138 research outputs found
Fast-Neutron Activation of Long-Lived Isotopes in Enriched Ge
We measured the production of \nuc{57}{Co}, \nuc{54}{Mn}, \nuc{68}{Ge},
\nuc{65}{Zn}, and \nuc{60}{Co} in a sample of Ge enriched in isotope 76 due to
high-energy neutron interactions. These isotopes, especially \nuc{68}{Ge}, are
critical in understanding background in Ge detectors used for double-beta decay
experiments. They are produced by cosmogenic-neutron interactions in the
detectors while they reside on the Earth's surface. These production rates were
measured at neutron energies of a few hundred MeV. We compared the measured
production to that predicted by cross-section calculations based on CEM03.02.
The cross section calculations over-predict our measurements by approximately a
factor of three depending on isotope. We then use the measured cosmic-ray
neutron flux, our measurements, and the CEM03.02 cross sections to predict the
cosmogenic production rate of these isotopes. The uncertainty in extrapolating
the cross section model to higher energies dominates the total uncertainty in
the cosmogenic production rate.Comment: Revised after feedback and further work on extrapolating cross
sections to higher energies in order to estimate cosmic production rates.
Also a numerical error was found and fixed in the estimate of the Co-57
production rat
Project 8 Phase III Design Concept
We present a working concept for Phase III of the Project 8 experiment,
aiming to achieve a neutrino mass sensitivity of ( C.L.)
using a large volume of molecular tritium and a phased antenna array. The
detection system is discussed in detail.Comment: 3 pages, 3 figures, Proceedings of Neutrino 2016, XXVII International
Conference on Neutrino Physics and Astrophysics, 4-9 July 2016, London, U
Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector
The Project 8 collaboration seeks to measure the absolute neutrino mass scale
by means of precision spectroscopy of the beta decay of tritium. Our technique,
cyclotron radiation emission spectroscopy, measures the frequency of the
radiation emitted by electrons produced by decays in an ambient magnetic field.
Because the cyclotron frequency is inversely proportional to the electron's
Lorentz factor, this is also a measurement of the electron's energy. In order
to demonstrate the viability of this technique, we have assembled and
successfully operated a prototype system, which uses a rectangular waveguide to
collect the cyclotron radiation from internal conversion electrons emitted from
a gaseous Kr source. Here we present the main design aspects of the
first phase prototype, which was operated during parts of 2014 and 2015. We
will also discuss the procedures used to analyze these data, along with the
features which have been observed and the performance achieved to date.Comment: 3 pages; 2 figures; Proceedings of Neutrino 2016, XXVII International
Conference on Neutrino Physics and Astrophysics, 4-9 July 2016, London, U
ADMX-Orpheus First Search for 70 eV Dark Photon Dark Matter: Detailed Design, Operations, and Analysis
Dark matter makes up 85% of the matter in the universe and 27% of its energy
density, but we don't know what comprises dark matter. It is possible that dark
matter may be composed of either axions or dark photons, both of which can be
detected using an ultra-sensitive microwave cavity known as a haloscope. The
haloscope employed by ADMX consists of a cylindrical cavity operating at the
TM mode and is sensitive to the QCD axion with masses of few eV.
However, this haloscope design becomes challenging to implement for higher
masses. This is because higher masses require smaller-diameter cavities,
consequently reducing the detection volume which diminishes the detected signal
power. ADMX-Orpheus mitigates this issue by operating a tunable,
dielectrically-loaded cavity at a higher-order mode, allowing the detection
volume to remain large. This paper describes the design, operation, analysis,
and results of the inaugural ADMX-Orpheus dark photon search between 65.5
eV (15.8 GHz) and 69.3 eV (16.8 GHz), as well as future directions
for axion searches and for exploring more parameter space.Comment: 21 pages, 29 figures. To be submitted to Physical Review D. arXiv
admin note: substantial text overlap with arXiv:2112.0454
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