Fission fragment mass and energy distributions as a function of incident neutron energy measured in a lead slowing-down spectrometer

Journal Article · Fri Jan 15 00:00:00 EST 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.014607· OSTI ID:21386552

Romano, C; Danon, Y; Block, R; Thompson, J; Blain, E ^[1]; Bond, E ^[2]

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1. Rensselaer Polytechnic Institute, Department of Mechanical, Aerospace, and Nuclear Engineering, NES 1-25, 110 8th Street, Troy, New York 12180 (United States)
2. Los Alamos National Lab, Los Alamos, New Mexico 87545 (United States)

A new method of measuring fission fragment mass and energy distributions as a function of incident neutron energy in the range from below 0.1 eV to 1 keV has been developed. The method involves placing a double-sided Frisch-gridded fission chamber in Rensselaer Polytechnic Institute's lead slowing-down spectrometer (LSDS). The high neutron flux of the LSDS allows for the measurement of the energy-dependent, neutron-induced fission cross sections simultaneously with the mass and kinetic energy of the fission fragments of various small samples. The samples may be isotopes that are not available in large quantities (submicrograms) or with small fission cross sections (microbarns). The fission chamber consists of two anodes shielded by Frisch grids on either side of a single cathode. The sample is located in the center of the cathode and is made by depositing small amounts of actinides on very thin films. The chamber was successfully tested and calibrated using 0.41+-0.04 ng of {sup 252}Cf and the resulting mass distributions were compared to those of previous work. As a proof of concept, the chamber was placed in the LSDS to measure the neutron-induced fission cross section and fragment mass and energy distributions of 25.3+-0.5 mug of {sup 235}U. Changes in the mass distributions as a function of incident neutron energy are evident and are examined using the multimodal fission mode model.

• OSTI ID: 21386552
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 81, Issue 1; Other Information: DOI: 10.1103/PhysRevC.81.014607; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDES
BERYLLIUM ISOTOPES
CALIFORNIUM 252
CROSS SECTIONS
ENERGY DEPENDENCE
ENERGY SPECTRA
FISSION
FISSION CHAMBERS
FISSION FRAGMENTS
KINETIC ENERGY
MASS
MASS DISTRIBUTION
NEUTRON FLUX
NEUTRONS
SLOWING-DOWN
SPECTROMETERS
THIN FILMS
URANIUM 235
ACTINIDE NUCLEI
ALKALINE EARTH ISOTOPES
ALPHA DECAY RADIOISOTOPES
BARYONS
CALIFORNIUM ISOTOPES
DISTRIBUTION
ELEMENTARY PARTICLES
ELEMENTS
ENERGY
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
FILMS
HADRONS
HEAVY NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZATION CHAMBERS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MEASURING INSTRUMENTS
METALS
MINUTES LIVING RADIOISOTOPES
NEUTRON DETECTORS
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
RADIATION DETECTORS
RADIATION FLUX
RADIOISOTOPES
SPATIAL DISTRIBUTION
SPECTRA
SPONTANEOUS FISSION RADIOISOTOPES
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES