NUCLEAR FISSION INDUCED BY RADIATIONLESS TRANSITIONS IN THE MU-MESONIC ATOMS Th$sup 232$, U$sup 235$, AND U$sup 238$ (thesis)

Technical Report · Tue May 01 04:00:00 EDT 1962

OSTI ID:4801650

Diaz, J A

The time distribution of fissions in Th/sup 232/,U/sup 235/, and U/sup 238/ induced by mesons( mu /sup -/) was measured with a multiplate gas- scintillation fission chamber. A significant number of prompt fissions that are not associated with meson( mu /sup -/) nuclear capture were observed. The work of Muknin et al. shows that the intensities of mu -mesic K x rays for these elements relative to Pb are 0.85 plus or minus 0.0 (Th/sup 232/), 0.77 plus or minus 0.04 (U/sup 238/), and 0.71 plus or minus 0.05 (U.sup 235/). This intensity reduction is qualitatively consistent with earlier predictions that, for these elements, a direct excitation of the nucleus competes with electromagnetic radiation in the transition to the ground state of the mesic atom. Resuits of measurements in this report indicate such direct nuclear excitation. The number of fissions observed can be made quantitatively consistent with the resuits of Muknin et al. and with photofission data when the effect on the fission barrier of the meson( mu ) in the 1S state of the mesic atom is taken into consideration. (auth)

• Research Organization: California. Univ., Berkeley. Lawrence Radiation Lab.
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-16-029662
• OSTI ID: 4801650
• Report Number(s): UCRL-10214
• Country of Publication: United States
• Language: English

Related Subjects

ATOMS
DISTRIBUTION
ELECTROMAGNETIC WAVES
ENERGY LEVELS
EXCITATION
FISSION
FISSION CHAMBERS
GASES
LEAD
MEASURED VALUES
MUONS
NUCLEI
PHYSICS
RADIATIONS
SCINTILLATIONS
THORIUM 232
TRANSITIONS
URANIUM 235
URANIUM 238
X RADIATION