral rate was 85.71%; 12 cases (14.29%) pass the test. The first diagnosis age of passing UNHS group was more later than two ears unpassing group (P < 0.001). In the unaccepting UNHS group, the average first diagnosis age of not sensitive to sounds group (19.69 ± 11.16 months) was more earlier than words dysplasia group (37.13 ± 15.62 months) and sudden hearing loss group (47.40 ± 24.70 months) (P < 0.01). The difference in the degree of hearing loss between accepting UNHS and unaccepting UNHS group had no statistical significance (P > 0.05). In unaccepting UNHS group ,the average first diagnosis age of the mild-to-moderate hearing loss group was later than the very severe hearing loss group (P < 0.01). Most of large vestibular aqueduct children can be found and receive diagnosis early by UNHS. But part of these patients with late-onset or progressive hearing loss, especially these with mild-to-moderate hearing loss cannot be found early, which should arouse our attention.

Large Payload Ground Transportation and Test Considerations

NASA Technical Reports Server (NTRS)

Rucker, Michelle A.

2016-01-01

During test and verification planning for the Altair lunar lander project, a National Aeronautics and Space Administration (NASA) study team identified several ground transportation and test issues related to the large payload diameter. Although the entire Constellation Program-including Altair-has since been canceled, issues identified by the Altair project serve as important lessons learned for payloads greater than 7 m diameter being considered for NASA's new Space Launch System (SLS). A transportation feasibility study found that Altair's 8.97 m diameter Descent Module would not fit inside available aircraft. Although the Ascent Module cabin was only 2.35 m diameter, the long reaction control system booms extended nearly to the Descent Module diameter, making it equally unsuitable for air transportation without removing the booms and invalidating assembly workmanship screens or acceptance testing that had already been performed. Ground transportation of very large payloads over extended distances is not generally permitted by most states, so overland transportation alone would not be an option. Limited ground transportation to the nearest waterway may be possible, but water transportation could take as long as 66 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA's Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary, which could increase cost, schedule, and technical risk. Once at the launch site, there are no facilities currently capable of accommodating the combination of large payload size and hazardous processing such as hypergolic fuels, pyrotechnic devices, and high pressure gasses. Ironically, the limiting factor to a national heavy lift strategy may not be the rocket technology needed to throw a heavy payload, but rather the terrestrial infrastructure-roads, bridges, airframes, and buildings-necessary to transport, acceptance test, and process large spacecraft. Failure to carefully consider where and how large spacecraft are manufactured, tested, and launched could result in unforeseen cost to modify existing (or develop new) infrastructure, or incur additional risk due to increased handling operations or eliminating key verifications.

The emergence of retail-based clinics in the United States: early observations.

PubMed

Laws, Margaret; Scott, Mary Kate

2008-01-01

Retail-based clinics have proliferated rapidly in the past two years, with approximately 1,000 sites in thirty-seven states representing almost three million cumulative visits. Clinic operators have evolved from a dispersed group of privately financed concerns to a concentrated, largely corporate-owned group. A major development has been the move to large-scale acceptance of insurance, deviating from the initial cash-pay model. Consumers' acceptance and the fact that the clinics appear to increase access for both the uninsured and the insured has encouraged providers and policymakers to consider this approach to basic, acute care while seeking a better understanding of these clinics.

Acceptance and Resistance to Corporate E-Learning: A Case from the Retail Sector

ERIC Educational Resources Information Center

Rabak, Lynne; Cleveland-Innes, Martha

2006-01-01

The purpose of this study was to investigate what influences employees' acceptance and resistance to a corporate e-learning initiative provided by a large retail chain. The research used a survey design to gather interview and survey data to examine the factors affecting learner interest in, and resistance to, training and e-learning. The results…

High-efficiency wavefunction updates for large scale Quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Kent, Paul; McDaniel, Tyler; Li, Ying Wai; D'Azevedo, Ed

Within ab intio Quantum Monte Carlo (QMC) simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunctions. The evaluation of each Monte Carlo move requires finding the determinant of a dense matrix, which is traditionally iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. For calculations with thousands of electrons, this operation dominates the execution profile. We propose a novel rank- k delayed update scheme. This strategy enables probability evaluation for multiple successive Monte Carlo moves, with application of accepted moves to the matrices delayed until after a predetermined number of moves, k. Accepted events grouped in this manner are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency. This procedure does not change the underlying Monte Carlo sampling or the sampling efficiency. For large systems and algorithms such as diffusion Monte Carlo where the acceptance ratio is high, order of magnitude speedups can be obtained on both multi-core CPU and on GPUs, making this algorithm highly advantageous for current petascale and future exascale computations.

Physiologic correlates to background noise acceptance

NASA Astrophysics Data System (ADS)

Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

2004-05-01

Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

A systematic review of patient acceptance of consumer health information technology.

PubMed

Or, Calvin K L; Karsh, Ben-Tzion

2009-01-01

A systematic literature review was performed to identify variables promoting consumer health information technology (CHIT) acceptance among patients. The electronic bibliographic databases Web of Science, Business Source Elite, CINAHL, Communication and Mass Media Complete, MEDLINE, PsycArticles, and PsycInfo were searched. A cited reference search of articles meeting the inclusion criteria was also conducted to reduce misses. Fifty-two articles met the selection criteria. Among them, 94 different variables were tested for associations with acceptance. Most of those tested (71%) were patient factors, including sociodemographic characteristics, health- and treatment-related variables, and prior experience or exposure to computer/health technology. Only ten variables were related to human-technology interaction; 16 were organizational factors; and one was related to the environment. In total, 62 (66%) were found to predict acceptance in at least one study. Existing literature focused largely on patient-related factors. No studies examined the impact of social and task factors on acceptance, and few tested the effects of organizational or environmental factors on acceptance. Future research guided by technology acceptance theories should fill those gaps to improve our understanding of patient CHIT acceptance, which in turn could lead to better CHIT design and implementation.

EDUCATING MANAGERS ABOUT QUALITY THROUGH CUSTOMER-SUPPLIER UNDERSTANDING

EPA Science Inventory

The successful implementation of a Quality System depends largely on the commitment to Quality by managers and their participation in the quality management process. oday, an accepted definition of quality is largely based on the concept of customer and supplier partnerships in a...

Large Payload Transportation and Test Considerations

NASA Technical Reports Server (NTRS)

Rucker, Michelle A.; Pope, James C.

2011-01-01

Ironically, the limiting factor to a national heavy lift strategy may not be the rocket technology needed to throw a heavy payload, but rather the terrestrial infrastructure - roads, bridges, airframes, and buildings - necessary to transport, acceptance test, and process large spacecraft. Failure to carefully consider how large spacecraft are designed, and where they are manufactured, tested, or launched, could result in unforeseen cost to modify/develop infrastructure, or incur additional risk due to increased handling or elimination of key verifications. During test and verification planning for the Altair project, a number of transportation and test issues related to the large payload diameter were identified. Although the entire Constellation Program - including Altair - was canceled in the 2011 NASA budget, issues identified by the Altair project serve as important lessons learned for future payloads that may be developed to support national "heavy lift" strategies. A feasibility study performed by the Constellation Ground Operations (CxGO) project found that neither the Altair Ascent nor Descent Stage would fit inside available transportation aircraft. Ground transportation of a payload this large over extended distances is generally not permitted by most states, so overland transportation alone would not have been an option. Limited ground transportation to the nearest waterway may be permitted, but water transportation could take as long as 66 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA s Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary, which could increase cost, schedule, and technical risk. Once at the launch site, there are no facilities currently capable of accommodating the combination of large payload size and hazardous processing (which includes hypergolic fuels, pyrotechnic devices, and high pressure gasses).

Nutritional characterisation of Zambian Moringa oleifera: acceptability and safety of short-term daily supplementation in a group of malnourished girls.

PubMed

Barichella, Michela; Pezzoli, Gianni; Faierman, Samanta A; Raspini, Benedetta; Rimoldi, Martina; Cassani, Erica; Bertoli, Simona; Battezzati, Alberto; Leone, Alessandro; Iorio, Laura; Ferri, Valentina; Pinelli, Giovanna; Pusani, Chiara; Bolliri, Carlotta; Cilia, Roberto; Caronni, Serena; De Marco, Patrizia; Cereda, Emanuele

2018-05-24

In Zambia, chronic malnutrition still is one of the most common problem among children. To fight against malnutrition, the easiest short-term solution could be to combine specific types of food with affordable local plants. A large variety of natural food resources grow in Zambia, such as Moringa oleifera (MO), whose leaves are known for their health benefits, but are not consumed much by local populations. We analysed Zambian MO powder obtained from dried leaves and found that it contains large amounts of protein, minerals and vitamins, such as iron, calcium and carotenoids. These characteristics make MO a good and sustainable complementary solution to malnutrition. We also evaluated the acceptability and the safety of dietary supplementation with MO powder in malnourished children for 30 days. A daily dose of 14 g daily was safe and well accepted. Its regular use in the menu of local populations may be viable proposition.

Automated Text Analysis Based on Skip-Gram Model for Food Evaluation in Predicting Consumer Acceptance

PubMed Central

Kim, Augustine Yongwhi; Choi, Hoduk

2018-01-01

The purpose of this paper is to evaluate food taste, smell, and characteristics from consumers' online reviews. Several studies in food sensory evaluation have been presented for consumer acceptance. However, these studies need taste descriptive word lexicon, and they are not suitable for analyzing large number of evaluators to predict consumer acceptance. In this paper, an automated text analysis method for food evaluation is presented to analyze and compare recently introduced two jjampong ramen types (mixed seafood noodles). To avoid building a sensory word lexicon, consumers' reviews are collected from SNS. Then, by training word embedding model with acquired reviews, words in the large amount of review text are converted into vectors. Based on these words represented as vectors, inference is performed to evaluate taste and smell of two jjampong ramen types. Finally, the reliability and merits of the proposed food evaluation method are confirmed by a comparison with the results from an actual consumer preference taste evaluation. PMID:29606960

Automated Text Analysis Based on Skip-Gram Model for Food Evaluation in Predicting Consumer Acceptance.

PubMed

Kim, Augustine Yongwhi; Ha, Jin Gwan; Choi, Hoduk; Moon, Hyeonjoon

2018-01-01

The purpose of this paper is to evaluate food taste, smell, and characteristics from consumers' online reviews. Several studies in food sensory evaluation have been presented for consumer acceptance. However, these studies need taste descriptive word lexicon, and they are not suitable for analyzing large number of evaluators to predict consumer acceptance. In this paper, an automated text analysis method for food evaluation is presented to analyze and compare recently introduced two jjampong ramen types (mixed seafood noodles). To avoid building a sensory word lexicon, consumers' reviews are collected from SNS. Then, by training word embedding model with acquired reviews, words in the large amount of review text are converted into vectors. Based on these words represented as vectors, inference is performed to evaluate taste and smell of two jjampong ramen types. Finally, the reliability and merits of the proposed food evaluation method are confirmed by a comparison with the results from an actual consumer preference taste evaluation.

Summer 2012 Colorado Wildfire Non-Profit Sector Case Study

DTIC Science & Technology

2012-11-01

all- populations shelter accommodating individuals with Access and Functional Needs (AFN) and sheltering for companion animals. Penrose Equestrian...Center was established as the large animal shelter and was managed by the El Paso County CART. Both companion and large animals were accepted for...themselves as safe- www.redcross.org/safeandwell. Information on sheltering companion animals at multiple locations is distributed. Large Animal

Teaching genetics prior to teaching evolution improves evolution understanding but not acceptance

PubMed Central

Mead, Rebecca; Hejmadi, Momna

2017-01-01

What is the best way to teach evolution? As microevolution may be configured as a branch of genetics, it being a short conceptual leap from understanding the concepts of mutation and alleles (i.e., genetics) to allele frequency change (i.e., evolution), we hypothesised that learning genetics prior to evolution might improve student understanding of evolution. In the UK, genetics and evolution are typically taught to 14- to 16-y-old secondary school students as separate topics with few links, in no particular order and sometimes with a large time span between. Here, then, we report the results of a large trial into teaching order of evolution and genetics. We modified extant questionnaires to ascertain students’ understanding of evolution and genetics along with acceptance of evolution. Students were assessed prior to teaching, immediately post teaching and again after several months. Teachers were not instructed what to teach, just to teach in a given order. Regardless of order, teaching increased understanding and acceptance, with robust signs of longer-term retention. Importantly, teaching genetics before teaching evolution has a significant (p < 0.001) impact on improving evolution understanding by 7% in questionnaire scores beyond the increase seen for those taught in the inverse order. For lower ability students, an improvement in evolution understanding was seen only if genetics was taught first. Teaching genetics first additionally had positive effects on genetics understanding, by increasing knowledge. These results suggest a simple, minimally disruptive, zero-cost intervention to improve evolution understanding: teach genetics first. This same alteration does not, however, result in a significantly increased acceptance of evolution, which reflects a weak correlation between knowledge and acceptance of evolution. Qualitative focus group data highlights the role of authority figures in determination of acceptance. PMID:28542179

Teaching genetics prior to teaching evolution improves evolution understanding but not acceptance.

PubMed

Mead, Rebecca; Hejmadi, Momna; Hurst, Laurence D

2017-05-01

What is the best way to teach evolution? As microevolution may be configured as a branch of genetics, it being a short conceptual leap from understanding the concepts of mutation and alleles (i.e., genetics) to allele frequency change (i.e., evolution), we hypothesised that learning genetics prior to evolution might improve student understanding of evolution. In the UK, genetics and evolution are typically taught to 14- to 16-y-old secondary school students as separate topics with few links, in no particular order and sometimes with a large time span between. Here, then, we report the results of a large trial into teaching order of evolution and genetics. We modified extant questionnaires to ascertain students' understanding of evolution and genetics along with acceptance of evolution. Students were assessed prior to teaching, immediately post teaching and again after several months. Teachers were not instructed what to teach, just to teach in a given order. Regardless of order, teaching increased understanding and acceptance, with robust signs of longer-term retention. Importantly, teaching genetics before teaching evolution has a significant (p < 0.001) impact on improving evolution understanding by 7% in questionnaire scores beyond the increase seen for those taught in the inverse order. For lower ability students, an improvement in evolution understanding was seen only if genetics was taught first. Teaching genetics first additionally had positive effects on genetics understanding, by increasing knowledge. These results suggest a simple, minimally disruptive, zero-cost intervention to improve evolution understanding: teach genetics first. This same alteration does not, however, result in a significantly increased acceptance of evolution, which reflects a weak correlation between knowledge and acceptance of evolution. Qualitative focus group data highlights the role of authority figures in determination of acceptance.

Ultra-Gradient Test Cavity for Testing SRF Wafer Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

N.J. Pogue, P.M. McIntyre, A.I. Sattarov, C. Reece

2010-11-01

A 1.3 GHz test cavity has been designed to test wafer samples of superconducting materials. This mushroom shaped cavity, operating in TE01 mode, creates a unique distribution of surface fields. The surface magnetic field on the sample wafer is 3.75 times greater than elsewhere on the Niobium cavity surface. This field design is made possible through dielectrically loading the cavity by locating a hemisphere of ultra-pure sapphire just above the sample wafer. The sapphire pulls the fields away from the walls so the maximum field the Nb surface sees is 25% of the surface field on the sample. In thismore » manner, it should be possible to drive the sample wafer well beyond the BCS limit for Niobium while still maintaining a respectable Q. The sapphire's purity must be tested for its loss tangent and dielectric constant to finalize the design of the mushroom test cavity. A sapphire loaded CEBAF cavity has been constructed and tested. The results on the dielectric constant and loss tangent will be presented« less

Preliminary Experience with ''In-Site'' Baking of Niobium Cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. Kneisel

In a series of experiments several single cell and multi-cell niobium cavities made from reactor grade and high RRR niobium (frequencies were 700 MHz, 1300 MHz and 1497 MHz) have been baked--after initial testing--in-situ around 145 C for up to 90 hours prior to being recooled. Surprisingly, all cavities showed significant improvements in Q-values between 4.2 and 1.6K. The BCS surface resistance was lowered by nearly a factor of two. This cannot be explained by solely a reduction of dielectric losses caused by adsorbates at the surface or by a decrease of the mean free path due to possibly diffusionmore » of oxygen into the surface layer. In several experiments also the high field behavior of the cavity improved after the in-situ baking procedure. The observed effect opens the possibility for the CEBAF upgrade cavities, which in turn will permit to run the cavities at higher gradients if field emission loading can be prevented. Utilizing this effect can possibly translate into sizeable cost savings since fewer modules are needed for the upgrade program.« less

Mott Polarimeter Upgrade at Jefferson Lab

NASA Astrophysics Data System (ADS)

McHugh, M.; Opper, A. K.; Grames, J.; Poelker, M.; Suleiman, R.; Horowitz, C.; Rhodes, S.; Roca Maza, X.; Sinclair, C.

2013-10-01

A Mott polarimeter with a design optimized for 5.5 MeV/c has been in routine use at the CEBAF accelerator for well over a decade, providing polarization measurements approaching 1% accuracy. Measurements with different target elements (Au, Ag, Cu) over decades of target thicknesses (100 - 10,000 angstroms), and beam energies between 2 and 8 MeV allow us to determine the effective analyzing power with a high degree of certainty. Recent and planned improvements in our polarimeter configuration, detectors and data acquisition system, coupled with a low 31 MHz repetition rate beam allow us to distinguish and suppress electrons that do not originate from the target foil. This work coupled with a significant effort to produce a detailed GEANT4 model of the polarimeter is part of an effort to determine systematic uncertainties at the level of the theoretically calculated analyzing power. We describe our activities and a series of planned measurements that will allow us to demonstrate and possibly improve the precision and accuracy of polarization measurements at JLab, as required for future parity violation experiments.

$$\\pi^0$$ Production with $K^-$ and $$\\pi^+$$ Beams at 530 GeV/c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanaro, Armando

1990-01-01

In thia theaia we report on measurements of inclusive neutral pion production at large transverse momenta (more » $$P_T$$) in collision of 530 GeV/c ($$\\sqrt{s}$$ = 31.5 GeV) $K^-$ and $$\\pi^+$$ beams with a copper and beryllium combined target. The $$\\pi^0$$ acceptance in center-of-mass rapidity is $$\\mid y \\mid$$ < 0.7, for $$P_T$$ values greater than 3.5 GeV/c (negative beam) and 4.25 GeV/c (positive beam). The data were taken using the large acceptance liquid argon calorimeter of the E706 spectrometer at Fermilab, and analyzed using the standard E706 reconstruction package. Ratios on $$\\pi^0$$ yields using $$\\pi^+, \\pi^-, K^-$$ and $p$ are presented. The results are used to examine issues of scaling in point-like hadronic collisions at high energies and large transverse momenta.« less

Drivers of an urban community's acceptance of a large desalination scheme for drinking water

NASA Astrophysics Data System (ADS)

Gibson, Fiona L.; Tapsuwan, Sorada; Walker, Iain; Randrema, Elodie

2015-09-01

Changing climates and growing populations have prompted policy makers to shift to more climate resilient, technology-driven water sources, such as seawater desalination. Desalination is a prominent water resource in the Middle East but countries in other parts of the world with similar scarcity issues and good access to sea water, such as Australia, have been comparatively slow to adopt it. This paper explores attitudes to desalination in Perth, Western Australia, and the factors that influence its acceptance. We compared individuals' acceptance of desalination over two time periods by using identical surveys administered in 2007 and 2012. We then examined the attitudinal factors - attitudes towards desalination and attitudes towards the environment - that influence acceptance. Acceptance of desalination was reasonably high and stable at both times (74% and 73% in 2007 and 2012 respectively). We found that respondents' attitudes to perceived outcomes and benefits, fairness, environmental obligation and risk were important predictors of their acceptance of desalination in both surveys. However the weight given to these aspects varied over time. The findings show that there is still mixed community sentiment towards desalination, which helps to explain why acceptance has not increased since desalination was introduced in 2006.

A prospective study of acceptance of pain and patient functioning with chronic pain.

PubMed

McCracken, Lance M; Eccleston, Christopher

2005-11-01

Acceptance of chronic pain is emerging as an important concept in understanding ways that chronic pain sufferers can remain engaged with valued aspects of life. Recent studies have relied heavily on cross-sectional investigations at a single time point. The present study sought to prospectively investigate relations between acceptance of chronic pain and patient functioning. A sample of adults referred for interdisciplinary treatment of severe and disabling chronic pain was assessed twice, an average of 3.9 months apart. Results showed that pain and acceptance were largely unrelated. Pain at Time 2 was weakly related to measures of functioning at Time 2. On the other hand, acceptance at Time 1 was consistently related to patient functioning at Time 2. Those patients who reported greater acceptance at Time 1 reported better emotional, social, and physical functioning, less medication consumption, and better work status at Time 2. These data suggest that willingness to have pain, and to engage in activity regardless of pain, can lead to healthy functioning for patients with chronic pain. Treatment outcome and process studies may demonstrate the potential for acceptance-based clinical methods for chronic pain management.

Public Acceptability in the UK and USA of Nudging to Reduce Obesity: The Example of Reducing Sugar-Sweetened Beverages Consumption.

PubMed

Petrescu, Dragos C; Hollands, Gareth J; Couturier, Dominique-Laurent; Ng, Yin-Lam; Marteau, Theresa M

2016-01-01

"Nudging"-modifying environments to change people's behavior, often without their conscious awareness-can improve health, but public acceptability of nudging is largely unknown. We compared acceptability, in the United Kingdom (UK) and the United States of America (USA), of government interventions to reduce consumption of sugar-sweetened beverages. Three nudge interventions were assessed: i. reducing portion Size, ii. changing the Shape of the drink containers, iii. changing their shelf Location; alongside two traditional interventions: iv. Taxation and v. Education. We also tested the hypothesis that describing interventions as working through non-conscious processes decreases their acceptability. Predictors of acceptability, including perceived intervention effectiveness, were also assessed. Participants (n = 1093 UK and n = 1082 USA) received a description of each of the five interventions which varied, by randomisation, in how the interventions were said to affect behaviour: (a) via conscious processes; (b) via non-conscious processes; or (c) no process stated. Acceptability was derived from responses to three items. Levels of acceptability for four of the five interventions did not differ significantly between the UK and US samples; reducing portion size was less accepted by the US sample. Within each country, Education was rated as most acceptable and Taxation the least, with the three nudge-type interventions rated between these. There was no evidence to support the study hypothesis: i.e. stating that interventions worked via non-conscious processes did not decrease their acceptability in either the UK or US samples. Perceived effectiveness was the strongest predictor of acceptability for all interventions across the two samples. In conclusion, nudge interventions to reduce consumption of sugar-sweetened beverages seem similarly acceptable in the UK and USA, being more acceptable than taxation, but less acceptable than education. Contrary to prediction, we found no evidence that highlighting the non-conscious processes by which nudge interventions may work decreases their acceptability. However, highlighting the effectiveness of all interventions has the potential to increase their acceptability.

Public acceptance of euthanasia in Europe: a survey study in 47 countries.

PubMed

Cohen, Joachim; Van Landeghem, Paul; Carpentier, Nico; Deliens, Luc

2014-02-01

In recent years, the European euthanasia debate has become more intense, and the practice was legalized in the Netherlands, Belgium, and Luxembourg. We aimed to determine the current degree of public acceptance of euthanasia across Europe and investigate what factors explain differences. Data were derived from the 2008 wave of the European Values Survey (EVS), conducted in 47 European countries (N = 67,786, response rate = 69 %). Acceptance of euthanasia was rated on a 1-10 scale. Relatively high acceptance was found in a small cluster of Western European countries, including the three countries that have legalized euthanasia and Denmark, France, Sweden and Spain. In a large part of Europe public acceptance was relatively low to moderate. Comparison with the results of the previous EVS wave (1999) suggests a tendency towards a polarization in Europe, with most of Western Europe becoming more permissive and most of Eastern Europe becoming less permissive. There is roughly a West-East division in euthanasia acceptance among the European public, making a pan-European policy approach to the issue difficult.

The Large-Scale Structure of Scientific Method

ERIC Educational Resources Information Center

Kosso, Peter

2009-01-01

The standard textbook description of the nature of science describes the proposal, testing, and acceptance of a theoretical idea almost entirely in isolation from other theories. The resulting model of science is a kind of piecemeal empiricism that misses the important network structure of scientific knowledge. Only the large-scale description of…

House Divided: The Splitting of Active Duty Civil Affairs Forces

DTIC Science & Technology

2009-12-01

DUAL HEADQUARTERS”) History records few instances where a majority of the population welcomes an occupying army. — Ivan Muscicant, Banana Wars, p...Review Report it may not be accepted by the society at large. A large-scale deployment of GPF forces could essentially peel away any further

Framing Innovation: Do Professional Learning Communities Influence Acceptance of Large-Scale Technology Initiatives?

ERIC Educational Resources Information Center

Nolin, Anna P.

2014-01-01

This study explored the role of professional learning communities for district leadership implementing large-scale technology initiatives such as 1:1 implementations (one computing device for every student). The existing literature regarding technology leadership is limited, as is literature on how districts use existing collaborative structures…

Consumer-orientated development of hybrid beef burger and sausage analogues.

PubMed

Neville, Michelle; Tarrega, Amparo; Hewson, Louise; Foster, Tim

2017-07-01

Hybrid meat analogues, whereby a proportion of meat has been partially replaced by more sustainable protein sources, have been proposed to provide a means for more sustainable diets in the future. Consumer testing was conducted to determine consumer acceptability of different formulations of Hybrid beef burgers and pork sausages in comparison with both meat and meat-free commercial products. Acceptability data were generated using the 9-point hedonic scale. Check-all-that-apply (CATA) questioning was used to determine the sensory attributes perceived in each product as well as information on the attributes of consumers' ideal products. It was identified that Hybrid products were generally well liked among consumers and no significant differences in consumer acceptability (p > .05) were identified between Hybrid and full meat products, whereas meat-free products were found to be less accepted. However, Hybrid sausages received higher acceptability scores (6.00-6.51) than Hybrid burgers (5.84-5.92) suggesting that format may have a large impact on consumer acceptability of Hybrid products. Correspondence Analysis (CA) indicated that Hybrid products were grouped with meat products in their sensory attributes. Penalty analysis found that a "meaty flavor" was the largest factor driving consumer acceptability in both burgers and sausages. Cluster analysis of consumer acceptability data identified key differences in overall acceptability between different consumer groups (consumers who only eat meat products and consumers who eat both meat and meat-free products). The Hybrid concept was found to bridge the acceptability gap between meat and meat-free products; however, further product reformulation is required to optimize consumer acceptability.

Not All Skepticism Is Equal: Exploring the Ideological Antecedents of Science Acceptance and Rejection

PubMed Central

Rutjens, Bastiaan T.; Sutton, Robbie M.; van der Lee, Romy

2017-01-01

Many topics that scientists investigate speak to people’s ideological worldviews. We report three studies—including an analysis of large-scale survey data—in which we systematically investigate the ideological antecedents of general faith in science and willingness to support science, as well as of science skepticism of climate change, vaccination, and genetic modification (GM). The main predictors are religiosity and political orientation, morality, and science understanding. Overall, science understanding is associated with vaccine and GM food acceptance, but not climate change acceptance. Importantly, different ideological predictors are related to the acceptance of different scientific findings. Political conservatism best predicts climate change skepticism. Religiosity, alongside moral purity concerns, best predicts vaccination skepticism. GM food skepticism is not fueled by religious or political ideology. Finally, religious conservatives consistently display a low faith in science and an unwillingness to support science. Thus, science acceptance and rejection have different ideological roots, depending on the topic of investigation. PMID:29191107

Authorities to Use US Military Force Since the Passage of the 1973 War Powers Resolution

DTIC Science & Technology

2016-05-26

Cambridge University Press, 2013), 55. 59 Third, the legislative branch and executive branches’ acceptance and reliance on the “all volunteer ...Andrew Bacevich recently explained the disadvantages of the All- Volunteer Force, Today, the people have by-and-large tuned out war or accept it as...than replicating the errors of Vietnam, the All- Volunteer Force has fostered new ones, chief among them a collective abrogation of civic

A novel beam optics concept in a particle therapy gantry utilizing the advantages of superconducting magnets.

PubMed

Gerbershagen, Alexander; Meer, David; Schippers, Jacobus Maarten; Seidel, Mike

2016-09-01

A first order design of the beam optics of a superconducting proton therapy gantry beam is presented. The possibilities of superconducting magnets with respect to the beam optics such as strong fields, large apertures and superposition of different multipole fields have been exploited for novel concepts in a gantry. Since various techniques used in existing gantries have been used in our first design steps, some examples of the existing superconducting gantry designs are described and the necessary requirements of such a gantry are explained. The study of a gantry beam optics design is based on superconducting combined function magnets. The simulations have been performed in first order with the conventional beam transport codes. The superposition of strong dipole and quadrupole fields generated by superconducting magnets enables the introduction of locally achromatic bending sections without increasing the gantry size. A rigorous implementation of such beam optics concepts into the proposed gantry design dramatically increases the momentum acceptance compared to gantries with normal conducting magnets. In our design this large acceptance has been exploited by the implementation of a degrader within the gantry and a potential possibility to use the same magnetic field for all energies used in a treatment, so that the superconducting magnets do not have to vary their fields during a treatment. This also enables very fast beam energy changes, which is beneficial for spreading the Bragg peak over the thickness of the tumor. The results show an improvement of its momentum acceptance. Large momentum acceptance in the gantry creates a possibility to implement faster dose application techniques. Copyright © 2016. Published by Elsevier GmbH.

Recent advances and future technologies for baled silages

USDA-ARS?s Scientific Manuscript database

Although the concept of ensiling large-round or large-square bales dates back to the late 1970’s, there have been many refinements to both equipment and management since that time, resulting in much greater acceptance by small or mid-sized dairy or beef producers. There are several reasons this sila...

Assessing Large-Scale Public Job Creation. R&D Monograph 67.

ERIC Educational Resources Information Center

Employment and Training Administration (DOL), Washington, DC.

