NETZSCH LFA 447 Nanoflash, Operating Instructions Manual

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Operating the Instrument
LFA 447
TM
01/09 J:\LFA447\CHAPTER4.doc
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Optical filters
The filter wheel has eight total positions. Positions 1 through 4 contain filters which can be
rotated into the path of the flashtube to reduce the power. The various flashtube powers are
available as follows:
Optional Neutral Density Filter(s)
%light (transmission)
Position 1 0%
Position 2 25%
Position 3 50%
Position 4 75%
Position 5 100%
Position 6 100%
Position 7 100%
Position 8 100%
The choice of flash power depends mainly on the thickness or heat capacity (product of mass and
specific heat) of the sample. Samples with a high heat capacity (product of mass and specific
heat) require more energy than samples with a low heat capacity.
If with the lowest possible energy (e.g. used for thin films: 190 V flash lamp voltage, short pulse)
no useful measuring results are achieved, it is recommended to use the filter to reduce the
power.