A new source of cold and ultracold neutrons

Steyerl, A.; Nagel, H.; Schreiber, Frank; Steinhauser, K. A.; Gähler, R.; Gläser, W.; Ageron, P.; Astruc, J.; Drexel, W.; Gervais, G.; Mampe, W.

doi:10.1016/0375-9601(86)90587-6

Cited by 254 publications

(152 citation statements)

References 16 publications

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“…The SUN-2 UCN source at the Institut Laue Langevin (ILL), Grenoble, France, is based on UCN production in superfluid 4 He cooled to temperatures below 1 K, where neutrons can become ultracold due to an inelastic singlephonon scattering process [78]. It converts cold neutrons with 0.89 nm wavelength of a beam deflected by an intercalated-graphite monochromator [69] to the beamline H172b with a flux density of 9 × 10 8 cm −2 s −1 nm −1 at "level C" of the ILL high-flux reactor.…”

Section: Measurements At the Superfluid He Source Sun-2 At The Inmentioning

confidence: 99%

“…It is based on the so-called 'Steyerl' turbine which mechanically Doppler-shifts neutrons towards UCN velocities. The facility is described in detail in [4]. Stored UCN densities of 36 UCN/cm 3 are reported.…”

Section: Measurements At the Edm Beamline Of The Pf2 Ucn Turbine Smentioning

confidence: 99%

“…The operating UCN sources under investigation were one out of four beamlines (the so-called EDM beamline) at PF2 (ILL) [4], Grenoble, France, at the TRIGA reactor of the Johannes Gutenberg University Mainz, Germany [53,60,61], at the Paul Scherrer Institute, Villigen, Switzerland [55,[62][63][64], and the new superfluid helium SUN-2 UCN source at ILL. 2 In January 2015 comparison measurements at the solid deuterium based UCN source of the Los Alamos National Laboratory (LANL), Los Alamos, USA, were performed [70], but due to the atypical performance of the UCN source at that time in comparison to the one given in Refs. [52,71,72] the LANL UCN collaboration did not wish to include the results in this paper.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of ultracold neutron sources for fundamental physics measurements

et al. 2017

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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 is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.

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Section: Measurements At the Superfluid He Source Sun-2 At The Inmentioning

confidence: 99%

Section: Measurements At the Edm Beamline Of The Pf2 Ucn Turbine Smentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of ultracold neutron sources for fundamental physics measurements

et al. 2017

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“…UCN densities at reactor sources have gradually increased with reactor power and improved techniques for extracting the UCN flux. The highest bottled densities reported in the literature, 41/cm 3 , have been obtained at the Institut Laue-Langevin (ILL) reactor in Grenoble [4].Measurements of the neutron electric dipole moment [5,6] and the neutron lifetime [7,8,9] attest to the utility of bottled UCNs for fundamental experiments with neutrons. UCNs may prove useful in improved measurements of angular correlations in neutron beta-decay [10,11], although experiments of this kind utilizing UCNs have not yet been performed.…”

mentioning

confidence: 99%

“…Superthermal UCN production, where the production rate of UCNs due to down-scattering in energy is larger than the combined up-scatter and nuclear-absorption rates in the material, was first proposed in 1975 by Golub and Pendlebury [12] in superfluid 4 He and experimentally investigated shortly thereafter [13,14]. In this process phonon creation in the liquid is used to down-scatter cold neutrons to the UCN regime, while up-scattering is suppressed by maintaining the superfluid at sufficiently low temperature.…”

mentioning

confidence: 99%

Measurements of Ultracold-Neutron Lifetimes in Solid Deuterium

Cl¹,

Anaya²,

Tj³

et al. 2002

Phys. Rev. Lett.

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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 ortho-deuterium as the source material. Superthermal UCN sources offer orders of magnitude improvement in the available densities of UCNs, and are of great importance to fundamental particle-physics experiments such as searches for a static electric dipole moment and lifetime measurements of the free neutron. These measurements are performed utilizing a SD2 source coupled to a spallation source of neutrons, providing a demonstration of UCN production in this geometry and permitting systematic studies of the influence of thermal up-scatter and contamination with para-deuterium on the UCN survival time.PACS numbers: 29.25. Dz, 28.20.Gd, 32.80.Pj Neutrons with kinetic energies less than 340 neV (corresponding to a temperature T< 5mK) can be trapped in material bottles and are referred to as ultracold neutrons (UCNs) [1,2,3]. UCN densities at reactor sources have gradually increased with reactor power and improved techniques for extracting the UCN flux. The highest bottled densities reported in the literature, 41/cm 3 , have been obtained at the Institut Laue-Langevin (ILL) reactor in Grenoble [4].Measurements of the neutron electric dipole moment [5,6] and the neutron lifetime [7,8,9] attest to the utility of bottled UCNs for fundamental experiments with neutrons. UCNs may prove useful in improved measurements of angular correlations in neutron beta-decay [10,11], although experiments of this kind utilizing UCNs have not yet been performed. All of these experimental programs have been limited by the available densities of UCNs.Superthermal UCN production, where the production rate of UCNs due to down-scattering in energy is larger than the combined up-scatter and nuclear-absorption rates in the material, was first proposed in 1975 by Golub and Pendlebury [12] in superfluid 4 He and experimentally investigated shortly thereafter [13,14]. In this process phonon creation in the liquid is used to down-scatter cold neutrons to the UCN regime, while up-scattering is suppressed by maintaining the superfluid at sufficiently low temperature. Because 4 He has no nuclear absorption, the only limitations to the density of UCNs accumulated are wall losses and neutron beta decay. The production of UCNs by this process has been observed and agrees with theoretical expectations [14,15,16,17,18].While superfluid 4 He is an excellent superthermal converter, a few other materials, such as solid deuterium (SD 2 ), satisfy the criteria for superthermal production. The limiting UCN density, ρ UCN , one can obtain using a SD 2 source is given by the product of the rate of UCNs production in the solid, R, and the lifetime of UCNs in the solid, τ SD : ρ UCN = Rτ SD . A storage bottle opened to such a source will come into density equilibrium with the density in the solid. This led to the proposal of a thi...

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Physics of the Neutron

Schreckenbach¹

2003

Digital Encyclopedia of Applied Physics

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The nuclear and particle physics of the free neutron is described for neutron energies in the range of nanoelectronvolts to megaelectronvolts. The interaction of the neutron with the atomic nucleus, which comprises scattering and absorption, and the reaction mechanism are discussed, including parity nonconserving processes. In neutron particle physics, the progress in neutron sources and neutron beams has yielded experimental results for sensitive tests of the standard model in particle physics and beyond and some key experiments are presented.

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A new source of cold and ultracold neutrons

Cited by 254 publications

References 16 publications

Comparison of ultracold neutron sources for fundamental physics measurements

Comparison of ultracold neutron sources for fundamental physics measurements

Measurements of Ultracold-Neutron Lifetimes in Solid Deuterium

Physics of the Neutron

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