Experimental Physics and
Industrial Control System

Heinrich du Toit <[email protected]> · Mon, 26 Nov 2007 16:25:47 +0200

Hi guys
I'm looking for some information on how you solve this problem...
We need to measure currents.. from harps and slits and faraday cups.
All of this gives of currents that is important.

Some of the currents we measure with keithleys but it is way to
expensive to buy keithleys for harps as you will need 100's of them :)
We need to measure currents between nA and uA range for harps and slits.

For faraday cups this sometimes goes to 100+ uA but our main problem is
harps/slits.
I hope that we are not the first to have this problem, is there some
cost effective method to solve this problem? That can give descent results.
The problem can basically be given as:

How do I measure 50+ current inputs (harp = 96, 4 per slit-set) across a
wide range (2nA fullscale = 50pA sensitive up to 100uA full scale) still
have resonable accuracy especially between the lines and have a descent
update rate and not 2 high noise levels.

(I guess noise can to some extend be solved with a software filter if
updates are high enough)
Thanks for your support :)
-Heinrich

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System