PHA - integral vs differential mode

[Probeman]

Ken Severin posted this to the Cameca and JEOL listservers, but I thought it's also worth posting here in case someone missed it:

I was explaining to a class about setting up gas detectors and the difference between differential and integral modes.  The question came up as to why one would ever operate in intergral mode.  I didn't have a good answer (obviously setting up really tight parameters in differential mode can cause problems) - why not use differential mode with wide windows instead of integral mode?

Is this a holdover from earlier electronics?

My response was simply that running differential with a wide window is generally how I set my PHAs up, because frankly, I can't remember a case in which I needed to run in integral mode without a window setting...

Possibly for a very low energy line with a funky detector where the PHA peak is extra wide?
john

[Philipp Poeml]

Yes, that is what we do here as well, we usually use differential mode with a 4 V window. Unless we really try to filter something, where we place the peak in a small window.
Good question, I would be interested in an answer too.

[Probeman]

Yes, that is what we do here as well, we usually use differential mode with a 4 V window. Unless we really try to filter something, where we place the peak in a small window.
Good question, I would be interested in an answer too.

I've found that using a tight PHA window in an attempt to avoid a high order interference, usually produces more problems than it solves, due to gain shifting between standards and unknowns- unless the intensities are very similar of course.

It's better in my opinion to simply let "all" the photons in and use the quantitative interference correction in PFE to deal with them properly.
john