The collimator provides a rectangular aperture. The primary collimator is positioned after the electron beam has reached a vertical orientation. A carbon steel collimator assembly is located just outboard of the beam tube window. A collimator is a device which narrows a beam of particles or waves. A rotary shutter is located outboard of the outer collimator assembly. To improve angular resolution, one must lengthen the collimator, and/or reduce the plate spacing. A PG-1M panoramic telescope with K-1 collimator can be used for sighting. The treatment head of a linear accelerator consists of both a primary and secondary collimator. This atomic hydrogen passes through a collimator and a magnetic state selector. The conventional method is to place a collimator over the detection crystal/PMT array. An internal collimator is installed in the outboard end of the HB-4 tube. The handle was also used to rotate the collimator forward for storage. As the sighting equipment on the plane set radar "Initiative" and collimator sights OPB-16. An internal collimator is installed at the outboard end. In the lower panel of the figure, a collimator has been added (blue bars).