PHA with Xe detectors

[JohnF]

As someone from the other side of the street (Cameca, all P10 flow detectors), I am somewhat mystified by the characteristic peaks we see here at ASU's 8530F on the LIF using the Xe-detectors; specifically for Fe Ka and Ti Ka.

They are clearly "forked" with both forks of the same height (at least on the Ti one I am starring at, with the left peak at 191.14 and the right peak at 19.25). Is this normal for a brand new Jeol probe? What is causing this behavior? On my Cameca, I will see clearly Ka1 and Ka2 but with clearly different intensities, and it is obvious which one to center on.

To be absolutely clear, I am talking about
(1) the characteristic X-ray Ka peak shape when a peak scan is done,
(2) where the PHA is adjusted/set properly-- the pulse center is sitting at 4-5 volts on the PHA distribution display (0.7-10 v display).

[John Donovan]

Can you attach or embed a small image of the PHA peak shape?

[Paul Carpenter]

John,

I am assuming you mean the ka1 ka2 doublet seen on an LiF wds scan (Ti on LiF for example).

On a sealed Xe detector you will see the Xe L-alpha escape peak for elements with energy just above the Xe L3 edge.

See http://xraysrv.wustl.edu/web/probe/manuals/pfw/PFWGS1.html#Carpenter_Startwin_PHA for more info.

Cheers,

Paul