A LIGHT LOCALIZER FOR USE AT LARGE DISTANCES FROM A RADIATION SOURCE

In the superconducting cyclotron used for neutron therapy at Harper Ho spital, space limitations prevented the use of a simple conventional l ight localizing system, employing a single mirror and a light source. The superconducting magnet coil is close to the neutron producing targ et and the vacuum window separating the acceleration chamber from atmo spheric pressure is situated similar to 56 cm from this target. Theref ore, the light localizing system must be designed to incorporate lense s, mirrors, an optical fiber light pipe and adjustment motors, in orde r to make the system compact enough to fit in the available space and to allow easy access for adjustment and alignment. The design of the l ight localizing system is explained in detail. (C) 1998 American Assoc iation of Physicists in Medicine. [S0094-2405(98)00706-8].