An Absolute Measurement of the Deuteron Photodisintegration of Cross Section, E[gamma]
Author : Troy Soos
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Page : 170 pages
File Size : 26,29 MB
Release : 1989
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Author : Troy Soos
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Page : 170 pages
File Size : 26,29 MB
Release : 1989
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Author : Brendan David Fox
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Page : pages
File Size : 50,10 MB
Release : 1996
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We have measured the absolute $rmsp2H(gamma,p)n$ angular distribution using the Illinois LASA detector at the Saskatchewan Accelerator Laboratory's tagged photon facility. Using 40 to 90 MeV photons, we aimed to measure the differential cross section with a statistical precision of typically 5% in angular bins of $3spcirc$ and energy bins of 2 MeV. Although our measurement achieved this goal, the contribution of systematic errors was larger than anticipated and thus compromised the utility of this result. Without these systematic errors, this measurement (when combined with the world data set) would have provided an extensive experimental data set with an accuracy which was better than the scatter between the various theoretical calculations for the interaction. Refinements to the treatment of the interaction would then have been testable. In particular, because the shape of the angular distribution in this energy regime is sensitive to meson exchange currents, it would have been possible to investigate the methods for incorporating these currents into calculations.
Author : P. T. Debevec
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Page : 0 pages
File Size : 10,9 MB
Release : 1991
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Author : Brendan David Fox
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Page : 398 pages
File Size : 49,83 MB
Release : 1996
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Author : Elaine Carol Schulte
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Page : 266 pages
File Size : 43,72 MB
Release : 2002
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Author : Thih-Yuen Tung
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Page : pages
File Size : 38,65 MB
Release : 1992
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Page : 4 pages
File Size : 46,33 MB
Release : 2001
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The first measurements of the d(gamma, p)n differential cross section at forward angles and photon energies above 4 GeV were performed at the Thomas Jefferson National Accelerator Facility (JLab). The results indicate evidence of an angular dependent scaling threshold. Results at theta{sub cm} = 37{sup o} are consistent with the constituent counting rules for E{sub gamma}H" 4 GeV, while those at 70{sup o} are consistent with the constituent counting rules for E{sub gamma} H" 1.5 GeV.
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Page : 9 pages
File Size : 47,17 MB
Release : 1997
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The first measurements of the differential cross section from d([gamma], p)n up to 4.0 GeV were performed at the Thomas Jefferson National Accelerator Facility (TJNAF, formerly CEBAF). Bremsstrahlung photons from electron beam impinging on a copper radiator and a liquid deuterium target were employed for this experiment. The experiment was performed in Hall C where the photoprotons at forward angles in the center-of-mass were detected in the High Momentum Spectrometer (HMS) and photoprotons at backward angles were detected in the Short Orbit Spectrometer (SOS). The bremsstrahlung photon energy was reconstructed from the measured proton momentum and angle using the two-body kinematics. We report the cross section results at the proton center-of-mass angles of 37° and 90°. These results are in good agreement with previous lower energy measurements. The 90° data continue to show the constituent-counting-rule behavior up to 4 GeV. The results will be compared with models based on QCD as well as those based on meson-exchange theory.
Author : I. Halpern
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Page : 12 pages
File Size : 14,79 MB
Release : 1949
Category : Deuterons
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Page : pages
File Size : 44,58 MB
Release : 2007
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A precision measurement of the d(gamma, n)p reaction was performed at the High Intensity gamma-ray Source (HIGS), which is located at the Duke Free Electron Laser Laboratory on the campus of Duke University. The gamma-ray beams were nearly 100% linearly polarized, allowing the angular distributions of both the analyzing power and unpolarized cross section to be measured at 14 and 16 MeV. The photons were incident on a heavy water target and the neutrons from the photodisintegration reaction were detected using the Blowfish detector array, which consists of 88 liquid scintillator detectors with large angular coverage. A transition matrix element (TME) analysis was performed on the data which allowed the amplitudes of the TMEs which contribute to the reaction at these energies to be extracted. This was done by invoking Watson's theorem, which fixes the relative TME phases using the n-p scattering phase shifts, leaving the TME amplitudes as free parameters in fits to the data. The results indicated very good agreement with a recent potential model calculation for the amplitudes of the three electric dipole (E1) p-waves, which account for over 90% of the cross section at these energies. The extracted TME amplitudes were then used to construct the observable which enters into the Gerasimov-Drell-Hearn (GDH) Sum Rule integrand. The results are the first experimental indication of a positive value of the GDH integrand in the region near photodisintegration threshold. A positive value at these energies has been shown by theory to be due to relativistic contributions.