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5-31
IM AQ6373-01EN
Mesurement
1
2
3
4
5
6
7
8
9
10
11
App
Index
Explanation
CHOP MODE
This mode activates the internal chopper of the monochromator.
When CHOP MODE is set to SWITCH, you can reduce the stray light specific to the
monochromator during measurements. You can set the CHOP MODE to SWITCH if the
sensitivity setting is HIGH1–HIGH3 or MID.
CHOP MODE Function List
CHOP
MODE
Function
Merit
Defect
OFF
Measurement according to
the stray light.
Measurement time
is rapid even for
high sensitivity
measurements.
Since the stray light
is also measured, the
low level component is
not accurate if the light
source is of high power.
Stray light suppression ratio:
40 dB or more
SWITCH
Two sweeps per
measurement are
performed. The first sweep
measures the stray light
component, and high
dynamic measurement is
possible through subtraction.
measurement can be
taken with stray light
removed.
If the measurement
duration is long, it is
influenced by temporal
changes in the
measured light.
Stray light suppression ratio:
60 dB or more
Stray Light from the Monochromator
The instrument has a newly designed, high-performance monochromator. Depending
on the measurement conditions, stray light at a level 30 to 50 dB below the original
spectrum, as well as other stray light specific to the monochromator may occur in
wavelength areas 100 to 200 nm from the peak wavelength. If this stray light is likely to
have a severe impact on measurements, the sensitivity can be set to MID or HIGH 1–3
and CHOP MODE can be set to SWITCH in order to reduce the effects of the stray light.
Waveform with CHOP MODE OFF
CHOP MODE set to SWITCH
5.9 Sensitivity Settings