To assess the feasibility of large-scale, countercyclical public job creation, a study was initiated. Job creation program activities were examined in terms of how many activities could be undertaken; what would be their costs; and what would be their characteristics (labor-intensity, skill-mix, and political acceptability) that might contribute…

Establishing a public umbilical cord blood stem cell bank for South Africa: an enquiry into public acceptability.

PubMed

Meissner-Roloff, Madelein; Pepper, Michael S

2013-12-01

South Africa (SA) faces a large unmet need for bone marrow (BM) transplantation, which could be alleviated in part by establishing a public umbilical cord blood stem cell bank (UCB SCB). Umbilical cord blood is an increasingly utilised source of hematopoietic stem cells for BM transplantation in addition to BM or mobilized peripheral blood stem cells. Establishing a public UCB SCB would therefore be a positive step towards improving the quality of health care in SA by providing for an important unmet need. This study takes the form of an enquiry into the acceptability of establishing a public bank through an interview with and questionnaire completed by mothers-to-be in the antenatal clinic of a large public hospital in SA. Initial results are positive, with 85 % of the participants in favour of establishing a public UCB SCB in SA. This initial probe will serve as a model for a more comprehensive national enquiry into public support and acceptability in different clinics, hospitals and provinces in SA.

Clinical research for delayed hemorrhage after endoscopic sphincterotomy

PubMed Central

Wang, Yundong; Han, Zhen; Niu, Xiaoping; Jia, Yuliang; Yuan, Heming; Zhang, Guozheng; He, Chiyi

2015-01-01

To analyze the effect of delayed hemorrhage after endoscopic sphincterotomy (EST) and compare the efficacy in improving complication between medicine treatment alone and medicine combined with endoscopic treatment. 1741 patients with EST admitted in Yijishan hospital of Wannan medical college from September 2009 to May 2014 were enrolled in this study. 32 cases suffered from delayed hemorrhage. The patients with delayed hemorrhage were evaluated through incision length of duodenal papilla, clinical manifestation, stool occult blood test and the difference of hemoglobin concentration between pre and post operation. 32 patients were divided into mild bleeding group, mild serious group and serious group through the speed and amount of bleeding. All cases in mild group accepted medicine treatment. Mild serious group were divided into medicine therapy group and medicine combined with endoscopic therapy group randomly. Serious group accepted vascular intervention therapy even traditional operation. The different treatments for delayed hemorrhage were judged by efficiency. The dates were analyzed by t-test or chi-square test. Nobody endured delayed hemorrhage who accepted small incision. Delayed hemorrhage was found in 7 patients out of 627 cases who accepted medium-large incision, 25 patients of 920 cases who accepted large incision. The patients who accepted lager EST were more dangerous than small EST (χ2=4.718, P=0.030) concerning delayed hemorrhage. 32 cases in 1741 patients suffered from delayed hemorrhage. 14 patients only have passed black stool after EST. Among 14 cases, 13 patients stop bleeding after medical therapy, and 1 case received endoscopic hemostasis. 15 cases with hematemesis or melena after EST, 7 patients who received combination therapy stop bleeding. 3 patients from 8 cases stop bleeding after single chemical treatment, 5 cases had to receive endoscopic hemostasis after ineffectual medical therapy. There are significant difference for concerning effect between combination therapy group and medical therapy group (P=0.026). 3 patients repeatedly vomited blood and develop to peripheral circulatory failure. Those patients all received vascular intervention therapy, 2 patients stop bleeding, 1 patient failed in vascular intervention therapy and given up emergency rescue and died. Large EST has more risks than small EST in concerning delayed hemorrhage. Delayed bleeding after EST should be treated by different levels. Adapted therapy should be recommend for patients with different levels bleeding. PMID:26131161

Grammaticality, Acceptability, and Probability: A Probabilistic View of Linguistic Knowledge.

PubMed

Lau, Jey Han; Clark, Alexander; Lappin, Shalom

2017-07-01

The question of whether humans represent grammatical knowledge as a binary condition on membership in a set of well-formed sentences, or as a probabilistic property has been the subject of debate among linguists, psychologists, and cognitive scientists for many decades. Acceptability judgments present a serious problem for both classical binary and probabilistic theories of grammaticality. These judgements are gradient in nature, and so cannot be directly accommodated in a binary formal grammar. However, it is also not possible to simply reduce acceptability to probability. The acceptability of a sentence is not the same as the likelihood of its occurrence, which is, in part, determined by factors like sentence length and lexical frequency. In this paper, we present the results of a set of large-scale experiments using crowd-sourced acceptability judgments that demonstrate gradience to be a pervasive feature in acceptability judgments. We then show how one can predict acceptability judgments on the basis of probability by augmenting probabilistic language models with an acceptability measure. This is a function that normalizes probability values to eliminate the confounding factors of length and lexical frequency. We describe a sequence of modeling experiments with unsupervised language models drawn from state-of-the-art machine learning methods in natural language processing. Several of these models achieve very encouraging levels of accuracy in the acceptability prediction task, as measured by the correlation between the acceptability measure scores and mean human acceptability values. We consider the relevance of these results to the debate on the nature of grammatical competence, and we argue that they support the view that linguistic knowledge can be intrinsically probabilistic. Copyright © 2016 Cognitive Science Society, Inc.

Evaluation of dose variation during total skin electron irradiation using thermoluminescent dosimeters.

PubMed

Weaver, R D; Gerbi, B J; Dusenbery, K E

1995-09-30

To determine acceptable dose variation using thermoluminescent dosimeters (TLD) in the treatment of Mycosis Fungoides with total skin electron beam (TSEB) irradiation. From 1983 to 1993, 22 patients were treated with total skin electron beam therapy in the standing position. A six-field technique was used to deliver 2 Gy in two days, treating 4 days per week, to a total dose of 35 to 40 Gy using a degraded 9 MeV electron beam. Thermoluminescent dosimeters were placed on several locations of the body and the results recorded. The variations in these readings were analyzed to determine normal dose variation for various body locations during TSEB. The dose to flat surfaces of the body was essentially the same as the dose to the prescription point. The dose to tangential surfaces was within +/- 10% of the prescription dose, but the readings showed much more variation (up to 24%). Thin areas of the body showed large deviations from the prescription dose along with a large amount of variation in the readings (up to 22%). Special areas of the body, such as the perineum and eyelid, showed large deviations from the prescription dose with very large (up to 40%) variations in the readings. The TLD results of this study will be used as a quality assurance check for all new patients treated with TSEB. The results of the TLDs will be compared with this baseline study to determine if the delivered dose is within acceptable ranges. If the TLD results fall outside the acceptable limits established above, then the patient position can be modified or the technique itself evaluated.

Accounting for patient size in the optimization of dose and image quality of pelvis cone beam CT protocols on the Varian OBI system.

PubMed

Wood, Tim J; Moore, Craig S; Horsfield, Carl J; Saunderson, John R; Beavis, Andrew W

2015-01-01

The purpose of this study was to develop size-based radiotherapy kilovoltage cone beam CT (CBCT) protocols for the pelvis. Image noise was measured in an elliptical phantom of varying size for a range of exposure factors. Based on a previously defined "small pelvis" reference patient and CBCT protocol, appropriate exposure factors for small, medium, large and extra-large patients were derived which approximate the image noise behaviour observed on a Philips CT scanner (Philips Medical Systems, Best, Netherlands) with automatic exposure control (AEC). Selection criteria, based on maximum tube current-time product per rotation selected during the radiotherapy treatment planning scan, were derived based on an audit of patient size. It has been demonstrated that 110 kVp yields acceptable image noise for reduced patient dose in pelvic CBCT scans of small, medium and large patients, when compared with manufacturer's default settings (125 kVp). Conversely, extra-large patients require increased exposure factors to give acceptable images. 57% of patients in the local population now receive much lower radiation doses, whereas 13% require higher doses (but now yield acceptable images). The implementation of size-based exposure protocols has significantly reduced radiation dose to the majority of patients with no negative impact on image quality. Increased doses are required on the largest patients to give adequate image quality. The development of size-based CBCT protocols that use the planning CT scan (with AEC) to determine which protocol is appropriate ensures adequate image quality whilst minimizing patient radiation dose.

Development and application of an acceptance testing model

NASA Technical Reports Server (NTRS)

Pendley, Rex D.; Noonan, Caroline H.; Hall, Kenneth R.

1992-01-01

The process of acceptance testing large software systems for NASA has been analyzed, and an empirical planning model of the process constructed. This model gives managers accurate predictions of the staffing needed, the productivity of a test team, and the rate at which the system will pass. Applying the model to a new system shows a high level of agreement between the model and actual performance. The model also gives managers an objective measure of process improvement.

Improved DC Gun and Insulator Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neubauer, Michael

Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diametermore » ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.« less

Development work for a superconducting linear collider

NASA Technical Reports Server (NTRS)

Matheisen, Axel

1995-01-01

For future linear e(+)e(-) colliders in the TeV range several alternatives are under discussion. The TESLA approach is based on the advantages of superconductivity. High Q values of the accelerator structures give high efficiency for converting RF power into beam power. A low resonance frequency for the RF structures can be chosen to obtain a large number of electrons (positrons) per bunch. For a given luminosity the beam dimensions can be chosen conservatively which leads to relaxed beam emittance and tolerances at the final focus. Each individual superconducting accelerator component (resonator cavity) of this linear collider has to deliver an energy gain of 25 MeV/m to the beam. Today s.c. resonators are in use at CEBAF/USA, at DESY/Germany, Darmstadt/Germany KEK/Japan and CERN/Geneva. They show acceleration gradients between 5 MV/m and 10 MV/m. Encouraging experiments at CEA Saclay and Cornell University showed acceleration gradients of 20 MV/m and 25 MV/m in single and multicell structures. In an activity centered at DESY in Hamburg/Germany the TESLA collaboration is constructing a 500 MeV superconducting accelerator test facility (TTF) to demonstrate that a linear collider based on this technique can be built in a cost effective manner and that the necessary acceleration gradients of more than 15 MeV/m can be reached reproducibly. The test facility built at DESY covers an area of 3.000 m2 and is divided into 3 major activity areas: (1) The testlinac, where the performance ofthe modular components with an electron beam passing the 40 m long acceleration section can be demonstrated. (2) The test area, where all individual resonators are tested before installation into a module. (3) The preparation and assembly area, where assembly of cavities and modules take place. We report here on the design work to reach a reduction of costs compared to actual existing superconducting accelerator structures and on the facility set up to reach high acceleration gradients in a reproducible way.

Public Acceptability in the UK and USA of Nudging to Reduce Obesity: The Example of Reducing Sugar-Sweetened Beverages Consumption

PubMed Central

Petrescu, Dragos C.; Hollands, Gareth J.; Couturier, Dominique-Laurent; Ng, Yin-Lam; Marteau, Theresa M.

2016-01-01

Background “Nudging”—modifying environments to change people’s behavior, often without their conscious awareness—can improve health, but public acceptability of nudging is largely unknown. Methods We compared acceptability, in the United Kingdom (UK) and the United States of America (USA), of government interventions to reduce consumption of sugar-sweetened beverages. Three nudge interventions were assessed: i. reducing portion Size, ii. changing the Shape of the drink containers, iii. changing their shelf Location; alongside two traditional interventions: iv. Taxation and v. Education. We also tested the hypothesis that describing interventions as working through non-conscious processes decreases their acceptability. Predictors of acceptability, including perceived intervention effectiveness, were also assessed. Participants (n = 1093 UK and n = 1082 USA) received a description of each of the five interventions which varied, by randomisation, in how the interventions were said to affect behaviour: (a) via conscious processes; (b) via non-conscious processes; or (c) no process stated. Acceptability was derived from responses to three items. Results Levels of acceptability for four of the five interventions did not differ significantly between the UK and US samples; reducing portion size was less accepted by the US sample. Within each country, Education was rated as most acceptable and Taxation the least, with the three nudge-type interventions rated between these. There was no evidence to support the study hypothesis: i.e. stating that interventions worked via non-conscious processes did not decrease their acceptability in either the UK or US samples. Perceived effectiveness was the strongest predictor of acceptability for all interventions across the two samples. Conclusion In conclusion, nudge interventions to reduce consumption of sugar-sweetened beverages seem similarly acceptable in the UK and USA, being more acceptable than taxation, but less acceptable than education. Contrary to prediction, we found no evidence that highlighting the non-conscious processes by which nudge interventions may work decreases their acceptability. However, highlighting the effectiveness of all interventions has the potential to increase their acceptability. PMID:27276222

Facing the malpractice crisis: academic physicians' willingness to accept quick fix solutions.

PubMed

Levine, Rachel B; Kravet, Steven J; Reed, Darcy A; Windish, Donna M; Wolfe, Leah; Wright, Scott M

2006-12-01

We sought to determine the willingness of academic physicians to accept strategies to contain institutional malpractice costs. We surveyed all 270 Department of Medicine physicians at a large academic center. Respondents were asked about their knowledge regarding malpractice premiums, willingness to reduce patient-care activities and accept decreases in compensation. The response rate was 80%. Respondents estimated the annual increase in malpractice premiums from 2004 to 2005 to be 29%. The true increase was 28% (P = 0.55). Almost all opposed eliminating patient care (95%) or providing patient care every other year at double effort and withdrawing from patient care on alternate years (97%). Seventy percent would limit their clinical procedures. Most physicians opposed salary reduction (97%) or decreases in fringe benefits (99%). Few academic physicians are willing to limit patient care or accept decreases in compensation to recoup institutional malpractice costs.

A Logically Centralized Approach for Control and Management of Large Computer Networks

ERIC Educational Resources Information Center

Iqbal, Hammad A.

2012-01-01

Management of large enterprise and Internet service provider networks is a complex, error-prone, and costly challenge. It is widely accepted that the key contributors to this complexity are the bundling of control and data forwarding in traditional routers and the use of fully distributed protocols for network control. To address these…

Competition versus Cooperation: Implications for Music Teachers Following Students Feedback from Participation in a Large-Scale Cooperative Music Festival

ERIC Educational Resources Information Center

Lowe, Geoffrey M.

2018-01-01

Competition is reported in the general education literature as having a largely detrimental impact upon student engagement and long-term motivation, yet competition has long been an accepted part of the music education ensemble landscape. Adjudicated ensemble competitions and competition-festivals are commonplace in most Australian states, as…

Synchronization of the DOE/NASA 100-kilowatt wind turbine generator with a large utility network

NASA Technical Reports Server (NTRS)

Gilbert, L. J.

1977-01-01

The DOE/NASA 100 kilowatt wind turbine generator system was synchronized with a large utility network. The system equipments and procedures associated with the synchronization process were described. Time history traces of typical synchronizations were presented indicating that power and current transients resulting from the synchronizing procedure are limited to acceptable magnitudes.

The Department of Defense and the Power of Cloud Computing: Weighing Acceptable Cost Versus Acceptable Risk

DTIC Science & Technology

2016-04-01

the DOD will put DOD systems and data at a risk level comparable to that of their neighbors in the cloud. Just as a user browses a Web page on the...proxy servers for controlling user access to Web pages, and large-scale storage for data management. Each of these devices allows access to the...user to develop applications. Acunetics.com describes Web applications as “computer programs allowing Website visitors to submit and retrieve data

Objective criteria for acceptability and constancy tests of digital subtraction angiography.

PubMed

de las Heras, Hugo; Torres, Ricardo; Fernández-Soto, José Miguel; Vañó, Eliseo

2016-01-01

Demonstrate an objective procedure to quantify image quality in digital subtraction angiography (DSA) and suggest thresholds for acceptability and constancy tests. Series of images were obtained in a DSA system simulating a small (paediatric) and a large patient using the dynamic phantom described in the IEC and DIN standards for acceptance tests of DSA equipment. Image quality was quantified using measurements of contrast-to-noise ratio (CNR). Overall scores combining the CNR of 10-100 mg/ml Iodine at a vascular diameter of 1-4 mm in a homogeneous background were defined. Phantom entrance surface air kerma (Ka,e) was measured with an ionisation chamber. The visibility of a low-contrast vessel in DSA images has been identified with a CNR value of 0.50 ± 0.03. Despite using 14 times more Ka,e (8.85 vs 0.63 mGy/image), the protocol for large patients showed a decrease in the overall score CNRsum of 67% (4.21 ± 0.06 vs 2.10 ± 0.05). The uncertainty in the results of the objective method was below 5%. Objective evaluation of DSA images using CNR is feasible with dedicated phantom measurements. An objective methodology has been suggested for acceptance tests compliant with the IEC/DIN standards. The defined overall scores can serve to fix a reproducible baseline for constancy tests, as well as to study the device stability within one acquisition series and compare different imaging protocols. This work provides aspects that have not been included in the recent European guidelines on Criteria for Acceptability of Medical Radiological Equipment. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Fragmentation of {sup 14}N, {sup 16}O, {sup 20}Ne, and {sup 24}Mg nuclei at 290 to 1000 MeV/nucleon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeitlin, C.; Miller, J.; Guetersloh, S.

We report fragmentation cross sections measured at 0 deg. for beams of {sup 14}N, {sup 16}O, {sup 20}Ne, and {sup 24}Mg ions, at energies ranging from 290 MeV/nucleon to 1000 MeV/nucleon. Beams were incident on targets of C, CH{sub 2}, Al, Cu, Sn, and Pb, with the C and CH{sub 2} target data used to obtain hydrogen-target cross sections. Using methods established in earlier work, cross sections obtained with both large-acceptance and small-acceptance detectors are extracted from the data and, when necessary, corrected for acceptance effects. The large-acceptance data yield cross sections for fragments with charges approximately half of themore » beam charge and above, with minimal corrections. Cross sections for lighter fragments are obtained from small-acceptance spectra, with more significant, model-dependent corrections that account for the fragment angular distributions. Results for both charge-changing and fragment production cross sections are compared to the predictions of the Los Alamos version of the quark gluon string model (LAQGSM) as well as the NASA Nuclear Fragmentation (NUCFRG2) model and the Particle and Heavy Ion Transport System (PHITS) model. For all beams and targets, cross sections for fragments as light as He are compared to the models. Estimates of multiplicity-weighted helium production cross sections are obtained from the data and compared to PHITS and LAQGSM predictions. Summary statistics show that the level of agreement between data and predictions is slightly better for PHITS than for either NUCFRG2 or LAQGSM.« less

TU-B-16A-01: To Which Journal Should I Submit My Paper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williamson, J; Mills, M; Klein, E

Research papers authored by Medical Physicists address a large spectrum of oncologic, imaging, or basic research problems; exploit a wide range of physical and engineering methodologies; and often describe the efforts of a multidisciplinary research team. Given the large number (about 100) competing journals accepting medical physics articles, it may not be clear to an individual author which journal is the best venue for disseminating their work to the scientific community. Relevant factors usually include the Journal’s audience and scientific impact, but also such factors as perceived acceptance rate, interest in their topic, and quality of service. The purpose ofmore » this symposium is to provide the medical physics community with an overview of scope, review processes, and article guidelines for the following journals: Medical Physics, International Journal of Radiation Biology and Physics, Journal of Applied Clinical Medical Physics, and Practical Radiation Oncology. The senior editors for each journal will provide details as to the journals review process, for example: single blind versus double blind reviews; the hierarchy of the review process in terms of editorial board structure; the reality of acceptance, in terms of acceptance rate; and the types of research the journal prefers to publish. The goal is to provide for authors guidance before they begin to write their papers, not only for proper formatting, but also that the readership is appropriate for the particular paper, hopefully increasing the likelihood of publication. Learning Objectives: To review each Journal’s submission and review process Guidance as to how to increase chances of acceptance To help decipher which journal is appropriate for a given work.« less

What factors determine therapists' acceptance of new technologies for rehabilitation – a study using the Unified Theory of Acceptance and Use of Technology (UTAUT).

PubMed

Liu, Lili; Miguel Cruz, Antonio; Rios Rincon, Adriana; Buttar, Vickie; Ranson, Quentin; Goertzen, Darrell

2015-01-01

The aim of this study was to examine what factors affect the acceptance behavior and use of new technologies for rehabilitation by therapists at a large rehabilitation hospital in Canada. A self-administrated paper-based survey was created by adapting scales with high levels of internal consistency in prior research using the Unified Theory of Acceptance and Use of Technology (UTAUT). Items were scored on a 7-point Likert scale, ranging from "strongly disagree (1)" to "strongly agree (7)". The target population was all occupational therapists (OT) and physical therapists (PT) involved with the provision of therapeutic interventions at the hospital. Our research model was tested using partial least squares (PLS) technique. Performance expectancy was the strongest salient construct for behavioral intention to use new technologies in rehabilitation, whereas neither effort expectancy nor social influence were salient constructs for behavioral intention to use new technologies; (4) facilitating condition and behavioral intention to use new technologies were salient constructs for current use of new technologies in rehabilitation, with facilitating condition the strongest salient for current use of new technologies in rehabilitation. In a large rehabilitation hospital where use of new technologies in rehabilitation is not mandatory, performance expectancy, or how the technology can help in therapists' work, was the most important factor in determining therapists' acceptance and use of technologies. However, effort expectancy and social influence constructs were not important, i.e. therapists were not influenced by the degree of difficulty or social pressures to use technologies. Behavioral intention and facilitating condition, or institutional support, are related to current use of new technologies in rehabilitation.

European public acceptance of euthanasia: socio-demographic and cultural factors associated with the acceptance of euthanasia in 33 European countries.

PubMed

Cohen, Joachim; Marcoux, Isabelle; Bilsen, Johan; Deboosere, Patrick; van der Wal, Gerrit; Deliens, Luc

2006-08-01

In many European countries, the last decade has been marked by an increasing debate about the acceptability and regulation of euthanasia and other end-of-life decisions in medical practice. Growing public sensibility to a 'right to die' for terminally ill patients has been one of the main constituents of these debates. Within this context, we sought to describe and compare acceptance of euthanasia among the general public in 33 European countries. We used the European Values Study data of 1999-2000 with a total of 41125 respondents (63% response rate) in 33 European countries. The main outcome measure concerned the acceptance of euthanasia (defined as 'terminating the life of the incurably sick', rated on a scale from 1 to 10). Results showed that the acceptance of euthanasia tended to be high in some countries (e.g. the Netherlands, Denmark, France, Sweden), while a markedly low acceptance was found in others (e.g. Romania, Malta and Turkey). A multivariate ordinal regression showed that weaker religious belief was the most important factor associated with a higher acceptance; however, there were also socio-demographic differences: younger cohorts, people from non-manual social classes, and people with a higher educational level tended to have a higher acceptance of euthanasia. While religious belief, socio-demographic factors, and also moral values (i.e. the belief in the right to self-determination) could largely explain the differences between countries, our findings suggest that perceptions regarding euthanasia are probably also influenced by national traditions and history (e.g. Germany). Thus, we demonstrated clear cross-national differences with regard to the acceptance of euthanasia, which can serve as an important basis for further debate and research in the specific countries.

Stigma and Postpartum Depression Treatment Acceptability Among Black and White Women in the First Six-Months Postpartum.

PubMed

Bodnar-Deren, Susan; Benn, E K T; Balbierz, Amy; Howell, E A

2017-07-01

Objective To measure stigma associated with four types of postpartum depression therapies and to estimate the association between stigma and the acceptance of these therapies for black and white postpartum mothers. Methods Using data from two postpartum depression randomized trials, this study included 481 black and white women who gave birth in a large urban hospital and answered a series of questions at 6-months postpartum. Survey items included socio demographic and clinical factors, attitudes about postpartum depression therapies and stigma. The associations between race, stigma, and treatment acceptability were examined using bivariate and multivariate analyses. Results Black postpartum mothers were less likely than whites to accept prescription medication (64 vs. 81%, p = 0.0001) and mental health counseling (87 vs. 93%, p = 0.001) and more likely to accept spiritual counseling (70 vs. 52%, p = 0.0002). Women who endorsed stigma about receipt of postpartum depression therapies versus those who did not were less likely to accept prescription medication, mental health and spiritual counseling for postpartum depression. Overall black mothers were less likely to report stigma associated with postpartum depression therapies. In adjusted models, black women versus white women remained less likely to accept prescription medication for postpartum depression (OR = 0.42, 95% CI 0.24-0.72) and stigma did not explain this difference. Conclusions Although treatment stigma is associated with lower postpartum depression treatment acceptance, stigma does not explain the lower levels of postpartum depression treatment acceptance among black women. More research is needed to understand treatment barriers for postpartum depression, especially among black women.

Interspecific utilisation of wax in comb building by honeybees

NASA Astrophysics Data System (ADS)

Hepburn, H. Randall; Radloff, Sarah E.; Duangphakdee, Orawan; Phaincharoen, Mananya

2009-06-01

Beeswaxes of honeybee species share some homologous neutral lipids; but species-specific differences remain. We analysed behavioural variation for wax choice in honeybees, calculated the Euclidean distances for different beeswaxes and assessed the relationship of Euclidean distances to wax choice. We tested the beeswaxes of Apis mellifera capensis, Apis florea, Apis cerana and Apis dorsata and the plant and mineral waxes Japan, candelilla, bayberry and ozokerite as sheets placed in colonies of A. m. capensis, A. florea and A. cerana. A. m. capensis accepted the four beeswaxes but removed Japan and bayberry wax and ignored candelilla and ozokerite. A. cerana colonies accepted the wax of A. cerana, A. florea and A. dorsata but rejected or ignored that of A. m. capensis, the plant and mineral waxes. A. florea colonies accepted A. cerana, A. dorsata and A. florea wax but rejected that of A. m. capensis. The Euclidean distances for the beeswaxes are consistent with currently prevailing phylogenies for Apis. Despite post-speciation chemical differences in the beeswaxes, they remain largely acceptable interspecifically while the plant and mineral waxes are not chemically close enough to beeswax for their acceptance.

Nurses' perceptions, acceptance, and use of a novel in-room pediatric ICU technology: testing an expanded technology acceptance model.

PubMed

Holden, Richard J; Asan, Onur; Wozniak, Erica M; Flynn, Kathryn E; Scanlon, Matthew C

2016-11-15

The value of health information technology (IT) ultimately depends on end users accepting and appropriately using it for patient care. This study examined pediatric intensive care unit nurses' perceptions, acceptance, and use of a novel health IT, the Large Customizable Interactive Monitor. An expanded technology acceptance model was tested by applying stepwise linear regression to data from a standardized survey of 167 nurses. Nurses reported low-moderate ratings of the novel IT's ease of use and low to very low ratings of usefulness, social influence, and training. Perceived ease of use, usefulness for patient/family involvement, and usefulness for care delivery were associated with system satisfaction (R 2  = 70%). Perceived usefulness for care delivery and patient/family social influence were associated with intention to use the system (R 2  = 65%). Satisfaction and intention were associated with actual system use (R 2  = 51%). The findings have implications for research, design, implementation, and policies for nursing informatics, particularly novel nursing IT. Several changes are recommended to improve the design and implementation of the studied IT.

25 CFR 163.12 - Harvesting restrictions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... will not be permitted unless provisions for natural and/or artificial reforestation of acceptable tree species is included in harvest plans. (b) Clearing of large contiguous areas will be permitted only on...

25 CFR 163.12 - Harvesting restrictions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... will not be permitted unless provisions for natural and/or artificial reforestation of acceptable tree species is included in harvest plans. (b) Clearing of large contiguous areas will be permitted only on...

25 CFR 163.12 - Harvesting restrictions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... will not be permitted unless provisions for natural and/or artificial reforestation of acceptable tree species is included in harvest plans. (b) Clearing of large contiguous areas will be permitted only on...

25 CFR 163.12 - Harvesting restrictions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... will not be permitted unless provisions for natural and/or artificial reforestation of acceptable tree species is included in harvest plans. (b) Clearing of large contiguous areas will be permitted only on...

Continent cutaneous diversion.

PubMed

Skinner, Eila C

2015-11-01

This article updates the recently reported intermediate to long-term results with the most commonly used forms of continent cutaneous urinary diversion, and to discuss approaches to early and late complications. Many variations on construction of a continent cutaneous diversion have been described. Results with large series of patients demonstrate acceptable results with all of them, but with a significant revision rate. Long-term complication rates and adaptation to robotic approaches have recently been described. Continent cutaneous diversion is rarely offered in the USA to patients undergoing cystectomy except in a few centers. Most studies have found a high complication rate and need for revision surgery in 10-20% of patients. However, functional results are acceptable and many patients are willing to accept the complications in exchange for avoiding an external appliance.

Acceptance alone is a better predictor of psychopathology and well-being than emotional competence, emotion regulation and mindfulness.

PubMed

Kotsou, Ilios; Leys, Christophe; Fossion, Pierre

2018-01-15

Emotional competence, emotion regulation, mindfulness and acceptance have all been strongly associated to emotional disorders and psychological well-being in multiple studies. However little research has compared the unique predictive ability of these different constructs. We hypothesised that they will all share a large proportion of common variance and that when compared to the broader constructs emotional competence, emotion regulation and mindfulness, acceptance alone would predict a larger proportion of unique variance METHODS: 228 participants from a community sample completed anonymously measures of anxiety, depression, happiness, acceptance, mindfulness, emotional competence and emotion regulation. We then ran multiple regressions to assess and compare the predictive ability of these different constructs. For measures of psychological distress, the acceptance measure uniquely accounted for between 4 and 30 times the variance that the emotional competence, emotion regulation and mindfulness measures did. These results are based on cross-sectional designs and non-clinical samples, longitudinal and experimental studies as clinical samples may be useful in order to assess the potential protective power of acceptance over time. Another limitation is the use of self-report questionnaires. Results confirmed our hypothesis, supporting the research on the importance of acceptance as a central factor in the understanding of the onset and maintenance of emotional disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

Lifetime evaluation of large format CMOS mixed signal infrared devices

NASA Astrophysics Data System (ADS)

Linder, A.; Glines, Eddie

2015-09-01

New large scale foundry processes continue to produce reliable products. These new large scale devices continue to use industry best practice to screen for failure mechanisms and validate their long lifetime. The Failure-in-Time analysis in conjunction with foundry qualification information can be used to evaluate large format device lifetimes. This analysis is a helpful tool when zero failure life tests are typical. The reliability of the device is estimated by applying the failure rate to the use conditions. JEDEC publications continue to be the industry accepted methods.

