Author Topic: PHA with Xe detectors  (Read 4077 times)

JohnF

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PHA with Xe detectors
« on: August 01, 2013, 07:20:56 AM »
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

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Re: PHA with Xe detectors
« Reply #1 on: August 01, 2013, 11:49:21 AM »
Can you attach or embed a small image of the PHA peak shape?
« Last Edit: August 01, 2013, 04:42:23 PM by John Donovan »
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Paul Carpenter

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Re: PHA with Xe detectors
« Reply #2 on: August 01, 2013, 04:30:39 PM »
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
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Washington University St. Louis