ATM shear in silicone pads

["Arjan te Marvelde (ELN)" <Arjan.te.Marvelde@eln.ericsson.se>]

Connecting the mirror cell to the mirror by means of a dab of silicone glue is, as i understand, the de-facto standard way of doing. 
However, if you look at cell and mirror materials, the differential expansion coefficient can be up to 20 um/m.K. If you assume a temperature range of +/- 15K and a typical dab distance of 10cm, the dabs will undergo a shear of +/- 30um.

Is there anybody who can say something about what the resulting force on the mirror is, as a function of dab area and thickness. I only get as far as: smaller and thicker dab means lower force, but i cannot stick a number on it. Maybe the effect is so small that you can just ignore it?

 ... Arjan te Marvelde