Author Topic: How To Simulate a Linear Beam Drift?  (Read 5220 times)

Probeman

  • Emeritus
  • *****
  • Posts: 2858
  • Never sleeps...
    • John Donovan
How To Simulate a Linear Beam Drift?
« on: May 05, 2014, 11:25:48 AM »
I want to do some testing of the beam drift correction and wondered if anyone can suggest a way to produce a nice linear beam drift during which I will do quantitative x-ray mapping... I'm looking for a method that will create a 5 to 10% drift per hour of the beam current.

Any ideas...?
The only stupid question is the one not asked!

Mike Jercinovic

  • Professor
  • ****
  • Posts: 92
    • UMass Geosciences Microprobe-SEM Facility
Re: How To Simulate a Linear Beam Drift?
« Reply #1 on: May 05, 2014, 01:08:01 PM »
On the SX50 you could write a task in SX_Local to set the condenser 1 and condenser 2 values, curr c1 (value) and curr c2 (value), with a wait X seconds and loop through that to accomplish this I imagine.  All you would need is to set current values for the start and end to empirically get the C1 and C2 values to figure out how far you want to go and how often to increment c1 and c2.  However, the actual c1 and c2 values may not vary perfectly linearly with current, so a function may need to be discovered here.  Anyway, maybe there is a similar command for the SX100 interpreter, but no programing structure is available there (unlike SX_local).  Of course, you may have already figured out how to access the individual condenser values via PfE (?) so you could write yourself a little utility to do this.  Should be interesting.  I am guessing that 10%would not be enough to have a non-linear response due to hysteresis issues over that time increment...

John, maybe you are the first person ever who deliberately wants to make his machine less stable...

John Donovan

  • Administrator
  • Emeritus
  • *****
  • Posts: 3304
  • Other duties as assigned...
    • Probe Software
Re: How To Simulate a Linear Beam Drift?
« Reply #2 on: May 05, 2014, 10:07:27 PM »
John, maybe you are the first person ever who deliberately wants to make his machine less stable...
Hi Mike,
Maybe. But I do know that a study of "failures modes" can often teach us something useful about reliability!   :)

Yes, you are totally correct. After posting that I realized that I should just write a short macro in Excel and use my Remote interface to control the fine condenser current during the map acquisition:

http://probesoftware.com/smf/index.php?board=9.0

 :-[
John J. Donovan, Pres. 
(541) 343-3400

"Not Absolutely Certain, Yet Reliable"