Accounting for patient size in the optimization of dose and image quality of pelvis cone beam CT protocols on the Varian OBI system

PubMed Central

Moore, Craig S; Horsfield, Carl J; Saunderson, John R; Beavis, Andrew W

2015-01-01

Objective: The purpose of this study was to develop size-based radiotherapy kilovoltage cone beam CT (CBCT) protocols for the pelvis. Methods: Image noise was measured in an elliptical phantom of varying size for a range of exposure factors. Based on a previously defined “small pelvis” reference patient and CBCT protocol, appropriate exposure factors for small, medium, large and extra-large patients were derived which approximate the image noise behaviour observed on a Philips CT scanner (Philips Medical Systems, Best, Netherlands) with automatic exposure control (AEC). Selection criteria, based on maximum tube current–time product per rotation selected during the radiotherapy treatment planning scan, were derived based on an audit of patient size. Results: It has been demonstrated that 110 kVp yields acceptable image noise for reduced patient dose in pelvic CBCT scans of small, medium and large patients, when compared with manufacturer's default settings (125 kVp). Conversely, extra-large patients require increased exposure factors to give acceptable images. 57% of patients in the local population now receive much lower radiation doses, whereas 13% require higher doses (but now yield acceptable images). Conclusion: The implementation of size-based exposure protocols has significantly reduced radiation dose to the majority of patients with no negative impact on image quality. Increased doses are required on the largest patients to give adequate image quality. Advances in knowledge: The development of size-based CBCT protocols that use the planning CT scan (with AEC) to determine which protocol is appropriate ensures adequate image quality whilst minimizing patient radiation dose. PMID:26419892

Large Payload Ground Transportation and Test Considerations

NASA Technical Reports Server (NTRS)

Rucker, Michelle A.

2016-01-01

Many spacecraft concepts under consideration by the National Aeronautics and Space Administration’s (NASA’s) Evolvable Mars Campaign take advantage of a Space Launch System payload shroud that may be 8 to 10 meters in diameter. Large payloads can theoretically save cost by reducing the number of launches needed--but only if it is possible to build, test, and transport a large payload to the launch site in the first place. Analysis performed previously for the Altair project identified several transportation and test issues with an 8.973 meters diameter payload. Although the entire Constellation Program—including Altair—has since been canceled, these issues serve as important lessons learned for spacecraft designers and program managers considering large payloads for future programs. A transportation feasibility study found that, even broken up into an Ascent and Descent Module, the Altair spacecraft would not fit inside available aircraft. Ground transportation of such large payloads over extended distances is not generally permitted, so overland transportation alone would not be an option. Limited ground transportation to the nearest waterway may be possible, but water transportation could take as long as 67 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA’s Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary, which could increase cost, schedule, and technical risk. Once at the launch site, there are no facilities currently capable of accommodating the combination of large payload size and hazardous processing such as hypergolic fuels, pyrotechnic devices, and high pressure gasses. Ironically, the limiting factor to a national heavy lift strategy may not be the rocket technology needed to throw a heavy payload, but rather the terrestrial infrastructure—roads, bridges, airframes, and buildings—necessary to transport, acceptance test, and process large spacecraft. Failure to carefully consider where and how large spacecraft are manufactured, tested, and launched could result in unforeseen cost to modify existing (or develop new) infrastructure, or incur additional risk due to increased handling operations or eliminating key verifications. Although this paper focuses on the canceled Altair spacecraft as a case study, the issues identified here have wide applicability to other large payloads, including concepts under consideration for NASA’s Evolvable Mars Campaign.

Frequency and predictors of seasonal influenza vaccination and reasons for refusal among patients at a large tertiary referral hospital.

PubMed

Masnick, Max; Leekha, Surbhi

2015-07-01

We assessed frequency and predictors of seasonal influenza vaccination acceptance among inpatients at a large tertiary referral hospital, as well as reasons for vaccination refusal. Over 5 seasons, >60% of patients unvaccinated on admission refused influenza vaccination while hospitalized; "believes not at risk" was the reason most commonly given.

Student Attitudes towards and Use of ICT in Course Study, Work and Social Activity: A Technology Acceptance Model Approach

ERIC Educational Resources Information Center

Edmunds, Rob; Thorpe, Mary; Conole, Grainne

2012-01-01

The increasing use of information and communication technology (ICT) in higher education has been explored largely in relation to student experience of coursework and university life. Students' lives and experience beyond the university have been largely unexplored. Research into student experience of ICT used a validated model--the technology…

Gap Acceptance During Lane Changes by Large-Truck Drivers—An Image-Based Analysis

PubMed Central

Nobukawa, Kazutoshi; Bao, Shan; LeBlanc, David J.; Zhao, Ding; Peng, Huei; Pan, Christopher S.

2016-01-01

This paper presents an analysis of rearward gap acceptance characteristics of drivers of large trucks in highway lane change scenarios. The range between the vehicles was inferred from camera images using the estimated lane width obtained from the lane tracking camera as the reference. Six-hundred lane change events were acquired from a large-scale naturalistic driving data set. The kinematic variables from the image-based gap analysis were filtered by the weighted linear least squares in order to extrapolate them at the lane change time. In addition, the time-to-collision and required deceleration were computed, and potential safety threshold values are provided. The resulting range and range rate distributions showed directional discrepancies, i.e., in left lane changes, large trucks are often slower than other vehicles in the target lane, whereas they are usually faster in right lane changes. Video observations have confirmed that major motivations for changing lanes are different depending on the direction of move, i.e., moving to the left (faster) lane occurs due to a slower vehicle ahead or a merging vehicle on the right-hand side, whereas right lane changes are frequently made to return to the original lane after passing. PMID:26924947

Gap Acceptance During Lane Changes by Large-Truck Drivers-An Image-Based Analysis.

PubMed

Nobukawa, Kazutoshi; Bao, Shan; LeBlanc, David J; Zhao, Ding; Peng, Huei; Pan, Christopher S

2016-03-01

This paper presents an analysis of rearward gap acceptance characteristics of drivers of large trucks in highway lane change scenarios. The range between the vehicles was inferred from camera images using the estimated lane width obtained from the lane tracking camera as the reference. Six-hundred lane change events were acquired from a large-scale naturalistic driving data set. The kinematic variables from the image-based gap analysis were filtered by the weighted linear least squares in order to extrapolate them at the lane change time. In addition, the time-to-collision and required deceleration were computed, and potential safety threshold values are provided. The resulting range and range rate distributions showed directional discrepancies, i.e., in left lane changes, large trucks are often slower than other vehicles in the target lane, whereas they are usually faster in right lane changes. Video observations have confirmed that major motivations for changing lanes are different depending on the direction of move, i.e., moving to the left (faster) lane occurs due to a slower vehicle ahead or a merging vehicle on the right-hand side, whereas right lane changes are frequently made to return to the original lane after passing.

Development and calibration of a new gamma camera detector using large square Photomultiplier Tubes

NASA Astrophysics Data System (ADS)

Zeraatkar, N.; Sajedi, S.; Teimourian Fard, B.; Kaviani, S.; Akbarzadeh, A.; Farahani, M. H.; Sarkar, S.; Ay, M. R.

2017-09-01

Large area scintillation detectors applied in gamma cameras as well as Single Photon Computed Tomography (SPECT) systems, have a major role in in-vivo functional imaging. Most of the gamma detectors utilize hexagonal arrangement of Photomultiplier Tubes (PMTs). In this work we applied large square-shaped PMTs with row/column arrangement and positioning. The Use of large square PMTs reduces dead zones in the detector surface. However, the conventional center of gravity method for positioning may not introduce an acceptable result. Hence, the digital correlated signal enhancement (CSE) algorithm was optimized to obtain better linearity and spatial resolution in the developed detector. The performance of the developed detector was evaluated based on NEMA-NU1-2007 standard. The acquired images using this method showed acceptable uniformity and linearity comparing to three commercial gamma cameras. Also the intrinsic and extrinsic spatial resolutions with low-energy high-resolution (LEHR) collimator at 10 cm from surface of the detector were 3.7 mm and 7.5 mm, respectively. The energy resolution of the camera was measured 9.5%. The performance evaluation demonstrated that the developed detector maintains image quality with a reduced number of used PMTs relative to the detection area.

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo

DOE PAGES

McDaniel, Tyler; D’Azevedo, Ed F.; Li, Ying Wai; ...

2017-11-07

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is therefore formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with applicationmore » of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. Here this procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi- core CPUs and GPUs.« less

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDaniel, Tyler; D’Azevedo, Ed F.; Li, Ying Wai

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is therefore formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with applicationmore » of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. Here this procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi- core CPUs and GPUs.« less

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo.

PubMed

McDaniel, T; D'Azevedo, E F; Li, Y W; Wong, K; Kent, P R C

2017-11-07

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is, therefore, formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with an application of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. This procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo, where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi-core central processing units and graphical processing units.

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo

NASA Astrophysics Data System (ADS)

McDaniel, T.; D'Azevedo, E. F.; Li, Y. W.; Wong, K.; Kent, P. R. C.

2017-11-01

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is, therefore, formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with an application of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. This procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo, where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi-core central processing units and graphical processing units.

Accelerating rejection-based simulation of biochemical reactions with bounded acceptance probability

NASA Astrophysics Data System (ADS)

Thanh, Vo Hong; Priami, Corrado; Zunino, Roberto

2016-06-01

Stochastic simulation of large biochemical reaction networks is often computationally expensive due to the disparate reaction rates and high variability of population of chemical species. An approach to accelerate the simulation is to allow multiple reaction firings before performing update by assuming that reaction propensities are changing of a negligible amount during a time interval. Species with small population in the firings of fast reactions significantly affect both performance and accuracy of this simulation approach. It is even worse when these small population species are involved in a large number of reactions. We present in this paper a new approximate algorithm to cope with this problem. It is based on bounding the acceptance probability of a reaction selected by the exact rejection-based simulation algorithm, which employs propensity bounds of reactions and the rejection-based mechanism to select next reaction firings. The reaction is ensured to be selected to fire with an acceptance rate greater than a predefined probability in which the selection becomes exact if the probability is set to one. Our new algorithm improves the computational cost for selecting the next reaction firing and reduces the updating the propensities of reactions.

Accelerating rejection-based simulation of biochemical reactions with bounded acceptance probability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thanh, Vo Hong, E-mail: vo@cosbi.eu; Priami, Corrado, E-mail: priami@cosbi.eu; Department of Mathematics, University of Trento, Trento

Stochastic simulation of large biochemical reaction networks is often computationally expensive due to the disparate reaction rates and high variability of population of chemical species. An approach to accelerate the simulation is to allow multiple reaction firings before performing update by assuming that reaction propensities are changing of a negligible amount during a time interval. Species with small population in the firings of fast reactions significantly affect both performance and accuracy of this simulation approach. It is even worse when these small population species are involved in a large number of reactions. We present in this paper a new approximatemore » algorithm to cope with this problem. It is based on bounding the acceptance probability of a reaction selected by the exact rejection-based simulation algorithm, which employs propensity bounds of reactions and the rejection-based mechanism to select next reaction firings. The reaction is ensured to be selected to fire with an acceptance rate greater than a predefined probability in which the selection becomes exact if the probability is set to one. Our new algorithm improves the computational cost for selecting the next reaction firing and reduces the updating the propensities of reactions.« less

Chronic Effects of Mild Neurotrauma: Putting the Cart Before the Horse?

PubMed Central

Castellani, Rudy J.; Perry, George; Iverson, Grant L.

2015-01-01

Accumulation of phosphorylated tau (p-tau) is accepted by many as a long-term consequence of repetitive mild neurotrauma, based largely on brain findings in boxers (dementia pugilistica) and, more recently, former professional athletes, military service members, and others exposed to repetitive head trauma. The pathogenic construct is also largely accepted and suggests that repetitive head trauma (typically concussions or subconcussive forces) acts on brain parenchyma to produce a deleterious neuroinflammatory cascade, encompassing p-tau templating, trans-synaptic neurotoxicity, progressive neurodegenerative disease, and associated clinical features. Some caution before accepting these concepts and assumptions is warranted, however. The association between history of concussion and findings of p-tau at autopsy is unclear. Concussions and subconcussive head trauma exposure are poorly defined in available cases and the clinical features reported in CTE are not at present distinguishable from other disorders. Because control groups are limited, the idea that p-tau drives the disease process via protein templating or some other mechanism is preliminary. Much additional research in CTE is needed to determine if it has unique neuropathology and clinical features, the extent to which the neuropathologic alterations cause the clinical features, and whether it can be identified accurately in a living person. PMID:25933385

Commissioning results of Nb 3Sn cavity vapor diffusion deposition system at JLab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eremeev, Grigory; Clemens, William A.; Macha, Kurt M.

2015-09-01

Nb 3Sn as a BCS superconductor with a superconducting critical temperature higher than that of niobium offers potential benefit for SRF cavities via a lower-than-niobium surface resistance at the same temperature and frequency. A Nb 3Sn vapor diffusion deposition system designed for coating of 1.5 and 1.3 GHz single-cell cavities was built and commissioned at JLab. As the part of the commissioning, RF performance at 2.0 K of a single-cell 1.5 GHz CEBAF-shaped cavity was measured before and after coating in the system. Before Nb 3Sn coating the cavity had a Q 0 of about 10 10 and was limitedmore » by the high field Q-slope at E acc ≅ 27 MV/m. Coated cavity exhibited the superconducting transition at about 17.9 K. The low-field quality factor was about 5∙10 9 at 4.3 K and 7∙10 9 at 2.0 K decreasing with field to about 1∙10 9 at E acc ≅ 8 MV/m at both temperatures. The highest field was limited by the available RF power.« less

A prototype of a beam steering assistant tool for accelerator operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Bickley; P. Chevtsov

2006-10-24

The CEBAF accelerator provides nuclear physics experiments at Jefferson Lab with high quality electron beams. Three experimental end stations can simultaneously receive the beams with different energies and intensities. For each operational mode, the accelerator setup procedures are complicated and require very careful checking of beam spot sizes and positions on multiple beam viewers. To simplify these procedures and make them reproducible, a beam steering assistant GUI tool has been created. The tool is implemented as a multi-window control screen. The screen has an interactive graphical object window, which is an overlay on top of a digitized live video imagemore » from a beam viewer. It allows a user to easily create and edit any graphical objects consisting of text, ellipses, and lines, right above the live beam viewer image and then save them in a file that is called a beam steering template. The template can show, for example, the area within which the beam must always be on the viewer. Later, this template can be loaded in the interactive graphical object window to help accelerator operators steer the beam to the specified area on the viewer.« less

Studies Of Coherent Synchrotron Radiation And Longitudinal Space Charge In The Jefferson Lab FEL Driver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tennant, Christopher D.; Douglas, David R.; Li, Rui

2014-12-01

The Jefferson Laboratory IR FEL Driver provides an ideal test bed for studying a variety of beam dynamical effects. Recent studies focused on characterizing the impact of coherent synchrotron radiation (CSR) with the goal of benchmarking measurements with simulation. Following measurements to characterize the beam, we quantitatively characterized energy extraction via CSR by measuring beam position at a dispersed location as a function of bunch compression. In addition to operating with the beam on the rising part of the linac RF waveform, measurements were also made while accelerating on the falling part. For each, the full compression point was movedmore » along the backleg of the machine and the response of the beam (distribution, extracted energy) measured. Initial results of start-to-end simulations using a 1D CSR algorithm show remarkably good agreement with measurements. A subsequent experiment established lasing with the beam accelerated on the falling side of the RF waveform in conjunction with positive momentum compaction (R56) to compress the bunch. The success of this experiment motivated the design of a modified CEBAF-style arc with control of CSR and microbunching effects.« less

Online canteens: awareness, use, barriers to use, and the acceptability of potential online strategies to improve public health nutrition in primary schools.

PubMed

Wyse, Rebecca; Yoong, Sze Lin; Dodds, Pennie; Campbell, Libby; Delaney, Tessa; Nathan, Nicole; Janssen, Lisa; Reilly, Kathryn; Sutherland, Rachel; Wiggers, John; Wolfenden, Luke

2017-03-01

Issue addressed This study of primary school principals assessed the awareness, use, barriers to use and acceptability of online canteens. Methods A telephone survey of 123 primary school principals within the Hunter New England Region of New South Wales, Australia was conducted from September 2014 to November 2014. Results Fifty-six percent of principals were aware of the existence of online canteens, with 8% having implemented such a system, and 38% likely to do so in the future. Medium/large schools were more likely to be aware of or to use online canteens, however there were no differences in awareness or use in relation to school rurality or socioeconomic advantage. Principals cited parent internet access as the most commonly identified perceived barrier to online canteen use, and the majority of principals (71-93%) agreed that it would be acceptable to implement a range of consumer behaviour strategies via an online canteen. Conclusions Study findings suggest that despite relatively low levels of current use, online canteens have the potential to reach a large proportion of school communities in the future, across geographical and socioeconomic divides, and that the nutrition interventions which they have the capacity to deliver are considered acceptable to school principals. So what? Online canteens may represent an opportunity to deliver nutrition interventions to school communities. Future research should examine the feasibility and potential effectiveness of interventions delivered via this modality.

People’s willingness to accept overdetection in cancer screening: population survey

PubMed Central

Jones, Caroline; Yang, Yaling; Oke, Jason; Hewitson, Paul

2015-01-01

Objectives To describe the level of overdetection people would find acceptable in screening for breast, prostate, and bowel cancer and whether acceptability is influenced by the magnitude of the benefit from screening and the cancer specific harms from overdetection. Design Online survey. Women were presented with scenarios on breast and bowel cancer, men with scenarios on prostate and bowel cancer. For each particular cancer, we presented epidemiological information and described the treatment and its consequences. Secondly, we presented two different scenarios of benefit: one indicating a 10% reduction in cancer specific mortality and the second indicating a 50% reduction. Setting Online survey of the population in the United Kingdom. Participants Respondents were part of an existing panel of people who volunteer for online research and were invited by email or online marketing. We recruited 1000 respondents, representative for age and sex for the UK population. Main outcome measures Number of cases of overdetection people were willing to accept, ranging from 0-1000 (complete screened population) for each cancer modality and each scenario of benefit. Results There was large variability between respondents in the level of overdetection they would find acceptable, with medians ranging from 113 to 313 cases of overdetection per 1000 people screened. Across all scenarios, 4-7% of respondents indicated they would accept no overdetection at all compared with 7-14% who thought that it would be acceptable for the entire screened population to be overdetected. Acceptability in screening for bowel cancer was significantly lower than for breast and prostate cancer. People aged 50 or over accepted significantly less overdetection, whereas people with higher education levels accepted more; 29% of respondents had heard of overdetection before. Conclusions Acceptability of overdetection in cancer screening is variable. Invitations for screening should include clear information on the likelihood and consequences of overdetection to allow people to make an informed choice. PMID:25736617

People's willingness to accept overdetection in cancer screening: population survey.

PubMed

Van den Bruel, Ann; Jones, Caroline; Yang, Yaling; Oke, Jason; Hewitson, Paul

2015-03-03

To describe the level of overdetection people would find acceptable in screening for breast, prostate, and bowel cancer and whether acceptability is influenced by the magnitude of the benefit from screening and the cancer specific harms from overdetection. Online survey. Women were presented with scenarios on breast and bowel cancer, men with scenarios on prostate and bowel cancer. For each particular cancer, we presented epidemiological information and described the treatment and its consequences. Secondly, we presented two different scenarios of benefit: one indicating a 10% reduction in cancer specific mortality and the second indicating a 50% reduction. Online survey of the population in the United Kingdom. Respondents were part of an existing panel of people who volunteer for online research and were invited by email or online marketing. We recruited 1000 respondents, representative for age and sex for the UK population. Number of cases of overdetection people were willing to accept, ranging from 0-1000 (complete screened population) for each cancer modality and each scenario of benefit. There was large variability between respondents in the level of overdetection they would find acceptable, with medians ranging from 113 to 313 cases of overdetection per 1000 people screened. Across all scenarios, 4-7% of respondents indicated they would accept no overdetection at all compared with 7-14% who thought that it would be acceptable for the entire screened population to be overdetected. Acceptability in screening for bowel cancer was significantly lower than for breast and prostate cancer. People aged 50 or over accepted significantly less overdetection, whereas people with higher education levels accepted more; 29% of respondents had heard of overdetection before. Acceptability of overdetection in cancer screening is variable. Invitations for screening should include clear information on the likelihood and consequences of overdetection to allow people to make an informed choice. © Van den Bruel et al 2015.

Quantification of uncertainty in machining operations for on-machine acceptance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Claudet, Andre A.; Tran, Hy D.; Su, Jiann-Chemg

2008-09-01

Manufactured parts are designed with acceptance tolerances, i.e. deviations from ideal design conditions, due to unavoidable errors in the manufacturing process. It is necessary to measure and evaluate the manufactured part, compared to the nominal design, to determine whether the part meets design specifications. The scope of this research project is dimensional acceptance of machined parts; specifically, parts machined using numerically controlled (NC, or also CNC for Computer Numerically Controlled) machines. In the design/build/accept cycle, the designer will specify both a nominal value, and an acceptable tolerance. As part of the typical design/build/accept business practice, it is required to verifymore » that the part did meet acceptable values prior to acceptance. Manufacturing cost must include not only raw materials and added labor, but also the cost of ensuring conformance to specifications. Ensuring conformance is a substantial portion of the cost of manufacturing. In this project, the costs of measurements were approximately 50% of the cost of the machined part. In production, cost of measurement would be smaller, but still a substantial proportion of manufacturing cost. The results of this research project will point to a science-based approach to reducing the cost of ensuring conformance to specifications. The approach that we take is to determine, a priori, how well a CNC machine can manufacture a particular geometry from stock. Based on the knowledge of the manufacturing process, we are then able to decide features which need further measurements from features which can be accepted 'as is' from the CNC. By calibration of the machine tool, and establishing a machining accuracy ratio, we can validate the ability of CNC to fabricate to a particular level of tolerance. This will eliminate the costs of checking for conformance for relatively large tolerances.« less

Freeform solar concentrator with a highly asymmetric acceptance cone

NASA Astrophysics Data System (ADS)

Wheelwright, Brian; Angel, J. Roger P.; Coughenour, Blake; Hammer, Kimberly

2014-10-01

A solar concentrator with a highly asymmetric acceptance cone is investigated. Concentrating photovoltaic systems require dual-axis sun tracking to maintain nominal concentration throughout the day. In addition to collecting direct rays from the solar disk, which subtends ~0.53 degrees, concentrating optics must allow for in-field tracking errors due to mechanical misalignment of the module, wind loading, and control loop biases. The angular range over which the concentrator maintains <90% of on-axis throughput is defined as the optical acceptance angle. Concentrators with substantial rotational symmetry likewise exhibit rotationally symmetric acceptance angles. In the field, this is sometimes a poor match with azimuth-elevation trackers, which have inherently asymmetric tracking performance. Pedestal-mounted trackers with low torsional stiffness about the vertical axis have better elevation tracking than azimuthal tracking. Conversely, trackers which rotate on large-footprint circular tracks are often limited by elevation tracking performance. We show that a line-focus concentrator, composed of a parabolic trough primary reflector and freeform refractive secondary, can be tailored to have a highly asymmetric acceptance angle. The design is suitable for a tracker with excellent tracking accuracy in the elevation direction, and poor accuracy in the azimuthal direction. In the 1000X design given, when trough optical errors (2mrad rms slope deviation) are accounted for, the azimuthal acceptance angle is +/- 1.65°, while the elevation acceptance angle is only +/-0.29°. This acceptance angle does not include the angular width of the sun, which consumes nearly all of the elevation tolerance at this concentration level. By decreasing the average concentration, the elevation acceptance angle can be increased. This is well-suited for a pedestal alt-azimuth tracker with a low cost slew bearing (without anti-backlash features).

Acceptance of selective contracting: the role of trust in the health insurer

PubMed Central

2013-01-01

Background In a demand oriented health care system based on managed competition, health insurers have incentives to become prudent buyers of care on behalf of their enrolees. They are allowed to selectively contract care providers. This is supposed to stimulate competition between care providers and both increase the quality of care and contain costs in the health care system. However, health insurers are reluctant to implement selective contracting; they believe their enrolees will not accept this. One reason, insurers believe, is that enrolees do not trust their health insurer. However, this has never been studied. This paper aims to study the role played by enrolees’ trust in the health insurer on their acceptance of selective contracting. Methods An online survey was conducted among 4,422 people insured through a large Dutch health insurance company. Trust in the health insurer, trust in the purchasing strategy of the health insurer and acceptance of selective contracting were measured using multiple item scales. A regression model was constructed to analyse the results. Results Trust in the health insurer turned out to be an important prerequisite for the acceptance of selective contracting among their enrolees. The association of trust in the purchasing strategy of the health insurer with acceptance of selective contracting is stronger for older people than younger people. Furthermore, it was found that men and healthier people accepted selective contracting by their health insurer more readily. This was also true for younger people with a low level of trust in their health insurer. Conclusion This study provides insight into factors that influence people’s acceptance of selective contracting by their health insurer. This may help health insurers to implement selective contracting in a way their enrolees will accept and, thus, help systems of managed competition to develop. PMID:24083663

Acceptance of selective contracting: the role of trust in the health insurer.

PubMed

Bes, Romy E; Wendel, Sonja; Curfs, Emile C; Groenewegen, Peter P; de Jong, Judith D

2013-10-02

In a demand oriented health care system based on managed competition, health insurers have incentives to become prudent buyers of care on behalf of their enrolees. They are allowed to selectively contract care providers. This is supposed to stimulate competition between care providers and both increase the quality of care and contain costs in the health care system. However, health insurers are reluctant to implement selective contracting; they believe their enrolees will not accept this. One reason, insurers believe, is that enrolees do not trust their health insurer. However, this has never been studied. This paper aims to study the role played by enrolees' trust in the health insurer on their acceptance of selective contracting. An online survey was conducted among 4,422 people insured through a large Dutch health insurance company. Trust in the health insurer, trust in the purchasing strategy of the health insurer and acceptance of selective contracting were measured using multiple item scales. A regression model was constructed to analyse the results. Trust in the health insurer turned out to be an important prerequisite for the acceptance of selective contracting among their enrolees. The association of trust in the purchasing strategy of the health insurer with acceptance of selective contracting is stronger for older people than younger people. Furthermore, it was found that men and healthier people accepted selective contracting by their health insurer more readily. This was also true for younger people with a low level of trust in their health insurer. This study provides insight into factors that influence people's acceptance of selective contracting by their health insurer. This may help health insurers to implement selective contracting in a way their enrolees will accept and, thus, help systems of managed competition to develop.

Use of organs from donors with bloodstream infection, pneumonia, and influenza: Results of a survey of infectious diseases practitioners.

PubMed

Mehta, Sanjay R; Logan, Cathy; Kotton, Camille N; Kumar, Deepali; Aslam, Saima

2017-02-01

Potential organ donors may be admitted with an infection to an intensive care unit, or contract a nosocomial infection during their stay, increasing the risk of potential transmission to the recipient. Because of a lack of practice guidelines and large-scale data on this topic, we undertook a survey to assess the willingness of transplant infectious diseases (ID) physicians to accept such organs. We performed a 10-question survey of ID providers from the American Society of Transplantation Infectious Disease Community of Practice to determine the scope of practice regarding acceptance of organs from donors with bloodstream infection, pneumonia, and influenza prior to organ procurement, as well as management of such infections following transplantation. Among 60 respondents to our survey, a majority indicated that organs would be accepted from donors bacteremic with streptococci (76%) or Enterobacteriaceae (73%) without evidence of drug resistance. Acceptance rates varied based on infecting organism, type of organ, and center size. Ten percent of respondents would accept an organ from a donor bacteremic with a carbapenem-resistant organism. Over 90% of respondents would accept an organ other than a lung from a donor with influenza on treatment, compared with 52% that would accept a lung in the same setting. This study is the first to our knowledge to survey transplant ID providers regarding acceptance of organs based on specific infections in the donor. These decisions are often based on limited published data and experience. Better characterization of the outcomes from donors with specific types of infection could lead to liberalization of organ acceptance practices across centers. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Religious Affiliation, Religiosity, Gender, and Rape Myth Acceptance: Feminist Theory and Rape Culture.

PubMed

Barnett, Michael D; Sligar, Kylie B; Wang, Chiachih D C

2018-04-01

Rape myths are false beliefs about rape, rape victims, and rapists, often prejudicial and stereotypical. Guided by feminist theory and available empirical research, this study aimed to examine the influences of gender, religious affiliation, and religiosity on rape myth acceptance of U.S. emerging adults. A sample of 653 university students aged 18 to 30 years were recruited from a large public university in the southern United States to complete the research questionnaires. Results indicated that individuals who identified as Roman Catholic or Protestant endorsed higher levels of rape myth acceptance than their atheist or agnostic counterparts. Men were found more likely to ascribe to rape myths than their female counterparts. Religiosity was positively associated with rape myth acceptance, even after controlling the effect of conservative political ideology. No significant interaction was found between gender and religious affiliation or gender and religiosity. Limitations, future research directions, and implications of the findings are discussed from the perspective of feminist theory.

Major psychological factors affecting acceptance of gene-recombination technology.

