From: "James Lerch" 
To: "ATM List" 
Reply-To: "James Lerch" 


----- Original Message -----
From: "Barry Keeney" 

>     Here's my question. He used a "gun" method to coat the smaller
> mirrors but can do the evap/boat systems I've seen in other ATM's
> systems.  Which system is is better for mirrors?


Hi Barry,

The answer depends on a lot of things, mostly on the dimensions of his
chamber, and the distance between the mirror and evaporative source (or
sources).

As far as a "Gun" method vs. evap/boat system, it depends on what
he mean by "Gun" (and if I understand the methods as well!)

If by "gun" he means 'Electron beam gun', and my understanding
that an electron beam gun uses an electro-magnetically focused beam of
electrons to heat the evaporative source to temperature (similar to how a
microwave oven works, but different) then either method should work fine as
long as the source is far enough away from the mirror so as to provide a
uniform coating thickness.

If by "gun" he means "Ion assisted deposition", then
this might be a superior option, again depending on multiple variables,
most of which being the distance between source and mirror surface.

This post is most likely not of much help, but you might point your 'new
found friend' over to our Yahoo group called "VacuumX" where we
might be able to assist him with any questions he may have.

http://groups.yahoo.com/group/vacuumX

Best of luck!

James

--- BBBS/NT v4.00 MP