Eliminating line of sight in elliptic guides using gravitational curving
(2011) International Workshop on Neutron Optics 634. p.100-103- Abstract
- Eliminating fast neutrons (lambda < 0.5 angstrom) by removing direct line of sight between the source and the target sample is a well established technique. This can be done with little loss of transmission for a straight neutron guide by horizontal curving. With an elliptic guide shape, however, curving the guide would result in a breakdown of the geometrical focusing mechanism inherent to the elliptical shape, resulting in unwanted reflections and loss of transmission. We present a new and yet untried idea by curving a guide in such a way as to follow the ballistic curve of a neutron in the gravitational field, while still retaining the elliptic shape seen from the accelerated reference frame of the neutron. Analytical calculations... (More)
- Eliminating fast neutrons (lambda < 0.5 angstrom) by removing direct line of sight between the source and the target sample is a well established technique. This can be done with little loss of transmission for a straight neutron guide by horizontal curving. With an elliptic guide shape, however, curving the guide would result in a breakdown of the geometrical focusing mechanism inherent to the elliptical shape, resulting in unwanted reflections and loss of transmission. We present a new and yet untried idea by curving a guide in such a way as to follow the ballistic curve of a neutron in the gravitational field, while still retaining the elliptic shape seen from the accelerated reference frame of the neutron. Analytical calculations and ray-tracing simulations show that this method is useful for cold neutrons at guide lengths in excess of 100 m. We will present some of the latest results for guide optimization relevant for instrument design at the ESS, in particular an off-backscattering spectrometer which utilizes the gravitational curving, for 6.66 angstrom neutrons over a guide length of 300m. (C) 2010 Elsevier B.V. All rights reserved. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1987661
- author
- Kleno, Kaspar H. ; Willendrup, Peter K. ; Knudsen, Erik and Lefmann, Kim LU
- organization
- publishing date
- 2011
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- keywords
- Neutron guide, ESS, Backscattering spectrometer, Ray-tracing simulations
- host publication
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- volume
- 634
- pages
- 100 - 103
- publisher
- Elsevier
- conference name
- International Workshop on Neutron Optics
- conference location
- Grenoble, France
- conference dates
- 2010-03-17 - 2010-03-19
- external identifiers
-
- wos:000290355100022
- scopus:79952992257
- ISSN
- 0168-9002
- DOI
- 10.1016/j.nima.2010.06.261
- language
- English
- LU publication?
- yes
- id
- 6772106a-9bf7-4731-bcdd-6246eebfc93c (old id 1987661)
- date added to LUP
- 2016-04-01 13:10:25
- date last changed
- 2022-01-27 17:45:28
@inproceedings{6772106a-9bf7-4731-bcdd-6246eebfc93c, abstract = {{Eliminating fast neutrons (lambda < 0.5 angstrom) by removing direct line of sight between the source and the target sample is a well established technique. This can be done with little loss of transmission for a straight neutron guide by horizontal curving. With an elliptic guide shape, however, curving the guide would result in a breakdown of the geometrical focusing mechanism inherent to the elliptical shape, resulting in unwanted reflections and loss of transmission. We present a new and yet untried idea by curving a guide in such a way as to follow the ballistic curve of a neutron in the gravitational field, while still retaining the elliptic shape seen from the accelerated reference frame of the neutron. Analytical calculations and ray-tracing simulations show that this method is useful for cold neutrons at guide lengths in excess of 100 m. We will present some of the latest results for guide optimization relevant for instrument design at the ESS, in particular an off-backscattering spectrometer which utilizes the gravitational curving, for 6.66 angstrom neutrons over a guide length of 300m. (C) 2010 Elsevier B.V. All rights reserved.}}, author = {{Kleno, Kaspar H. and Willendrup, Peter K. and Knudsen, Erik and Lefmann, Kim}}, booktitle = {{Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}}, issn = {{0168-9002}}, keywords = {{Neutron guide; ESS; Backscattering spectrometer; Ray-tracing simulations}}, language = {{eng}}, pages = {{100--103}}, publisher = {{Elsevier}}, title = {{Eliminating line of sight in elliptic guides using gravitational curving}}, url = {{http://dx.doi.org/10.1016/j.nima.2010.06.261}}, doi = {{10.1016/j.nima.2010.06.261}}, volume = {{634}}, year = {{2011}}, }