12. 3-min /sup 256/Cf and 43-min /sup 258/Md and systematics of the spontaneous fission propertiesof heavy nuclides

Journal Article · Fri Feb 29 23:00:00 EST 1980 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.21.972· OSTI ID:5482680

Hoffman, D C; Wilhelmy, J B; Weber, J; Daniels, W R; Hulet, E K; Lougheed, R W; Landrum, J H; Wild, J F; Dupzyk, R J

The new isotope 12.3-min /sup 256/Cf was produced via the /sup 254/Cf(t,p) reaction, and a new 43-min isomer of /sup 258/Md was produced via the /sup 255/Es(..cap alpha..,n) reaction. The fragment mass and kinetic energy distributions from the spontaneous fission of /sup 256/Cf were found to be very similar to those from the spontaneous fission of lighter Cf isotopes. The mass division is primarily asymmetric, and the average total kinetic energy is 189.8 +- 0.9 MeV. The 43-min /sup 258/Md presumably decays by electron capture and provides an opportunity to study the mass and kinetic energy distributions from the spontaneous fission of the 380-..mu..s /sup 258/Fm daughter. The observed narrow, symmetric mass distribution and the most probable total kinetic energy of 238 +- 3 MeV are similar to those reported for the spontaneous fission of /sup 259/Fm but show a sharp increase in symmetric mass division and total kinetic energy compared to /sup 257/Fm and the lighter Fm isotopes. No such abrupt change in properties was observed for /sup 256/Cf, which, like /sup 258/Fm, has 158 neutrons. The marked difference between the spontaneous fission properties of the heavier Fm isotopes and those of other spontaneously fissioning nuclides is compared to some theoretical predictions.

• Research Organization: Los Alamos Scientific Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 5482680
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 21:3; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA REACTIONS
BETA DECAY
CALIFORNIUM 254 TARGET
CALIFORNIUM 256
CALIFORNIUM ISOTOPES
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
DECAY
DETECTION
DIRECT REACTIONS
EINSTEINIUM 255 TARGET
ELECTRON CAPTURE DECAY
ENERGY
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIUM 259
FERMIUM ISOTOPES
FISSION
FISSION FRAGMENT DETECTION
HALF-LIFE
HEAVY NUCLEI
ISOTOPES
KINETIC ENERGY
MASS SPECTRA
MENDELEVIUM 258
MENDELEVIUM ISOTOPES
MINUTES LIVING RADIOISOTOPES
MULTI-NUCLEON TRANSFER REACTIONS
NEUTRON SPECTRA
NUCLEAR REACTIONS
NUCLEI
ODD-ODD NUCLEI
PROTON SPECTRA
RADIATION DETECTION
RADIOISOTOPES
SPECTRA
SPONTANEOUS FISSION
TARGETS
THREE-NUCLEON TRANSFER REACTIONS
TRANSFER REACTIONS
TRITON REACTIONS
TWO-NUCLEON TRANSFER REACTIONS