Compton Scattering on $^{209}Bi$ at HI$\gamma$S From $E_{\gamma}=11-30$ MeV

ORAL

Abstract

New data collected at the High Intensity $\gamma$-ray Source (HI$\gamma$S) were taken to investigate the Iso-Vector Giant Dipole (IVGDR) and Giant Quadrupole (IVGQR) Resonance Regions in $^{209}$Bi, $E_{\gamma}=11-30$ MeV. Linearly polarized $\vec{\gamma}$-rays were incident upon an isotopically pure ($>$99.9\%) $^{209}$Bi target and the scattered $\gamma$-rays were detected using the HI$\gamma$S NaI Detector Array (HINDA). HINDA is an array of large (10''x10'') core detectors surrounded by 3'' thick NaI shields that are segmented optically into 8 individual segments. This assembly was run in an anti-coincidence mode to reduce background and improve the resolution as well as a coincidence mode to isolate the first escape peak. During the 150 hour run, the nearly mono-energetic $\vec{\gamma}$-ray intensities were $1\times10^{5}-1\times10^{7}\gamma$'s/sec on target and statistical accuracies of 1-3\% were achieved. Preliminary analysis of angular distributions of cross sections and analyzing powers as well as absolute cross sections will be reported.

*Supported by US DOE Grant Nos. DE-FG02-97ER41033, DE-FG02-03ER41231 and NSF Grant No. PHY-0619183.

Authors

  • S.S. Henshaw

    • TUNL
  • M.W. Ahmed

  • N. Brown

  • B.A. Perdue

  • S. Stave

  • H.R. Weller

    • Duke U/TUNL
  • P.P. Martel

  • A. Teymurazyan

  • R. Miskimen

    • UMass
  • R.M. Prior

  • M.C. Spraker

    • NGCSU
  • R. Pywell

    • USask
  • G. Feldman

    • GWU
  • A.M. Nathan

    • UIUC
  • S. Whisnant

    • JMU