Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Quantum Electronics

On control of kinematic parameters of ultracold neutrons in waveguides

Лев Абрамович Ривлин

Published Oct 15, 2010• 1 citation
Publisher

Abstract

The possibility of controlling the kinematic parameters of ultracold neutrons (UCNs) is analysed by the example of a waveguide transfer and transformation of 2D images in ultracold neutrons and by the example of an increase in the concentration and deceleration/acceleration of ultracold neutrons during their transport in the waveguide with a variable cross section. The critical parameters of the problem are estimated, which indicates both consistency of the proposed approach and the emerging experimental limitations.

DOI
10.1070/qe2010v040n08abeh014290

Related papers

NANOPARTICLES AS A POSSIBLE MODERATOR FOR AN ULTRACOLD NEUTRON SOURCE

Валерий Викторович Несвижевский, G. Pignol, Konstantin V. Protasov

Ultracold and very cold neutrons (UCN and VCN) interact strongly with nanoparticles due to the similarity of their wavelengths and nanoparticles sizes. We analyze the hypothesis that this interaction can provide efficient cooling of neutrons by ultracold nanoparticles at certain experimental conditions, thus increasing the density of UCN by many orders of magnitude. The present analytical and numerical description of the problem is limited to the model of independent nanoparticles at zero temperature. Constraints of application of this model are discussed.

arXiv:nucl-th/0510021•International Journal of Nanoscience•Dec 1, 2007•22 citations

A new escape channel for ultracold neutrons in traps

Peter W. Geltenbort, Валерий Викторович Несвижевский, D. G. Kartashov +9 more

A surprising new escape channel for ultracold neutrons (UCNs) in traps was reported recently. It could be relevant to the long-standing puzzle of the “too high” loss rate of UCNs from traps, which has yet to be completely understood and eliminated. In the present work we positively identify the new phenomenon and investigate it in detail. The escape of UCNs from traps is due to rare events in which their energy undergoes a small increase (∼10 −7 eV). The reason for such an energy gain and its impact on the physics of UCN storage is still to be investigated.

Journal of Experimental and Theoretical Physics Letters•Aug 1, 1999•9 citations

Ultracold Neutron Sources: An Essentially Enhanced Optimal Operation Temperature for Ortho-Deuterium-Based Superthermal Converters

Erik Walz, C. Morkel

There is a longstanding dogma in the physics of ultracold neutrons (UCN): The optimal temperature of ortho-deuterium based UCN-sources must not exceed $5\,\mathrm{K}$. This value has been established by the pioneering work of Golub et al. decades ago, utilizing previously established cross sections for solid ortho-deuterium. But recently, an improved calculation of the crucial 1-phonon up-scattering cross section - using the so-called corrected Incoherent Approximation - leads to a new upper limit for the optimal operation temperature of ortho-deuterium based UCN sources. After a discussion of the relevant cross sections of the \(\mathrm{D}_2\)-molecule we conclude that the optimal temperature lies between $10\,\mathrm{K}$ and $12\,\mathrm{K}$, a factor 2 higher than estimated earlier. This offers significantly relaxed cryogenic conditions for UCN experiments with solid ortho-deuterium and especially for the operation of ortho-deuterium based ultracold neutron sources.

arXiv:2608.23587•Aug 12, 2026•0 citations

First ever storage of ultracold neutrons in a magnetic trap made of permanent magnets

В. Ф. Ежов, A. Z. Andreev, A.A. Glushkov +13 more

Further improvement in the accuracy of any neutron lifetime experiment by means of ultracold neutrons (UCN) in material bottles is limited due to unavoidable systematic effects when the UCN are reflected from the walls. However, such effects can be excluded in principle if magnetic trapping of UCN is used. The storage of UCN in a small magnetic trap made of permanent magnets was demonstrated for the first time ever. The measured storage time in this feasibility study was (882 ± 16) s. At this level of accuracy no depolarization was observed.

