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A Cold Neutron Monochromator and Scattering Apparatus; Monochromateur et appareillage pour la diffusion de neutrons lents; Monokhromator dlya ''kholodnykh'' nejtronov i pribor dlya rasseyaniya; Monocromador y aparato de dispersion para neutrones frios

Conference:

Abstract

A narrow band of neutron wavelengths (4 A and greater) is selected from a collimated neutron beam obtained from the Dido reactor at Harwell. These neutrqps are scattered by various samples and the energy transfer of the scattered neutrons measured using time-of-flight techniques. The neutrons, moderated by a liquid hydrogen source in the reactor pass through first a liquid nitrogen- cooled filter, then a single crystal of bismuth and finally they are ''chopped'' by a magnesium-cadmium high- speed curved slot rotor. In this apparatus the wavelength spread of 0. 3 A at 4 . 1 A is determined primarily by the Be-Bi filter, while the time spread (8 {mu}s) is determined by the rotor. The monochromated neutron bursts from this rotor are scattered by a sample and detected in one of two counter arrays. When studying liquid or polycrystalline samples an array of six BF{sub 3}, counter assemblies (each 2 inches x 24 inches in area)are used covering scatter angles from 20{sup o} to 90{sup o}. This array is placed below the neutron beam. Above the line of the neutron beam is a second array consisting of three scintillators 2 inches in diameter, which is used for the study of  More>>
Authors:
Harris, D; Cocking, S J; Egelstaff, P A; Webb, F J [1] 
  1. Nuclear Physics Division, Aere, Harwell, Didcot, Berks (United Kingdom)
Publication Date:
Jan 15, 1963
Product Type:
Conference
Resource Relation:
Conference: Symposium on Inelastic Scattering of Neutrons in Solids and Liquids, Chalk River (Canada), 10-14 Sep 1962; Other Information: Abstract also available in Russian. Figs., 1 tab., 12 refs.; Related Information: In: Inelastic Scattering of Neutrons in Solids and Liquids. V. I. Proceedings of the Symposium on Inelastic Scattering of Neurons in Solids and Liquids| 486 p.
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BF3 COUNTERS; BISMUTH; COLD NEUTRONS; DIDO REACTOR; FILTERS; HYDROGEN; LIQUIDS; MONOCRYSTALS; NEUTRON BEAMS; NEUTRON DIFFRACTION; NITROGEN; PHOSPHORS; POLYCRYSTALS; ROTORS; TIME-OF-FLIGHT METHOD; WAVELENGTHS
OSTI ID:
22086591
Research Organizations:
International Atomic Energy Agency, Vienna (Austria); United Nations Educational, Scientific and Cultural Organization (France)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13R0077045029
Submitting Site:
INIS
Size:
page(s) 107-118
Announcement Date:
Apr 18, 2013

Conference:

Citation Formats

Harris, D, Cocking, S J, Egelstaff, P A, and Webb, F J. A Cold Neutron Monochromator and Scattering Apparatus; Monochromateur et appareillage pour la diffusion de neutrons lents; Monokhromator dlya ''kholodnykh'' nejtronov i pribor dlya rasseyaniya; Monocromador y aparato de dispersion para neutrones frios. IAEA: N. p., 1963. Web.
Harris, D, Cocking, S J, Egelstaff, P A, & Webb, F J. A Cold Neutron Monochromator and Scattering Apparatus; Monochromateur et appareillage pour la diffusion de neutrons lents; Monokhromator dlya ''kholodnykh'' nejtronov i pribor dlya rasseyaniya; Monocromador y aparato de dispersion para neutrones frios. IAEA.
Harris, D, Cocking, S J, Egelstaff, P A, and Webb, F J. 1963. "A Cold Neutron Monochromator and Scattering Apparatus; Monochromateur et appareillage pour la diffusion de neutrons lents; Monokhromator dlya ''kholodnykh'' nejtronov i pribor dlya rasseyaniya; Monocromador y aparato de dispersion para neutrones frios." IAEA.
@misc{etde_22086591,
title = {A Cold Neutron Monochromator and Scattering Apparatus; Monochromateur et appareillage pour la diffusion de neutrons lents; Monokhromator dlya ''kholodnykh'' nejtronov i pribor dlya rasseyaniya; Monocromador y aparato de dispersion para neutrones frios}
author = {Harris, D, Cocking, S J, Egelstaff, P A, and Webb, F J}
abstractNote = {A narrow band of neutron wavelengths (4 A and greater) is selected from a collimated neutron beam obtained from the Dido reactor at Harwell. These neutrqps are scattered by various samples and the energy transfer of the scattered neutrons measured using time-of-flight techniques. The neutrons, moderated by a liquid hydrogen source in the reactor pass through first a liquid nitrogen- cooled filter, then a single crystal of bismuth and finally they are ''chopped'' by a magnesium-cadmium high- speed curved slot rotor. In this apparatus the wavelength spread of 0. 3 A at 4 . 1 A is determined primarily by the Be-Bi filter, while the time spread (8 {mu}s) is determined by the rotor. The monochromated neutron bursts from this rotor are scattered by a sample and detected in one of two counter arrays. When studying liquid or polycrystalline samples an array of six BF{sub 3}, counter assemblies (each 2 inches x 24 inches in area)are used covering scatter angles from 20{sup o} to 90{sup o}. This array is placed below the neutron beam. Above the line of the neutron beam is a second array consisting of three scintillators 2 inches in diameter, which is used for the study of single crystal samples. The output of each counter is fed into a tape recording system which has 500 time channels available for each counter. This apparatus has been used to study neutron scattering from several gaseous, liquid and crystalline samples and the most recent measurements are presented in other papers in these proceedings. [French] Les auteurs extraient une bande etroite de neutrons ( 4 A et plus) d'un faisceau collimate de neutrons produits par le reacteur Dido de Harwell. On fait diffuser ces neutrons au moyen de divers echantillons et on mesure le transfert d'energie des neutrons diffuses par la methode du temps de vol. Les neutrons ralentis par de l'hydrogene liquide place dans le reacteur passent d'abord dans un filtre refroidi a l'azote liquide, puis dans un monocristal de bismuth. Finalement, un rotor a rainures courbes en magnesium et cadmium, ayant une vitesse de rotation elevee, les laisse passer par bouffees. Dans cet appareil, le filtre Be-Bi sert a determiner la dispersion de la longueur d'onde (comprise entre 0,3 A et 4,1 A) et le rotor, la dispersion en fonction du temps (8 {mu}s). Les bouffees de neutrons monochromatiques provenant du rotor sont diffusees par un echantillon et detectees dans l'une de deux series de compteurs. Lorsqu'on etudie des echantillons liquides ou polycristallins, on emploie une serie de compteurs BF{sub 3} (dimensions: 2 x 2 4 pouces) couvrant des angles de diffusion variant de 20{sup o} a 90{sup o}. Cette serie est placee en-dessous du faisceau de neutrons. Au-dessus de l'axe du faisceau neutronique se trouve la deuxieme serie comprenant trois scintillateurs (diametre 2 pouces) pour etudier des echantillons de monocristaux. Chaque compteur agit sur un systeme d'enregistrement a bande magnetique qui comporte 500 canaux utilisables pour chacun des compteurs. Les auteurs se sont servis de cet appareil pour etudier la diffusion des neutrons dans plusieurs echantillons gazeux, liquides et cristallins. Dans d'autres memoires presentes au Colloque ils donnent les resultats des dernieres mesures faites. (author) [Spanish] De un haz colimado de neutrones, emitido por el reactor Dido de Harwell, se selecciona una estrecha banda de longitudes de onda neutronicas (4 A y mayores). Estos neutrones son dispersados por varias muestras y la energia por ellos cedida se mide segun el metodo del tiempo de vuelo. Los neutrones, moderados por una fuente de hidrogeno liquido situada en el reactor, atraviesan primero un filtro refrigerado por nitrogeno liquido, seguidamente un monocristal de bismuto, siendo, por ultimo ''interceptados'' por un rotor de ranura curva, de magnesio-cadmio animado de gran velocidad. En este aparato el ensanchamiento de longitud de onda (0, 3A a 4,1 A) queda principalmente determinado por el filtro de Be-Bi, y el de tiempo (8 {mu}s), por el rotor. Las rafagas de neutrales monocromaticos provenientes del rotor son dispersadas por una muestra y detectadas en uno de dos dispositivos de recuento. Cuando se estudian muestras liquidas o policristalinas, se utiliza un dispositivo de seis contadores (de BF{sub 3} de superficie unitaria) de 2 pulgadas por 24 pulgadas para angulos, de dispersion comprendidos entre 20{sup o} y 90{sup o}. Este dispositivo se coloca debajo del haz neutronico. Por encima del eje del haz, se instala otro dispositivo integrado por tres centelleadores de 2 pulgadas de diametro, que se utiliza para estudiar muestras monocristalinas. Las senales emitidas por cada contador se transmiten a un grabador de cinta que dispone de 500 canales de tiempo para cada contador. El aparato se ha utilizado para estudiar la dispersion de neutrones por varias muestras gaseosas, liquidas y cristalinas. Las mediciones masrecientesse exponen en otras memorias presentadas al Simposio. (author)}
place = {IAEA}
year = {1963}
month = {Jan}
}