PubMed

Tanaka, Yutaka

2004-12-01

The purpose of this study was to verify the validity of a causal model that was made to predict the acceptance of gene-recombination technology. A structural equation model was used as a causal model. First of all, based on preceding studies, the factors of perceived risk, perceived benefit, and trust were set up as important psychological factors determining acceptance of gene-recombination technology in the structural equation model. An additional factor, "sense of bioethics," which I consider to be important for acceptance of biotechnology, was added to the model. Based on previous studies, trust was set up to have an indirect influence on the acceptance of gene-recombination technology through perceived risk and perceived benefit in the model. Participants were 231 undergraduate students in Japan who answered a questionnaire with a 5-point bipolar scale. The results indicated that the proposed model fits the data well, and showed that acceptance of gene-recombination technology is explained largely by four factors, that is, perceived risk, perceived benefit, trust, and sense of bioethics, whether the technology is applied to plants, animals, or human beings. However, the relative importance of the four factors was found to vary depending on whether the gene-recombination technology was applied to plants, animals, or human beings. Specifically, the factor of sense of bioethics is the most important factor in acceptance of plant gene-recombination technology and animal gene-recombination technology, and the factors of trust and perceived risk are the most important factors in acceptance of human being gene-recombination technology.

A pilot study on the functional performance and acceptability of an innovative female condom (Wondaleaf®) in Malaysia.

PubMed

Ting, Rachel Sing-Kiat; Wong, Ee-Lynn; Tnay, Jessie Koh-Sing

2018-01-01

Female condom (FC) has been available for over 30 years, but it still lacks wide acceptability. To overcome misdirection and invagination occurring in FC and to provide a wider area of protection, Wondaleaf ® (WL), a new-generation adhesive FC, was recently invented. This pioneering study sought to assess the acceptability and functional performance of WL among Malaysian women. A mixed method survey was conducted in three cities of Malaysia, recruiting sexually active heterosexual women, aged 18-50, by snowball sampling method. Participants were provided with WL and initially surveyed to rate its performance in five coital usages over 2 months. After that, the participants underwent a second survey to rate their satisfaction and acceptability toward WL. Descriptive statistics on clinical failure rates were tabulated with correlational analysis performed to identify major variables contributing to WL's functional performance and acceptability. Out of the 51 enrolled participants, 31 women completed the required surveys. WL's total clinical failure rate was 2.60% (out of 155 condom uses) with above-average ratings of functional performance. The ease of use significantly correlated with ratings of no slippage and no misdirection. The confidence in WL's safety features significantly correlated with a sense of empowerment and protection. WL has a relatively low risk of clinical failures and an overall favorable acceptability among Malaysian women. However, this study also showed that its future usage largely depends on partner acceptability. It may have the potential of complementing the existing barrier toward contraceptive use. Further studies are needed to understand the global acceptability of WL.

Belief versus acceptance: why do people not believe in evolution?

PubMed

Williams, James D

2009-11-01

Despite being an established and accepted scientific theory for 150 years, repeated public polls show that evolution is not believed by large numbers of people. This essay examines why people do not accept evolution and argues that its poor representation in some science textbooks allows misconceptions, established and reinforced in early childhood, to take hold. There is also a lack of up-to-date examples of evidence for evolution in school textbooks. Poor understanding by science graduates and teachers of the nature of science and incorrect definitions by them of key terminology, serve only to undermine efforts to improve public understanding of evolution. This paper has several recommendations, including the introduction of evolution to primary age children and a call to bring evolution back as the central tenet of biology.

Corrected Mean-Field Model for Random Sequential Adsorption on Random Geometric Graphs

NASA Astrophysics Data System (ADS)

Dhara, Souvik; van Leeuwaarden, Johan S. H.; Mukherjee, Debankur

2018-03-01

A notorious problem in mathematics and physics is to create a solvable model for random sequential adsorption of non-overlapping congruent spheres in the d-dimensional Euclidean space with d≥ 2 . Spheres arrive sequentially at uniformly chosen locations in space and are accepted only when there is no overlap with previously deposited spheres. Due to spatial correlations, characterizing the fraction of accepted spheres remains largely intractable. We study this fraction by taking a novel approach that compares random sequential adsorption in Euclidean space to the nearest-neighbor blocking on a sequence of clustered random graphs. This random network model can be thought of as a corrected mean-field model for the interaction graph between the attempted spheres. Using functional limit theorems, we characterize the fraction of accepted spheres and its fluctuations.

Return to normality after a radiological emergency.

PubMed

Lochard, J; Prêtre, S

1995-01-01

Some preliminary considerations from the management of post-accident situations connected to large scale and high land contamination are presented. The return to normal, or at least acceptable living conditions, as soon as reasonably achievable, and the prevention of the possible emergence of a post-accident crisis is of key importance. A scheme is proposed for understanding the dynamics of the various phases after an accident. An attempt is made to characterize some of the parameters driving the acceptability of post-accident situations. Strategies to return to normal living conditions in contaminated areas are considered.

Search for {eta}-mesic helium using WASA-at-COSY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moskal, P.; Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Juelich

2010-08-05

The installation of the WASA detector at the cooler synchrotron COSY opened the possibility to search for {eta}-mesic helium with high statistics and high acceptance. A search for the {sup 4}He--{eta} bound state is conducted via an exclusive measurement of the excitation function for the dd{yields}{sup 3}Hep{pi}{sup -} reaction varying continuously the beam momentum around the threshold for the dd{yields}{sup 4}He{eta} reaction. Ramping of the beam momentum and taking advantage of the large acceptance of the WASA detector allows to minimize systematical uncertainities.

Truncation of CPC solar collectors and its effect on energy collection

NASA Astrophysics Data System (ADS)

Carvalho, M. J.; Collares-Pereira, M.; Gordon, J. M.; Rabl, A.

1985-01-01

Analytic expressions are derived for the angular acceptance function of two-dimensional compound parabolic concentrator solar collectors (CPC's) of arbitrary degree of truncation. Taking into account the effect of truncation on both optical and thermal losses in real collectors, the increase in monthly and yearly collectible energy is also evaluated. Prior analyses that have ignored the correct behavior of the angular acceptance function at large angles for truncated collectors are shown to be in error by 0-2 percent in calculations of yearly collectible energy for stationary collectors.

Summary of Research 1992

DTIC Science & Technology

1992-12-01

Tutorial on Their Data Sharing," The International Journal on Very Large Data Bases (VLDB Journal ), Vol. 1, No. 1, July 1992. Hsiao, D. K., "Federated...Databases and Systems: A Tutorial on Their Resource Consolidation," The International Journal on Very Large Data Bases (VLDB Journal ), Vol. 1, No. 2...Game: Normal Approximation," accepted extensions of games and considers for publication by International possible applications. Journal of Game Theory

Analysis of Large Scale Spatial Variability of Soil Moisture Using a Geostatistical Method

DTIC Science & Technology

2010-01-25

2010 / Accepted: 19 January 2010 / Published: 25 January 2010 Abstract: Spatial and temporal soil moisture dynamics are critically needed to...scale observed and simulated estimates of soil moisture under pre- and post-precipitation event conditions. This large scale variability is a crucial... dynamics is essential in the hydrological and meteorological modeling, improves our understanding of land surface–atmosphere interactions. Spatial and

Simulator study of flight characteristics of a large twin-fuselage cargo transport airplane during approach and landing

NASA Technical Reports Server (NTRS)

Grantham, W. D.; Deal, P. L.; Keyser, G. L., Jr.; Smith, P. M.

1983-01-01

A six degree-of-freedom, ground-based simulator study was conducted to evaluate the low speed flight characteristics of a twin fuselage cargo transport airplane and to compare these characteristics with those of a large, single fuselage (reference) transport configuration which was similar to the Lockheed C-5C airplane. The primary piloting task was the approach and landing. The results indicated that in order to achieve "acceptable' low speed handling qualities on the twin fuselage concept, considerable stability and control augmentation was required, and although the augmented airplane could be landed safely under adverse conditions, the roll performance of the aircraft had to be improved appreciably before the handling qualities were rated as being "satisfactory.' These ground-based simulation results indicated that a value of t sub phi = 30 (time required to bank 30 deg) less than 6 sec should result in "acceptable' roll response characteristics, and when t sub phi = 30 is less than 3.8 sec, "satisfactory' roll response should be attainable on such large and unusually configured aircraft as the subject twin fuselage cargo transport concept.

Researchers' views of the acceptability of restrictive provisions in clinical trial agreements with industry sponsors.

PubMed

Mello, Michelle M; Clarridge, Brian R; Studdert, David M

2005-01-01

We conducted a mail survey of 884 U.S. medical school faculty active in clinical research to elicit their views about the acceptability of provisions in contracts for industry-sponsored clinical trials that would restrict investigators' academic freedom and control over trials. We compared their responses to results from a similar survey of research administrators at 107 medical schools. There was substantial variation among clinical researchers in their acceptability judgments, with a relatively large proportion of clinical trial investigators willing to accept provisions that give industry sponsors considerable control over the dissemination of research results. There were significant differences in the perceptions of clinical trial investigators versus other recently published clinical researchers; investigators with a high versus low percentage of research support from industry; junior versus senior faculty; and investigators at institutions with high versus low National Institute of Health (NIH) funding ranks. There was also a significant divergence of views in a number of areas between clinical trialists and research administrators who negotiate clinical trial contracts on their behalf. Medical school faculty could benefit from additional guidance about what their institution views as acceptable parameters for industry-sponsored clinical trial agreements.

Hereditary hemochromatosis: awareness and genetic testing acceptability in Western Romania.

PubMed

Neghina, Adriana Maria; Anghel, Andrei

2010-12-01

a public health strategy to promote early diagnosis of hemochromatosis gene (HFE)-related hemochromatosis (HFE-HH) largely depends on people's acceptance of available screening tests. The present study aimed at evaluating patient awareness of HFE-HH and their acceptance of DNA testing in western Romania. a total of 221 participants were randomly recruited from the ambulatory unit of the Emergency County Hospital in Timisoara, Romania. They received brief information on HFE-HH and were assessed for the signs and symptoms of hemochromatosis. HFE genotyping was offered to all of them. Only two cases (0.9%) had previous knowledge of HFE-HH. Twenty-one cases (9.5%) underwent genetic testing. Characteristics associated with test acceptance were age <45 years, male gender, and educational attainment. Acceptance was associated with a desire to know if they had HFE-HH (85.7%). The most prevalent refusal reason was a desire for more information (41%). larger educational programs are required to increase people's awareness about HFE-HH in western Romania. Nevertheless, within health care settings, the importance of disease detection and patient's educational background appear to be essential for achieving high rates of participation in the genetic test.

Internet-delivered acceptance-based behaviour therapy for generalized anxiety disorder: A randomized controlled trial.

PubMed

Dahlin, Mats; Andersson, Gerhard; Magnusson, Kristoffer; Johansson, Tomas; Sjögren, Johan; Håkansson, Andreas; Pettersson, Magnus; Kadowaki, Åsa; Cuijpers, Pim; Carlbring, Per

2016-02-01

Generalized anxiety disorder (GAD) is a disabling condition which can be treated with cognitive behaviour therapy (CBT). The present study tested the effects of therapist-guided internet-delivered acceptance-based behaviour therapy on symptoms of GAD and quality of life. An audio CD with acceptance and mindfulness exercises and a separate workbook were also included in the treatment. Participants diagnosed with GAD (N = 103) were randomly allocated to immediate therapist-guided internet-delivered acceptance-based behaviour therapy or to a waiting-list control condition. A six month follow-up was also included. Results using hierarchical linear modelling showed moderate to large effects on symptoms of GAD (Cohen's d = 0.70 to 0.98), moderate effects on depressive symptoms (Cohen's d = 0.51 to 0.56), and no effect on quality of life. Follow-up data showed maintained effects. While there was a 20% dropout rate, sensitivity analyses showed that dropouts did not differ in their degree of change during treatment. To conclude, our study suggests that internet-delivered acceptance-based behaviour therapy can be effective in reducing the symptoms of GAD. Copyright © 2015 Elsevier Ltd. All rights reserved.

Emperical Tests of Acceptance Sampling Plans

NASA Technical Reports Server (NTRS)

White, K. Preston, Jr.; Johnson, Kenneth L.

2012-01-01

Acceptance sampling is a quality control procedure applied as an alternative to 100% inspection. A random sample of items is drawn from a lot to determine the fraction of items which have a required quality characteristic. Both the number of items to be inspected and the criterion for determining conformance of the lot to the requirement are given by an appropriate sampling plan with specified risks of Type I and Type II sampling errors. In this paper, we present the results of empirical tests of the accuracy of selected sampling plans reported in the literature. These plans are for measureable quality characteristics which are known have either binomial, exponential, normal, gamma, Weibull, inverse Gaussian, or Poisson distributions. In the main, results support the accepted wisdom that variables acceptance plans are superior to attributes (binomial) acceptance plans, in the sense that these provide comparable protection against risks at reduced sampling cost. For the Gaussian and Weibull plans, however, there are ranges of the shape parameters for which the required sample sizes are in fact larger than the corresponding attributes plans, dramatically so for instances of large skew. Tests further confirm that the published inverse-Gaussian (IG) plan is flawed, as reported by White and Johnson (2011).

Trust in risk regulation: cause or consequence of the acceptability of GM food?

PubMed

Poortinga, Wouter; Pidgeon, Nick F

2005-02-01

Although there is ample empirical evidence that trust in risk regulation is strongly related to the perception and acceptability of risk, it is less clear what the direction of this relationship is. This article explores the nature of the relationship, using three separate data sets on perceptions of genetically modified (GM) food among the British public. The article has two discrete but closely interrelated objectives. First, it compares two models of trust. More specifically, it investigates whether trust is the cause (causal chain account) or the consequence (associationist view) of the acceptability of GM food. Second, this study explores whether the affect heuristic can be applied to a wider number of risk-relevant concepts than just perceived risk and benefit. The results suggest that, rather than a determinant, trust is an expression or indicator of the acceptability of GM food. In addition, and as predicted, "affect" accounts for a large portion of the variance between perceived risk, perceived benefit, trust in risk regulation, and acceptability. Overall, the results support the associationist view that specific risk judgments are driven by more general evaluative judgments The implications of these results for risk communication and policy are discussed.

Evaluation of aggregate subgrade materials used as pavement subgrade/granular subbase.

DOT National Transportation Integrated Search

2015-07-01

With recent focus on sustainable construction practices and the ever-increasing transportation costs and scarcity of : natural resources, integration of large-size and marginally acceptable aggregates and recycled materials (e.g., : reclaimed asphalt...

Pros and Cons of the Acceleration Scheme (NF-IDS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Alex; Bogacz, Slawomir

The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and beam shaping can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a nonâ scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. Pros and cons of various stages are discussed here in detail. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain acrossmore » the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. Close proximity of strong solenoids and superc« less

Acceptance criteria for urban dispersion model evaluation

NASA Astrophysics Data System (ADS)

Hanna, Steven; Chang, Joseph

2012-05-01

The authors suggested acceptance criteria for rural dispersion models' performance measures in this journal in 2004. The current paper suggests modified values of acceptance criteria for urban applications and tests them with tracer data from four urban field experiments. For the arc-maximum concentrations, the fractional bias should have a magnitude <0.67 (i.e., the relative mean bias is less than a factor of 2); the normalized mean-square error should be <6 (i.e., the random scatter is less than about 2.4 times the mean); and the fraction of predictions that are within a factor of two of the observations (FAC2) should be >0.3. For all data paired in space, for which a threshold concentration must always be defined, the normalized absolute difference should be <0.50, when the threshold is three times the instrument's limit of quantification (LOQ). An overall criterion is then applied that the total set of acceptance criteria should be satisfied in at least half of the field experiments. These acceptance criteria are applied to evaluations of the US Department of Defense's Joint Effects Model (JEM) with tracer data from US urban field experiments in Salt Lake City (U2000), Oklahoma City (JU2003), and Manhattan (MSG05 and MID05). JEM includes the SCIPUFF dispersion model with the urban canopy option and the urban dispersion model (UDM) option. In each set of evaluations, three or four likely options are tested for meteorological inputs (e.g., a local building top wind speed, the closest National Weather Service airport observations, or outputs from numerical weather prediction models). It is found that, due to large natural variability in the urban data, there is not a large difference between the performance measures for the two model options and the three or four meteorological input options. The more detailed UDM and the state-of-the-art numerical weather models do provide a slight improvement over the other options. The proposed urban dispersion model acceptance criteria are satisfied at over half of the field experiments.

User acceptance of a picture archiving and communication system (PACS) in a Saudi Arabian hospital radiology department

PubMed Central

2012-01-01

Background Compared with the increasingly widespread use of picture archiving and communication systems (PACSs), knowledge concerning users’ acceptance of such systems is limited. Knowledge of acceptance is needed given the large (and growing) financial investment associated with the implementation of PACSs, and because the level of user acceptance influences the degree to which the benefits of the systems for healthcare can be realized. Methods A Technology Acceptance Model (TAM) was used to assess the level of acceptance of the host PACS by staff in the radiology department at King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia. A questionnaire survey of 89 PACS users was employed to obtain data regarding user characteristics, perceived usefulness (PU) (6 items), perceived ease of use (PEU) (4 items), a change construct (4 items), and a behavior (acceptance) construct (9 items). Respondents graded each item in each construct using five-point likert scales. Results Surveyed users reported high levels of PU (4.33/5), PEU (4.15/5), change (4.26/5), and acceptance (3.86/5). The three constructs of PU, PEU, and change explained 41 % of the variation in PACS user acceptance. PU was the most important predictor, explaining 38 % of the variation on its own. The most important single item in the explanatory constructs was that users found PACS to have improved the quality of their work in providing better patient care. Technologists had lower acceptance ratings than did clinicians/radiologists, but no influence on acceptance level was found due to gender, age, or length of experience using the PACS. Although not directly measured, there appeared to be no cultural influence on either the level of acceptance or its determinants. Conclusions User acceptance must be considered when an organization implements a PACS, in order to enhance its successful adoption. Health organizations should adopt a PACS that offers all required functions and which is likely to generate high PU on the part of its users, rather than a system that is easy to use. Training/familiarization programs should aim at establishing high levels of PU in all users, particularly technologists. Health organizations are advised to measure all the factors that influence the acceptance of a PACS by their staff, in order to optimize the productivity of the system and realize the potential benefits to the greatest extent possible. PMID:22640490

Professor Attitudes and Beliefs about Teaching Evolution

NASA Astrophysics Data System (ADS)

Barnes, Maryann Elizabeth

Teaching evolution has been shown to be a challenge for faculty, in both K-12 and postsecondary education. Many of these challenges stem from perceived conflicts not only between religion and evolution, but also faculty beliefs about religion, it's compatibility with evolutionary theory, and it's proper role in classroom curriculum. Studies suggest that if educators engage with students' religious beliefs and identity, this may help students have positive attitudes towards evolution. The aim of this study was to reveal attitudes and beliefs professors have about addressing religion and providing religious scientist role models to students when teaching evolution. 15 semi-structured interviews of tenured biology professors were conducted at a large Midwestern universiy regarding their beliefs, experiences, and strategies teaching evolution and particularly, their willingness to address religion in a class section on evolution. Following a qualitative analysis of transcripts, professors did not agree on whether or not it is their job to help students accept evolution (although the majority said it is not), nor did they agree on a definition of "acceptance of evolution". Professors are willing to engage in students' religious beliefs, if this would help their students accept evolution. Finally, professors perceived many challenges to engaging students' religious beliefs in a science classroom such as the appropriateness of the material for a science class, large class sizes, and time constraints. Given the results of this study, the author concludes that instructors must come to a consensus about their goals as biology educators as well as what "acceptance of evolution" means, before they can realistically apply the engagement of student's religious beliefs and identity as an educational strategy.

High acceptability for cell phone text messages to improve communication of laboratory results with HIV-infected patients in rural Uganda: a cross-sectional survey study.

PubMed

Siedner, Mark J; Haberer, Jessica E; Bwana, Mwebesa Bosco; Ware, Norma C; Bangsberg, David R

2012-06-21

Patient-provider communication is a major challenge in resource-limited settings with large catchment areas. Though mobile phone usership increased 20-fold in Africa over the past decade, little is known about acceptability of, perceptions about disclosure and confidentiality, and preferences for cell phone communication of health information in the region. We performed structured interviews of fifty patients at the Immune Suppression Syndrome clinic in Mbarara, Uganda to assess four domains of health-related communication: a) cell phone use practices and literacy, b) preferences for laboratory results communication, c) privacy and confidentiality, and d) acceptability of and preferences for text messaging to notify patients of abnormal test results. Participants had a median of 38 years, were 56% female, and were residents of a large catchment area throughout southwestern Uganda. All participants expressed interest in a service to receive information about laboratory results by cell phone text message, stating benefits of increased awareness of their health and decreased transportation costs. Ninety percent reported that they would not be concerned for unintended disclosure. A minority additionally expressed concerns about difficulty interpreting messages, discouragement upon learning bad news, and technical issues. Though all respondents expressed interest in password protection of messages, there was also a strong desire for direct messages to limit misinterpretation of information. Cell phone text messaging for communication of abnormal laboratory results is highly acceptable in this cohort of HIV-infected patients in rural Uganda. The feasibility of text messaging, including an optimal balance between privacy and comprehension, should be further studied.

Using Mindfulness- and Acceptance-Based Treatments With Clients From Nondominant Cultural and/or Marginalized Backgrounds: Clinical Considerations, Meta-Analysis Findings, and Introduction to the Special Series.

PubMed

Fuchs, Cara; Lee, Jonathan K; Roemer, Lizabeth; Orsillo, Susan M

2013-02-01

A growing body of research suggests that mindfulness- and acceptance-based principles can increase efforts aimed at reducing human suffering and increasing quality of life. A critical step in the development and evaluation of these new approaches to treatment is to determine the acceptability and efficacy of these treatments for clients from nondominant cultural and/or marginalized backgrounds. This special series brings together the wisdom of clinicians and researchers who are currently engaged in clinical practice and treatment research with populations who are historically underrepresented in the treatment literature. As an introduction to the series, this paper presents a theoretical background and research context for the papers in the series, highlights the elements of mindfulness- and acceptance-based treatments that may be congruent with culturally responsive treatment, and briefly outlines the general principles of cultural competence and responsive treatment. Additionally, the results of a meta-analysis of mindfulness- and acceptance-based treatments with clients from nondominant cultural and/or marginalized backgrounds are presented. Our search yielded 32 studies totaling 2,198 clients. Results suggest small (Hedges' g=.38, 95% CI=.11 - .64) to large (Hedges' g=1.32, 95% CI=.61 - 2.02) effect sizes for mindfulness- and acceptance-based treatments, which varied by study design.

Resource quality or competition: why increase resource acceptance in the presence of conspecifics?

PubMed Central

Nufio, César R.; Papaj, Daniel R.

2011-01-01

Some animal species increase resource acceptance rates in the presence of conspecifics. Such responses may be adaptive if the presence of conspecifics is a reliable indicator of resource quality. Similarly, these responses could represent an adaptive reduction in choosiness under high levels of scramble competition. Although high resource quality and high levels of scramble competition should both favor increased resource acceptance, the contexts in which the increase occurs should differ. In this paper, we tested the effect of social environment on egg-laying and aggressive behavior in the walnut fly, Rhagoletis juglandis, in multiple contexts to determine whether increased resource acceptance in the presence of conspecifics was better viewed as a response to increased host quality or increased competition. We found that grouped females oviposit more readily than isolated females when provided small (low-quality) artificial hosts but not when provided large (high-quality) artificial hosts, indicating that conspecific presence reduces choosiness. Increased resource acceptance was observed even when exposure to conspecifics was temporally or spatially separate from exposure to the resource. Finally, we found that individuals showed reduced aggression after being housed in groups, as expected under high levels of scramble competition. These results indicate that the pattern of resource acceptance in the presence of conspecifics may be better viewed as a response to increased scramble competition rather than as a response to public information about resource quality. PMID:22479135

Resource quality or competition: why increase resource acceptance in the presence of conspecifics?

PubMed

Davis, Jeremy M; Nufio, César R; Papaj, Daniel R

2011-07-01

Some animal species increase resource acceptance rates in the presence of conspecifics. Such responses may be adaptive if the presence of conspecifics is a reliable indicator of resource quality. Similarly, these responses could represent an adaptive reduction in choosiness under high levels of scramble competition. Although high resource quality and high levels of scramble competition should both favor increased resource acceptance, the contexts in which the increase occurs should differ. In this paper, we tested the effect of social environment on egg-laying and aggressive behavior in the walnut fly, Rhagoletis juglandis, in multiple contexts to determine whether increased resource acceptance in the presence of conspecifics was better viewed as a response to increased host quality or increased competition. We found that grouped females oviposit more readily than isolated females when provided small (low-quality) artificial hosts but not when provided large (high-quality) artificial hosts, indicating that conspecific presence reduces choosiness. Increased resource acceptance was observed even when exposure to conspecifics was temporally or spatially separate from exposure to the resource. Finally, we found that individuals showed reduced aggression after being housed in groups, as expected under high levels of scramble competition. These results indicate that the pattern of resource acceptance in the presence of conspecifics may be better viewed as a response to increased scramble competition rather than as a response to public information about resource quality.

The Effect of Repeated Reading with Pairs of Students in a Large-Group Setting on Fluency and Comprehension for Students at Risk for Reading Failure

ERIC Educational Resources Information Center

Frame, John N.

2011-01-01

Problem: Some students are failing to develop acceptable reading skills; however, instructional time allocated to reading fluency can increase reading comprehension. The purpose of this study was to compare students who received repeated reading with pairs of students in a large-group setting with those who did not in terms of reading fluency,…

Learning to Stand: The Acceptability and Feasibility of Introducing Standing Desks into College Classrooms

PubMed Central

Benzo, Roberto M.; Gremaud, Allene L.; Jerome, Matthew; Carr, Lucas J.

2016-01-01

Prolonged sedentary behavior is an independent risk factor for multiple negative health outcomes. Evidence supports introducing standing desks into K-12 classrooms and work settings to reduce sitting time, but no studies have been conducted in the college classroom environment. The present study explored the acceptability and feasibility of introducing standing desks in college classrooms. A total of 993 students and 149 instructors completed a single online needs assessment survey. This cross-sectional study was conducted during the fall semester of 2015 at a large Midwestern University. The large majority of students (95%) reported they would prefer the option to stand in class. Most students (82.7%) reported they currently sit during their entire class time. Most students (76.6%) and instructors (86.6%) reported being in favor of introducing standing desks into college classrooms. More than half of students and instructors predicted having access to standing desks in class would improve student’s “physical health”, “attention”, and “restlessness”. Collectively, these findings support the acceptability of introducing standing desks in college classrooms. Future research is needed to test the feasibility, cost-effectiveness and efficacy of introducing standing desks in college classrooms. Such studies would be useful for informing institutional policies regarding classroom designs. PMID:27537901

Visual field structure in the Empress Leilia, Asterocampa leilia (Lepidoptera, Nymphalidae): dimensions and regional variation in acuity.

PubMed

Rutowski, Ronald L; Warrant, Eric J

2002-02-01

Male Empress Leilia butterflies ( Asterocampa leilia) use a sit-and-wait tactic to locate mates. To see how vision might influence male behavior, we studied the morphology, optics, and receptor physiology of their eyes and found the following. (1) Each eye's visual field is approximately hemispherical with at most a 10 degrees overlap in the fields of the eyes. There are no large sexual differences in visual field dimensions. (2) In both sexes, rhabdoms in the frontal and dorsal ommatidia are longer than those in other eye regions. (3) Interommatidial angles are smallest frontally and around the equator of the eye. Minimum interommatidial angles are 0.9-1 degrees in males and 1.3-1.4 degrees in females. (4) Acceptance angles of ommatidia closely match interommatidial angles in the frontal region of the eye. We conclude that vision in these butterflies is mostly monocular and that males have more acute vision than females, especially in the frontal region (large facets, small interommatidial angles, small acceptance angles, long rhabdoms, and a close match between interommatidial angles and acceptance angles). This study also suggests that perched males direct their most acute vision where females are likely to appear but show no eye modifications that appear clearly related to a mate-locating tactic.

Acceptability of financial incentives and penalties for encouraging uptake of healthy behaviours: focus groups.

PubMed

Giles, Emma L; Sniehotta, Falko F; McColl, Elaine; Adams, Jean

2015-01-31

There is evidence that financial incentive interventions, which include both financial rewards and also penalties, are effective in encouraging healthy behaviours. However, concerns about the acceptability of such interventions remain. We report on focus groups with a cross-section of adults from North East England exploring their acceptance of financial incentive interventions for encouraging healthy behaviours amongst adults. Such information should help guide the design and development of acceptable, and effective, financial incentive interventions. Eight focus groups with a total of 74 adults were conducted between November 2013 and January 2014 in Newcastle upon Tyne, UK. Focus groups lasted approximately 60 minutes and explored factors that made financial incentives acceptable and unacceptable to participants, together with discussions on preferred formats for financial incentives. Verbatim transcripts were thematically coded and analysed in Nvivo 10. Participants largely distrusted health promoting financial incentives, with a concern that individuals may abuse such schemes. There was, however, evidence that health promoting financial incentives may be more acceptable if they are fair to all recipients and members of the public; if they are closely monitored and evaluated; if they are shown to be effective and cost-effective; and if clear health education is provided alongside health promoting financial incentives. There was also a preference for positive rewards rather than negative penalties, and for shopping vouchers rather than cash incentives. This qualitative empirical research has highlighted clear suggestions on how to design health promoting financial incentives to maximise acceptability to the general public. It will also be important to determine the acceptability of health promoting financial incentives in a range of stakeholders, and in particular, those who fund such schemes, and policy-makers who are likely to be involved with the design, implementation and evaluation of health promoting financial incentive schemes.

