RE: Revisiting a old problem - measuring the insertion device gap

["Deborah Quock" <quock@aps.anl.gov>]

Josh,

Try http://www.laserdesign.com/default.htm for laser measurement and control
solutions.

This company has experience in the aerospace industry.

HTH,

Debby



-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov]
On Behalf Of Josh Stein
Sent: Tuesday, July 22, 2008 9:35 AM
To: tech-talk@aps.anl.gov
Subject: Revisiting a old problem - measuring the insertion device gap

Community,

 We have been tasked with designing an interlock system involving the 
measurement of our Insertion Devices here at the APS. Being a machine 
protection system, it would be preferable to use an independent source 
of measurement than is currently used by the control system. In the past 
it has been an awkward problem coming up with accurate absolute 
measurements of the gap due primarily to the fact that - by necessity - 
the area to be measured is typically under a high radiation environment.

I'm trying to approach this problem from a fresh start - without any of 
the existing baggage currently encumbering the control system.

So my question to everyone is simple to state, but I cannot come up with 
a reasonable solution:

1) For each Insertion Device (ID) the system will need accurate (within 
a few microns) and absolute measurement of the gap in two places (up and 
down-stream).
2) The transducers need to be radiation "proof" - things like plastics, 
teflon and electronics will not survive long enough (if at all) to be viable

In a nutshell, that's really it.

I've investigated a few leads which seem promising, but would like to 
hear fresh ideas from the experts (you guys).

Thanks in advance,
--Josh