.. include:: ../substitutions.txt

.. _horizontal_sample_preparation:
    
Sample preparation for the Horizontal Optical Dilatometer 
==============================================================

The optical dilatometer frames two opposite sides of the sample with two independent optics. 

In order to achive the best focus the sample should be:
    
    * machined to a trapezoidal shape, in such a way that the lengths of the faces parallel to the optical path are minimized
    * placed on an alumina holding plate, in order to avoid elastic friction with holding rods
    * aligned to the end of the holding rods, in such a way that the border distances from the optics are equal and the focus distance is the same
    * placed in the middle of the furnace, so that the maximum expansion excursion is available both towards the left optic and towards the right optic