asymptotic cone of acceptance

asymptotic cone of acceptance

[ā‚sim′täd·ik ¦kōn əv ik′sep·təns]
(geophysics)
The solid angle in the celestial sphere from which particles have to come in order to contribute significantly to the counting rate of a given neutron monitor on the surface of the earth.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.