McDonold, Theory of Simple Liquids, 2nd edn (Acad. A precision measurement also provides a self consistency check of the unitarity of the CKM mixing. It is the most important experimental parameter in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. Benjamin, Inc., Advanced Book Program Reading, Massachusetts, London, Amsterdam, Don Mills, Ontario, Sidney, Tokyo, 1975)& The neutron lifetime plays an important role in both nuclear astrophysics and in furthering the understanding of weak interactions in the Standard Model. Forster, Hydrodynamic Fluctuations, Broken Symmetry, and Correlation Functions (W.A. Benjamin, Inc., Advanced Book Program Reading, Massachusetts, London, Amsterdam, Don Mills, Ontario, Sidney, Tokyo, 1975). Google Scholar D.I.&author=Plakida N.M.&publication_year=1977&journal=Phys. Google Scholar A.V.&publication_year=1976&journal=Fiz. Google Scholar R.&publication_year=1996&journal=Rev. Google Scholar A.L.&author=Belyaev S.T.&publication_year=1999&journal=Phys. Google Scholar V.F.&publication_year=1982&journal=Phys. Google Scholar V.F.&publication_year=1978&journal=Can. Watson, Collision Theory (John Wiley and Sons Inc., New York, London, Sydney, 1964)& Watson, Collision Theory (John Wiley and Sons Inc., New York, London, Sydney, 1964). Google Scholar K.M.&publication_year=1957&journal=Phys. Google Scholar V.V.&author=Strelkov A.V.&author=Geltenbort P.&author=Iadjiev P.S.&publication_year=1999&journal=Eur. Google Scholar L.&author=Geltenbort P.&author=Korobkina E.&author=Morozov V.&author=Panin Yu.&author=Steyerl A.&publication_year=1998&journal=Pis'ma v ZETP&volume=68&pages=663 Lamoreaux, Ultra-cold Neutrons (Adam Hilger, Bristol, Philadelphia and New York, IOP Publishing Ltd, 1991)& Lamoreaux, Ultra-cold Neutrons (Adam Hilger, Bristol, Philadelphia and New York, IOP Publishing Ltd, 1991). Ignatovich, The Physics of Ultracold Neutrons (Oxford, Clarendon Press, 1990)& Ignatovich, The Physics of Ultracold Neutrons (Oxford, Clarendon Press, 1990). Google Scholar R.&author=Pendlebury J.M.&publication_year=1979&journal=Rep. Google Scholar A.&publication_year=1977&journal=Springer Tracts Mod. Lovesey, Theory of Neutron Scattering from Condensed Matter (Oxford, Clarendon Press, 1984), Vols. Tarasov, Low Energy Neutron Physics (Amsterdam, North Holland, 1968)&
Tarasov, Low Energy Neutron Physics (Amsterdam, North Holland, 1968). Turchin, Slow Neutrons (Jerusalem: Israel Programm for Scientific Translations, 1965)& Turchin, Slow Neutrons (Jerusalem: Israel Programm for Scientific Translations, 1965). No commercial reproduction, distribution, display or performance rights in this work are provided.V.F. National Institute of Standards and Technology (NIST) This research used resources of ANL's ATLAS facility, which is a DOE Office of Science User Facility. Department of Energy, Office of Science, Office of Nuclear Physics, under Contracts No. National Science Foundation under Grant No. This work is also supported in part by the U.S. Department of Commerce, in providing support for facilities used in this work. We acknowledge the support of the NIST, U.S. (Received 10 February 2016 published 13 June 2016) High-sensitivity measurement of He3−He4 isotopic ratios for ultracold neutron experiments We also argue that there is a clear path forward to sensitivity increases of at least another order of magnitude. Measurements of ^3He/^4He in samples relevant to the measurement of the neutron lifetime indicate the need for substantial corrections. We demonstrate an approach to such a measurement using accelerator mass spectroscopy, reaching the 10^(−14) level of sensitivity, several orders of magnitude more sensitive than other techniques. Research efforts ranging from studies of solid helium to searches for a neutron electric dipole moment require isotopically purified helium with a ratio of ^3He to ^4He at levels below that which can be measured using traditional mass spectroscopy techniques.
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