Geo,

What is the high energy position and purpose for both? I’m seeing W in the spectra is this the high energy position run? What Is the purpose of the W 1mm collimator on a 25mm detector? The collimator and filter is used on the x-ray exit. ?Can you do the same run without it and close up detector.

The newer commercial units use a 45 deg setup with the detector the closest to the sample and it runs well down into the 1-2 keV range.

Dud

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Back to Obsidian.?
One of my wife Betty's finds in New Mexico

A nice lump with a broken tendril the end of which is glass smooth. Perfect for micro beam XRFing.

1mm beam and 1mm hole in sensor's W collimator. 300 seconds, the sensor is moved back to the high energy position, which eliminates tungsten XRF activation in the collimator. It is moved much closer when lowest energies are to be observed, due to air attenuation in the path of those low energies. Normally they are studied in a vacuum for this reason.

High def pic of the setup and .mca attached.

Note the exciter beam path- .? This closer to conventional and the 45 degrees is the angle of the beam to target and of the XRF to the sensor for 90 degrees total. Commercial units are arranged with the exciter and sensor both facing nearly? the same way, more like the RAPCAP arrangement we use.