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"The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter? "

All that is to be determined Charles. It well may be much worse than that, if the low energies in the beam are what's helping to dig out the low energy XRF signals we are looking for.

I agree about our perspective points of view too.?

You system is as ideal as can be for your main task, and your display program is an advancement in the area of display and identification, especially for the audience of that group. Now the photography meets the same standard too. No one has added all those dimensions in one place to the amateur mineral group before.? All for science' sake, and I applaud that.

For you and others I would recommend trying a paper filter over the exciter source, just to see.

The rest is for the X-Ray Physics and X-Ray Optics crowd. We now have an inexpensive but powerful tool in our toolbox that wasn't there 2 days ago.

Geo

----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: XRF <[email protected]>
Sent: Wed, 28 Oct 2020 08:33:01 -0400 (EDT)
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup

The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter?? Was all that low energy activity that is filtered out detrimental or beneficial when the button is used to stimulate XRF in the target?

I come at this from a different perspective.? I use the Si-PIN with an Am241 exciter to identify minerals.? In my experience the XRF coming from the target is much stronger than the noise introduced by the Am241, which is mounted on a shield and facing away from the detector.? Attached is a scan of xenotime, which shows a large Y component as well as some U and Pb.? I turned on the Am241 reference lines to show that the Np and Au peaks are very small in comparison.? One quickly learns to recognize and ignore them when identifying the important peaks that emanate from the target: Ti, Mn, Fe, Ta, Th, U, Y, Zr, Nb, REEs.

Charles

On Wed, Oct 28, 2020 at 1:57 AM <GEOelectronics@...> wrote:

After trying many slight thickness variations of Source Filter components, the best result is show in the second picture.

First up is the spectra coming out of the Am exciter source with just a paper alpha blocking filter. That alone made significant improvements at the low end vs no alpha filter. The goal of this project is to apply a filter to the source that will effectively remove most of the low energy component that is caused by Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe.




Now a filter applied to the source and another Gamma Spectrum ran.




Thanks to member Dudley Emer for the design of the filter elements and thicknesses, based on selective filtering using the K-edge X-Ray absorption effect.

Geo