Moving crystal slow-neutron wavelength analyser

1973 ◽  
Vol 106 (3) ◽  
pp. 461-464 ◽  
Author(s):  
B. Buras ◽  
J.K. Kjems
Keyword(s):  
Slow Neutron ◽  
Neutron Wavelength

scholarly journals Clustering of Diamond Nanoparticles, Fluorination and Efficiency of Slow Neutron Reflectors

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1945
Author(s):  
Aleksander Aleksenskii ◽  
Markus Bleuel ◽  
Alexei Bosak ◽  
Alexandra Chumakova ◽  
Artur Dideikin ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Red Light ◽  
Coherent Scattering ◽  
Slow Neutron ◽  
Diameter Distribution ◽  
Absolute Cross Section ◽  
X Ray Diffraction ◽  
Nanoparticle Diameter ◽  
Transmission Electron ◽  
Neutron Wavelength

Neutrons can be an instrument or an object in many fields of research. Major efforts all over the world are devoted to improving the intensity of neutron sources and the efficiency of neutron delivery for experimental installations. In this context, neutron reflectors play a key role because they allow significant improvement of both economy and efficiency. For slow neutrons, Detonation NanoDiamond (DND) powders provide exceptionally good reflecting performance due to the combination of enhanced coherent scattering and low neutron absorption. The enhancement is at maximum when the nanoparticle diameter is close to the neutron wavelength. Therefore, the mean nanoparticle diameter and the diameter distribution are important. In addition, DNDs show clustering, which increases their effective diameters. Here, we report on how breaking agglomerates affects clustering of DNDs and the overall reflector performance. We characterize DNDs using small-angle neutron scattering, X-ray diffraction, scanning and transmission electron microscopy, neutron activation analysis, dynamical light scattering, infra-red light spectroscopy, and others. Based on the results of these tests, we discuss the calculated size distribution of DNDs, the absolute cross-section of neutron scattering, the neutron albedo, and the neutron intensity gain for neutron traps with DND walls.

Rubidium in Barium Stars

2020 ◽  
Author(s):  
M P Roriz ◽  
M Lugaro ◽  
C B Pereira ◽  
N A Drake ◽  
S Junqueira ◽  
...  
Keyword(s):  
Neutron Source ◽  
Slow Neutron ◽  
Asymptotic Giant Branch ◽  
Neutron Density ◽  
Data Sets ◽  
Agb Stars ◽  
Branching Points ◽  
Theoretical Predictions ◽  
Low Mass ◽  
Chemically Peculiar Stars

Abstract Barium (Ba) stars are chemically peculiar stars that display in their atmospheres the signature of the slow neutron-capture (the s-process) mechanism that occurs in asymptotic giant branch (AGB) stars, a main contributor to the cosmic abundances. The observed chemical peculiarity in these objects is not due to self-enrichment, but to mass transfer between the components of a binary system. The atmospheres of Ba stars are therefore excellent astrophysical laboratories providing strong constraints for the nucleosynthesis of the s-process in AGB stars. In particular, rubidium (Rb) is a key element for the s-process diagnostic because it is sensitive to the neutron density and therefore its abundance can reveal the main neutron source for the s-process in AGB stars. We present Rb abundances for a large sample of 180 Ba stars from high resolution spectra (R = 48000), and we compare the observed [Rb/Zr] ratios with theoretical predictions from AGB s-process nucleosynthesis models. The target Ba stars in this study display [Rb/Zr] <0, showing that Rb was not efficiently produced by the activation of branching points. Model predictions from the Monash and FRUITY data sets of low-mass (≲ 4 M⊙) AGB stars are able to cover the Rb abundances observed in the target Ba stars. These observations indicate that the 13C(α,n)16O reaction is the main neutron source of the s-process in the low-mass AGB companions of the observed Ba stars. We have not found in the present study candidate companion for IR/OH massive AGB stars.

Slow Neutron Resonances inIn113andIn115

1952 ◽  
Vol 87 (1) ◽  
pp. 161-162 ◽  
Author(s):  
V. L. Sailor ◽  
L. B. Borst
Keyword(s):  
Slow Neutron

Nevis Synchrocyclotron Slow Neutron Velocity Spectrometer

1960 ◽  
Vol 31 (5) ◽  
pp. 481-489 ◽  
Author(s):  
J. Rainwater ◽  
W. W. Havens ◽  
J. S. Desjardins ◽  
J. L. Rosen
Keyword(s):  
Slow Neutron

Measurement of the slow neutron spectrum in a physical mock up of the reactor in the I. V. Kurchatov beloyarskoe GR power station

1963 ◽  
Vol 15 (6) ◽  
pp. 1266-1270
Author(s):  
Yu. Yu. Glazkov ◽  
B. G. Dubovskii ◽  
G. A. Ilyasova ◽  
V. I. Kozlov ◽  
V. V. Smelov ◽  
...  
Keyword(s):  
Neutron Spectrum ◽  
Slow Neutron ◽  
Power Station

Slow-Neutron Ternary Fission of Uranium-235

Nature ◽  
1951 ◽  
Vol 168 (4275) ◽  
pp. 590-591 ◽  
Author(s):  
E. W. TITTERTON
Keyword(s):  
Slow Neutron ◽  
Ternary Fission
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