Journal of Research of the National Institute of Standards and Technology•Jul 1, 2005•23 citations

Storage of ultracold neutrons in a volume coated with diamondlike carbon

F. Atchison, B. Blau, M. Daum +17 more

Ultracold neutrons (UCN) with energy up to the Fermi potential were stored for the first time in a volume coated with diamondlike carbon. As a function of the UCN energy and wall temperature of the storage volume, we measured the wall loss parameter \ensuremath{\eta} and obtained $\ensuremath{\eta}=(3.1\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\cdot\else\textperiodcentered\fi{}{10}^{\ensuremath{-}4}$ at $T=290$ K and $\ensuremath{\eta}=(1.8\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\cdot\else\textperiodcentered\fi{}{10}^{\ensuremath{-}4}$ at $T=115$ K.

Physical Review C•Nov 9, 2006•31 citations

Investigations with ultracold neutrons

V. K. Ignatovich, V.I. Luschikov

Experimental and theoretical studies in the physics of ultracold neutrons are reviewed. Experimental methods and the interaction of ultracold neutrons with matter and fields are discussed. Possible applications of ultracold neutrons are considered.

•Mar 1, 1984•0 citations
The possibility of controlling the kinematic parameters of ultracold neutrons (UCNs) is analysed by the example of a waveguide transfer and transformation of 2D images in ultracold neutrons and by the example of an increase in the concentration and deceleration/acceleration of ultracold neutrons during their transport in the waveguide with a variable cross section. The critical parameters of the problem are estimated, which indicates both consistency of the proposed approach and the emerging experimental limitations.
Ultracold and very cold neutrons (UCN and VCN) interact strongly with nanoparticles due to the similarity of their wavelengths and nanoparticles sizes. We analyze the hypothesis that this interaction can provide efficient cooling of neutrons by ultracold nanoparticles at certain experimental conditions, thus increasing the density of UCN by many orders of magnitude. The present analytical and numerical description of the problem is limited to the model of independent nanoparticles at zero temperature. Constraints of application of this model are discussed.
A surprising new escape channel for ultracold neutrons (UCNs) in traps was reported recently. It could be relevant to the long-standing puzzle of the “too high” loss rate of UCNs from traps, which has yet to be completely understood and eliminated. In the present work we positively identify the new phenomenon and investigate it in detail. The escape of UCNs from traps is due to rare events in which their energy undergoes a small increase (∼10 −7 eV). The reason for such an energy gain and its impact on the physics of UCN storage is still to be investigated.
There is a longstanding dogma in the physics of ultracold neutrons (UCN): The optimal temperature of ortho-deuterium based UCN-sources must not exceed 5 K5\,\mathrm{K}5K. This value has been established by the pioneering work of Golub et al. decades ago, utilizing previously established cross sections for solid ortho-deuterium. But recently, an improved calculation of the crucial 1-phonon up-scattering cross section - using the so-called corrected Incoherent Approximation - leads to a new upper limit for the optimal operation temperature of ortho-deuterium based UCN sources. After a discussion of the relevant cross sections of the D2\mathrm{D}_2D2​-molecule we conclude that the optimal temperature lies between 10 K10\,\mathrm{K}10K and 12 K12\,\mathrm{K}12K, a factor 2 higher than estimated earlier. This offers significantly relaxed cryogenic conditions for UCN experiments with solid ortho-deuterium and especially for the operation of ortho-deuterium based ultracold neutron sources.
Further improvement in the accuracy of any neutron lifetime experiment by means of ultracold neutrons (UCN) in material bottles is limited due to unavoidable systematic effects when the UCN are reflected from the walls. However, such effects can be excluded in principle if magnetic trapping of UCN is used. The storage of UCN in a small magnetic trap made of permanent magnets was demonstrated for the first time ever. The measured storage time in this feasibility study was (882 ± 16) s. At this level of accuracy no depolarization was observed.
Ultracold neutrons (UCN) with energy up to the Fermi potential were stored for the first time in a volume coated with diamondlike carbon. As a function of the UCN energy and wall temperature of the storage volume, we measured the wall loss parameter \ensuremath{\eta} and obtained $\ensuremath{\eta}=(3.1\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\cdot\else\textperiodcentered\fi{}{10}^{\ensuremath{-}4}$ at T=290T=290T=290 K and $\ensuremath{\eta}=(1.8\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\cdot\else\textperiodcentered\fi{}{10}^{\ensuremath{-}4}$ at T=115T=115T=115 K.