7.4 Procedure of Wavelength Accuracy Automatic Check
After wavelength calibration by "WAVE ADJ" ends, the wavelength accuracy automatic check is
automatically started. The wavelength accuracy of each point is automatically checked by the
following procedure using the 254 nm, 507 nm (2-order light) and 761 nm (3-order light) of the
emission line of the low-pressure Hg (Mercury) lamp. During the wavelength accuracy check,
"CHECKING XX XXX" is displayed.
Function of WAVE CHECK in FACTORY
1. Detection of grating home position
The spectrophotometer determines the wavelength referenced to the grating home position. First,
the home positions of the grating on the excitation and emission sides are automatically detected.
2. Movement of the excitation-side grating to the 254 nm position
The emission-side grating is aligned with the 254 nm position determined in 5. Next, the
excitation-side grating is gradually rotated from near 250 nm slightly below 254 nm for the low-
pressure Hg (Mercury) lamp, and the light intensity peak is recorded by the emission-side light
sensor. The wavelength value of the maximum value is obtained by using the span correction
coefficient (S value) calculated in 19, and is recorded as 254 nm on the excitation side.
3. Movement of the excitation-side grating to the 507 nm position
The excitation-side grating is gradually rotated from near 500 nm slightly below 507 nm for the
low-pressure Hg (Mercury) lamp, and the light intensity peak is recorded by the emission-side
light sensor. The wavelength value of this maximum value is obtained by using the span
correction coefficient (S value) calculated in 19, and is recorded as 507 nm on the excitation side.
4. Movement of the excitation-side grating to the 761 nm position
The excitation-side grating is gradually rotated from near 755 nm slightly below 761 nm for the
low-pressure Hg (Mercury) lamp, and the light intensity peak is recorded by the emission-side
light sensor. The wavelength value of this maximum value is obtained by using the span
correction coefficient (S value) calculated in 19, and is recorded as 761 nm on the excitation side.
Hg lamp
stabilization
time
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