A pilot study on the functional performance and acceptability of an innovative female condom (Wondaleaf®) in Malaysia

PubMed Central

Wong, Ee-Lynn; Tnay, Jessie Koh-Sing

2018-01-01

Background Female condom (FC) has been available for over 30 years, but it still lacks wide acceptability. To overcome misdirection and invagination occurring in FC and to provide a wider area of protection, Wondaleaf® (WL), a new-generation adhesive FC, was recently invented. This pioneering study sought to assess the acceptability and functional performance of WL among Malaysian women. Methods A mixed method survey was conducted in three cities of Malaysia, recruiting sexually active heterosexual women, aged 18–50, by snowball sampling method. Participants were provided with WL and initially surveyed to rate its performance in five coital usages over 2 months. After that, the participants underwent a second survey to rate their satisfaction and acceptability toward WL. Descriptive statistics on clinical failure rates were tabulated with correlational analysis performed to identify major variables contributing to WL’s functional performance and acceptability. Results Out of the 51 enrolled participants, 31 women completed the required surveys. WL’s total clinical failure rate was 2.60% (out of 155 condom uses) with above-average ratings of functional performance. The ease of use significantly correlated with ratings of no slippage and no misdirection. The confidence in WL’s safety features significantly correlated with a sense of empowerment and protection. Conclusion WL has a relatively low risk of clinical failures and an overall favorable acceptability among Malaysian women. However, this study also showed that its future usage largely depends on partner acceptability. It may have the potential of complementing the existing barrier toward contraceptive use. Further studies are needed to understand the global acceptability of WL. PMID:29440937

Einstein's Jury: Trial by Telescope

NASA Astrophysics Data System (ADS)

Crelinsten, Jeffrey

2007-03-01

While Einstein's theory of relativity ultimately laid the foundation for modern studies of the universe, it took a long time to be accepted. Between 1905 and 1930, relativity was poorly understood and Einstein worked hard to try to make it more accessible to scientists and scientifically literate laypeople. Its acceptance was largely due to the astronomy community, which undertook precise measurements to test Einstein's astronomical predictions. The well-known 1919 British eclipse expeditions that made Einstein famous did not convince most scientists to accept relativity. The 1920s saw numerous attempts to measure light-bending, as well as solar line displacements and even ether-drift. How astronomers approached the ``Einstein problem'' in these early years before and after the First World War, and how the public reacted to what they reported, helped to shape attitudes we hold today about Einstein and his ideas.

Feasibility and acceptability of a child sexual abuse prevention program for childcare professionals: comparison of a web-based and in-person training.

PubMed

Rheingold, Alyssa A; Zajac, Kristyn; Patton, Meghan

2012-01-01

Recent prevention research has established the efficacy of some child sexual abuse prevention programs targeting adults; however, less is known about the feasibility of implementing such programs. The current study examines the feasibility and acceptability of a child sexual abuse prevention program for child care professionals provided in two different formats: in person and Web based. The sample consisted of 188 child care professionals from a large-scale, multisite, randomized controlled trial. Findings indicate that both in-person and online training formats are feasible to implement and acceptable to professionals. When comparing formats, the in-person format was favored in terms of comfort level and likelihood of sharing information with others. These findings have significant implications for dissemination of child sexual abuse prevention programs for child care professionals.

"Tobacco Truths": Health Magazine, Clinical Epidemiology, and the Cigarette Connection.

PubMed

Wilmshurst, Sara

2015-01-01

In the 1950s, Health, a magazine published by the Health League of Canada, was nonchalant about the risks of smoking and largely ignored early epidemiological studies of lung cancer. In the 1960s the magazine stopped accepting cigarette advertising and began to oppose smoking. Health's writers adjusted to new knowledge; the magazine gradually accepted clinical epidemiology as a source of medical knowledge and recognized smoking as a public health risk. As Canada's only devoted health publication for a lay audience at the time, Health provides a unique window into ways that smoking and health were portrayed to its readers.

Method for Improving Separation of Carbohydrates from Wood Pulping Liquors and Wood or Biomass Hydrolysis Liquors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Compere, A L; Marcoccia, B S; Elliott, J

2012-08-31

Work with industrial partners to perform the studies needed to commercialize U.S. patent 7,699,958 for separation of carbohydrates from wood pulping liquors and wood or biomass hydrolysis liquors. These include: 1) selection of the best pulp mill liquor withdrawal sites, 2) additional purification or enzyme hydrolysis required to obtain acceptable sugar feedstocks, 3) and work with partners to optimize the stream and purification methods to provide acceptable feedstocks for algal fuels and industrial chemicals production, and 4) preparation of samples large enough for testing by downstream partners.

Aircraft Maintenance Engineering: Factors Impacting Airlines E-Maintenance Technologies, Authoring and Illustrations

NASA Astrophysics Data System (ADS)

Karayianes, Frank

The purpose of this research was to evaluate factors influencing acceptance and use of technologies in the field of aircraft maintenance authoring, graphics, and documentation. Maintenance engineering authors convert complex engineering used in aircraft production and transform that data using technology (tools) into usable technical publications data. While the current literature includes a large volume of research in technology acceptance in various domains of industry and business, the problem is that no such studies exist with respect to the aircraft maintenance engineering authoring, allowing any number of tools to be used and acceptance to be unsure. The study was based on theoretical approaches of the Technology Acceptance Model and the associated hypothesis related to eight research questions. A survey questionnaire was developed for data collection from a selected population of aircraft maintenance engineering authors. Data collected from 148 responses were exposed to a range of statistical methods and analyses. Analysis of data were performed within the structural equation model using exploratory factor analysis, confirmatory factor analysis, and a range of regression methods. The analyses generally provided results consistent with prior literature. Two survey questions yielded unexpected results contrary to similar studies. The relationship between prior experience and job level did not show a significant relationship with perceived usefulness or perceived ease of use. Other results included the significant relationship between Perceived Usefulness and Perceived Ease of Use with Technology acceptance. Recommendations include understanding how Technology Acceptance can be improved for the industry and the need for further research not covered to refine recommendations for technology acceptance related to the aviation industry.

Recruitment and retention of rural nursing students: a retrospective study.

PubMed

Bigbee, Jeri; Mixon, Diana

2013-01-01

The shortage of registered nurses is an issue globally, but particularly in rural and remote areas. Previous research in medicine suggests that recruiting students from rural backgrounds is an effective strategy to enhance the supply of rural healthcare providers. This strategy has not been widely adopted or evaluated in nursing. The purpose of this study was to compare rural and urban nursing students in relation to application, admission, and retention/graduation trends at a metropolitan state university in the Pacific Northwest area of the USA. A retrospective longitudinal descriptive design was used, analyzing existing data from 2005 to 2010. The sample included 1283 applicants, accepted students, and graduates. Rural-urban classification was made using rural urban commuting area (RUCA) codes based on high school zip codes, identifying 356 (28%) rural and 927 (72%) urban individuals. The data were analyzed quantitatively, assessing demographic characteristics along with application, admission and retention/graduation rates. The analysis indicated no significant differences between the rural and urban samples in relation to age, gender, parents' level of education, income, or retention rates. The acceptance rate for rural students (66.3%) was significantly lower than for urban students (73.1%) (p=0.015). When rural subgroups (isolated, small rural and large rural) were examined, the isolated group (n=61) had the highest acceptance rate of any rural or urban group (75%). This group was the least ethnically diverse (95% Caucasian), was the least likely to be first-generation college (22%), had the highest percentage of females (85%) and had the highest entering grade point average (3.65 on a four-point scale). In contrast, the subgroup including individuals from large rural communities (n=182) had the lowest acceptance rate (64%), the lowest retention rate 85%, the lowest entering grade point average (3.42), and the highest percentage of first-generation college individuals (50.9%). The findings suggest that students from rural backgrounds achieve similar levels of success in nursing education, despite lower acceptance rates, when compared with urban students. Addressing issues related to lower acceptance rates for rural nursing students, including targeted recruitment and support efforts with students interested in pursuing nursing at the junior and senior high school levels, may be indicated. Further research is indicated to explore differences among rural subgroups in relation to preparation for and achievement in nursing education. Greater research attention is also needed to assess if nursing students from rural backgrounds tend to practice in rural areas more than students from urban backgrounds, similar to previous research in medicine. Because students tend to practice near their place of education, nursing education programs may need to consider locating outside of large urban areas to promote rural practice. Inclusion of rural content and clinical experiences within nursing curricula is also recommended.

Field test of a motorcycle safety education course for novice riders

DOT National Transportation Integrated Search

1982-07-01

The purpose of this study was to subject the Motorcycle Safety Foundation's Motorcycle Rider Course (MRC) to a large-scale field test designed to evaluate the following aspects of the course: (1) Instructional Effectiveness, (2) User Acceptance, and ...

Registration of 'Prevail' hard red spring wheat

USDA-ARS?s Scientific Manuscript database

Grower and end-user acceptance of new Hard Red Spring Wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent upon satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also contribute...

Seattle wide-area information for travelers (SWIFT) : consumer acceptance study

DOT National Transportation Integrated Search

1998-10-19

The Seattle Wide-area Information for Travelers (SWIFT) 0perational Test was intended to evaluate the performance of a large-scale, urban Advanced Traveler Information System (ATIS) deployment in the Seattle area. With the majority of the SWIFT syste...

Possible Employee Wariness Stifles Telehealth's Acceptance.

PubMed

Diamond, Frank

2017-04-01

Workers still haven't bought in. A lot hinges on this question: Do you feel comfortable getting a diagnosis or being treated for a condition by someone on a screen? Large employers especially are willing to bet that the answer is yes.

SUMMARY OF SOLIDIFICATION/STABILIZATION SITE DEMONSTRATIONS AT UNCONTROLLED HAZARDOUS WASTE SITES

EPA Science Inventory

Four large-scale solidification/stabilization demonstrations have occurred under EPA's SITE program. In general, physical testing results have been acceptable. Reduction in metal leachability, as determined by the TCLP test, has been observed. Reduction in organic leachability ha...

Evaluation of Production Version of the NASA Improved Inorganic-Organic Separator

NASA Technical Reports Server (NTRS)

Sheibley, D.

1983-01-01

The technology of an inorganic-organic (I/O) separator, which demonstrated improved flexibility, reduced cost, production feasibility and improved cycle life was developed. Substrates to replace asbestos and waterbased separator coatings to replace the solvent based coatings were investigated. An improved fuel cell grade asbestos sheet was developed and a large scale production capability for the solvent based I/O separator was demonstrated. A cellulose based substrate and a nonwoven polypropylene fiber substrate were evaluated as replacements for the asbestos. Both the cellulose and polypropylene substrates were coated with solvent based and water based coatings to produce a modified I/O separator. The solvent based coatings were modified to produce aqueous separator coatings with acceptable separator properties. A single ply fuel cell grade asbestos with a binder (BTA) was produced. It has shown to be an acceptable substrate for the solvent and water based separator coatings, an acceptable absorber for alkaline cells, and an acceptable matrix for alkaline fuel cells. The original solvent based separator (K19W1), using asbestos as a substrate, was prepared.

Analysis of the acceptance of autonomous planetary science data collection by field of inquiry

NASA Astrophysics Data System (ADS)

Straub, Jeremy

2015-06-01

The acceptance of autonomous control technologies in planetary science has met significant resistance. Many within this scientific community question the efficacy of autonomous technologies for making decisions regarding what data to collect, how to process it and its processing. These technologies, however, can be used to significantly increase the scientific return on mission investment by removing limitations imposed by communications bandwidth constraints and communications and human decision making delays. A fully autonomous mission, in an ideal case, could be deployed, perform most of the substantive work itself (possibly relying on human assistance for dealing with any unexpected or unexplained occurrences) and return an answer to a scientific question along with data selected to allow scientists to validate software performance. This paper presents the results of a survey of planetary scientists which attempts to identify the root causes of the impediments to the use of this type of technology and identify pathways to its acceptance. Previous work considered planetary science as a single large community. This paper contrasts the differences in acceptance between component fields of planetary science.

Pitfalls and Precautions When Using Predicted Failure Data for Quantitative Analysis of Safety Risk for Human Rated Launch Vehicles

NASA Technical Reports Server (NTRS)

Hatfield, Glen S.; Hark, Frank; Stott, James

2016-01-01

Launch vehicle reliability analysis is largely dependent upon using predicted failure rates from data sources such as MIL-HDBK-217F. Reliability prediction methodologies based on component data do not take into account system integration risks such as those attributable to manufacturing and assembly. These sources often dominate component level risk. While consequence of failure is often understood, using predicted values in a risk model to estimate the probability of occurrence may underestimate the actual risk. Managers and decision makers use the probability of occurrence to influence the determination whether to accept the risk or require a design modification. The actual risk threshold for acceptance may not be fully understood due to the absence of system level test data or operational data. This paper will establish a method and approach to identify the pitfalls and precautions of accepting risk based solely upon predicted failure data. This approach will provide a set of guidelines that may be useful to arrive at a more realistic quantification of risk prior to acceptance by a program.

Attitude of Health Care Workers (HCWs) toward Patients Affected by HIV/AIDS and Drug Users: A Cross-Sectional Study.

PubMed

Ledda, Caterina; Cicciù, Francesca; Puglisi, Beatrice; Ramaci, Tiziana; Nunnari, Giuseppe; Rapisarda, Venerando

2017-03-09

Caring for HIV/AIDS patients and/or drug users requires health care workers (HCWs) to have good knowledge of the issues. Cultural differences in HCWs, combined with professional ethics and personal beliefs, could also result in conflicting attitudes, leading to difficulties related to looking after people affected by HIV/AIDS or drug users. A cross-sectional study was carried out to assess the attitude towards HIV/AIDS patients and/or drug users in a sample of workers operating in a large university hospital in southern Italy. A total of 736 workers were surveyed from May to November 2016. During the periodic occupational health surveillance, a questionnaire was administered about attitudes of discrimination, acceptance and fear towards these patients. Respondents showed average levels of acceptance to HIV/AIDS and drug user patients. As years of experience and professional training increased, scores for discrimination, acceptance of HIV/AIDS, acceptance of drug users and fear decreased. Factors positively influencing levels of attitudes were being female and younger. Supplementary education is needed to strengthen the awareness of HCWs.

On-demand microbicide products: design matters.

PubMed

Patel, Sravan Kumar; Rohan, Lisa Cencia

2017-12-01

Sexual intercourse (vaginal and anal) is the predominant mode of human immunodeficiency virus (HIV) transmission. Topical microbicides used in an on-demand format (i.e., immediately before or after sex) can be part of an effective tool kit utilized to prevent sexual transmission of HIV. The effectiveness of prevention products is positively correlated with adherence, which is likely to depend on user acceptability of the product. The development of an efficacious and acceptable product is therefore paramount for the success of an on-demand product. Acceptability of on-demand products (e.g., gels, films, and tablets) and their attributes is influenced by a multitude of user-specific factors that span behavioral, lifestyle, socio-economic, and cultural aspects. In addition, physicochemical properties of the drug, anatomical and physiological aspects of anorectal and vaginal compartments, issues relating to large-scale production, and cost can impact product development. These factors together with user preferences determine the design space of an effective, acceptable, and feasible on-demand product. In this review, we summarize the interacting factors that together determine product choice and its target product profile.

Acceptability and Use of the Diaphragm and Replens® Lubricant Gel for HIV Prevention in Southern Africa

PubMed Central

Cheng, Helen; van der Straten, Ariane; Chidanyika, Agnes C.; Lince, Naomi; Blanchard, Kelly; Ramjee, Gita; Nkala, Busisiwe; Padian, Nancy S.

2009-01-01

The acceptability and use of the diaphragm and lubricant gel were assessed as part of a large randomized controlled trial to determine the effectiveness of the methods in women’s HIV acquisition. 2,452 intervention-arm women were enrolled at five Southern African clinics and followed quarterly for 12–24 months. Acceptability and use data were collected by face-to-face interviews at Month 3 and Exit. Participants were “very comfortable” with the physical mechanics of diaphragm use throughout the trial, and approval of the gel consistency, quantity and the applicator was high. At Exit, consistent disclosure of use (AOR 1.97, 95% CI: 1.10–3.55); an overall high diaphragm rating (AOR 1.84, 95% CI: 1.45–2.34) and perception of partner approval (AOR 1.75, 95% CI: 1.35–2.26) were the most significant acceptability factors independently associated with consistent use. Despite being female-initiated, disclosure of use to male partners and his perceived approval of the products were factors significantly associated with their consistent use. PMID:19757018

Software Manages Documentation in a Large Test Facility

NASA Technical Reports Server (NTRS)

Gurneck, Joseph M.

2001-01-01

The 3MCS computer program assists and instrumentation engineer in performing the 3 essential functions of design, documentation, and configuration management of measurement and control systems in a large test facility. Services provided by 3MCS are acceptance of input from multiple engineers and technicians working at multiple locations;standardization of drawings;automated cross-referencing; identification of errors;listing of components and resources; downloading of test settings; and provision of information to customers.

Post-Attack Economic Stabilization Issues for Federal, State, and Local Governments

DTIC Science & Technology

1985-02-01

workers being transfered from large urban areas to production facilities in areas of lower risk . In another case, rent control staff should be quickly...food supermarkets , which do not universally accept bank cards. 3 0 A requirement will still exist for a large number of credit cards. While there is some...separate system is required for rationing. For example, the increasingly popular automatic teller machine ( ATM ) debit card routinely accesses both a

Social-emotional competence and early adolescents' peer acceptance in school: Examining the role of afternoon cortisol.

PubMed

Oberle, Eva

2018-01-01

The present study investigated the role of afternoon cortisol in social-emotional competence and peer acceptance in early adolescence. To date, research on basal cortisol activity and social development in childhood and adolescence has predominately focused on understanding maladjustment and dysfunction in development. The degree to which basal cortisol is also involved in positive adjustment and social functioning remains largely unexplored. A total of 154 early adolescents (46% female; Mean age = 11.26; SD = .65) from diverse ethnic backgrounds provided self-reports of perspective taking, peer reports of acceptance by classmates, peer reports of prosocial behaviors, and saliva samples to assess basal cortisol. As expected and in alignment with previous research, afternoon cortisol, perspective taking, prosocial behaviors, and peer acceptance were all positively correlated. Path analyses followed by bootstrapping analyses revealed that the direct path from higher afternoon cortisol to higher levels of prosocial behavior was fully mediated by perspective taking skills. The direct path from higher afternoon cortisol to peer acceptance was fully mediated by perspective taking skills and prosocial behavior. The findings are discussed within the broader context of previous research on cortisol and social adjustment in childhood and early adolescence. The practical relevance of the findings is considered.

Multimodal activity monitoring for home rehabilitation of geriatric fracture patients--feasibility and acceptance of sensor systems in the GAL-NATARS study.

PubMed

Marschollek, Michael; Becker, Marcus; Bauer, Jürgen M; Bente, Petra; Dasenbrock, Lena; Elbers, Katharina; Hein, Andreas; Kolb, Gerald; Künemund, Harald; Lammel-Polchau, Christopher; Meis, Markus; Meyer Zu Schwabedissen, Hubertus; Remmers, Hartmut; Schulze, Mareike; Steen, Enno-Edzard; Thoben, Wilfried; Wang, Ju; Wolf, Klaus-Hendrik; Haux, Reinhold

2014-01-01

Demographic change will lead to a diminishing care workforce faced with rising numbers of older persons in need of care, suggesting meaningful use of health-enabling technologies, and home monitoring in particular, to contribute to supporting both the carers and the persons in need. We present and discuss the GAL-NATARS study design along with first results regarding technical feasibility of long-term home monitoring and acceptance of different sensor modalities. Fourteen geriatric participants with mobility-impairing fractures were recruited in three geriatric clinics. Following inpatient geriatric rehabilitation, their homes were equipped with ambient sensor components for three months. Additionally, a wearable accelerometer was employed. Technical feasibility was assessed by system and component downtimes, technology acceptance by face-to-face interviews. The overall system downtime was 6%, effected by two single events, but not by software failures. Technology acceptance was rated very high by all participants at the end of the monitoring periods, and no interference with their social lives was reported. Home-monitoring technologies were well-accepted by our participants. The information content of the data still needs to be evaluated with regard to clinical outcome parameters as well as the effect on the quality of life before recommending large-scale implementations.

Feasibility and Acceptability of Internet-delivered Cognitive Behavioral Therapy for Chronic Pain in Adolescents With Sickle Cell Disease and Their Parents.

PubMed

Palermo, Tonya M; Dudeney, Joanne; Santanelli, James P; Carletti, Alexie; Zempsky, William T

2018-03-01

Pain is a clinical hallmark of sickle cell disease (SCD), and is rarely optimally managed. Cognitive-behavioral therapy (CBT) for pain has been effectively delivered through the Internet in other pediatric populations. We tested feasibility and acceptability of an Internet-delivered CBT intervention in 25 adolescents with SCD (64% female, mean age=14.8 y) and their parents randomized to Internet CBT (n=15) or Internet Pain Education (n=10). Participants completed pretreatment/posttreatment measures. Eight dyads completed semistructured interviews to evaluate treatment acceptability. Feasibility indicators included recruitment and participation rates, engagement and adherence to intervention, and completion of outcome measures. In total, 87 referrals were received from 9 study sites; our recruitment rate was 60% from those families approached for screening. Among participants, high levels of initial intervention engagement (>90%), and adherence (>70%) were demonstrated. Most participants completed posttreatment outcome and diary measures (>75%). Retention at posttreatment was 80%. High treatment acceptability was reported in interviews. Our findings suggest that Internet-delivered CBT for SCD pain is feasible and acceptable to adolescents with SCD and their parents. Engagement and adherence were good. Next steps are to modify recruitment plans to enhance enrollment and determine efficacy of Internet CBT for SCD pain in a large multisite randomized controlled trial.

Achieving online consent to participation in large-scale gene-environment studies: a tangible destination.

PubMed

Wood, Fiona; Kowalczuk, Jenny; Elwyn, Glyn; Mitchell, Clive; Gallacher, John

2011-08-01

Population based genetics studies are dependent on large numbers of individuals in the pursuit of small effect sizes. Recruiting and consenting a large number of participants is both costly and time consuming. We explored whether an online consent process for large-scale genetics studies is acceptable for prospective participants using an example online genetics study. We conducted semi-structured interviews with 42 members of the public stratified by age group, gender and newspaper readership (a measure of social status). Respondents were asked to use a website designed to recruit for a large-scale genetic study. After using the website a semi-structured interview was conducted to explore opinions and any issues they would have. Responses were analysed using thematic content analysis. The majority of respondents said they would take part in the research (32/42). Those who said they would decline to participate saw fewer benefits from the research, wanted more information and expressed a greater number of concerns about the study. Younger respondents had concerns over time commitment. Middle aged respondents were concerned about privacy and security. Older respondents were more altruistic in their motivation to participate. Common themes included trust in the authenticity of the website, security of personal data, curiosity about their own genetic profile, operational concerns and a desire for more information about the research. Online consent to large-scale genetic studies is likely to be acceptable to the public. The online consent process must establish trust quickly and effectively by asserting authenticity and credentials, and provide access to a range of information to suit different information preferences.

Present status of the low energy linac-based slow positron beam and positronium spectrometer in Saclay

NASA Astrophysics Data System (ADS)

Liszkay, L.; Comini, P.; Corbel, C.; Debu, P.; Grandemange, P.; Pérez, P.; Rey, J.-M.; Reymond, J.-M.; Ruiz, N.; Sacquin, Y.; Vallage, B.

2014-04-01

A new slow positron beamline featuring a large acceptance positronium lifetime spectrometer has been constructed and tested at the linac-based slow positron source at IRFU CEA Saclay, France. The new instrument will be used in the development of a dense positronium target cloud for the GBAR experiment. The GBAR project aims at precise measurement of the gravitational acceleration of antihydrogen in the gravitational field of the Earth. Beyond application in fundamental science, the positron spectrometer will be used in materials research, for testing thin porous films and layers by means of positronium annihilation. The slow positron beamline is being used as a test bench to develop further instrumentation for positron annihilation spectroscopy (Ps time-of-flight, pulsed positron beam). The positron source is built on a low energy linear electron accelerator (linac). The 4.3 MeV electron energy used is well below the photoneutron threshold, making the source a genuine on-off device, without remaining radioactivity. The spectrometer features large BGO (Bismuth Germanate) scintillator detectors, with sufficiently large acceptance to detect all ortho-positronium annihilation lifetime components (annihilation in vacuum and in nanopores).

Many Scientists Welcome the Reluctance of Congress to Back Large Increases for "Star Wars" Research.

ERIC Educational Resources Information Center

Cordes, Colleen

1987-01-01

Ronald Reagan's Strategic Defense Initiative (SDI) program has inspired heated debate on campuses, and many scientists have pledged not to accept federal money for SDI research, for a variety of political, economic, and scientific reasons. (MSE)

College men's intimate partner violence attitudes: contributions of adult attachment and gender role stress.

PubMed

McDermott, Ryon C; Lopez, Frederick G

2013-01-01

Primary prevention of men's intimate partner violence (IPV) toward women in dating relationships is an important area of psychological inquiry and a significant concern for counselors working with college student populations. Previous research has identified that certain beliefs condoning or accepting physical, sexual, and psychological violence in relationships are key risk factors for IPV perpetration; however, comparatively few studies have examined the social and relational variables related to IPV acceptance attitudes. In the present study, we proposed and tested a structural model examining the combined contributions of adult attachment dimensions (i.e., attachment anxiety and attachment avoidance) and masculine gender role stress in the prediction of IPV acceptance attitudes in a large sample of college men (N = 419). We hypothesized that the relationship between attachment insecurity and IPV acceptance attitudes would be partially mediated by men's gender role stress. A partially mediated model produced the best indices of model fit, accounting for 31% of the variance in an IPV acceptance attitudes latent variable. A bootstrapping procedure confirmed the significance of mediation effects. These results suggest that aspects of adult attachment insecurity are associated with tendencies to experience stress from violations of rigidly internalized traditional male role norms, which, in turn, are associated with acceptance of IPV. Findings are further discussed in relation to adult attachment theory (Mikulincer & Shaver, 2007), gender role strain theory (Pleck, 1995), and their implications for IPV prevention in college student populations. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Barriers to physicians' adoption of healthcare information technology: an empirical study on multiple hospitals.

PubMed

Lin, Chihung; Lin, I-Chun; Roan, Jinsheng

2012-06-01

Prior research on technology usage had largely overlooked the issue of user resistance or barriers to technology acceptance. Prior research on the Electronic Medical Records had largely focused on technical issues but rarely on managerial issues. Such oversight prevented a better understanding of users' resistance to new technologies and the antecedents of technology rejection. Incorporating the enablers and the inhibitors of technology usage intention, this study explores physicians' reactions towards the electronic medical record. The main focus is on the barriers, perceived threat and perceived inequity. 115 physicians from 6 hospitals participated in the questionnaire survey. Structural Equation Modeling was employed to verify the measurement scale and research hypotheses. According to the results, perceived threat shows a direct and negative effect on perceived usefulness and behavioral intentions, as well as an indirect effect on behavioral intentions via perceived usefulness. Perceived inequity reveals a direct and positive effect on perceived threat, and it also shows a direct and negative effect on perceived usefulness. Besides, perceived inequity reveals an indirect effect on behavioral intentions via perceived usefulness with perceived threat as the inhibitor. The research finding presents a better insight into physicians' rejection and the antecedents of such outcome. For the healthcare industry understanding the factors contributing to physicians' technology acceptance is important as to ensure a smooth implementation of any new technology. The results of this study can also provide change managers reference to a smooth IT introduction into an organization. In addition, our proposed measurement scale can be applied as a diagnostic tool for them to better understand the status quo within their organizations and users' reactions to technology acceptance. By doing so, barriers to physicians' acceptance can be identified earlier and more effectively before leading to technology rejection.

Utilization of physicochemical variables developed from changes in sensory attributes and consumer acceptability to predict the shelf life of fresh-cut mango fruit.

PubMed

Salinas-Hernández, Rosa María; González-Aguilar, Gustavo A; Tiznado-Hernández, Martín Ernesto

2015-01-01

Sensory evaluation is the ideal tool for shelf-life determination. With the objective to develop an easy shelf-life indicator, color (L*, a*, b*, chroma and hue angle), total soluble solids (TSS), firmness (F), pH, acidity, and the sensory attributes of appearance, brightness, browning, odor, flavor, texture, color, acidity and sweetness were evaluated in fresh cut mangoes (FCM) stored at 5, 10, 15 and 20 °C. Overall acceptability was evaluated by consumers. Correlation analysis between sensory attributes and physicochemical variables was carried out. Physicochemical cut-off points based on sensory attributes and consumer acceptability was obtained by regression analysis and utilized to estimate FCM shelf-life by kinetic models fitted to each variable. The validation of the model was done by comparing the shelf life estimated by kinetic models and consumers. It was recorded large correlations between appearance, brightness, and color with L*; appearance and color with chroma and hue angle; sweetness and flavor with TSS, and between F and texture. The shelf life estimated based on consumer using a 9 point hedonic scale was in the range of 10-12, 2.3-2.6, 1.3-1.5 and 1.0-1.1 days for 5, 10, 15 and 20 °C. It was recorded large correlation coefficients between the shelf life estimated by consumer acceptability scores and physicochemical variables. Kinetic models based on physicochemical variables showed a tendency to overestimate the shelf life as compared with the models bases on the sensory attributes. It was concluded that physicochemical variables can be used as a tool to estimate the FCM shelf life.

High acceptability for cell phone text messages to improve communication of laboratory results with HIV-infected patients in rural Uganda: a cross-sectional survey study

PubMed Central

2012-01-01

Background Patient-provider communication is a major challenge in resource-limited settings with large catchment areas. Though mobile phone usership increased 20-fold in Africa over the past decade, little is known about acceptability of, perceptions about disclosure and confidentiality, and preferences for cell phone communication of health information in the region. Methods We performed structured interviews of fifty patients at the Immune Suppression Syndrome clinic in Mbarara, Uganda to assess four domains of health-related communication: a) cell phone use practices and literacy, b) preferences for laboratory results communication, c) privacy and confidentiality, and d) acceptability of and preferences for text messaging to notify patients of abnormal test results. Results Participants had a median of 38 years, were 56% female, and were residents of a large catchment area throughout southwestern Uganda. All participants expressed interest in a service to receive information about laboratory results by cell phone text message, stating benefits of increased awareness of their health and decreased transportation costs. Ninety percent reported that they would not be concerned for unintended disclosure. A minority additionally expressed concerns about difficulty interpreting messages, discouragement upon learning bad news, and technical issues. Though all respondents expressed interest in password protection of messages, there was also a strong desire for direct messages to limit misinterpretation of information. Conclusions Cell phone text messaging for communication of abnormal laboratory results is highly acceptable in this cohort of HIV-infected patients in rural Uganda. The feasibility of text messaging, including an optimal balance between privacy and comprehension, should be further studied. PMID:22720901

Quarter of a century of female sterilization in Jos, Central Nigeria.

