Jenway 6305 - Manual (Page 15)

15
3.2 SPECTROSCOPY MEASUREMENT
There are four main components of a spectrophotometer. These are a light source to emit a high
and constant amount of energy over the full wavelength range; a method for separating the light
into discreet wavelengths; a sample holder and a light detector.
The optical layout of the 6305 spectrophotometer is shown below:
Figure 3.2.1 – Diagram of light path
The light from the xenon lamp is focused onto the grating, with 1200 lines per millimeter, which
separates the light into discreet wavelengths. The diffracted spectrum of light then passes through
a further slit and lens arrangement before passing through the sample in the sample chamber
from left to right. The light which is not absorbed by the sample is transmitted through a collecting
lens and onto the signal detector. The photo-diode detector used is mounted directly onto the
detector PCB and is used to calculate the % transmittance. The result is displayed either as %
transmittance or absorbance on the instrument display.