Portable autonomous spectrophotometer for the spectral analysis in the ultra violet, of liquid samples

摘要

The instrument sends a beam of light through two test tubes (2,3) of e.g. quartz from a <2>H2 discharge lamp (4) via a converging lens (L1) which forms an image of the discharge region at the entry slit (F) of a spectrograph (SP). The incident light is reflected by a concave mirror (MC) to a reflection grating (R). The lamp is preheated for e.g. 10 s before the striking voltage is applied. The discharge current is regulated to a fixed point on the normal curve for e.g. 2 s while the luminosity is stabilised. An array of photodiodes (DP) in the focal plane of the mirror and slit is sampled to obtain the desired spectral information.