702 research outputs found
Development of High Intensity Neutron Source at the European Spallation Source
The European Spallation Source being constructed in Lund, Sweden will provide
the user community with a neutron source of unprecedented brightness. By 2025,
a suite of 15 instruments will be served by a high-brightness moderator system
placed above the spallation target. The ESS infrastructure, consisting of the
proton linac, the target station, and the instrument halls, allows for
implementation of a second source below the spallation target. We propose to
develop a second neutron source with a high-intensity moderator able to (1)
deliver a larger total cold neutron flux, (2) provide high intensities at
longer wavelengths in the spectral regions of Cold (4-10 \AA ), Very Cold
(10-40 \AA ), and Ultra Cold (several 100 \AA ) neutrons, as opposed to Thermal
and Cold neutrons delivered by the top moderator. Offering both unprecedented
brilliance, flux, and spectral range in a single facility, this upgrade will
make ESS the most versatile neutron source in the world and will further
strengthen the leadership of Europe in neutron science. The new source will
boost several areas of condensed matter research such as imaging and spin-echo,
and will provide outstanding opportunities in fundamental physics
investigations of the laws of nature at a precision unattainable anywhere else.
At the heart of the proposed system is a volumetric liquid deuterium moderator.
Based on proven technology, its performance will be optimized in a detailed
engineering study. This moderator will be complemented by secondary sources to
provide intense beams of Very- and Ultra-Cold Neutrons.Comment: 12 pages, 4 figures, proceeding of the 23rd meeting of the
International Collaboration on Advanced Neutron Sources (ICANS XXIII) 13th -
18th October 2019 in Chattanooga, Tennesse
"m=1" coatings for neutron guides
A substantial fraction of the price for a supermirror neutron guide system is the shielding, which is needed because of the gamma radiation produced as a result of neutron absorption in the supermirror layers. Traditional coatings have been made of nickel-titanium heterostructures, but Ni and Ti also have a fairly high absorption cross section for cold and thermal neutrons. We examine a number of alternatives to Ni as part of a study to reduce the gamma radiation from neutron guides. Materials such as diamond and Be have higher neutron scattering density than Ni, smaller absorption cross section, and when a neutron is absorbed they emit gamma photons with lower energies. We present reflectivity data comparing Ni with Be and preliminary results from diamond coatings showing there use as neutron guide coatings. Calculations show that Be and diamond coatings emit two orders of magnitude fewer gamma photons compared to Ni, mainly because of the lower absorption cross section
"m=1" coatings for neutron guides
A substantial fraction of the price for a supermirror neutron guide system is the shielding, which is needed because of the gamma radiation produced as a result of neutron absorption in the supermirror layers. Traditional coatings have been made of nickel-titanium heterostructures, but Ni and Ti also have a fairly high absorption cross section for cold and thermal neutrons. We examine a number of alternatives to Ni as part of a study to reduce the gamma radiation from neutron guides. Materials such as diamond and Be have higher neutron scattering density than Ni, smaller absorption cross section, and when a neutron is absorbed they emit gamma photons with lower energies. We present reflectivity data comparing Ni with Be and preliminary results from diamond coatings showing there use as neutron guide coatings. Calculations show that Be and diamond coatings emit two orders of magnitude fewer gamma photons compared to Ni, mainly because of the lower absorption cross section
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