| 摘要 |
<p>The appts. comprises a light source and, on the same optical axis, a condenser lens, a cylindrical lens, a first polariser and a gap through which the film of material passes. Further along the axis is a second polariser, an optical system and a photoelectric receiver. The optical system is supported in two opaque covers which are divided by the space through which the material passes. The optical system comprises a tubular element mounted to slide on a support, and containing objective and eyepiece lenses similar to those of a microscope. A rack on the tube enables a small toothed wheel controlled from outside to be used to move the tube. The light is focussed on to the detector whose signal is fed via a signal shaping circuit to a pulse counter via a cable.</p> |
