6
The fibers used are terminated with SMA connectors that have been carefully
polished to achieve adequate optical performance. Luzchem uses high-OH fibers to
optimize ultraviolet performance. For model SPR-01 the fiber used is 300
µ
m in
diameter. The minimum allowed momentary radius is 60 mm (~2.5 inches), and the
minimum long term radius is 100 mm (4 inches). Bending the fiber beyond these
limits can cause permanent damage that also invalidates the calibration factors. Fiber
replacement requires recalibration of the instrument.
Instructions for SPR-01 only
When installing the fiber, the connection should be “finger tight”. Do not use tools
for this purpose.
The female SMA connector on the detector head should not move when installing or
disconnecting the fiber. It has been installed with a special adhesive that under
normal force conditions will prevent the female connector on the detector head from
moving. If this connector moves it will be necessary to reinstall it matching exactly
the calibration distance. Contact Luzchem for assistance.
2.4.
Attenuator
Luzchem spectroradiometers are supplied with a PTFE film attenuator that reduces
the light input by about one order of magnitude. A generic transmission curve is
supplied with all attenuators.
Luzchem can perform a custom NIST traceable calibration for the attenuator supplied
with the system. For many applications the attenuator is not essential; however, for
some solar and sunbed applications, the attenuator may be useful to increase the
dynamic range of the instrument.
2.5.
Verification lamp (model SPR-01 only)
Model SPR-01 includes a low pressure mercury lamp that operates with 4 AA
batteries. The lamp is controlled by a switch at the back of the instrument. This
switch does not need to be on to operate the radiometer, but only to use the
verification lamp. The verification lamp has the spectrum of Figure 2.3 (this is a
power spectrum), with a characteristic band at 254 nm that should be within
±
1 nm of
the wavelength read.