LIFETIME OF THE FIRST EXCITED STATE OF Li$sup 7$

Journal Article · Fri May 01 04:00:00 EDT 1959 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.114.862· OSTI ID:4237590

Swann, C P; Rasmussen, V K; Metzger, F R

The Li/sup 7/(p,p )Li/sup 7*/ reaction was used as the source of Doppler- broadened 478-kev gamma rays to deiermine the mean life of the first excited state of Li/sup 7/ by the nuclear resonance fluorescence technique. Both scattering and self-absorption experiments using both LiF and Li as the scattering and absorbing materials were performed. The resonance scattering gives a mean life of (1.09 plus or minus 0.07) x l0/sup -13/ sec after a 2% correction for slowing down of the Li/sup 7*/ nuclei has been made. This correction follows from the measured stopping cross sections for lithium ions. An additional correction, for the effect of collisions in which the Li/sup 7*/ nuclei lose a large fraction of their energy, is found difficult to estimate, although it is certainly not more than a few percent. For this reason, the scattering measurement f s regarded as giving a lower limit for the mean life. The self-absorption measurements gfve a mean life of (1.l5 plus or minus 0.l4) x 10/sup -13/ sec. Debye temperatures of 400 and 700 deg K were used for Li and LiF, respectively. The error given, about twice the statistical error of the data, includes estimates of the effect of other experimental uncertainties. (auth)

• Research Organization: Franklin Inst., Swarthmore, Penna.
• NSA Number: NSA-13-017267
• OSTI ID: 4237590
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 114; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ABSORPTION
DOPPLER EFFECT
ENERGY LEVELS
ERRORS
EXCITATION
GAMMA RADIATION
HALF-LIFE
INELASTIC SCATTERING
LITHIUM
LITHIUM 7
LITHIUM FLUORIDES
MEASURED VALUES
PHYSICS AND MATHEMATICS
PROTON BEAMS
PROTONS
RESONANCE
SCATTERING
SPECTRAL SHIFT