PHYSICS DIVISION ANNUAL PROGRESS REPORT FOR PERIOD ENDING MARCH 10, 1959
The longitudinal polarization of P/sup 32/ beta rays was measured to an accuracy of about 2% by the method of Mott scattering from gold. The observed momentum spectrum of singly chnrged Li/sup 6/ recoils from the decay of He/sup 6/ shows that the Gamow-Teller interaction is predominantiy axial-vector. The gamma spectra of Rh/sup 106/ and Ag/sup 106/ were investigated with scintillation spectrometers. Levels and transitions in Pd/sup 106/ are proposed. Measurements of neutron radiative capture cross sections in the kev region were made by a new method involving fast time-of-flight techniques and a large liquid scintillator tank. The total neutron cross section of Be was remeasured from 1.9 to 4.5 Mev. The angular distribution of fragments from the fust-neutron-induced fission of U/sup 235/ was measured for neutron energies between 420 and 3700 kev. The absolute neutron absorption cross sections of Cu, Zn, Ag, Sb, Au, and Pb were measured at 27 kev by use of a spherical-shell transmission method. Total cross sections of elements in the range of A from 35 to 76 were measured in the energy range from 3 to 30 kev. Resonance parameters were extracted and strength functions calculated. Fastchopper time-of-flight spectrometer studies were made on enriched samples of I/sup 129/, U/sup 233/, U/sup 234/, U/sup 235/, Pu/s up 240/, Lu/sup 175/ Lu/sup 176/ Ta/sup 180/, on natural-abundance samples of Ta and La, and on samples of Am/sup 241/. The resonances observed were analyzed and compared with theoretical predictions of level spacings. General properties are derived for fundamental-mode thermal neutron distributions in heterogeneous pulsed systems. Nuclear spins of 5 and 4 were measured for I/sup 130/ and I/sup 132/ by means of the atomic-beam magnetic-resonance technique. Zeeman data of Blank and wavelength data of Gatterer and Junkes on the spectra of Dy were used with IBM605 calculated wave numbers on Edlen scale to couple two of the energy- level doublets reported by Paulson and Blank. Infrared spectra obtained for the stable cubic phases and two metastable phases, of NH/sub 3/ and ND/sub 3/ are discussed. The results of single-crystal neutron diffraction investigations of the antiferromagnetic structures of CrCl/sub 3/ and FeCl/sub 3/ are presented. Preliminary neutrcn diffraction observations on HoN at low temperatures indicate that this compound becomes ferromagnetic below about 20 K and that the Ho/sup 3+/ ions in the magnetic lattice have an ordered magnetic moment of 8.0 sintering time 1.0 Bohr magnetons. Neutron diffraction investigations of metallic cerium at low temperatures and of antiferromagnetism in CrF/sub 2/ and CrCl/sub 2/ arc reported. Helium is showm to be a satisfuctory filling gas for lowtemperature ionization chambers. A theoretical and experimental study of germanium surfuce barrier counters at low temperatures indicated very satisfactory characteristics. A double focusing, uniform field magnet was designed and constructed for the analysis of charged particles from nuclear reactions. A new time-of-flight measuring apparatus is described which differs from conventional time-to-pulse-amplitude converters in that it produces a d-c output large enough to be fed directly into a multichannel sorting device. (For preceding period see ORNL-2610.) (W.D.M.)
- Research Organization:
- Oak Ridge National Lab., Tenn.
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-13-014609
- OSTI ID:
- 4256978
- Report Number(s):
- ORNL-2718
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-59
- Country of Publication:
- United States
- Language:
- English
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ABSORPTION- ANGULAR DISTRIBUTION- BOHR MAGNETON- COPPER- CROSS SECTIONS- ENERGY- FISSION PRODUCTS- GOLD- IODINE 130- KEV RANGE- LEAD- MEASURED VALUES- NEUTRONS- RESONANCE- SILVER- URANIUM 235- ZINC
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