1,068 research outputs found
Nuclear forensics using gamma-ray spectroscopy
Much of George Dracoulis's research career was devoted to utilizing gamma-ray
spectroscopy in fundamental studies in nuclear physics. This same technology is
useful in a wide range of applications in the area of nuclear forensics. Over
the past several years, our research group has made use of both high- and low-
resolution gamma ray spectrometers to: identify the first sample of plutonium
large enough to be weighed; determine the yield of the Trinity nuclear
explosion; measure fission fragment yields as a function of target nucleus and
neutron energy; and observe fallout in the U. S. from the Fukushima nuclear
reactor accident.Comment: 3 pages; 7 figures; conference proceedin
Observations of Fallout from the Fukushima Reactor Accident in San Francisco Bay Area Rainwater
We have observed fallout from the recent Fukushima Dai-ichi reactor accident
in samples of rainwater collected in the San Francisco Bay area. Gamma ray
spectra measured from these samples show clear evidence of fission products -
131,132I, 132Te, and 134,137Cs. The activity levels we have measured for these
isotopes are very low and pose no health risk to the public.Comment: 5 pages, 2 figure
Evidence against correlations between nuclear decay rates and Earth-Sun distance
We have reexamined our previously published data to search for evidence of
correlations between the rates for the alpha, beta-minus, beta-plus, and
electron-capture decays of 22Na, 44Ti, 108Agm, 121Snm, 133Ba, and 241Am and the
Earth-Sun distance. We find no evidence for such correlations and set limits on
the possible amplitudes of such correlations substantially smaller than those
observed in previous experiments
Wavelength independent interferometer
A polychromatic interferometer utilizing a plurality of parabolic reflective surfaces to properly preserve the fidelity of light wavefronts irrespective of their wavelengths as they pass through the instrument is disclosed. A preferred embodiment of the invention utilizes an optical train which comprises three off-axis parabolas arranged in conjunction with a beam-splitter and a reference mirror to form a Twyman-Green interferometer. An illumination subsystem is provided and comprises a pair of lasers at different preselected wavelengths in the visible spectrum. The output light of the two lasers is coaxially combined by means of a plurality of reflectors and a grating beam combiner to form a single light source at the focal point of the first parabolic reflection surface which acts as a beam collimator for the rest of the optical train. By using visible light having two distinct wavelengths, the present invention provides a long equivalent wavelength interferogram which operates at visible light wherein the effective wavelength is equal to the product of the wavelengths of the two laser sources divided by their difference in wavelength. As a result, the invention provides the advantages of what amounts to long wavelength interferometry but without incurring the disadvantage of the negligible reflection coefficient of the human eye to long wavelength frequencies which would otherwise defeat any attempt to form an interferogram at that low frequency using only one light source
Prospects for CUORE and Latest Results from CUORICINO
CUORE (Cryogenic Underground Observatory for Rare Events) is a proposed next generation experiment designed to search for the neutrinoless DBD of {sup 130}Te using a bolometric technique. The present status of the CUORE is presented along with the latest results from its operating prototype, CUORICINO
Cosmogenic-neutron activation of TeO2 and implications for neutrinoless double-beta decay experiments
Flux-averaged cross sections for cosmogenic-neutron activation of natural
tellurium were measured using a neutron beam containing neutrons of kinetic
energies up to 800 MeV, and having an energy spectrum similar to that of
cosmic-ray neutrons at sea-level. Analysis of the radioisotopes produced
reveals that 110mAg will be a dominant contributor to the cosmogenic-activation
background in experiments searching for neutrinoless double-beta decay of
130Te, such as CUORE and SNO+. An estimate of the cosmogenic-activation
background in the CUORE experiment has been obtained using the results of this
measurement and cross-section measurements of proton activation of tellurium.
Additionally, the measured cross sections in this work are also compared with
results from semi-empirical cross-section calculations.Comment: 11 pages, 5 figure
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