ON THE INTENSITY OF NONRADIATIVE TRANSITIONS IN $mu$-MESIC ATOMS

Journal Article · Sat Oct 01 04:00:00 EDT 1960 · Zhur. Eksptl'. I Teoret Fiz.

OSTI ID:4096864

Balats, M Ya; Kondrat'ev, L N; Landsberg, L G; Lebedev, P I; Obukhov, B V; Pontecorvo, B

A systematic study is made of 2P--lS transition intensities in mesic Pb, Bi, Th, U/sup 235/, and U/sup 236/ and the spectra are plotted and normalized. Special attention is given to the background level. The background intensity is strongly reduced by a Cherenkov gas threshold counter, eliminating almost all electrons and reducing the number of pions in the muon beam. The background of 3D--2P transitions at a pulse amplitude corresponding to 2P-- lS was measured using molybdenum and cadmium specimens. Tabulated data show identical intensities for lead and bismuth. The nuclear level density at 6 Mev is abnormally small in lead and bismuth, thus their portion of nonradiative transitions is almost nil, while in other nuclei the nonradiative effect was obvious. Fission, spallation with one neutron emission, and return to the ground state with gamma emissions take place as a result of nuclear excitation by 2P- 1S transitions. Nonradiative fission is impossible due to the mu /sup -/ Coulomb field and neutron emission is impossible due to energy considerations. The relatively small difference of the 2P--lS nonradiative intensity in U/sup 238/ and U/sup 235/ leads to an assu mption that the''combined'' mechanism in groung- state return plays an importart part in"nonnradiative trasnsitions." (R.V.J.)

• Research Organization: Joint Inst. for Nuclear Physics, Dubna, U.S.S.R.
• NSA Number: NSA-15-010124
• OSTI ID: 4096864
• Journal Information: Zhur. Eksptl'. I Teoret Fiz., Journal Name: Zhur. Eksptl'. I Teoret Fiz. Vol. Vol: 39
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

ATOMIC MODELS
ATOMS
BACKGROUND
BEAMS
BISMUTH
CADMIUM
CHERENKOV COUNTERS
EFFICIENCY
ELECTRIC FIELDS
ELECTRIC POTENTIAL
ELECTRONS
ENERGY LEVELS
EXCITATION
FISSION
GAMMA RADIATION
GASES
LEAD
MEASURED VALUES
MESIC ATOMS
MESONS
MOLYBDENUM
MUONS
NEUTRONS
NUCLEAR MODELS
NUCLEAR THEORY
PHYSICS
PIONS
SPECTRA
TARGETS
THORIUM
URANIUM 235
URANIUM 238