An improvement in the value of the energy of the first excited state in {sup 229}Th

Technical Report · Thu Apr 01 04:00:00 EST 1993

DOI:https://doi.org/10.2172/10170391· OSTI ID:10170391

Helmer, R G; Reich, C W

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 < 0.1 keV; later, the authors reported a value of {minus}1 {plus_minus} 4 eV. Since the existence of a nuclear state at this very low energy is of considerable interest, measurements of its energy, half-life and modes of excitation and deexcitation are important. In an attempt to improve the level energy, the authors have measured over 175 {gamma}-ray spectra with several combinations of radionuclides. In comparison with their earlier study, they have considered more {gamma} rays in {sup 229}Th, used more well-measured reference lines, used more detectors, used detectors with better low-energy resolution, more closely matched peak count rates, and specifically considered certain systematic errors. From this large set of measurements they have deduced a value of 3.5 {plus_minus} 1.0 eV for the energy of this level.

• Research Organization: EG and G Idaho, Inc., Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 10170391
• Report Number(s): EGG-NRP--10693; ON: DE93016594
• Country of Publication: United States
• Language: English

Related Subjects

663110
663590
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
A = 220 AND ABOVE
AMERICIUM 241
BINDING ENERGY
COMPARATIVE EVALUATIONS
EV RANGE 01-10
EXCITATION
EXCITED STATES
EXPERIMENTAL DATA
GAMMA SPECTRA
GENERAL AND AVERAGE PROPERTIES OF NUCLEI AND NUCLEAR ENERGY LEVELS
GROUND STATES
HAFNIUM 172
HALF-LIFE
LUTETIUM 172
RADIATION DETECTORS
TERBIUM 161
THORIUM 229
URANIUM 233