PerkinElmer AVIO 200, Hardware Manual

Page: 80 / 309

System Description
78
Wavelength Correction
The optical system uses a two-component, active wavelength stabilizing system. The
overall stability is controlled by temperature and neon in the optics housing.
Any residual deviations are compensated for by measuring a neon reference
spectrum simultaneously with each measurement of an analytical emission line. The
output from a neon discharge lamp is collected by an optical fiber and projected onto
the top half of the intermediate slit in the monochromator, which is the entrance to
the Echelle monochromator. The neon spectrum passes through the Echelle system
with the analytical radiation and illuminates the top array of the detector. The neon
spectrum acts as a wavelength scale to enable active wavelength correction.
ICP Source
RF Generator
The Avio 200 uses a 40-MHz free-running solid state RF generator. The RF power
from the solid state oscillator is used to ionize the argon in the torch and excite the
atoms of the liquid sample so that they emit energy at their atomic wavelength in the
form of photons. The photons from the torch are detected optically and measured
electronically in the spectrometer section of the Avio 200. The photons are displayed
in terms of wavelength and intensity, which are converted to sample concentration.
The RF generator provides a power output of 1000 to 1500 watts. The power output
levels are computer-controlled and may be adjusted in one-watt steps for different
sample matrices.
The RF generator is designed with RF Power Control (RFPC), using a power control
loop which maintains the plasma setting regardless of line voltage fluctuations and
changes in the plasma.