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Proceedings Paper

New measurements with a perfect crystal cavity for neutrons
Author(s): Martin R. Jaekel; Colin J. Carlile; Erwin Jericha; Dagmar E. Schwab; Helmut Rauch
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Paper Abstract

VESTA (the Viennese nEutron STorage Apparatus) is an experiment for storing cold neutrons with a wavelength of 6.27 Angstrom, installed at the pulsed neutron source ISIS. A highly monochromatic neutron beam ((Delta) k/k approximately 4*10-5) is trapped by Bragg reflections between two precisely parallel silicon crystal plates in backscattering geometry. Entry and exit of the neutrons into and from the storage system is achieved by using the Zeeman energy shift caused by a short pulsed magnetic field at the crystal plates when the neutron pulse, to be stored or released, is passing by. With a significantly improved signal to background ratio, it was possible to store up to 6 neutron pulses simultaneously for the first time. By varying the storage time separately for each pulse, the feasibility of neutron beam manipulations in time and space was demonstrated. The influence of the magnetic field strength on the transmission of a perfect crystal has been investigated. After optimizing the alignment of the storage cavity, neutrons were stored for up to 4.2 seconds, which corresponds to a flight path of 2.66 km inside VESTA, or to 2500 consecutive Bragg-reflections. Currently, a new storage device, 'VESTA Type 2,' is under construction. In this case the energy shift for neutron entry and exit will be achieved by using a pulsed hf-spin flipper and a static NMR magnet. It can be expected that by removing the pulsed magnets of the existing device and by reducing other sources of vibration, the storage time and efficiency can be further improved.

Paper Details

Date Published: 23 November 1999
PDF: 7 pages
Proc. SPIE 3767, EUV, X-Ray, and Neutron Optics and Sources, (23 November 1999); doi: 10.1117/12.371134
Show Author Affiliations
Martin R. Jaekel, Atominstitut der Oesterreichischen Universitaeten and Rutherford Appleton Lab. (United Kingdom)
Colin J. Carlile, Rutherford Appleton Lab. (France)
Erwin Jericha, Technische Univ. Wien (Austria)
Dagmar E. Schwab, Atominstitut der Oesterreichischen Universitaeten (Austria)
Helmut Rauch, Atominstitut der Oesterreichischen Universitaeten (Austria)

Published in SPIE Proceedings Vol. 3767:
EUV, X-Ray, and Neutron Optics and Sources
Carolyn A. MacDonald; Kenneth A. Goldberg; Juan R. Maldonado; Huaiyu Heather Chen-Mayer; Stephen P. Vernon, Editor(s)

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