Hitachi ZA3000 Series, Инструкция по эксплуатации

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10.1
10 - 7

Background Detection
Background detection in the [Dry Test] is a function for
monitoring the reference signal (REF) in the drying
stage and judging the timing of the end of drying from a
change in the reference signal, thereby setting a drying
time.
In the Zeeman method, background absorption can be
thought as a reference signal. Generally, in case of a
solution sample, the solvent evaporates in the drying
stage and the vapor absorbs the beam from the light
source, so background absorption occurs. This causes
a rise in the reference signal. When the solvent is
vaporized completely, the background absorption due to
the vapor will end. Therefore, the reference signal falls
and returns to the baseline. In case of a solvent such
as water, light absorption is significant in the shorter
wavelength region and particularly in the wavelength
region shorter than 200 nm, the background absorption
due to the vaporization is conspicuous.
In the background detection function, it is first judged
that the background was detected upon detection of a
rise in the reference signal beyond the [Detection Start]
level set in the Temp. Program Test Conditions window.
Then, it is judged that the background absorption ended
when the reference signal fell below the set [Detection
End] level, and the background detection is terminated.
On termination of the background detection, sample
drying is judged to be completed and a time period
taken from the start of measurement and the end of
background detection is reflected as a necessary drying
time onto the temperature program.
When you put a check mark for [Background Detection]
by clicking its check box, the background can be
detected under the set conditions.