Thermal neutron transport near a moderator discontinuity using the method of weighted residuals - II. Cold neutron sources

Moon, J R; Beynon, T.D.

doi:10.1088/0022-3727/6/4/309

Cited by 7 publications

(3 citation statements)

References 16 publications

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“…Such materials would be capable of reflecting the majority of the CN spectrum from the LD 2 source, so that the inelastic scattering off ambient Be might no longer be needed to prevent neutron leakage from the moderator. Cooling the reflector, which would increase the volume of the low-temperature neutron field [37], might then lead to an additional gain in CN flux. -Deuterated clathrate hydrates have not only potential as VCN moderators but also as reflectors to cover the CN range from standard LD 2 cold sources.…”

Section: Use Of Advanced Reflectorsmentioning

confidence: 99%

Very cold and ultra cold neutron sources for ESS

Zanini

Dian

DiJulio

et al. 2023

JNR

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The goal of the “Workshop on Very Cold and Ultra Cold Neutron Sources for ESS” was to discuss scientific cases, ideas and possibilities for the implementation of sources of Very Cold and Ultra Cold neutrons at the European Spallation Source. The ESS facility, presently under construction, offers several possibilities for in-pile UCN or VCN sources, in primis thanks to the available space below the spallation target where additional neutron sources can be placed to complement those above the target. Neutron beams can be extracted over a wide angular range with a grid of forty-two beamports with 6° average angular separation, allowing future instruments to be installed which may view either the upper or lower moderator systems. Of greatest interest for fundamental physics is the so-called Large Beamport foreseen for the NNBAR experiment. This beamport is also particularly well suited to feed a UCN source, for which several ideas were presented that employ either superfluid helium or solid deuterium as established neutron converter materials. Concepts for VCN sources make use of novel materials for VCN production and/or advanced reflectors to increase yields in the coldest part of the neutron spectrum from a cryogenic neutron source. In this paper we discuss these ideas and the possible locations of UCN and VCN sources at ESS.

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Section: Use Of Advanced Reflectorsmentioning

confidence: 99%

Very cold and ultra cold neutron sources for ESS

Zanini

Dian

DiJulio

et al. 2023

JNR

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“…1 It is also clear from our study that the presence of collective motion in liquid hydrogen should be taken into account in analyzing the transport of low-energy neutrons in liquid hydrogen. 24 ' 25 …”

Section: = [X Itt S (O-h 2 )Xqc)+x Itt S (P-h 2 )X(100-x)]; Z S (V J^mentioning

confidence: 99%

Effect of Collective Oscillations on Low-Energy Thermal-Neutron Scattering and Transport in Liquid Hydrogen

Tewari

Swaminathan

1980

Phys. Rev. Lett.

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A thermal-neutron inelastic scattering kernel based on recently observed collective motion in liquid hydrogen, taken to be of quasicrystalline nature with an appropriate chemical binding energy, is found to explain the experimental pulsed neutron and steadystate spectra studies at 20 K. Thus the collective motion plays a very significant role in the transport of low-energy thermal neutrons in liquid hydrogen.

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“…The object of this paper is to apply the weighted residuals solution of the integral transport equation to examine the angular and scalar neutron fluxes near such temperature discontinuities in large volumes of light water and of graphite. Detailed accounts of this method of solution have been given in earlier publications Moon 1972, Moon andBeynon 1973, hereafter referred to as I and I1 respectively). In I we examined the basic mathematics of the technique and established its accuracy by comparing its predictions for neutron behaviour near a discontinuity with exact transport theory results obtained using a synthetic scattering kernel.…”

Section: Introductionmentioning

confidence: 99%

Thermal neutron transport near a moderator discontinuity using the method of weighted residuals: III. Temperature discontinuities in graphite and light water

Beynon¹,

Moon²

1973

J. Phys. D: Appl. Phys.

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A detailed analysis is made of the spatial variation of the effective thermal neutron temperature near temperature discontinuities in large volumes of graphite and light water. For graphite comparisons are made with recent measurements by Day. It is seen that it is important that proper consideration be made for the gradient of the epithermal flux. For water a number of predictions are made for both poisoned and unpoisoned systems and some doubt is cast on the feasibility of such measurements for determining the accuracy of different scattering kernels for light water. It is demonstrated, for both graphite and light water, that additional information can be obtained by extracting neutron beams at angles other than perpendicular to the axis of the system.

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Thermal neutron transport near a moderator discontinuity using the method of weighted residuals - II. Cold neutron sources

Cited by 7 publications

References 16 publications

Very cold and ultra cold neutron sources for ESS

Very cold and ultra cold neutron sources for ESS

Effect of Collective Oscillations on Low-Energy Thermal-Neutron Scattering and Transport in Liquid Hydrogen

Thermal neutron transport near a moderator discontinuity using the method of weighted residuals: III. Temperature discontinuities in graphite and light water

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