Tuesday, June 25, 2013

1306.5367 (B. Dong et al.)

Beam Patterns of the Five hundred metre Aperture Spherical Telescope: Optimization    [PDF]

B. Dong, J. L. Han
The Five hundred meter Aperture Spherical Telescope (FAST) uses adaptive spherical panels to realize the huge collecting area for radio waves. In this paper, we try to explore the optimal parameters for the curvature radius of spherical panels and the focal distance by comparison of the calculated beam patterns. We show that to get the best beam shape and maximum gain, the optimal curvature radius of panels is around 300m, and a small shift of focal distance of a few cm is needed. The aperture efficiency can be improved by ~10 at 3GHz by this small shift. We also try to optimize the panel positioning for the best beam, and find that panel shifts of a few mm can improve the beam pattern by a similar extent. Our results indicate that the accurate control of the feed and panel position to the mm level is very crucial to the stability of FAST performance.
View original: http://arxiv.org/abs/1306.5367

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