Production of a clean neutron gas for decay and scattering experiments

Dobrozemsky, R.

doi:10.1016/0029-554x(74)90681-8

Cited by 18 publications

(7 citation statements)

References 9 publications

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“…This makes background a potentially severe problem at steady-state neutron sources because their fluxes are limited to a value of about 1 × 10 15 cm −2 s −1 . The production of a clean neutron gas for experiments with free neutrons was discussed in [17]. A thermal neutron density of 1.4 × 10 7 cm −3 was achieved in a cavity of the ASTRA reactor (7 MW power) with residual gas density of about 1 × 10 9 cm −3 .…”

Section: Direct Measurement Of the Nn-scattering Lengthmentioning

confidence: 99%

Direct measurement of the neutron neutron scattering cross section at the reactor YAGUAR

Furman

Лычагин

Muzichka

et al. 2002

J. Phys. G: Nucl. Part. Phys.

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We propose to perform the first measurement of the neutron–neutron scattering cross section in the through-channel of the pulsed aperiodic reactor YAGUAR (Snezhinsk, Russia). Such a measurement directly determines the neutron–neutron scattering length, and by comparison with the proton–proton scattering length bears upon the issue of charge symmetry of the nuclear force. The proposed experimental set-up, as well as modelling of the neutron density and of the frequency of neutron–neutron collisions is described. Experimental results are reported on the formation and optimization of the thermal neutron field inside the through-channel of the reactor YAGUAR. The instantaneous value of 1.1 × 1018 cm−2 s−1 obtained for the thermal neutron flux density is large enough to perform the first direct neutron–neutron scattering length measurement.

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Section: Direct Measurement Of the Nn-scattering Lengthmentioning

confidence: 99%

Direct measurement of the neutron neutron scattering cross section at the reactor YAGUAR

Furman

Лычагин

Muzichka

et al. 2002

J. Phys. G: Nucl. Part. Phys.

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“…It was used, among others, to insert Cu foils for measurements of the neutron beam intensity profile inside the DV, removing the necessity to extrapolate from beam profile measurements further up-and downstream of the DV, which had introduced a significant uncertainty in the past. 63 Cu and 65 Cu of the foil are activated by neutrons from the beam with half-lives of 12.7 h of 64 Cu and 5.1 min of 66 Cu. The X-rays and β + particles of 64 Cu in the activated Cu foil are imaged using a X-ray imaging plate and an image plate scanner.…”

Section: Electrodementioning

confidence: 99%

“…aSPECT utilizes gold-coated electrodes to obtain inert electrode surfaces, to achieve a high temporal stability of the surface properties, and to avoid any potential surface charges on an electrically insulating oxide layer [65]. The work function of these electrodes modifies the actual retardation voltage measured between the DV and AP electrode.…”

Section: Impact Of Spatial and Temporal Variations Of The Work Functionmentioning

confidence: 99%

Improved determination of the $β$-$\overlineν_e$ angular correlation coefficient $a$ in free neutron decay with the $a$SPECT spectrometer

Beck,

Guardia,

Baeßler

et al. 2019

Preprint

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We report on a precise measurement of the electron-antineutrino angular correlation (a coefficient) in free neutron beta-decay from the aSPECT experiment. The a coefficient is inferred from the recoil energy spectrum of the protons which are detected in 4π by the aSPECT spectrometer using magnetic adiabatic collimation with an electrostatic filter. Data are presented from a 100 days run at the Institut Laue Langevin in 2013. The sources of systematic errors are considered and included in the final result. We obtain a = −0.10430(84) which is the most precise measurement of the neutron a coefficient to date. From this, the ratio of axial-vector to vector coupling constants is derived giving |λ| = 1.2677(28).

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“…The main parameters of the respective experiment are: energy of YAGUAR pulse is up to ~30 MJ, a repetition rate is one per day, number of neutrons, flied out from the reactor per pulse ~10 18 , duration of the pulse is ~1 ms, the thermal neutron flux density in central cavity of the reactor reaches ~10 18 n/cm 2 /s. Effective density of "neutron target" could be ~ 10 13 n/cm 3 , number of n-n collision per pulse estimates as ~10 7 and an expected number of n-n scattered neutrons, counted by the detector (100÷300) per pulse. The basic idea of the experiment is to use time-of-flight (TOF) method for separating of nn-scattering events from all other false effects.…”

Section: Strategy Of Experimentsmentioning

confidence: 99%

“…This is so called a radiation degassing of the cavity and the first collimator walls. The effect was studied [7] for steady reactor. The preliminary qualitative estimations gave us some hopes that this background has not to be essential for our case.…”

Section: Strategy Of Experimentsmentioning

confidence: 99%

Current Status of the Experiment on Direct Measurement of Neutron-Neutron Scattering Length at the Reactor YAGUAR

Furman¹,

Muzichka²,

Crawford³

et al. 2009

AIP Conference Proceedings

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It is proposed in 2002 the new experiment on the first direct measurement of neutronneutron scattering on the powerful pulsed reactor YAGUAR placed at Snezhinsk, Ural region, Russia. After that an extensive work has been done for modeling of background conditions and an optimization of the setup design. To make the experiment feasible it was necessary to suppress the background of various origins for more than 16 (for thermal neutrons) and 14 (for fast neutrons) orders of magnitude. In 2003 it had been drilled under reactor and equipped a channel for time-of-flight measurements. During next two years at this channel there were carried out a series of test experiments aimed at checking out an accuracy of background condition modeling. A good agreement of the measured results with the calculated values allowed us to realize the final design of full scale setup. During 2005-2006 it has been manufactured and after vacuum tests at JINR the setup has been mounted at YAGUAR reactor hall. In 2006-2007 the calibration measurements with noble gases have been carried out. The obtained results confirmed a validity of the full scale experiment modeling and allowed to verify necessary calibration. The first preliminary experiments for nn-scattering were performed at April 2008. The results are discussed.

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Production of a clean neutron gas for decay and scattering experiments

Cited by 18 publications

References 9 publications

Direct measurement of the neutron neutron scattering cross section at the reactor YAGUAR

Direct measurement of the neutron neutron scattering cross section at the reactor YAGUAR

Improved determination of the $β$-$\overlineν_e$ angular correlation coefficient $a$ in free neutron decay with the $a$SPECT spectrometer

Current Status of the Experiment on Direct Measurement of Neutron-Neutron Scattering Length at the Reactor YAGUAR

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