On the possibility of placing a universal neutron diffractometer in an inclined channel of the PIK reactor
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PPARATUS
On the Possibility of Placing a Universal Neutron Diffractometer in an Inclined Channel of the PIK Reactor N. O. Elyutina, b, D. V. Lvova, and A. N. Tyulyusova, b a
Institute for Theoretical and Experimental Physics, Moscow, 117218 Russia email: [email protected] b Moscow Engineering Physics Institute, National Research Nuclear University, Moscow, 115409 Russia Received February 14, 2011
Abstract—The possibility of placing a universal neutron diffractometer, which is designed for working with perfect crystals, in one of the inclined channels of the PIK reactor is discussed. It is proposed to use a double monochromator block (DMB) in the vertical plane and mounting crystals in the antiparallel position with reflection at a Bragg angle of 15°. In this configuration, a set of wellknown monochromator crystals (pyro lytic graphite, SiO2, Si, Ge, Cu, and Pb) provides transmission bands of quasimonochromatic neutrons in the range of 1–1.8 Å. The angular and energy distributions of neutrons transmitted through the DMB are cal culated. A scheme of the block for filtering radiations is proposed, and its parameters are calculated. The principles of instrument operation in a physical room (beyond the DMB) are determined. DOI: 10.1134/S106377451107011X
DOUBLE MONOCHROMATOR BLOCK OF UND
INTRODUCTION The highflux PIK reactor, which is being built at the St. Petersburg Nuclear Physics Institute (PNPI), is a mixeduse system. It is considered a base for future neutron studies in the Russian Federation [1]. One of the components of the channel equipment of the PIK reactor is a set of inclined experimental channels (IECs), which are located in a special (inclinedchan nel) room; the IEC axes make an angle of 60° with the horizontal plane. In contrast to the room of horizontal experimental channels and the neutronguide room, the installation of which can be considered completed, the IEC installation is under way. The purpose of this study was to demonstrate (using the example of uni versal neutron diffractometer (UND) [2]) the possi bility of installing the instruments designed for work ing with horizontal neutron beams in the inclined channel room. Neutron diffraction and smallangle scattering are known to be the most widespread techniques for studying solidstate objects; they constitute a consid erable part of experimental resources and studies car ried out on stationary reactors. The UND (see [2] for integral appearance) combines the potentials of a sin glecrystal diffractometer and a triplecrystal spec trometer and allows one to deal with perfect crystals (the assembly of double and triplecrystal schemes). As a result, experiments in the range of thermal neu trons with an angular resolution of few seconds can be performed. These instruments, being rather compli cated, are not produced commercially, and there are only few such systems in the world.
Neutron diffraction studies are performed on devices designed for horizontal neutron beams. Thus, the problem of neutronbeam rotation arises. In pra
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