Neutron Lifetime Experiment Based on an Accordion-Like UCN Storage Volume Coated With "Low Temperature Fomblin".
A new type of per-fluorinated polymer, "Low Temperature Fomblin," has been tested as a wall coating in an ultracold neutron (UCN) storage experiment using a gravitational storage system. The data show a UCN reflection loss coefficient η as low as ≈ 5 × 10(-6) in the temperature range 105 K to 150 K. We plan to use this oil in a new type of neutron lifetime measurement, where a bellows system ("accordion") enables to vary the trap size in a wide range while the total surface area and distribution of surface area over height remain constant. These unique characteristics, in combination with application of the scaling technique developed by W. Mampe et al. in 1989, ensure exact linearity for the extrapolation from inverse storage lifetimes to the inverse neutron lifetime. Linearity holds for any energy dependence of loss coefficient µ(E). Using the UCN source at the Institut Laue Langevin we expect to achieve a lifetime precision below ±1 s.
Harvard University, Cambridge, MA, USA.
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Yerozolimsky
University of Rhode Island, Kingston, RI, USA.
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Steyerl
University of Rhode Island, Kingston, RI, USA.
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Kwon
Joint Institute for Nuclear Research, Dubna, Russia.
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Luschikov
Joint Institute for Nuclear Research, Dubna, Russia.
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Strelkov
Institut Laue Langevin, Grenoble, France.
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Geltenbort
Osaka University, Japan.
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Achiwa
Paul Scherrer Institut, Villigen, Switzerland.
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Pichlmaier
Paul Scherrer Institut, Villigen, Switzerland.
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Fierlinger
neutron lifetime; ultracold neutrons