PubMed

Mutihir, Josiah T; Nyango, D D

2011-03-01

The study was to assess the types and trend of female sterilization between January 1985 and December 2009 (25 years) in Jos, Central Nigeria. There were 25,313 new acceptors of modern contraceptive methods out of which 4,951 (19.6%) were female sterilizations. Minilaparotomy was the commonest method of female sterilization. Local anaesthesia was the commonest anaesthetic utilized. The women were mostly women of relatively older age, grandmultiparous and with large family size. The women were of mean of 38.4 years, and 60% had more than 5 children at the time of sterilization. Interval sterilization constituted 78.5% of the female sterilizations. The acceptance of female sterilization, however, has declined over the years, as acceptance of the long acting contraceptive implants increases. Female sterilization by minilaparotomy under local anaesthesia was found to be feasible, cost effective and acceptable by majority of clients, and recommended for integration into minor gynaecological procedures in our institutions.

Living with hypertrophic cardiomyopathy and an implantable defibrillator.

PubMed

Magnusson, Peter; Jonsson, Jessica; Mörner, Stellan; Fredriksson, Lennart

2017-05-10

ICDs efficiently terminate life-threatening arrhythmias, but complications occur during long-term follow-up. Patients' own perspective is largely unknown. The aim of the study was to describe experiences of hypertrophic cardiomyopathy (HCM) patients with implantable defibrillators (ICDs). We analyzed 26 Swedish patient interviews using hermeneutics and latent content analysis. Patients (aged 27-76 years) were limited by HCM especially if it deteriorates into heart failure. The ICD implies safety, gratitude, and is accepted as a part of the body even when inappropriate ICD shocks are encountered. Nobody regretted the implant. Both the disease and the ICD affected professional life and leisure time activities, especially at younger ages. Family support was usually strong, but sometimes resulted in overprotection, whereas health care focused on medical issues. Despite limitations, patients adapted, accepted, and managed challenges. HCM patients with ICDs reported good spirit and hope even though they had to adapt and accept limitations over time.

Performance of the improved larger acceptance spectrometer: VAMOS++

NASA Astrophysics Data System (ADS)

Rejmund, M.; Lecornu, B.; Navin, A.; Schmitt, C.; Damoy, S.; Delaune, O.; Enguerrand, J. M.; Fremont, G.; Gangnant, P.; Gaudefroy, L.; Jacquot, B.; Pancin, J.; Pullanhiotan, S.; Spitaels, C.

2011-08-01

Measurements and ion optic calculations showed that the large momentum acceptance of the VAMOS spectrometer at GANIL could be further increased from ˜11% to ˜30% by suitably enlarging the dimensions of the detectors used at the focal plane. Such a new detection system built for the focal plane of VAMOS is described. It consists of larger area detectors (1000 mm×150 mm) namely, a Multi-Wire Parallel Plate Avalanche Counter (MWPPAC), two drift chambers, a segmented ionization chamber and an array of Si detectors. Compared to the earlier existing system (VAMOS), we show that the new system (VAMOS++) has a dispersion-independent momentum acceptance. Additionally, a start detector (MWPPAC) has been introduced near the target to further improve the mass resolution to ˜1/220. The performance of the VAMOS++ spectrometer is demonstrated using measurements of residues formed in the collisions of 129Xe at 967 MeV on 197Au.

Electron-ion collider: The next QCD frontier: Understanding the glue that binds us all

DOE Office of Scientific and Technical Information (OSTI.GOV)

Accardi, A.; Albacete, J. L.; Anselmino, M.

This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decadesmore » and, in particular, the focused ten-week program on “Gluons and quark sea at high energies” at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them. It has been benefited profoundly from inputs by the users’ communities of BNL and JLab. Furthermore, this White Paper offers the promise to propel the QCD science program in the US, established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.« less

NEW EPICS/RTEMS IOC BASED ON ALTERA SOC AT JEFFERSON LAB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Jianxun; Seaton, Chad; Allison, Trent L.

A new EPICS/RTEMS IOC based on the Altera System-on-Chip (SoC) FPGA is being designed at Jefferson Lab. The Altera SoC FPGA integrates a dual ARM Cortex-A9 Hard Processor System (HPS) consisting of processor, peripherals and memory interfaces tied seamlessly with the FPGA fabric using a high-bandwidth interconnect backbone. The embedded Altera SoC IOC has features of remote network boot via U-Boot from SD card or QSPI Flash, 1Gig Ethernet, 1GB DDR3 SDRAM on HPS, UART serial ports, and ISA bus interface. RTEMS for the ARM processor BSP were built with CEXP shell, which will dynamically load the EPICS applications atmore » runtime. U-Boot is the primary bootloader to remotely load the kernel image into local memory from a DHCP/TFTP server over Ethernet, and automatically run RTEMS and EPICS. The first design of the SoC IOC will be compatible with Jefferson Lab’s current PC104 IOCs, which have been running in CEBAF 10 years. The next design would be mounting in a chassis and connected to a daughter card via standard HSMC connectors. This standard SoC IOC will become the next generation of low-level IOC for the accelerator controls at Jefferson Lab.« less

Deeply Virtual Compton Scattering (DVCS) Run (E12-06-114) in Hall A of Thomas Jefferson National Accelerator Facility (TJNAF)

NASA Astrophysics Data System (ADS)

Karki, Bishnu; DVCS Hall A of JLab Collaboration; JLab Hall A Collaboration

2017-01-01

Generalized Parton Distributions (GPDs) provide a information about transverse position and longitudinal momentum distribution of partons in the nucleon along with the correlation between transverse position and longitudinal momentum of partons. GPDs also provide access to the contribution of orbital momentum of partons to nucleon total spin. The DVCS is one of the favorite reaction to measure the GPDs because it is simplest process that can be described in terms of GPDs. DVCS refers to scattering of virtual photon off the nucleon (γ* N -> γN). The DVCS experiment (E12-06-114) in Hall A will be running again in Fall 2016, to complete proposed DVCS kinematics. We use the polarized electron beam from CEBAF with energy ranging from 8 GeV to 11 GeV and measure high statistics polarized and unpolarized cross section of H(e,e' γ)p and map it to extract GPDs of proton. The wide range of Q2 scan (2.7 <=Q2 >= 9 GeV2) for xB ranging from 0.3 to 0.6 are performed. The Q2 dependence of the cross section allows one to quantify the contribution of higher twist terms. In this talk the status of experiment will be presented.

Electron-ion collider: The next QCD frontier: Understanding the glue that binds us all

DOE PAGES

Accardi, A.; Albacete, J. L.; Anselmino, M.; ...

2016-09-08

This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decadesmore » and, in particular, the focused ten-week program on “Gluons and quark sea at high energies” at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them. It has been benefited profoundly from inputs by the users’ communities of BNL and JLab. Furthermore, this White Paper offers the promise to propel the QCD science program in the US, established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.« less

Multipass Steering: A Reference Implementation

NASA Astrophysics Data System (ADS)

Hennessey, Michael; Tiefenback, Michael

2015-10-01

We introduce a reference implementation of a protocol to compute corrections that bring all beams in one of the CEBAF linear accelerators (linac) to axis, including, with a larger tolerance, the lowest energy pass using measured beam trajectory data. This method relies on linear optics as representation of the system; we treat beamline perturbations as magnetic field errors localized to regions between cryomodules, providing the same transverse momentum kick to each beam. We produce a vector of measured beam position data with which we left-multiply the pseudo-inverse of a coefficient array, A, that describes the transport of the beam through the linac using parameters that include the magnetic offsets of the quadrupole magnets, the instrumental offsets of the BPMs, and the beam initial conditions. This process is repeated using a reduced array to produce values that can be applied to the available correcting magnets and beam initial conditions. We show that this method is effective in steering the beam to a straight axis along the linac by using our values in elegant, the accelerator simulation program, on a model of the linac in question. The algorithms in this reference implementation provide a tool for systematic diagnosis and cataloging of perturbations in the beam line. Supported by Jefferson Lab, Old Dominion University, NSF, DOE.

SU-F-T-538: CyberKnife with MLC for Treatment of Large Volume Tumors: A Feasibility Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bichay, T; Mayville, A

2016-06-15

Purpose: CyberKnife is a well-documented modality for SRS and SBRT treatments. Typical tumors are small and 1–5 fractions are usually used. We determined the feasibility of using CyberKnife, with an InCise multileaf collimator option, for larger tumors undergoing standard dose and fractionation. The intent was to understand the limitation of using this modality for other external beam radiation treatments. Methods: Five tumors from different anatomical sites with volumes from 127.8 cc to 1,320.5 cc were contoured and planned on a Multiplan V5.1 workstation. The target average diameter ranged from 7 cm to 13 cm. The dose fractionation was 1.8–2.0 Gy/fractionmore » and 25–45 fractions for total doses of 45–81 Gy. The sites planned were: pancreas, head and neck, prostate, anal, and esophagus. The plans were optimized to meet conventional dose constraints based on various RTOG protocols for conventional fractionation. Results: The Multiplan treatment planning system successfully generated clinically acceptable plans for all sites studied. The resulting dose distributions achieved reasonable target coverage, all greater than 95%, and satisfactory normal tissue sparing. Treatment times ranged from 9 minutes to 38 minutes, the longest being a head and neck plan with dual targets receiving different doses and with multiple adjacent critical structures. Conclusion: CyberKnife, with the InCise multileaf collimation option, can achieve acceptable dose distributions in large volume tumors treated with conventional dose and fractionation. Although treatment times are greater than conventional accelerator time; target coverage and dose to critical structures can be kept within a clinically acceptable range. While time limitations exist, when necessary CyberKnife can provide an alternative to traditional treatment modalities for large volume tumors.« less

Large-Scale Structure and Hyperuniformity of Amorphous Ices

NASA Astrophysics Data System (ADS)

Martelli, Fausto; Torquato, Salvatore; Giovambattista, Nicolas; Car, Roberto

2017-09-01

We investigate the large-scale structure of amorphous ices and transitions between their different forms by quantifying their large-scale density fluctuations. Specifically, we simulate the isothermal compression of low-density amorphous ice (LDA) and hexagonal ice to produce high-density amorphous ice (HDA). Both HDA and LDA are nearly hyperuniform; i.e., they are characterized by an anomalous suppression of large-scale density fluctuations. By contrast, in correspondence with the nonequilibrium phase transitions to HDA, the presence of structural heterogeneities strongly suppresses the hyperuniformity and the system becomes hyposurficial (devoid of "surface-area fluctuations"). Our investigation challenges the largely accepted "frozen-liquid" picture, which views glasses as structurally arrested liquids. Beyond implications for water, our findings enrich our understanding of pressure-induced structural transformations in glasses.

Anisogamy in the dinoflagellate Noctiluca?

NASA Astrophysics Data System (ADS)

Schnepf, E.; Drebes, G.

1993-10-01

We disagree on the generally accepted elements of the description of the sexual life cycle of Noctiluca as presented by Zingmark (1970a), namely that (1) the swarmers of Noctiluca are isogametes, that (2) the zygote develops directly into a large trophont, and we question that (3) Noctiluca is a diplont with meiosis occurring during the formation of the swarmers. We observed a highly distinct attraction between swarmers (microgametes?) and certain large cells (macrogametes?) which resemble adult trophonts in shape and size. Noctiluca thus appears to be anisogamous, and the zygote does not need to grow to become a large trophont.

Innovative approaches for understanding seasonal influenza vaccine declination in healthcare personnel support development of new campaign strategies.

PubMed

Schult, Tamara M; Awosika, Ebi R; Hodgson, Michael J; Hirsch, Pamela R; Nichol, Kristin L; Dyrenforth, Sue R; Moore, Scott C

2012-09-01

The main objectives of our study were to explore reasons for seasonal influenza vaccine acceptance and declination in employees of a large integrated healthcare system and to identify underlying constructs that influence acceptance versus declination. Secondary objectives were to determine whether vaccine acceptance varied by hospital location and to identify facility-level measures that explained variability. A national health promotion survey of employees was conducted that included items on vaccination in the 2009-2010 influenza season. The survey was administered with two other institutional surveys in a stratified fashion: approximately 40% of participating employees were randomly assigned to complete the health promotion survey. National single-payer healthcare system with 152 hospitals. Employees of the healthcare system in 2010 who responded to the survey. Factor analysis was used to identify underlying constructs that influenced vaccine acceptance versus declination. Mean factor scores were examined in relation to demographic characteristics and occupation. Multilevel logistic regression models were used to determine whether vaccine acceptance varied by location and to identify facility-level measures that explained variability. Four factors were identified related to vaccine declination and were labeled as (1) "don't care," (2) "don't want," (3) "don't believe," and (4) "don't know." Significant differences in mean factor scores existed by demographic characteristics and occupation. Vaccine acceptance varied by location, and vaccination rates in the previous year were an important facility-level predictor. Results should guide interventions that tailor messages on the basis of particular reasons for declination. Occupation-specific and culturally appropriate messaging should be considered. Continued efforts will be taken to better understand how workplace context influences vaccine acceptance.

Cystic fibrosis heterozygote screening in 5,161 pregnant women

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witt, D.R.; Hallam, P.; Blumberg, B.

A screening program for cystic fibrosis (CF) heterozygotes was conducted in a large HMO prenatal population, to evaluate the level of interest among eligible patients, the effectiveness of prescreening education, attitudes toward the screening process, psychological effects, and utilization of prenatal diagnosis and its outcomes. The heterozygote identification rate and frequency of specific CFTR mutations were also assessed. Identified carriers were offered genetic counseling and testing of male partners. Prenatal diagnosis was offered if both partners were identified as carriers. A total of 5,161 women underwent carrier testing; 947 others completed survey instruments only. The acceptance rate of screening wasmore » high (78%), and pretest education by videotape was generally effective. Adverse psychological effects were not reported. Participants generally found screening to be desirable and useful. Screening identified 142 female heterozygotes, 109 couples in which the male partner was not a carrier, and 7 high-risk couples. The incidence of R117H mutations was much higher than expected. The number of identified carriers was much lower in Hispanics than in Caucasians. We conclude that large-scale prenatal screening for CF heterozygotes in the absence of a family history of CF is an acceptable method for identifying couples at risk for affected fetuses. Sufficient pretest education can be accomplished efficiently, test insensitivity is well accepted, adverse psychological events are not observed, and general patient satisfaction is high. 66 refs., 1 fig., 8 tabs.« less

A large-scale peer teaching programme - acceptance and benefit.

PubMed

Schuetz, Elisabeth; Obirei, Barbara; Salat, Daniela; Scholz, Julia; Hann, Dagmar; Dethleffsen, Kathrin

2017-08-01

The involvement of students in the embodiment of university teaching through peer-assisted learning formats is commonly applied. Publications on this topic exclusively focus on strictly defined situations within the curriculum and selected target groups. This study, in contrast, presents and evaluates a large-scale structured and quality-assured peer teaching programme, which offers diverse and targeted courses throughout the preclinical part of the medical curriculum. The large-scale peer teaching programme consists of subject specific and interdisciplinary tutorials that address all scientific, physiological and anatomic subjects of the preclinical curriculum as well as tutorials with contents exceeding the formal curriculum. In the study year 2013/14 a total of 1,420 lessons were offered as part of the programme. Paper-based evaluations were conducted over the full range of courses. Acceptance and benefit of this peer teaching programme were evaluated in a retrospective study covering the period 2012 to 2014. Usage of tutorials by students who commenced their studies in 2012/13 (n=959) was analysed from 2012 till 2014. Based on the results of 13 first assessments in the preclinical subjects anatomy, biochemistry and physiology, the students were assigned to one of five groups. These groups were compared according to participation in the tutorials. To investigate the benefit of tutorials of the peer teaching programme, the results of biochemistry re-assessments of participants and non-participants of tutorials in the years 2012 till 2014 (n=188, 172 and 204, respectively) were compared using Kolmogorov-Smirnov- and Chi-square tests as well as the effect size Cohen's d. Almost 70 % of the students attended the voluntary additional programme during their preclinical studies. The students participating in the tutorials had achieved different levels of proficiency in first assessments. The acceptance of different kinds of tutorials appears to correlate with their performance in first assessments. 94% of the students participating in tutorials offered in the study year 2013/14 rated the tutorials as "excellent" or "good". An objective benefit has been shown by a significant increase in re-assessment scores with an effect size between the medium and large magnitudes for participants of tutorials compared to non-participants in the years 2012, 2013 and 2014. In addition, significantly higher pass rates of re-assessments could be observed. Acceptance, utilisation and benefit of the assessed peer teaching programme are high. Beyond the support of students, a contribution to the individualisation of studies and teaching is made. Further studies are necessary to investigate possible influences of large-scale peer teaching programmes, for example on the reduction of study length and drop-off rates, as well as additional effects on academic achievements. Copyright © 2017. Published by Elsevier GmbH.

Effective Therapy for College Students. Alternatives to Traditional Counseling.

ERIC Educational Resources Information Center

Hanfmann, Eugenia

Clinical professionals are offered practical guidelines for organizing psychological counseling services that will be acceptable and available to large numbers of students without being exorbitantly expensive. Detailed accounts are given on therapeutic and administrative procedures that have proven highly effective at Brandeis University's…

75 FR 75897 - Electronic Funds Transfer of Depository Taxes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-07

... the Financial Management Service to discontinue the system that processes FTD coupons, the temporary... Financial Management Service (FMS) considered current market conditions. In the last 18 months, more than 100 financial institutions, large and small, have stopped accepting FTD coupons. In many states, few...

High Transverse Momentum Triggered Correlations over a Large Pseudorapidity Acceptance in Au+Au Collisions at sNN=200GeV

NASA Astrophysics Data System (ADS)

Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

2010-02-01

A measurement of two-particle correlations with a high transverse momentum trigger particle (pTtrig>2.5GeV/c) is presented for Au+Au collisions at sNN=200GeV over the uniquely broad longitudinal acceptance of the PHOBOS detector (-4<Δη<2). A broadening of the away-side azimuthal correlation compared to elementary collisions is observed at all Δη. As in p+p collisions, the near side is characterized by a peak of correlated partners at small angle relative to the trigger particle. However, in central Au+Au collisions an additional correlation extended in Δη and known as the “ridge” is found to reach at least |Δη|≈4. The ridge yield is largely independent of Δη over the measured range, and it decreases towards more peripheral collisions. For the chosen pTtrig cut, the ridge yield is consistent with zero for events with less than roughly 100 participating nucleons.

High energy density aluminum-oxygen cell

NASA Technical Reports Server (NTRS)

Rudd, E. J.; Gibbons, D. W.

1993-01-01

An alternative to a secondary battery as the power source for vehicle propulsion is a fuel cell. An example of this is the metal-air fuel cell using metals such as aluminum, zinc, or iron. Aluminum is a particularly attractive candidate, having high energy and power densities, being environmentally acceptable, and having a large, established industrial base for production and distribution. An aluminum-oxygen system is currently under development for a UUV test vehicle, and recent work has focussed upon low corrosion aluminum alloys and an electrolyte management system for processing the by-products of the energy-producing reactions. This paper summarizes the progress made in both areas. Anode materials capable of providing high utilization factors over current densities ranging from S to 150 mA/sq cm have been identified. These materials are essential to realizing an acceptable mission life for the UUV. With respect to the electrolyte management system, a filter/precipitator unit has been successfully operated for over 250 hours in a large scale, half-cell system.

Analyzing the test process using structural coverage

NASA Technical Reports Server (NTRS)

Ramsey, James; Basili, Victor R.

1985-01-01

A large, commercially developed FORTRAN program was modified to produce structural coverage metrics. The modified program was executed on a set of functionally generated acceptance tests and a large sample of operational usage cases. The resulting structural coverage metrics are combined with fault and error data to evaluate structural coverage. It was shown that in the software environment the functionally generated tests seem to be a good approximation of operational use. The relative proportions of the exercised statement subclasses change as the structural coverage of the program increases. A method was also proposed for evaluating if two sets of input data exercise a program in a similar manner. Evidence was provided that implies that in this environment, faults revealed in a procedure are independent of the number of times the procedure is executed and that it may be reasonable to use procedure coverage in software models that use statement coverage. Finally, the evidence suggests that it may be possible to use structural coverage to aid in the management of the acceptance test processed.

Nonportable computed radiography of the chest--radiologists' acceptance

NASA Astrophysics Data System (ADS)

Gennari, Rose C.; Gur, David; Miketic, Linda M.; Campbell, William L.; Oliver, James H., III; Plunkett, Michael B.

1994-04-01

Following a large ROC study to assess diagnostic accuracy of PA chest computed radiography (CR) images displayed in a variety of formats, we asked nine experienced radiologists to subjectively assess their acceptance of and preferences for display modes in primary diagnosis of erect PA chest images. Our results indicate that radiologists felt somewhat less comfortable interpreting CR images displayed on either laser-printed films or workstations as compared to conventional films. The use of four minified images were thought to somewhat decrease diagnostic confidence, as well as to increase the time of interpretation. The reverse mode (black bone) images increased radiologists' confidence level in the detection of soft tissue abnormalities.

The new Heavy-ion MCP-based Ancillary Detector DANTE for the CLARA-PRISMA Setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valiente-Dobon, J. J.; Gadea, A.; Corradi, L.

2006-08-14

The CLARA-PRISMA setup is a powerful tool for spectroscopic studies of neutron-rich nuclei produced in multi-nucleon transfer and deep-inelastic reactions. It combines the large acceptance spectrometer PRISMA with the {gamma}-ray array CLARA. At present, the ancillary heavy-ion detector DANTE, based on Micro-Channel Plates to be installed at the CLARA-PRISMA setup, is being constructed at LNL. DANTE will open the possibility of measuring {gamma}-{gamma} Doppler-corrected coincidences for the events outside the acceptance of PRISMA. In this presentation, it is described the heavy-ion detector DANTE, as well as the performances of the first prototype.

Optimal temperature ladders in replica exchange simulations

NASA Astrophysics Data System (ADS)

Denschlag, Robert; Lingenheil, Martin; Tavan, Paul

2009-04-01

In replica exchange simulations, a temperature ladder with N rungs spans a given temperature interval. Considering systems with heat capacities independent of the temperature, here we address the question of how large N should be chosen for an optimally fast diffusion of the replicas through the temperature space. Using a simple example we show that choosing average acceptance probabilities of about 45% and computing N accordingly maximizes the round trip rates r across the given temperature range. This result differs from previous analyses which suggested smaller average acceptance probabilities of about 23%. We show that the latter choice maximizes the ratio r/N instead of r.

Percutaneous Radiofrequency Ablation of a Small Renal Mass Complicated by Appendiceal Perforation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boone, Judith, E-mail: j.boone@amc.uva.nl; Bex, Axel, E-mail: a.bex@nki.nl; Prevoo, Warner, E-mail: w.prevoo@nki.nl

2012-06-15

Percutaneous radiofrequency ablation (RFA) has gained wide acceptance as nephron-sparing therapy for small renal masses in select patients. Generally, it is a safe procedure with minor morbidity and acceptable short-term oncologic outcome. However, as a result of the close proximity of vital structures, such as the bowel, ureter, and large vessels, to the ablative field, complications regarding these structures may occur. This is the first article describing appendiceal perforation as a complication of computed tomography-guided RFA despite hydrodissection. When performing this innovative and promising procedure one should be aware of the possibility of particular minor and even major complications.

Low-lift-to-drag-ratio approach and landing studies using a CV-990 airplane

NASA Technical Reports Server (NTRS)

Kock, B. M.; Fulton, F. L.; Drinkwater, F. J., III

1972-01-01

The results are presented of a flight-test program utilizing a CV-990 airplane, flow in low-lift-to-drag-ratio (L/D) configurations, to simulate terminal area operation, approach, and landing of large unpowered vehicles. The results indicate that unpowered approaches and landings are practical with vehicles of the size and performance characteristics of the proposed shuttle vehicle. Low L/D landings provided touchdown dispersion patterns acceptable for operation on runways of reasonable length. The dispersion pattern was reduced when guidance was used during the final approach. High levels of pilot proficiency were not required for acceptable performance.

What's a Guy To Do?: Contraceptive Responsibility, Confronting Masculinity, and the History of Vasectomy in Canada.

PubMed

Shropshire, Sarah

2014-01-01

Despite the growing popularity of vasectomy in recent years, historians have largely ignored the history of the procedure. The current article provides a preliminary examination of voluntary male sterilization in Canada and, in so doing, challenges the gendered paradigm scholars have often applied to the history of contraception. State-sponsored Medicare and late decriminalization of contraception are discussed as factors that slowed widespread adoption of vasectomy in Canada while evolving surgical techniques are highlighted for their role in increasing acceptability of the procedure. The article explores how evolving definitions of hegemonic masculinity have both hindered and encouraged acceptance of vasectomy over time.

Individual differences in loss aversion and preferences for skewed risks across adulthood.

PubMed

Seaman, Kendra L; Green, Mikella A; Shu, Stephen; Samanez-Larkin, Gregory R

2018-06-01

In a previous study, we found adult age differences in the tendency to accept more positively skewed gambles (with a small chance of a large win) than other equivalent risks, or an age-related positive-skew bias. In the present study, we examined whether loss aversion explained this bias. A total of 508 healthy participants (ages 21-82) completed measures of loss aversion and skew preference. Age was not related to loss aversion. Although loss aversion was a significant predictor of gamble acceptance, it did not influence the age-related positive-skew bias. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

When is it OK to be drunk? Situational and cultural variations in the acceptability of visible intoxication in the UK and Norway.

PubMed

Fjær, Eivind Grip; Pedersen, Willy; von Soest, Tilmann; Gray, Paul

2016-03-01

Research on norms regulating drunken behaviour has tended to focus on differences between different countries and cultures rather than variations within them. Here, we examine whether there are: (i) situation-specific differences in the acceptability of visible intoxication among students in the UK and Norway; (ii) whether there are situation-specific and overall differences in this regard between the two countries; and finally (iii) to what degree possible differences reflect individual characteristics such as use of alcohol, perceived harm of alcohol consumption, and broader value orientation. Students at one British (n=473) and one Norwegian (n=472) university responded to a survey including a battery of questions assessing the acceptability of visible intoxication in different situations, such as with friends, with work colleagues, with family members, and situations where children are present. Data were also collected regarding alcohol consumption, perceived harms of alcohol consumption, and value orientation. Analyses of covariance were performed to assess patterns in the acceptability of visible intoxication across different situations, and the relative contributions of country, alcohol consumption, perceived harm of alcohol consumption and human values. In both countries, visible intoxication was rated as most acceptable in situations involving friends and colleagues. Students from both countries rated visible intoxication least acceptable in situations where children are present. However, both overall, and in situations where children or family members are present, acceptability of visible intoxication scores were higher in the UK than Norway. These differences persisted after control for other variables. The study demonstrates large situational variation in acceptability of drunken behaviour, pointing to a fine-meshed set of norms regulating alcohol use and drunken behaviour within the two cultures, with the UK standing out as a more alcohol-liberal culture than Norway. Such differences underline how norms regulating drunken behaviour are culturally constituted. Copyright © 2015 Elsevier B.V. All rights reserved.

Acceptance sampling for attributes via hypothesis testing and the hypergeometric distribution

NASA Astrophysics Data System (ADS)

Samohyl, Robert Wayne

2017-10-01

This paper questions some aspects of attribute acceptance sampling in light of the original concepts of hypothesis testing from Neyman and Pearson (NP). Attribute acceptance sampling in industry, as developed by Dodge and Romig (DR), generally follows the international standards of ISO 2859, and similarly the Brazilian standards NBR 5425 to NBR 5427 and the United States Standards ANSI/ASQC Z1.4. The paper evaluates and extends the area of acceptance sampling in two directions. First, by suggesting the use of the hypergeometric distribution to calculate the parameters of sampling plans avoiding the unnecessary use of approximations such as the binomial or Poisson distributions. We show that, under usual conditions, discrepancies can be large. The conclusion is that the hypergeometric distribution, ubiquitously available in commonly used software, is more appropriate than other distributions for acceptance sampling. Second, and more importantly, we elaborate the theory of acceptance sampling in terms of hypothesis testing rigorously following the original concepts of NP. By offering a common theoretical structure, hypothesis testing from NP can produce a better understanding of applications even beyond the usual areas of industry and commerce such as public health and political polling. With the new procedures, both sample size and sample error can be reduced. What is unclear in traditional acceptance sampling is the necessity of linking the acceptable quality limit (AQL) exclusively to the producer and the lot quality percent defective (LTPD) exclusively to the consumer. In reality, the consumer should also be preoccupied with a value of AQL, as should the producer with LTPD. Furthermore, we can also question why type I error is always uniquely associated with the producer as producer risk, and likewise, the same question arises with consumer risk which is necessarily associated with type II error. The resolution of these questions is new to the literature. The article presents R code throughout.

HPV vaccine acceptance among African-American mothers and their daughters: an inquiry grounded in culture.

