The dependence of the gravity effect in elliptic neutron guides on the source size

• Published in: Journal of physics. Conference series Vol. 528; no. 1; pp. 12008 - 9
• Main Authors: Nekrassov, D, Zendler, C, Lieutenant, K
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2014
• Subjects: Computer simulation; Design engineering; Distortion; Flight paths; Gravitation; Neutron beams; Neutrons; Particle physics; Physics; Simulation; Spallation
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/528/1/012008

Elliptic neutron guides are expected to be widely used for construction of long neutron beamlines at the future European Spallation Source and other facilities due to their superiour transmission properties compared to conventional straight guides. At the same time, neutrons traveling long distances are subject to the action of gravity that can significantly modify their flight paths. In this work, the influence of gravity on a neutron beam propagating through elliptic guides is studied for the first time in a systematic way with Monte-Carlo simulations. It is shown that gravity leads to significant distortions of the phase space during propagation through long elliptic guides, but this effect can be recovered by a sufficiently large source size. The results of this analysis should be taken into account during design of long neutron instruments at the ESS and other facilities.