Doppler measurements of /sup 238/U

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1981

OSTI ID:6258446

Aminfar, H

Using filtered beams of neutrons from MURR at three energies (2, 24 and 144 keV), which span the energy range in which the Doppler effect of /sup 238/U is most sensitive, average transmission measurements were made for /sup 238/U metal, /sup 238/U/sub 3/O/sub 8/, /sup 238/UO/sub 2/ and /sup 238/UC to investigate the thickness and temperature dependence of the EATCS (Effective Average Total Cross Section) of /sup 238/U. To study the self shielding effect of /sup 238/U metal, U/sub 3/O/sub 8/, UO/sub 2/ and UC at room temperature, measurements were made for different sample thicknesses at all three energies. The selfshielding effect was larger for strongly-bonded materials (U/sub 3/O/sub 8/ and UO/sub 2/) which have sharper resonances. EATCS were measured at 2 keV as a function of temperature between 300 K and 1295 K for /sup 238/U in U/sub 3/O/sub 8/, UO/sub 2/ and UC. Temperature-related density effects were suppressed by measuring simultaneously the gamma-rays passing through the sample. The EATCS of /sup 238/U metal (a weakly-bonded solid) as a function of temperature was larger than the increase in the EATCS of /sup 238/U in U/sub 3/O/sub 8/, UO/sub 2/ and UC (strongly-bonded solids). A stepwise increase was obtained in the EATCS of /sup 238/U metal at the melting point. This step is attributed to changes in the crystalling binding of /sup 238/U metal, which are directly related to the sudden change in the thermal motion of the /sup 238/U atoms. Measured values were compared with the empirical model, which employs the method of stochastically generating a set of pseudo resonance parameters from the initial resonance input parameters for both s-waves and p-waves.

• Research Organization: Missouri Univ., Columbia (USA)
• OSTI ID: 6258446
• Country of Publication: United States
• Language: English

Related Subjects

654003* -- Radiation & Shielding Physics-- Neutron Interactions with Matter
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYONS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
CROSS SECTIONS
DATA
DIMENSIONS
DOPPLER EFFECT
ELEMENTARY PARTICLES
ELEMENTS
ENERGY DEPENDENCE
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
FERMIONS
HADRONS
HEAVY NUCLEI
INFORMATION
ISOTOPES
METALS
NEUTRAL-PARTICLE TRANSPORT
NEUTRON TRANSPORT
NEUTRONS
NUCLEI
NUCLEONS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RADIATION TRANSPORT
RADIOISOTOPES
THICKNESS
TOTAL CROSS SECTIONS
TRANSMISSION
URANIUM 238
URANIUM CARBIDES
URANIUM COMPOUNDS
URANIUM ISOTOPES
URANIUM OXIDES
YEARS LIVING RADIOISOTOPES