PubMed

Galbraith-Gyan, Kayoll V; Lechuga, Julia; Jenerette, Coretta M; Palmer, Mary H; Moore, Angelo D; Hamilton, Jill B

2017-05-29

Much of the research on African-Americans' HPV vaccine acceptance has largely focused on racial/ethnic differences related to cognitive, socio-economical, and structural factors that contribute to differences in HPV vaccine acceptance and completion. A growing body of literature suggest that cultural factors, such as mistrust of healthcare providers (HCPs) and the healthcare system, religion, and social norms related to appropriate sexual behaviors, also plays a prominent role in their HPV vaccine acceptance. However, these studies were limited in their use of theoretical approaches necessary to conceptualize and operationalize culture. To explore the influence of culture on African-American mothers' and daughters' HPV vaccine acceptance using the PEN-3, a culturally-centered conceptual framework. Grounded theory techniques were used to explore cultural factors that influenced the acceptance of the HPV vaccine among African-American mothers (n = 28) and their daughters (n = 34). Positive attitudes towards vaccination stemmed from beliefs that the HPV vaccine has cancer prevention benefits and that vaccinations in general protected against infectious diseases. Negative attitudes stemmed from beliefs that the HPV vaccine was too new, not effective, daughters were too young, and that vaccines were not a one-size-fits-all intervention. Majority of mothers and daughters indicated that their religious doctrine did not impede their HPV vaccination decisions. For a few mothers, religious beliefs could not be separated from their HPV vaccination decisions and ultimately deterred HPV vaccine acceptance. HCP recommendations were valued however mothers were often dissatisfied with the detail of information communicated. Support networks provided both positive and negative types of social support to mothers and daughters. The media highlighted the cancer prevention benefits of the HPV vaccine and unintentionally communicated negative information of the HPV vaccine, which deterred HPV vaccine acceptance. Study findings can inform the development of culturally appropriate interventions that advances the evidence on cervical cancer prevention.

Digital soil mapping as a tool for quantifying state-and-transition models

USDA-ARS?s Scientific Manuscript database

Ecological sites and associated state-and-transition models (STMs) are rapidly becoming important land management tools in rangeland systems in the US and around the world. Descriptions of states and transitions are largely developed from expert knowledge and generally accepted species and community...

Oak regeneration why big is better

Treesearch

Paul P. Kormanik; Shi-Jean S. Sung; T.L. Kormanik; Stanley J. Zarnoch

1995-01-01

It is generally accepted that large preharvest advanced oak regeneration is required for maintaining a significant oak component in future stands. However, developing advanced oak regeneration on productive sites has been difficult because stand prescriptions encouraging oak regeneration are the same conditions that favor development of potentially faster growing...

Evaluating the Quality of Transfer versus Nontransfer Accounting Principles Grades.

ERIC Educational Resources Information Center

Colley, J. R.; And Others

1996-01-01

Using 1989-92 student records from three colleges accepting large numbers of transfers from junior schools into accounting, regression analyses compared grades of transfer and nontransfer students. Quality of accounting principle grades of transfer students was not equivalent to that of nontransfer students. (SK)

What's the Matter with "Technology-Enhanced Learning"?

ERIC Educational Resources Information Center

Bayne, Sian

2015-01-01

In recent years, "technology-enhanced learning", or "TEL", has become a widely accepted term in the UK and Europe for describing the interface between digital technology and higher education teaching, to a large extent taking the place of other recently popular terminologies such as "e-learning", "learning…

A Five-Phase Model for Clinical-Outcome Research

ERIC Educational Resources Information Center

Robey, Randall R.

2004-01-01

Through a variety of approaches, speech-language pathologists and audiologists have produced strong evidence that treatments are generally potent. However, we have largely ignored the accepted standards for clinical-outcome testing used throughout the broader research community (e.g., by other clinical disciplines, federal regulators, and…

Virtual and Virtuous Realities of Workplace Literacy.

ERIC Educational Resources Information Center

Castleton, Geraldine

Workplace literacy has been a recent addition to the field of literacy education and research, achieving a level of "commonsense" acceptability so that its meaning(s) or constructions have largely gone unchallenged. A study, therefore, explored the concepts of "work,""workers," and "literacy," not so much to…

JPRS Report, Near East and South Asia.

DTIC Science & Technology

1989-07-11

stan for all practical purposes has accepted the Indian hegemony", a fact which is in negation of our existence. Now when Indonesians, Malaysians ...excise revenues. And the rigid censorship, along with high cinema tickets because of heavy taxes, killed the film industry and the large revenues

Designing a two-rank acceptance sampling plan for quality inspection of geospatial data products

NASA Astrophysics Data System (ADS)

Tong, Xiaohua; Wang, Zhenhua; Xie, Huan; Liang, Dan; Jiang, Zuoqin; Li, Jinchao; Li, Jun

2011-10-01

To address the disadvantages of classical sampling plans designed for traditional industrial products, we originally propose a two-rank acceptance sampling plan (TRASP) for the inspection of geospatial data outputs based on the acceptance quality level (AQL). The first rank sampling plan is to inspect the lot consisting of map sheets, and the second is to inspect the lot consisting of features in an individual map sheet. The TRASP design is formulated as an optimization problem with respect to sample size and acceptance number, which covers two lot size cases. The first case is for a small lot size with nonconformities being modeled by a hypergeometric distribution function, and the second is for a larger lot size with nonconformities being modeled by a Poisson distribution function. The proposed TRASP is illustrated through two empirical case studies. Our analysis demonstrates that: (1) the proposed TRASP provides a general approach for quality inspection of geospatial data outputs consisting of non-uniform items and (2) the proposed acceptance sampling plan based on TRASP performs better than other classical sampling plans. It overcomes the drawbacks of percent sampling, i.e., "strictness for large lot size, toleration for small lot size," and those of a national standard used specifically for industrial outputs, i.e., "lots with different sizes corresponding to the same sampling plan."

Social matching of food intake and the need for social acceptance.

PubMed

Robinson, Eric; Tobias, Talia; Shaw, Lucy; Freeman, Elyse; Higgs, Suzanne

2011-06-01

In a social eating context individuals tend to match their food intake to that of eating companions, regardless of whether the other person is eating a large amount. However, relatively little is known about the underlying processes of food intake matching. Findings from behavioural mimicry research suggest that individuals may copy how those around them act in order to facilitate social interactions and ingratiate themselves. The present paper reports two studies which were designed to examine whether ingratiation strategies may in part explain social matching of food intake in young females. In Study 1, female dyads completed a problem solving task together whilst having access to chocolate M&M's. We hypothesised that the extent to which individuals have a need to be socially accepted (trait self esteem) and are competent in social interactions (trait empathy) would predict the degree of matching. In Study 2 we directly manipulated the desire to ingratiate by priming social acceptance in half of participants prior to eating popcorn in the presence of a high eating confederate. In Study 1, both self esteem and empathy were associated with degree of matching within female dyads. In Study 2, priming social acceptance reduced the matching effect in females. These findings suggest that desire for social acceptance may be an underlying cause of social matching of food intake. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mega-geomorphology: Mars vis a vis Earth

NASA Technical Reports Server (NTRS)

Sharp, R. P.

1985-01-01

The areas of chaotic terrain, the giant chasma of the Valles Marineris region, the complex linear and circular depressions of Labyrinthus Noctis on Mars all suggest the possibility of large scale collapse of parts of the martian crust within equatorial and sub equatorial latitudes. It seems generally accepted that the above features are fossil, being perhaps, more than a billion years old. It is possible that parts of Earth's crust experienced similar episodes of large scale collapse sometime early in the evolution of the planet.

Baron Kelvin of Largs: an economical engineer.

PubMed

Fara, Patricia

2007-12-01

William Thomson--honoured as Baron Kelvin of Largs--was Victorian Britain's most famous physicist, especially celebrated for laying the trans-Atlantic telegraph cable. As well as profiting financially from his many engineering projects, Kelvin introduced influential theories about energy and electromagnetism, all strongly coloured by his industrial experiences and the thrifty attitudes of Scottish Christians. Never accepting radioactivity as an additional energy source to the sun, he insisted that the Earth's life span was far too short for evolution to have taken place.

Large project experiences with object-oriented methods and reuse

NASA Technical Reports Server (NTRS)

Wessale, William; Reifer, Donald J.; Weller, David

1992-01-01

The SSVTF (Space Station Verification and Training Facility) project is completing the Preliminary Design Review of a large software development using object-oriented methods and systematic reuse. An incremental developmental lifecycle was tailored to provide early feedback and guidance on methods and products, with repeated attention to reuse. Object oriented methods were formally taught and supported by realistic examples. Reuse was readily accepted and planned by the developers. Schedule and budget issues were handled by agreements and work sharing arranged by the developers.

Religious aspects of assisted reproduction

PubMed Central

Sallam, HN; Sallam, NH

2016-01-01

Abstract Human response to new developments regarding birth, death, marriage and divorce is largely shaped by religious beliefs. When assisted reproduction was introduced into medical practice in the last quarter of the twentieth century, it was fiercely attacked by some religious groups and highly welcomed by others. Today, assisted reproduction is accepted in nearly all its forms by Judaism, Hinduism and Buddhism, although most Orthodox Jews refuse third party involvement. On the contrary assisted reproduction is totally unacceptable to Roman Catholicism, while Protestants, Anglicans, Coptic Christians and Sunni Muslims accept most of its forms, which do not involve gamete or embryo donation. Orthodox Christians are less strict than Catholic Christians but still refuse third party involvement. Interestingly, in contrast to Sunni Islam, Shi’a Islam accepts gamete donation and has made provisions to institutionalize it. Chinese culture is strongly influenced by Confucianism, which accepts all forms of assisted reproduction that do not involve third parties. Other communities follow the law of the land, which is usually dictated by the religious group(s) that make(s) the majority of that specific community. The debate will certainly continue as long as new developments arise in the ever-evolving field of assisted reproduction. PMID:27822349

Aspects and implications of bear reintroduction: Chapter 6

USGS Publications Warehouse

Clark, Joseph D.; Hayward, Matt W.; Somers, Michael J.

2009-01-01

Bear reintroduction has been practiced worldwide with varying degrees of success.  Homing is a significant issue for American black bears, Ursus americanus, and winter-release techniques of females with cubs have been successfully used to improve settling rates and survival. Reintroduction success for all bear species appears to be positively correlated with translocation distance, and success is greater for subadults and females. Animals bred or held in captivity are usually poor candidates for reintroduction, but that may be the only option for some rare species. Habitat analyses are routinely performed, but patch size and configuration may also be important considerations for choosing future reintroduction sites for these wide-ranging species. Biological realities aside, socio-political impediments are more difficult to overcome because of real and perceived threats to human safety and property. Poor public acceptance and understanding were the most important reasons for some bear reintroduction failures, and conservation biologists need to develop methods for identifying areas where co-habitation suitability is high. Citizen-led approaches to develop acceptable restoration strategies may be useful for gaining public acceptance of large-carnivore reintroduction efforts, and public acceptance is where the greatest challenge lies.

The feasibility and acceptability of nurse-led chronic disease management interventions in primary care: An integrative review.

PubMed

Stephen, Catherine; McInnes, Susan; Halcomb, Elizabeth

2018-02-01

To explore the feasibility and acceptability of nurse-led chronic disease management and lifestyle risk factor reduction interventions in primary care (general practice/family practice). Growing international evidence suggests that interventions delivered by primary care nurses can assist in modifying lifestyle risk factors and managing chronic disease. To date, there has been limited exploration of the feasibility and acceptability of such interventions. Integrative review guided by the work of Whittemore and Knafl (). Database search of CINAHL, Medline and Web of Science was conducted to identify relevant literature published between 2000-2015. Papers were assessed for methodological quality and data abstracted before thematic analysis was undertaken. Eleven papers met the inclusion criteria. Analysis uncovered four themes: (1) facilitators of interventions; (2) barriers to interventions; (3) consumer satisfaction; and (4) primary care nurse role. Literature supports the feasibility and acceptability of nurse-led interventions in primary care for lifestyle risk factor modification. The ongoing sustainability of these interventions rests largely on organizational factors such as funding, educational pathways and professional support of the primary care nursing role. Further robust research around primary care nurse interventions is required to strengthen the evidence base. © 2017 John Wiley & Sons Ltd.

Pitfalls and Precautions When Using Predicted Failure Data for Quantitative Analysis of Safety Risk for Human Rated Launch Vehicles

NASA Technical Reports Server (NTRS)

Hatfield, Glen S.; Hark, Frank; Stott, James

2016-01-01

Launch vehicle reliability analysis is largely dependent upon using predicted failure rates from data sources such as MIL-HDBK-217F. Reliability prediction methodologies based on component data do not take into account risks attributable to manufacturing, assembly, and process controls. These sources often dominate component level reliability or risk of failure probability. While consequences of failure is often understood in assessing risk, using predicted values in a risk model to estimate the probability of occurrence will likely underestimate the risk. Managers and decision makers often use the probability of occurrence in determining whether to accept the risk or require a design modification. Due to the absence of system level test and operational data inherent in aerospace applications, the actual risk threshold for acceptance may not be appropriately characterized for decision making purposes. This paper will establish a method and approach to identify the pitfalls and precautions of accepting risk based solely upon predicted failure data. This approach will provide a set of guidelines that may be useful to arrive at a more realistic quantification of risk prior to acceptance by a program.

Expertise in unexpected places: Children's acceptance of information from gender counter-stereotypical experts.

PubMed

Boseovski, Janet J; Hughes, Chelsea; Miller, Stephanie E

2016-01-01

The current study examined children's willingness to accept novel information from expert informants with nontraditional gender role interests. Four- to 8-year-olds heard conflicting information about traditionally feminine or masculine domains from a gender counter-stereotypical expert (e.g., a boy with expertise in ballet) and a layperson of the other gender (e.g., a girl with little knowledge about ballet). Participants were asked which informant was correct, who they would prefer to learn from in the future, and to rate their liking of each informant. Overall, participants selected the gender counter-stereotypical expert as correct. Four- to 5-year-olds reported a preference to learn from same-gender participants in the future irrespective of expertise, whereas 6- to 8-year-olds reported wanting to learn from counter-stereotypical experts. Boys showed relatively greater acceptance of information from a male counter-stereotypical expert than from a female counter-stereotypical expert. Although participants reported greater liking of same-gender informants, liking evaluations were largely positive irrespective of gender norm deviations. Implications for children's acceptance of gender nonconforming activities are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Initial Assessment of the Acceptability of a Push-Pull Aedes aegypti Control Strategy in Iquitos, Peru and Kanchanaburi, Thailand

PubMed Central

Paz-Soldan, Valerie A.; Plasai, Valaikanya; Morrison, Amy C.; Rios-Lopez, Esther J.; Guedez-Gonzales, Shirly; Grieco, John P.; Mundal, Kirk; Chareonviriyaphap, Theeraphap; Achee, Nicole L.

2011-01-01

As part of a larger research program evaluating chemical threshold levels for a Push-Pull intervention to reduce man-vector (Aedes aegypti) contact, this qualitative study explored local perceptions and strategies associated with mosquito control within dengue-endemic communities in Peru and Thailand. Focus groups were used to provide preliminary information that would identify possible public acceptance issues to the Push-Pull strategy in each site. Nine focus group discussions (total of 102 individuals) conducted between September 2008 and March 2009 examined several themes: 1) current mosquito control practices; 2) perceptions of spatial repellency and contact irritancy versus killing mosquitoes; and 3) initial perceptions toward mosquito host-seeking traps. Results indicate participants use household-level strategies for insect control that reveal familiarity with the concept of spatial repellent and contact irritant actions of chemicals and that placing traps in the peridomestic environment to remove repelled mosquitoes was acceptable. Preliminary evidence suggests a Push-Pull strategy should be well accepted in these locations. These results will be beneficial for developing future large scale push-pull interventions and are currently being used to guide insecticide application strategies in (entomological) proof-of-concept studies using experimental huts. PMID:21292886

Equal status in Ultimatum Games promotes rational sharing.

PubMed

Han, Xiao; Cao, Shinan; Bao, Jian-Zhang; Wang, Wen-Xu; Zhang, Boyu; Gao, Zi-You; Sánchez, Angel

2018-01-19

Experiments on the Ultimatum Game (UG) repeatedly show that people's behaviour is far from rational. In UG experiments, a subject proposes how to divide a pot and the other can accept or reject the proposal, in which case both lose everything. While rational people would offer and accept the minimum possible amount, in experiments low offers are often rejected and offers are typically larger than the minimum, and even fair. Several theoretical works have proposed that these results may arise evolutionarily when subjects act in both roles and there is a fixed interaction structure in the population specifying who plays with whom. We report the first experiments on structured UG with subjects playing simultaneously both roles. We observe that acceptance levels of responders approach rationality and proposers accommodate their offers to their environment. More precisely, subjects keep low acceptance levels all the time, but as proposers they follow a best-response-like approach to choose their offers. We thus find that status equality promotes rational sharing while the influence of structure leads to fairer offers compared to well-mixed populations. Our results are far from what is observed in single-role UG experiments and largely different from available predictions based on evolutionary game theory.

Psychometric properties including reliability, validity and responsiveness of the Majeed pelvic score in patients with chronic sacroiliac joint pain.

PubMed

Bajada, Stefan; Mohanty, Khitish

2016-06-01

The Majeed scoring system is a disease-specific outcome measure that was originally designed to assess pelvic injuries. The aim of this study was to determine the psychometric properties of the Majeed scoring system for chronic sacroiliac joint pain. Internal consistency, content validity, criterion validity, construct validity and responsiveness to change was assessed prospectively for the Majeed scoring system in a cohort of 60 patients diagnosed with sacroiliac joint pain. This diagnosis was confirmed with CT-guided sacroiliac joint anaesthetic block. The overall Majeed score showed acceptable internal consistency (Cronbach alpha = 0.63). Similarly, it showed acceptable floor (0 %) and ceiling (0 %) effects. On the other hand, the domains of pain, work, sitting and sexual intercourse had high (>30 %) floor effects. Significant correlation with the physical component of the Short Form-36 (p = 0.005) and Oswestry disability index (p ≤ 0.001) was found indicating acceptable criterion validity. The overall Majeed score showed acceptable construct validity with all five developed hypotheses showing significance (p ≤ 0.05). The overall Majeed score showed acceptable responsiveness to change with a large (≥0.80) effect size and standardized response mean. Overall the Majeed scoring system demonstrated acceptable psychometric properties for outcome assessment in chronic sacroiliac joint pain. Thus, its use in this condition is adequate. However, some domains demonstrated suboptimal performance indicating that improvement might be achieved with the development of an outcome measure specific for sacroiliac joint dysfunction and degeneration.

Acceptability and potential effectiveness of commercial portion control tools amongst people with obesity.

PubMed

Almiron-Roig, Eva; Domínguez, Angélica; Vaughan, David; Solis-Trapala, Ivonne; Jebb, Susan A

2016-12-01

Exposure to large portion sizes is a risk factor for obesity. Specifically designed tableware may modulate how much is eaten and help with portion control. We examined the experience of using a guided crockery set (CS) and a calibrated serving spoon set (SS) by individuals trying to manage their weight. Twenty-nine obese adults who had completed 7-12 weeks of a community weight-loss programme were invited to use both tools for 2 weeks each, in a crossover design, with minimal health professional contact. A paper-based questionnaire was used to collect data on acceptance, perceived changes in portion size, frequency, and type of meal when the tool was used. Scores describing acceptance, ease of use and perceived effectiveness were derived from five-point Likert scales from which binary indicators (high/low) were analysed using logistic regression. Mean acceptance, ease of use and perceived effectiveness were moderate to high (3·7-4·4 points). Tool type did not have an impact on indicators of acceptance, ease of use and perceived effectiveness (P>0·32 for all comparisons); 55 % of participants used the CS on most days v. 21 % for the SS. The CS was used for all meals, whereas the SS was mostly used for evening meals. Self-selected portion sizes increased for vegetables and decreased for chips and potatoes with both tools. Participants rated both tools as equally acceptable, easy to use and with similar perceived effectiveness. Formal trials to evaluate the impact of such tools on weight control are warranted.

Acceptability of unsupervised HPV self-sampling using written instructions.

PubMed

Waller, J; McCaffery, K; Forrest, S; Szarewski, A; Cadman, L; Austin, J; Wardle, J

2006-01-01

The study measured the acceptability of self-sampling for human papillomavirus (HPV) testing in the context of cervical cancer screening. Women carried out self-sampling unsupervised, using a written instruction sheet. Participants were women attending either a family planning clinic or a primary care trust for routine cervical screening. Women (n = 902) carried out self-sampling for HPV testing and then a clinician did a routine cervical smear and HPV test. Immediately after having the two tests, participants completed a measure of acceptability for both tests, and answered questions about ease of using the instruction sheet and willingness to use self-sampling in the future. The majority of women found self-sampling more acceptable than the clinician-administered test, but there was a lack of confidence that the test had been done correctly. Significant demographic differences in attitudes were found, with married women having more favourable attitudes towards self-sampling than single women, and Asian women having more negative attitudes than women in other ethnic groups. Intention to use self-sampling in the future was very high across all demographic groups. Self-sampling for HPV testing was highly acceptable in this large and demographically diverse sample, and women were able to carry out the test alone, using simple written instructions. Consistent with previous studies, women were concerned about doing the test properly and this issue will need to be addressed if self-sampling is introduced. More work is needed to see whether the demographic differences we found are robust and to identify reasons for lower acceptability among single women and those from Asian background.

Acceptance- and mindfulness-based interventions for the treatment of chronic pain: a meta-analytic review.

PubMed

Veehof, M M; Trompetter, H R; Bohlmeijer, E T; Schreurs, K M G

2016-01-01

The number of acceptance- and mindfulness-based interventions for chronic pain, such as acceptance and commitment therapy (ACT), mindfulness-based stress reduction (MBSR), and mindfulness-based cognitive therapy (MBCT), increased in recent years. Therefore an update is warranted of our former systematic review and meta-analysis of studies that reported effects on the mental and physical health of chronic pain patients. Pubmed, EMBASE, PsycInfo and Cochrane were searched for eligible studies. Current meta-analysis only included randomized controlled trials (RCTs). Studies were rated for quality. Mean quality did not improve in recent years. Pooled standardized mean differences using the random-effect model were calculated to represent the average intervention effect and, to perform subgroup analyses. Outcome measures were pain intensity, depression, anxiety, pain interference, disability and quality of life. Included were twenty-five RCTs totaling 1285 patients with chronic pain, in which we compared acceptance- and mindfulness-based interventions to the waitlist, (medical) treatment-as-usual, and education or support control groups. Effect sizes ranged from small (on all outcome measures except anxiety and pain interference) to moderate (on anxiety and pain interference) at post-treatment and from small (on pain intensity and disability) to large (on pain interference) at follow-up. ACT showed significantly higher effects on depression and anxiety than MBSR and MBCT. Studies' quality, attrition rate, type of pain and control group, did not moderate the effects of acceptance- and mindfulness-based interventions. Current acceptance- and mindfulness-based interventions, while not superior to traditional cognitive behavioral treatments, can be good alternatives.

Extracting Silicon From Sodium-Process Products

NASA Technical Reports Server (NTRS)

Kapur, V.; Sanjurjo, A.; Sancier, K. M.; Nanis, L.

1982-01-01

New acid leaching process purifies silicon produced in reaction between silicon fluoride and sodium. Concentration of sodium fluoride and other impurities and byproducts remaining in silicon are within acceptable ranges for semi-conductor devices. Leaching process makes sodium reduction process more attractive for making large quantities of silicon for solar cells.

An Overhead Projection Demonstration of Optical Activity

ERIC Educational Resources Information Center

Hill, John W.

1973-01-01

Describes the use of two polarizing lenses, a yellow filter, an oatmeal bos, a piece of cardboard, a 1,000 ml beaker, and an overhead projector to demonstrate compound optical activity to large classes. Indicates the presence of an accuracy within 1-2 degrees of usually acceptable data. (CC)

Effect of a combination of two rice herbicides on the cyanobacterium, Nostoc spongiaeforme

USDA-ARS?s Scientific Manuscript database

Cyanobacteria grow in California rice fields where they form large mats that may smoother seedlings or cause them to dislodge, resulting in yield loss. The most troublesome species is Nostoc spongiaeforme. It is very difficult to control using currently accepted methods, i.e., aerial applications of...

Evaluative Indices Assigned to Contraceptive Methods by University Undergraduates

ERIC Educational Resources Information Center

McDermott, Robert J.; Malo, Teri L.; Dodd, Virginia J.; Daley, Ellen M.; Mayer, Alyssa B.

2011-01-01

Background: Preordinate attitudes and beliefs about contraception may influence acceptance or rejection of a particular method. Purpose: We examined the attitudes about contraception methods held by undergraduate students (N=792) at two large southeastern universities in the United States. Methods: Twelve methods were rated on 40 semantic…

Evaluation of Columbia, USMARC-Composite, Suffolk, and Texel rams at terminal sires in an extensive rangeland production system

USDA-ARS?s Scientific Manuscript database

Crossing proven, superior terminal-sire sheep breeds with well-adapted maternal breeds provide opportunity to increase lamb carcass value, while maintaining acceptable environmental adaptation in crossbred lambs. Large, lean terminal-sire breeds, such as the Suffolk and Columbia, have been typicall...

TECHNICAL CHALLENGES INVOLVED IN IMPLEMENTATION OF VOC REACTIVITY-BASED CONTROL OF OZONE

EPA Science Inventory

The control of VOC emissions based on their individual contribution to ozone formation has been the subject of intensive discussion and research in the past five years, and has gained a large degree of acceptance in the air pollution regulatory community for certain industrial op...

Adam Smith and the Rhetoric of Style.

ERIC Educational Resources Information Center

Moran, Michael G.

Historians of rhetoric have generally accepted the view that Adam Smith rejected the principles of classical rhetoric. However, while there can be no doubt that Smith greatly truncated the five classical arts of rhetoric (invention, arrangement, style, memory, and delivery) by reducing his concerns largely to style and arrangement, he did not…

The Making of Curriculum.

ERIC Educational Resources Information Center

Goodson, Ivor

The study of how subjects are or are not accepted for inclusion into the curriculum is an area which has largely been ignored but which offers opportunities for a new integration of historical, sociological, and educational approaches. Some of the areas open for such study include the structural and political factors influencing the making of…

Patterns in the Use of OCLC by Academic Library Cataloging Departments.

ERIC Educational Resources Information Center

Moore, Barbara

1981-01-01

A survey of the cataloging departments of 166 OCLC-member academic libraries showed that these libraries do not rely exclusively on OCLC for card production and that a large majority do not accept non-Library of Congress OCLC records without substantial checking. Three references are noted. (Author/FM)

Student Acceptance of Clickers in Large Introductory Business Classes

ERIC Educational Resources Information Center

Preis, Michael W.; Kellar, Gregory M.; Crosby, Elizabeth

2011-01-01

Today's NetGen students require more multimedia and interactive learning environments and greater participation than previous generations. Personal response devices (PRDs, sometimes called Audience Response Devices or ARDs, better known as clickers) show promise in helping to meet that need. This article explores the literature of PRDs to develop…

Visual versus mechanised leucocyte differential counts: costing and evaluation of traditional and Hemalog D methods.

PubMed

Hudson, M J; Green, A E

1980-11-01

Visual differential counts were examined for efficiency, cost effectiveness, and staff acceptability within our laboratory. A comparison with the Hemalog D system was attempted. The advantages and disadvantages of each system are enumerated and discussed in the context of a large general hospital.

Chapter 8: Fire Performance of Cross-Laminated Timber Assemblies (2012 US Edition)

Treesearch

Christian Dagenais; Robert H. White; Kuma Sumathipala

2012-01-01

Cross-laminated timber (CLT) is a promising wood-based structural component and has potential to provide cost-effective building solutions for residential, commercial and institutional buildings as well as large industrial facilities. Market acceptance of CLT requires that it meets the applicable building code requirements.

International opportunities resource guide for the transportation development industry : accessing tools to grow internationally

DOT National Transportation Integrated Search

1978-05-01

A large number of bridges on two-lane rural highways are narrow bridges. While there is no universally accepted definition of this type of bridge, it is generally considered to be one where the roadway and/or shoulders narrow significantly. It has be...

Validation, acceptance, and extension of a predictive model of reproductive toxicity using ToxCast data

EPA Science Inventory

The EPA ToxCast research program uses a high-throughput screening (HTS) approach for predicting the toxicity of large numbers of chemicals. Phase-I tested 309 well-characterized chemicals (mostly pesticides) in over 500 assays of different molecular targets, cellular responses an...

On Validity Theory and Test Validation

ERIC Educational Resources Information Center

Sireci, Stephen G.

2007-01-01

Lissitz and Samuelsen (2007) propose a new framework for conceptualizing test validity that separates analysis of test properties from analysis of the construct measured. In response, the author of this article reviews fundamental characteristics of test validity, drawing largely from seminal writings as well as from the accepted standards. He…

Long-term pavement monitoring program : development of pavement monitoring : prepared for alternative development workshop

DOT National Transportation Integrated Search

1984-08-01

Long-term monitoring efforts have been carried on for a number of years at state and national level and have been generally accepted. However, the shape that it takes in the future will depend very largely upon the decisions that are made in this Wor...

Effect of Grade Retention in First Grade on Psychosocial Outcomes

ERIC Educational Resources Information Center

Wu, Wei; West, Stephen G.; Hughes, Jan N.

2010-01-01

In a 4-year longitudinal study, the authors investigated effects of retention in first grade on children's externalizing and internalizing behaviors; social acceptance; and behavioral, cognitive, and affective engagement. From a large multiethnic sample (n = 784) of children below the median on literacy at school entrance, 124 retained children…

The VLAB OER Experience: Modeling Potential-Adopter Student Acceptance

ERIC Educational Resources Information Center

Raman, Raghu; Achuthan, Krishnashree; Nedungadi, Prema; Diwakar, Shyam; Bose, Ranjan

2014-01-01

Virtual Labs (VLAB) is a multi-institutional Open Educational Resources (OER) initiative, exclusively focused on lab experiments for engineering education. This project envisages building a large OER repository, containing over 1650 virtual experiments mapped to the engineering curriculum. The introduction of VLAB is a paradigm shift in an…

Creating Social Presence in Online Environments

ERIC Educational Resources Information Center

Aragon, Steven R.

2003-01-01

During the last decade, the Internet has significantly changed the way learning is delivered and facilitated in both educational and noneducational settings. Advocates of Internet-based instruction are largely positive and optimistic about its potential. Before it can be fully accepted by the mainstream public and educational community, however,…

Richey, D.G.; Driscoll, C.T.; Likens, G.B.

Treesearch

1997-01-01

The phase out of chlorofluorocharbons (CFCs) has resulted in the use of hydrochlorofluorocharbons (HCFCs) and hydrofluorocarbons (HFCs) as environmentally acceptable alternative chemicles. Trifluoroacetic acid (TFA) has been identified as a degradation byproduct of these compounds, which largely returns the Earth's surface via precipitation. Little is known about...

