Walz MINI-PAM - Special Information on MINI-PAM;B

CHAPTER 8 COMPONENTS OF THE MINI-PAM
quanta m
-2
s
-1
at 0.6 kHz and 5 µmol quanta m
-2
s
-1
at 20 kHz. These
values are lowered to 1/5 when the burst mode is active. At such low
intensities an "actinic effect" of the measuring light normally can be
excluded.
8.1.2 Special information on MINI-PAM/B
Recently strong blue LEDs with an emission peak around 470
nm have become available and the MINI-PAM/B was developed
which employs such LED as measuring light source. Using 470 nm
measuring light has a number of technical and practical
consequences which shall be briefly outlined.
• Excitation filters:
The 470 nm LED light is passing through a set of short-pass
filters with λ < 620 nm (Balzers DT Cyan special).
• Detector filters:
The PIN-photodetector is protected by a set of long-pass filters
with λ > 650 nm (Balzers R65 and Schott RG 645).
• Measuring light:
At the same intensity setting (MEAS-INT) the integrated
intensity of the measuring light pulses of the blue version is less
than that of the red version by approximately a factor of 3.
Therefore, the MEAS-INT can be applied at higher settings
without the risk of an actinic effect.
• Actinic light:
The actinic light passes the same filters as the measuring light.
Therefore, the short-pass wavelength of 620 nm not only applies
to measuring light but to actinic light and saturation pulse light
as well. Consequently, as the red component of the halogen lamp
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