An excited state of [sup 229]Th at 3. 5 eV

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.49.1845· OSTI ID:5017427

Helmer, R G; Reich, C W ^[1]

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1. Idaho National Engineering Laboratory, E and G Idaho, Inc., Idaho Falls, Idaho 83415 (United States)

It has been known for many years that the first excited state of [sup 229]Th lies close to the ground state. Originally this energy was given as [lt]0.1 keV; later, the authors reported a value of [minus]1[plus minus]4 eV. In an attempt to improve the value for this level energy, we have remeasured the energies of a number of [gamma] rays from [sup 223]U whose positions in the [sup 229]Th level scheme can be used to establish it. Compared with our earlier study, we have considered more [gamma] rays in [sup 229]Th, used more well-measured energy calibration and reference lines, used more detectors, used detectors with better low-energy resolution, more closely matched the counting rates in the [gamma]-ray peaks whose relative energy is measured, and specifically considered certain systematic errors. More than 111 [gamma]-ray spectra have been measured. From this large set of measurements we have deduced a value of 3.5[plus minus]1.0 eV for the energy of this level.

• DOE Contract Number: AC07-76ID01570
• OSTI ID: 5017427
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 49:4; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

663220* -- Electromagnetic Transitions-- (1992-)
663590 -- Nuclear Mass Ranges-- A=220 & Above-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EVEN-ODD NUCLEI
GAMMA SPECTROSCOPY
HEAVY ION DECAY RADIOISOTOPES
HEAVY NUCLEI
ISOTOPES
M1-TRANSITIONS
MULTIPOLE TRANSITIONS
NEON 24 DECAY RADIOISOTOPES
NUCLEI
RADIOISOTOPES
SPECTROSCOPY
SPONTANEOUS FISSION RADIOISOTOPES
THORIUM 229
THORIUM ISOTOPES
URANIUM 233
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES