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A measurement of the neutron lifetime $\tau_{n}$ performed by the absolute counting of in-beam neutrons and their decay protons has been completed. Protons confined in a quasi-Penning trap were accelerated onto a silicon detector held at a…

We propose a method to increase both the neutron storage time and the precision of its lifetime measurements by at least tenfold. The storage of ultracold neutrons (UCN) in material traps now provides the most accurate measurements of…

Instrumentation and Detectors · Physics 2021-11-22 P. D. Grigoriev , A. M. Dyugaev

We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium SD2. This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid…

To increase the storage time of ultracold neutrons (UCN) inside the material traps it is promising to cover the trap walls by liquid 4He, the material which does not absorb neutrons at all. A rough side wall of UCN trap holds the required…

Instrumentation and Detectors · Physics 2023-08-30 Pavel D. Grigoriev , Arseniy V. Sadovnikov , Vladislav D. Kochev , Alexander M. Dyugaev

The precise determination of the free neutron lifetime is of great significance in modern precision physics. This key observable is linked to the mixing of up and down quarks via the Cabibbo-Kobayashi-Maskawa matrix element $V_{ud}$, and…

The neutron lifetime is determined for now most accurately by two methods --the so-called "beam method" and the method of neutron storage in a trap. The goal of this research is to obtain the neutron lifetime with a higher precision by…

Nuclear Experiment · Physics 2020-01-23 Valerius V. Vasiliev

Different geometries for the neutron lifetime measurements by the method of ultracold neutron storage in material traps and additional possibilities for the neutron storage in the magnetic storage ring are considered.

Nuclear Experiment · Physics 2011-04-07 Yu. N. Pokotilovski

The neutron lifetime is important in understanding the production of light nuclei in the first minutes after the big bang and it provides basic information on the charged weak current of the standard model of particle physics. Two different…

The most precise determination of the neutron lifetime using the beam method was completed in 2005 and reported a result of $\tau_n = (886.3 \pm 1.2 [\textrm{stat}] \pm 3.2 [\textrm{syst}])$ s. The dominant uncertainties were attributed to…

Nuclear Experiment · Physics 2013-11-28 A. T. Yue , M. S. Dewey , D. M. Gilliam , G. L. Greene , A. B. Laptev , J. S. Nico , W. M. Snow , F. E. Wietfeldt

The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN…

The analysis of experiments on measuring neutron lifetime has been made. The latest most accurate result of measuring neutron lifetime [Phys. Lett. B 605, 72 (2005)] 878.5 \pm 0.8 s differs from the world average value [Phys. Lett. B 667, 1…

Nuclear Experiment · Physics 2011-04-22 A. P. Serebrov , A. K. Fomin

Ultracold neutrons (UCNs) are a useful tool for fundamental physics experiments. They can be used to probe the lifetime of free neutrons, search for new CP violating processes and exotic interactions beyond the Standard Model, perform…

Instrumentation and Detectors · Physics 2021-04-07 Stefan Döge , Jürgen Hingerl , Christoph Morkel

Ultracold neutrons (UCN) are free neutrons that can be stored in experimental setups for several minutes. Some of the most important properties of the neutron, such as its tiny permanent electric dipole moment and its beta decay lifetime,…

Nuclear Experiment · Physics 2020-06-09 Klaus Kirch , Bernhard Lauss

Three-dimensional magnetic confinement of neutrons is reported. Neutrons are loaded into an Ioffe-type superconducting magnetic trap through inelastic scattering of cold neutrons with 4He. Scattered neutrons with sufficiently low energy and…

We installed a source for ultracold neutrons at a new, dedicated spallation target at TRIUMF. The source was originally developed in Japan and uses a superfluid-helium converter cooled to 0.9$\,$K. During an extensive test campaign in…

We present experimental measurements of the properties of a liquid "Fomblin" surface obtained by the quasielastic scattering of laser light. The properties include the surface tension and viscosity as a function of temperature. The results…

Nuclear Experiment · Physics 2010-05-27 S. K. Lamoreaux , R. Golub

We report experiments on the production of ultracold neutrons (UCN) in a converter of superfluid helium coated with fluorinated grease. We employed our technique of window-free extraction of accumulated UCN from the helium, in which they…

Nuclear Experiment · Physics 2008-02-01 O. Zimmer , P. Schmidt-Wellenburg , M. Assmann , M. Fertl , J. Klenke , S. Mironov , H. -F. Wirth , B. van den Brandt

The results of measurements performed using UCN storing method are in good agreement. The latest most accurate measurements of the neutron decay asymmetry and neutron lifetime measurements by storage method are in agreement within the…

Nuclear Experiment · Physics 2020-03-05 A. P. Serebrov , M. E. Chaikovskii , G. N. Klushnikov , O. M. Zherebtsov , A. V. Chechkin

We analyze accumulation of ultracold neutrons (UCN) in a superfluid-helium converter vessel surrounded by a magnetic multipole reflector. We solved the spin-dependent rate equation, employing formulas valid for adiabatic spin transport of…

Instrumentation and Detectors · Physics 2015-03-05 O. Zimmer , R. Golub

Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example…