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Computerized systems for ultralow temperature polarized nuclei time reversal and parity experiments

Description: From nuclear science symposium; San Francisco, California, USA (14 Nov 1973). Experiments for studying nuclear polarization phenomena at ultralow temperatures require extreme precision in the collected data. The polarization of the applied field must be changed periodically and the data from gamma-ray spectra must be reduced as the experiment progresses. These experiments sometime run for days in order to obtain good statistical data and to reduce any errors induced by the system instrumentation. A computerized system used to automate the necessary control and data handling functions for this class of experiment is described. (auth)
Date: January 1, 1973
Creator: Handy, L.E. & Steyert, W.A.
Partner: UNT Libraries Government Documents Department

Spectra of $gamma$-rays from capture of 2 eV to 9 x 10$sup 4$ eV neutrons by $sup 181$Ta

Description: Using new experimental techniques, the spectra of $gamma$-rays from the capture of neutrons by $sup 181$Ta were measured at the Livermore 100-MeV linac for neutrons from 2 eV to 9 x 10$sup 4$ eV with a (Ge(Li)-NaI) three-crystal spectrometer. Individual primary $gamma$-ray lines were resolved to 1778-keV excitation in $sup 182$Ta. Neutron resonances were resolved to 200-eV neutron energy. Data analysis techniques and codes were developed to extract positions and intensities of resolved transitions from the large data matrices accumulated in this experiment. Techniques were developed to unfold the unresolved $gamma$- ray spectra using the simple response of the three-crystal spectrometer. The resolved transition data were used to place 110 states with spin and parity assignments in the $sup 182$Ta level diagram below 1780-keV excitation. A set of 1240 E1 transition strengths were analyzed to extract 1.38 +- 0.11 degrees of freedom for the most likely chisquared fit to the distribution of widths. The E1 strength function was extracted for E/sub gamma/ = 4 to 6 MeV and compared with previous results. The $gamma$-ray spectra for E/sub gamma/ = 1.5 to 6.1 MeV were unfolded for neutron energy groups between 20 and 9 x 10$sup 4$ eV. Below 5-MeV $gamma$-ray energy no dependence of the spectral shape on neutron energy was observed. (30 figures, 4 tables) (auth)
Date: April 30, 1976
Creator: Stelts, M.L.
Partner: UNT Libraries Government Documents Department