Ultracold-neutron production in a pulsed-neutron beam line

Lavelle, C. M.; Liu, C.-Y.; Fox, W.; Manus, Gregory; McChesney, Patrick; Salvat, Daniel; Shin, Yunchang; Makela, M.; Morris, C. L.; Saunders, Alexander; Couture, A.; Young, A. R.

doi:10.1103/physrevc.82.015502

Cited by 13 publications

(23 citation statements)

References 40 publications

(54 reference statements)

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“…In fact, since the volume of the SD 2 only fills 1/3 of the volume below the flapper valve, the actual peak densities were only observed to be 3000 UCN/cm 3 . We note also that in the latest in-beam study at LANSCE, 34 the UCN effective production cross section was measured to be 1.27 × 10 −7 b per molecule for the UCN energy range of 0-300 neV, in agreement with the cross sections of Atchison,33 when these are integrated over the neutron spectrum from LANSCE flight path FP-12, which is characterized by the neutron temperature of 35 K.…”

Section: Ucn Productionsupporting

confidence: 75%

“…These lifetimes, measured in solid orthodeuterium at temperatures below 12 K, 30 are long enough to yield high densities in a spallation driven source, in agreement with theoretical calculations, 31 and correspondingly high densities were measured in a small scale prototype UCN source. 32 UCN production rates in solid ortho-deuterium measured in experiments at PSI 33 and at LANSCE 34 have verified the earlier work in more quantitative and controlled experiments.…”

Section: Introductionsupporting

confidence: 75%

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Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

Saunders

Makela

Bagdasarova

et al. 2013

Review of Scientific Instruments

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A.; Makela, M.; Bagdasarova, Y.; et al., "Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source," Rev. Sci. Instrum. 84, 013304 (2013); http://dx.doi.org/10.1063/1.4770063 REVIEW OF SCIENTIFIC INSTRUMENTS 84, 013304 (2013) Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultracold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates compare well with predictions from the Monte Carlo code MCNPX and the UCN rates agree with our custom UCN Monte Carlo code. The source is shown to perform as modeled. The maximum delivered UCN density at the exit from the biological shield is 52(9) UCN/cc with a solid deuterium volume of ∼1500 cm 3 .

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Section: Ucn Productionsupporting

confidence: 75%

Section: Introductionsupporting

confidence: 75%

Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

Saunders

Makela

Bagdasarova

et al. 2013

Review of Scientific Instruments

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“…Historically the first method of the UCN spectroscopy was the time-of-flight technique [1]. As a direct and universal method of measuring the neutron speed, it has been successfully used in numerous experiments with UCN (see for example [2][3][4][5][6]). …”

Section: Introductionmentioning

confidence: 99%

Time-of-flight Fourier UCN spectrometer

Kulin

Frank

Goryunov

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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We describe a new time-of-flight Fourier spectrometer for investigation of UCN diffraction by a moving grating. The device operates in the regime of a discrete set of modulation frequencies. The results of the first experiments show that the spectrometer may be used for obtaining UCN energy spectra in the energy range of 60÷200 neV with a resolution of about 5 neV. The accuracy of determination of the line position was estimated to be several units of 10 −10 eV

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“…Especially large difference between the incoherent approach and coherent one was found in the case of UCN up-scattering with phonon annihilation in the temperature range of 5-10 K: the first one 3-4 times surpassed the second one. These new calculations found some experimental confirmation in [26].…”

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confidence: 68%

UCN transport simulation in solid deuterium crystals

Pokotilovski

2012

Nuclear Instruments and Methods in Physics Research Section A:

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The extraction efficiency of ultracold neutrons from cryogenic moderators depends critically on the neutron transparency of the moderator material. A Monte Carlo simulation of the probability of the UCN going out from non-ideal (disordered) solid deuterium crystals has been performed. It was based on the use of a correlation function describing the density fluctuations in a disordered material, the latter being inferred from the measured very low neutron energy total cross sections for this material.Ultracold neutrons [1] (UCN, the energy below ∼ 0.3µeV), which can be contained in closed volumes, have found important applications in the investigation of fundamental properties of the neutron [2].The best UCN source -ILL UCN turbine [3] yields maximum UCN density in a trap of ∼ 50 n/cm 3 and, respectively, the flux ∼ 5 × 10 3 n cm −2 s −1 . Recent years brought hope for significant progress in the intensity of very low energy neutron beams. This is connected with the possible use of the most effective cold moderators: solid deuterium or solid deuterocarbons at low temperatures of ∼ 5 -10 K for production of very cold neutrons.The most promising and popular material for the UCN converter is solid deuterium. The first test of the UCN production in solid deuterium has been performed by the PNPI group [4], which then has been studying experimentally the UCN production in deuterium during many years [5][6][7][8][9][10][11].The first estimate of the UCN production and up-scattering cross sections in solid deuterium was made in [12]. The phonon frequency spectrum of solid deuterium was calculated in [13] using the dispersion relations measured in [14]. Later calculations in the incoherent approximation [15] of the UCN scattering on phonons in solid deuterium reproduced the results of [13], this publication also 1

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Ultracold-neutron production in a pulsed-neutron beam line

Cited by 13 publications

References 40 publications

Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

Time-of-flight Fourier UCN spectrometer

UCN transport simulation in solid deuterium crystals

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