Active Gaming: Is "Virtual" Reality Right for Your Physical Education Program?

ERIC Educational Resources Information Center

Hansen, Lisa; Sanders, Stephen W.

2012-01-01

Active gaming is growing in popularity and the idea of increasing children's physical activity by using technology is largely accepted by physical educators. Teachers nationwide have been providing active gaming equipment such as virtual bikes, rhythmic dance machines, virtual sporting games, martial arts simulators, balance boards, and other…

Validity and Reliability of a Scale Assessing Attitudes toward Mainstreaming.

ERIC Educational Resources Information Center

Green, Kathy; And Others

1983-01-01

In a study involving 50 undergraduate and graduate education students the Attitudes Toward Mainstreaming Scale was found to have a large first factor with adequate reliability. There was a low correlation between knowledge and ATMS scores, although knowledge was more strongly related to classroom acceptance of exceptional students. (CL)

Institutional Autonomy Revisited: Autonomy Justified and Accounted

ERIC Educational Resources Information Center

Moses, Ingrid

2007-01-01

Australian universities have enjoyed large-scale autonomy. In a society that increasingly regards university education from an instrumentalist point of view, universities' anxious safeguarding of their autonomy is widely seen as an attempt to evade accountability. Yet there has been an acceptance that a corollary to autonomy is accountability.…

Integrity-Based Budgeting

ERIC Educational Resources Information Center

Kaleba, Frank

2008-01-01

The central problem for the facility manager of large portfolios is not the accuracy of data, but rather data integrity. Data integrity means that it's (1) acceptable to the users; (2) based upon an objective source; (3) reproducible; and (4) internally consistent. Manns and Katsinas, in their January/February 2006 Facilities Manager article…

Three In-Course Assessment Reforms to Improve Higher Education Learning Outcomes

ERIC Educational Resources Information Center

Sadler, D. Royce

2016-01-01

A current international concern is that, for too large a proportion of graduates, their higher order cognitive and practical capabilities are below acceptable levels. The constituent courses of academic programmes are the most logical sites for developing these capabilities. Contributing to patchy attainment are deficiencies in three particular…

Analysis of the effectiveness of various cross-sections in large-span post-tensioned ceilings

NASA Astrophysics Data System (ADS)

Bednarz, K.

2018-03-01

The correct construction of large span, slim post-tensioned concrete slabs is conditioned by an appropriate cross-section selection. It is generally accepted that the thinnest slab can be constructed using the full cross-section as the largest compression stress storage. However, completely different cross-sections may help to overcome large spans. The paper presents the results of the computational analysis of several types of cross-sections (full, with internal relieving inserts and ribbed) in the application to a post-tensioned slab with a span of 15.0m. Based on the results presented, appropriate conclusions were drawn.

Comparison of energy flows in deep inelastic scattering events with and without a large rapidity gap

NASA Astrophysics Data System (ADS)

Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Repond, J.; Schlereth, J.; Stanek, R.; Talaga, R. L.; Thron, J.; Arzarello, F.; Ayad, R.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Bruni, P.; Romeo, G. Cara; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Ciralli, F.; Contin, A.; D'Auria, S.; Del Papa, C.; Frasconi, F.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Maccarrone, G.; Margotti, A.; Massam, T.; Nania, R.; Nemoz, C.; Palmonari, F.; Polini, A.; Sartorelli, G.; Timellini, R.; Garcia, Y. Zamora; Zichichi, A.; Bargende, A.; Crittenden, J.; Desch, K.; Diekmann, B.; Doeker, T.; Feld, L.; Frey, A.; Geerts, M.; Geitz, G.; Grothe, M.; Hartmann, H.; Haun, D.; Heinloth, K.; Hilger, E.; Jakob, H.-P.; Katz, U. F.; Mari, S. M.; Mass, A.; Mengel, S.; Mollen, J.; Paul, E.; Rembser, Ch.; Schattevoy, R.; Schneider, J.-L.; Schramm, D.; Stamm, J.; Wedemeyer, R.; Campbell-Robson, S.; Cassidy, A.; Dyce, N.; Foster, B.; George, S.; Gilmore, R.; Heath, G. P.; Heath, H. F.; Llewellyn, T. J.; Morgado, C. J. S.; Norman, D. J. P.; O'Mara, J. A.; Tapper, R. J.; Wilson, S. S.; Yoshida, R.; Rau, R. R.; Arneodo, M.; Iannotti, L.; Schioppa, M.; Susinno, G.; Bernstein, A.; Caldwell, A.; Gialas, I.; Parsons, J. A.; Ritz, S.; Sciulli, F.; Straub, P. B.; Wai, L.; Yang, S.; Borzemski, P.; Chwastowski, J.; Eskreys, A.; Piotrzkowski, K.; Zachara, M.; Zawiejski, L.; Adamczyk, L.; Bednarek, B.; Eskreys, K.; Jeleń, K.; Kisielewska, D.; Kowalski, T.; Rulikowska-Zarȩbska, E.; Suszycki, L.; Zajaç, J.; Kȩdzierski, T.; Kotański, A.; Przybycień, M.; Bauerdick, L. A. T.; Behrens, U.; Bienlein, J. K.; Böttcher, S.; Coldewey, C.; Drews, G.; Flasiński, M.; Gilkinson, D. J.; Göttlicher, P.; Gutjahr, B.; Haas, T.; Hagge, L.; Hain, W.; Hasell, D.; Heßling, H.; Hultschig, H.; Iga, Y.; Joos, P.; Kasemann, M.; Klanner, R.; Koch, W.; Köpke, L.; Kötz, U.; Kowalski, H.; Kröger, W.; Krüger, J.; Labs, J.; Ladage, A.; Löhr, B.; Löwe, M.; Lüke, D.; Mainusch, J.; Mańczak, O.; Ng, J. S. T.; Nickel, S.; Notz, D.; Ohrenberg, K.; Roco, M.; Rohde, M.; Roldán, J.; Schneekloth, U.; Schroeder, J.; Schulz, W.; Selonke, F.; Stiliaris, E.; Voß, T.; Westphal, D.; Wolf, G.; Youngman, C.; Grabosch, H. J.; Leich, A.; Meyer, A.; Rethfeldt, C.; Schlenstedt, S.; Barbagli, G.; Pelfer, P.; Anzivino, G.; De Pasquale, S.; Qian, S.; Votano, L.; Bamberger, A.; Freidhof, A.; Poser, T.; Söldner-Rembold, S.; Theisen, G.; Trefzger, T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; Fleck, I.; Forbes, J. R.; Jamieson, V. A.; Raine, C.; Saxon, D. H.; Stavrianakou, M.; Wilson, A. S.; Dannemann, A.; Holm, U.; Horstmann, D.; Kammerlocher, H.; Krebs, B.; Neumann, T.; Sinkus, R.; Wick, K.; Badura, E.; Burow, B. D.; Fürtjes, A.; Lohrmann, E.; Milewski, J.; Nakahata, M.; Pavel, N.; Poelz, G.; Schott, W.; Terron, J.; Zetsche, F.; Bacon, T. C.; Beuselinck, R.; Butterworth, I.; Gallo, E.; Harris, V. L.; Hung, B. H.; Long, K. R.; Miller, D. B.; Morawitz, P. P. O.; Prinias, A.; Sedgbeer, J. K.; Whitfield, A. F.; Mallik, U.; McCliment, E.; Wang, M. Z.; Zhang, Y.; Cloth, P.; Filges, D.; An, S. H.; Hong, S. M.; Kim, C. O.; Kim, T. Y.; Nam, S. W.; Park, S. K.; Suh, M. H.; Yon, S. H.; Imlay, R.; Kartik, S.; Kim, H.-J.; McNeil, R. R.; Metcalf, W.; Nadendla, V. K.; Barreiro, F.; Cases, G.; Graciani, R.; Hernández, J. M.; Hervás, L.; Labarga, L.; del Peso, J.; Puga, J.; de Trocóniz, J. F.; Ikraiam, F.; Mayer, J. K.; Smith, G. R.; Corriveau, F.; Hanna, D. S.; Hartmann, J.; Hung, L. W.; Lim, J. N.; Matthews, C. G.; Mitchell, J. W.; Patel, P. M.; Sinclair, L. E.; Stairs, D. G.; Laurent, M. St.; Ullmann, R.; Bashkirov, V.; Dolgoshein, B. A.; Stifutkin, A.; Bashindzhagyan, G. L.; Ermolov, P. F.; Gladilin, L. K.; Golubkov, Y. A.; Kobrin, V. D.; Kuzmin, V. A.; Proskuryakov, A. S.; Savin, A. A.; Shcheglova, L. M.; Solomin, A. N.; Zotov, N. P.; Bentvelsen, S.; Botje, M.; Chlebana, F.; Dake, A.; Engelen, J.; de Jong, P.; de Kamps, M.; Kooijman, P.; Kruse, A.; O'Dell, V.; Tenner, A.; Tiecke, H.; Verkerke, W.; Vreeswijk, M.; Wiggers, L.; de Wolf, E.; van Woudenberg, R.; Acosta, D.; Bylsma, B.; Durkin, L. S.; Honscheid, K.; Li, C.; Ling, T. Y.; McLean, K. W.; Murray, W. N.; Park, I. H.; Romanowski, T. A.; Seidlein, R.; Bailey, D. S.; Blair, G. A.; Byrne, A.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Daniels, D.; Devenish, R. C. E.; Harnew, N.; Lancaster, M.; Luffman, P. E.; McFall, J.; Nath, C.; Quadt, A.; Uijterwaal, H.; Walczak, R.; Wilson, F. F.; Yip, T.; Abbiendi, G.; Bertolin, A.; Brugnera, R.; Carlin, R.; Dal Corso, F.; De Giorgi, M.; Dosselli, U.; Gasparini, F.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Bulmahn, J.; Butterworth, J. M.; Feild, R. G.; Oh, B. Y.; Whitmore, J. J.; D'Agostini, G.; Iori, M.; Marini, G.; Mattioli, M.; Nigro, A.; Hart, J. C.; McCubbin, N. A.; Prytz, K.; Shah, T. P.; Short, T. L.; Barberis, E.; Cartiglia, N.; Dubbs, T.; Heusch, C.; Van Hook, M.; Hubbard, B.; Lockman, W.; Sadrozinski, H. F.-W.; Seiden, A.; Biltzinger, J.; Seifert, R. J.; Walenta, A. H.; Zech, G.; Abramowicz, H.; Dagan, S.; Levy, A.; Hasegawa, T.; Hazumi, M.; Ishii, T.; Kuze, M.; Mine, S.; Nagasawa, Y.; Nagira, T.; Nakao, M.; Suzuki, I.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Chiba, M.; Hamatsu, R.; Hirose, T.; Homma, K.; Kitamura, S.; Nagayama, S.; Nakamitsu, Y.; Cirio, R.; Costa, M.; Ferrero, M. I.; Lamberti, L.; Maselli, S.; Peroni, C.; Sacchi, R.; Solano, A.; Staiano, A.; Dardo, M.; Bailey, D. C.; Bandyopadhyay, D.; Benard, F.; Brkic, M.; Crombie, M. B.; Gingrich, D. M.; Hartner, G. F.; Joo, K. K.; Levman, G. M.; Martin, J. F.; Orr, R. S.; Sampson, C. R.; Teuscher, R. J.; Catterall, C. D.; Jones, T. W.; Kaziewicz, P. B.; Lane, J. B.; Saunders, R. S.; Shulman, J.; Blankenship, K.; Kochocki, J.; Lu, B.; Mo, L. W.; Bogusz, W.; Charchuła, K.; Ciborowski, J.; Gajewski, J.; Grzelak, G.; Kasprzak, M.; Krzyżanowski, M.; Muchorowski, K.; Nowak, R. J.; Pawlak, J. M.; Tymieniecka, T.; Wróblewski, A. K.; Zakrzewski, J. A.; Żarnecki, A. F.; Adamus, M.; Eisenberg, Y.; Glasman, C.; Karshon, U.; Revel, D.; Shapira, A.; Ali, I.; Behrens, B.; Dasu, S.; Fordham, C.; Foudas, C.; Goussiou, A.; Loveless, R. J.; Reeder, D. D.; Silverstein, S.; Smith, W. H.; Tsurugai, T.; Bhadra, S.; Frisken, W. R.; Furutani, K. M.; ZEUS Collaboration

1994-11-01

Energy flows in deep inelastic electron-proton scattering are investigated at a centre-of-mass energy of 269 GeV for the range Q2 ≥ 10 GeV 2 using the ZEUS detector. A comparison is made between events with and without a large rapidity gap between the hadronic system and the proton direction. The energy flows, corrected for detector acceptance and resolution, are shown for these two classes of events in both the HERA laboratory frame and the Breit frame. From the differences in the shapes of these energy flows we conclude that QCD radiation is suppressed in the large-rapidity-gap eents compared to the events without a large rapidity gap.

To Accept or Refuse Patient's Gift in Money? and How? - Case Report with Review.

PubMed

Kos, Vesna

2016-11-01

This report describes a (rare) situation when a patient's first gift to a young doctor was in money. This happened in very specific circumstances - in a refugee camp during the War in Croatia. The data are taken from a large study on gifts, conducted on a representative sample of Croatian general practitioners (GPs), N = 265, from 2358 in total. Pro and contra factors are discussed, considering tradition and customs, but also a lack of knowledge of young doctors in handling gifts in general. The intention of this report is primarily educative, with review of (scarce) literature, and recommendations, where the generally accepted rules might have exceptions.

Photochemically Etched Construction Technology Developed for Digital Xenon Feed Systems

NASA Technical Reports Server (NTRS)

Otsap, Ben; Cardin, Joseph; Verhey, Timothy R.; Rawlin, Vincent K.; Mueller, Juergen; Aadlund, Randall; Kay, Robert; Andrews, Michael

2005-01-01

Electric propulsion systems are quickly emerging as attractive options for primary propulsion in low Earth orbit, in geosynchronous orbit, and on interplanetary spacecraft. The driving force behind the acceptance of these systems is the substantial reduction in the propellant mass that can be realized. Unfortunately, system designers are often forced to utilize components designed for chemical propellants in their electric systems. Although functionally acceptable, these relatively large, heavy components are designed for the higher pressures and mass flow rates required by chemical systems. To fully realize the benefits of electric propulsion, researchers must develop components that are optimized for the low flow rates, critical leakage needs, low pressures, and limited budgets of these emerging systems.

Nonlinear optical properties of flux growth KTiOPO4

NASA Astrophysics Data System (ADS)

Stolzenberger, Richard A.

1988-09-01

The properties of large flux grown KTiOPO4 second harmonic generators were measured. A technique which provides a sensitive assessment of crystal uniformity is described. Optically perfect second harmonic generation crystals of up to 1 cu cm were found to have nonlinear optical properties comparable with those grown by other methods. A Q-switched Nd:YAG laser was used to determine temperature acceptance width-length product (20 C cm), angular acceptance width-length product (13 mrad cm), and doubling efficiency (50 percent). Spectral bandwidth (4.5 A cm) and wavefront distortion (1/4 wave at 633 nm) were also measured. The dependence of these properties on crystal homogeneity is demonstrated.

Heave motion prediction of a large barge in random seas by using artificial neural network

NASA Astrophysics Data System (ADS)

Lee, Hsiu Eik; Liew, Mohd Shahir; Zawawi, Noor Amila Wan Abdullah; Toloue, Iraj

2017-11-01

This paper describes the development of a multi-layer feed forward artificial neural network (ANN) to predict rigid heave body motions of a large catenary moored barge subjected to multi-directional irregular waves. The barge is idealized as a rigid plate of finite draft with planar dimensions 160m (length) and 100m (width) which is held on station using a six point chain catenary mooring in 50m water depth. Hydroelastic effects are neglected from the physical model as the chief intent of this study is focused on large plate rigid body hydrodynamics modelling using ANN. Even with this assumption, the computational requirements for time domain coupled hydrodynamic simulations of a moored floating body is considerably costly, particularly if a large number of simulations are required such as in the case of response based design (RBD) methods. As an alternative to time consuming numerical hydrodynamics, a regression-type ANN model has been developed for efficient prediction of the barge's heave responses to random waves from various directions. It was determined that a network comprising of 3 input features, 2 hidden layers with 5 neurons each and 1 output was sufficient to produce acceptable predictions within 0.02 mean squared error. By benchmarking results from the ANN with those generated by a fully coupled dynamic model in OrcaFlex, it is demonstrated that the ANN is capable of predicting the barge's heave responses with acceptable accuracy.

Branding water

PubMed Central

Dolnicar, Sara; Hurlimann, Anna; Grün, Bettina

2014-01-01

Branding is a key strategy widely used in commercial marketing to make products more attractive to consumers. With the exception of bottled water, branding has largely not been adopted in the water context although public acceptance is critical to the implementation of water augmentation projects. Based on responses from 6247 study participants collected between 2009 and 2012, this study shows that (1) different kinds of water – specifically recycled water, desalinated water, tap water and rainwater from personal rainwater tanks – are each perceived very differently by the public, (2) external events out of the control of water managers, such as serious droughts or floods, had a minimal effect on people's perceptions of water, (3) perceptions of water were stable over time, and (4) certain water attributes are anticipated to be more effective to use in public communication campaigns aiming at increasing public acceptance for drinking purposes. The results from this study can be used by a diverse range of water stakeholders to increase public acceptance and adoption of water from alternative sources. PMID:24742528

Does acceptance of power distance influence propensities for problematic Internet use? Evidence from a cross-cultural study.

PubMed

Montag, Christian; Duke, Éilish; Sha, Peng; Zhou, Min; Sindermann, Cornelia; Li, Mei

2016-12-01

Several studies suggest that Asian countries are particularly afflicted by problematic Internet use (PIU). The present study investigates whether individual differences in the acceptance of power distance can be linked to overuse of the Internet in Germany and in China. Power distance has been discussed as an essential dimension on which Asian and Western societies differ. In the present study, we investigate two large non-clinical samples from Germany (n = 297) and China (n = 556) to address this question. Both in Germany and in China, high acceptance of power distance was positively associated with PIU. These effects were more pronounced in China compared with Germany. Moreover, the observed effects were stronger in males compared with females. Clearly, these findings are just a starting point and need to be replicated in the future. Clinical populations and a further important difference variable - collectivism - also merit consideration in future work. © 2015 Wiley Publishing Asia Pty Ltd.

Tolerability, usability and acceptability of dissolving microneedle patch administration in human subjects

PubMed Central

Arya, Jaya; Henry, Sebastien; Kalluri, Haripriya; McAllister, Devin V.; Pewin, Winston P.; Prausnitz, Mark R.

2017-01-01

To support translation of microneedle patches from pre-clinical development into clinical trials, this study examined the effect of microneedle patch application on local skin reactions, reliability of use and acceptability to patients. Placebo patches containing dissolving microneedles were administered to fifteen human participants. Microneedle patches were well tolerated in the skin with no pain or swelling and only mild erythema localized to the site of patch administration that resolved fully within seven days. Microneedle patches could be administered by hand without the need of an applicator and delivery efficiencies were similar for investigator-administration and self-administration. Microneedle patch administration was not considered painful and the large majority of subjects were somewhat or fully confident that they self-administered patches correctly. Microneedle patches were overwhelmingly preferred over conventional needle and syringe injection. Altogether, these results demonstrate that dissolving microneedle patches were well tolerated, easily usable and strongly accepted by human subjects, which will facilitate further clinical translation of this technology. PMID:28285193

The "RAPID" cognitive-behavioral therapy program for inattentive children: preliminary findings.

PubMed

Young, Susan

2013-08-01

The objectives of the current study were to ascertain feasibility and acceptability of directly delivering a cognitive-behavioral therapy (CBT) group intervention for inattentive children in a school setting, to examine the reliability of the RATE-CQuestionnaires that accompany the program, and to determine whether they can be used to measure outcome. Eighty-eight parents/carers, their children (age 8-11), and teachers at mainstream primary schools in London participated by completing the RATE-C Questionnaires; 48 participated in the group treatment following which the Questionnaires were readministered together with a semistructured interview. The intervention had a completion rate of 92%. Postgroup interviews supported the acceptability of a direct intervention with young children. Reliability of the RATE-C Total scores was excellent for parent/carer, child, and teacher ratings; postintervention parent/carer ratings indicated significant improvement on scales of attention, emotion, and conduct with medium to large effect. The results support the reliability of the RATE-C Scales, and feasibility and acceptability of the RAPID intervention.

Degenerative lumbosacral stenosis in working dogs: current concepts and review.

PubMed

Worth, A J; Thompson, D J; Hartman, A C

2009-12-01

Degenerative lumbosacral stenosis (DLSS) is characterised by intervertebral disc degeneration, with secondary bony and soft-tissue changes leading to compression of the cauda equina. Large-breed, active and working dogs are the most commonly affected by DLSS. Specific manipulative tests allow the clinician to form a high suspicion of DLSS, and initiate investigation. Changes seen using conventional radiography are unreliable, and although contrast radiography represents an improvement, advanced imaging is accepted as the diagnostic method of choice. Treatment involves decompression and/or stabilisation procedures in working dogs, although conservative management may be acceptable in pet dogs with mild signs. Prognosis for return to work is only fair, and there is a high rate of recurrence following conventional surgery. Stabilisation procedures are associated with the potential for failure of the implant, and their use has not gained universal acceptance. A new surgical procedure, dorsolateral foramenotomy, offers a potential advance in the management of DLSS. everal aspects of the pathogenesis, heritability and optimal treatment approach remain uncertain.

Long-term acceptability, durability and bio-efficacy of ZeroVector® durable lining for vector control in Papua New Guinea.

PubMed

Kuadima, Joseph J; Timinao, Lincoln; Naidi, Laura; Tandrapah, Anthony; Hetzel, Manuel W; Czeher, Cyrille; Pulford, Justin

2017-02-28

This study examined the acceptability, durability and bio-efficacy of pyrethroid-impregnated durable lining (DL) over a three-year period post-installation in residential homes across Papua New Guinea (PNG). ZeroVector ® ITPS had previously been installed in 40 homes across four study sites representing a cross section of malaria transmission risk and housing style. Structured questionnaires, DL visual inspections and group interviews (GIs) were completed with household heads at 12- and 36-months post-installation. Three DL samples were collected from all households in which it remained 36-months post-installation to evaluate the bio-efficacy of DL on Anopheles mosquitoes. Bio-efficacy testing followed WHO guidelines for the evaluation of indoor residual spraying. The DL was still intact in 86 and 39% of study homes at the two time periods, respectively. In homes in which the DL was still intact, 92% of household heads considered the appearance at 12-months post installation to be the same as, or better than, that at installation compared to 59% at 36-months post-installation. GIs at both time points confirmed continuing high acceptance of DL, based in large part of the perceived attractiveness and functionality of the material. However, participants frequently asserted that they, or their family members, had ceased or reduced their use of mosquito nets as a result of the DL installation. A total of 16 houses were sampled for bio-efficacy testing across the 4 study sites at 36-months post-installation. Overall, combining all sites and samples, both knock-down at 30 min and mortality at 24 h were 100%. The ZeroVector ® DL installation remained highly acceptable at 36-months post-installation, the material and fixtures proved durable and the efficacy against malaria vectors did not decrease. However, the DL material had been removed from over 50% of the original study homes 3 years post-installation, largely due to deteriorating housing infrastructure. Furthermore, the presence of the DL installation appeared to reduce ITN use among many participating householders. The study findings suggest DL may not be an appropriate vector control method for large-scale use in the contemporary PNG malaria control programme.

An examination of acceptability of HPV vaccination among African American women and Latina immigrants.

PubMed

Scarinci, Isabel C; Garcés-Palacio, Isabel C; Partridge, Edward E

2007-10-01

This study examined the acceptability of preventive human papillomavirus (HPV) vaccination among Latina immigrants and African American women through eight focus groups (n = 55, 28 Latinas and 27 African Americans). Latinas were between 17 and 39 years old (x = 27.9) and African Americans between 19 and 39 (x = 24.3). Approximately 86% of Latinas and 7% of African Americans were married or living with a partner; 10.7% of Latinas and 53.8% of African Americans reported having health insurance; 60.7% of Latinas and 77.8% of African Americans had never heard about HPV. Following a brief presentation about cervical cancer and HPV, participants were questioned about the acceptability of a preventive HPV vaccine. Overall, both groups indicated that an HPV preventive vaccine would be acceptable. However, African Americans were more skeptical, citing concerns about effectiveness and side effects. Another African American concern was whether vaccinated women would perceive themselves as being protected from HPV, leading them to increased promiscuity or unprotected sex. African Americans' motivating factors for vaccine use included receiving education/information about the vaccine, affordable prices, good results in trials, and knowing others who had already gotten vaccinated. Latina immigrants, on the other hand, unanimously stated that they would get the vaccine. However, they believed that multiple credible sources of information (educational talks, doctor's office, television, churches, and other women) needed to promote the vaccine before the Latino community at large would accept it. These findings suggest that unique educational strategies need to be developed, based on the needs and perceptions of the targeted audience, in order to achieve wide-spread acceptability of this vaccine.

Consumer acceptability and understanding of front-of-pack nutrition labels.

PubMed

Mejean, C; Macouillard, P; Péneau, S; Hercberg, S; Castetbon, K

2013-10-01

Front-of-pack (FOP) nutrition labelling has been proposed as a tool for helping consumers make healthy choices. Before determining its effects on consumer behaviour, factors involved in its use must be elucidated, i.e. understanding and acceptability on the part of the consumer. Among five FOP labels, we sought to determine which formats were most easily understood and accepted by a large sample of adults. Among 39 370 adults who participated in the French Nutrinet-Santé cohort study, understanding and indicators of acceptability (attitude, liking, visual attractiveness and perceived cognitive workload) were measured for five FOP labels: The currently used 'multiple traffic lights' (MTL) and 'simple traffic lights' (STL), and the 'colour range' logo (CR), the 'green tick' and the PNNS logo. We investigated the contribution of the different elements to consumer perception of FOP labels using multiple correspondence analyses. Over half of the sample population showed a high level of understanding and perceived no discomfort in terms of the different logos. Label formats were positioned along an acceptability gradient ranging from acceptance to rejection, consisting of 'liking', 'attractiveness' and indicators of perceived cognitive workload. MTL was significantly more often liked and was viewed as reliable and informative. MTL, STL and the green tick performed better than the CR and PNNS logos in terms of ease of identification and comprehension. CR was clearly the least appreciated and it had the most complex format. Consumers prefer FOP labels which give complete, reliable and simplified information on the nutrient quality of foods. © 2013 The Authors Journal of Human Nutrition and Dietetics © 2013 The British Dietetic Association Ltd.

Randomized Controlled Trial of Online Acceptance and Commitment Therapy for Fibromyalgia.

PubMed

Simister, Heather D; Tkachuk, Gregg A; Shay, Barbara L; Vincent, Norah; Pear, Joseph J; Skrabek, Ryan Q

2018-03-02

In this study, 67 participants (95% female) with fibromyalgia (FM) were randomly assigned to an online acceptance and commitment therapy (online ACT) and treatment as usual (TAU; ACT + TAU) protocol or a TAU control condition. Online ACT + TAU participants were asked to complete 7 modules over an 8-week period. Assessments were completed at pre-treatment, post-treatment, and 3-month follow-up periods and included measures of FM impact (primary outcome), depression, pain, sleep, 6-minute walk, sit to stand, pain acceptance (primary process variable), mindfulness, cognitive fusion, valued living, kinesiophobia, and pain catastrophizing. The results indicated that online ACT + TAU participants significantly improved in FM impact, relative to TAU (P <.001), with large between condition effect sizes at post-treatment (1.26) and follow-up (1.59). Increases in pain acceptance significantly mediated these improvements (P = .005). Significant improvements in favor of online ACT + TAU were also found on measures of depression (P = .02), pain (P = .01), and kinesiophobia (P = .001). Although preliminary, this study highlights the potential for online ACT to be an efficacious, accessible, and cost-effective treatment for people with FM and other chronic pain conditions. Online ACT reduced FM impact relative to a TAU control condition in this randomized controlled trial. Reductions in FM impact were mediated by improvements in pain acceptance. Online ACT appears to be a promising intervention for FM. Copyright © 2018 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Automated array assembly, phase 2

NASA Technical Reports Server (NTRS)

Carbajal, B. G.

1979-01-01

Tasks of scaling up the tandem junction cell (TJC) from 2 cm x 2 cm to 6.2 cm and the assembly of several modules using these large area TJC's are described. The scale-up of the TJC was based on using the existing process and doing the necessary design activities to increase the cell area to an acceptably large area. The design was carried out using available device models. The design was verified and sample large area TJCs were fabricated. Mechanical and process problems occurred causing a schedule slippage that resulted in contract expiration before enough large-area TJCs were fabricated to populate the sample tandem junction modules (TJM). A TJM design was carried out in which the module interconnects served to augment the current collecting buses on the cell. No sample TJMs were assembled due to a shortage of large-area TJCs.

Multiple Deficits in ADHD: Executive Dysfunction, Delay Aversion, Reaction Time Variability, and Emotional Deficits

ERIC Educational Resources Information Center

Sjowall, Douglas; Roth, Linda; Lindqvist, Sofia; Thorell, Lisa B.

2013-01-01

Background: The notion that ADHD constitutes a heterogeneous disorder is well accepted. However, this study contributes with new important knowledge by examining independent effects of a large range of neuropsychological deficits. In addition, the study investigated whether deficits in emotional functioning constitute a dissociable component of…

The Rhetoric of the Paneled Page: Comics and Composition Pedagogy

ERIC Educational Resources Information Center

Sealey-Morris, Gabriel

2015-01-01

While comics have received widespread acceptance as a literary genre, instructors and scholars in Rhetoric and Composition have been slower to adopt comics, largely because of a lingering difficulty understanding how the characteristics of the form relate to our work in the classroom. Using as guides the "WPA Outcomes Statement for First-Year…