Standardising arrangement for twin beam photometer - deflects reference beam to measuring photocell for initial arrangement and includes shutter to interrupt either beam

摘要

In a twin-beam photo-meter, a light source (1) radiates a beam of light to a beam splitter (2) at which it is divided into a measuring beam (4) and a reference beam (5). The measuring beam is reflected by a device such as a mirror (3) and passes through a cuvette (6) which contains the sample to be measured. The transmitted beam (4') impinges on a photocell (8). The reference beam (5) pases through a cuvette (7) containing the reference standard to a second beam splitter (9). The transmitted reference beam (5') impinges on a second photocell (12). The deflected reference beam passes to the first photocell (8) by way of a second mirror (10). A shutter device (11) pivots to interrupt either the beam from the measuring cell or the beam from the reference cell to permit the two photocells to be set up initially.