Mikrophotometrie

Summary The possibilities of microphotometry, and the demands to be made upon a microphotometer, are investigated and the resulting principles for construction are discussed. The advantage of a stable combination of a one-ray spectrophotometer with a high performance research microscope is stressed. The use of a photomultiplier as receiver of light energy is recommended, owing to its high degree of sensitivity. The preparation can be observed through a binocular tube and photomicrographs taken with a photomicrographic camera. A cell holder built into the illumination system serves for the usual spectrophotometry and the results obtained microscopically can be compared with macroscopic measurements. The illumination can rapidly be changed from monochromatic to white light (originating from a low voltage lamp, for visual observation, photography, fluorescence measurements).The smallest photometric spot by which exact absorption measurements in the visible spectral region can be made, has a diameter of about 3 µ. A well adjusted field diaphragm is of decisive importance.It should be possible to arrange a considerable degree of automation in the measuring process.