GE UV-1 2. General Description, 2.1 Basic principle

2. General Description

2.1 Basic principle	GE Healthcare LKB Monitor UV-1 consists of an optical unit
	containing the flow cell, lamp, filter assemblies and preamplifiers, and a
	control unit containing the signal processing circuits. The two units are
	connected via a multi-core cable hardwired from the control unit to
	the optical unit. Connection to the recorder and the mains supply is
	made via the control unit.
	The single path Monitor UV-1 is a dual beam instrument with a
	sample cell and a reference cell. Optical path lengths are 10 mm,
	3 mm, or 2 mm depending upon the flow cell chosen.
	Note:	Flow cell S-2 has only the sample cell.

The sample cell and reference cell are angled to receive light from the same point in the lamp (Fig. 1) thus assuring a stable base-line by negating the effects of variations in lamp intensity.

The lamp is powered by a stabilized DC to AC converter operating at 20 kHz to maximize its efficiency. Lamp output is independent of variations in the line voltage.

Light from the lamp passes through an aperture (254 nm, 405 nm) or a fluorescence converter (280 nm) and through the reference cell and sample cell. The light output from each cell passes through an interference filter and falls onto a solid state photo-detector whose output is a linear function of the light intensity (Fig. 1 and Fig. 2).

Fig. 1. Optical path.