Archived - New X-ray Detector

[Jon Rosenstiel]

Ran across this unit on eBay, new, still in the crate. An EDAX 10mm^2 Si(Li) CDU (Compact Detector Unit). Originally made to mount on an Amray scanning electron microscope.

I attached a couple of graphs showing the resolution difference between the EDAX detector and my old Ortec detector. The EDAX comes in at 150 eV FWHM on the 6.4 keV Ka x-ray of Fe. (She'll do FWHM of 136.9 eV on the 5.9 keV Mn x-ray) The Ortec can only manage 403 eV on the same source. Originally (maybe 30 years ago) the Ortec would have been a close match for the EDAX, but over the years repeated temperature cycling has taken its toll on a Si(Li) detector that was not made to be temperature cycled. The considerably more modern EDAX detector element will handle repeated temperature cycling. (That's good for me)!

Anyway, had to show off my new toy...

Jon Rosenstiel

[attachment=2]EDAX, Co-57.jpg[/attachment]
[attachment=1]EDAX spec.gif[/attachment][attachment=0]Ortec spec.gif[/attachment]

[Richard Hull]

Very sweet! I am very envious. You are set up for looking at XRF stuff.

The basement o' x-rays.

Thanks for sharing this with us.

Richard Hull

[Starfire]

what can I say Jon -- Drool!

[Jon Rosenstiel]

Only problem having something like this is.... it makes me want to throw rocks at my NaI detector!

Jon Rosenstiel

[Richard Hull]

Will this thing track up into the 0.1-3mev range like a NaI detector will?

Richard Hull

[Jon Rosenstiel]

Richard Hull wrote:
> Will this thing track up into the 0.1-3mev range like a NaI detector will?

No, it starts to peter out around 40 keV. What I was refering to was it's resolution, stability and linearity.

Jon Rosenstiel

[Richard Hull]

You bet! That is what I thought. That is the key with low end X-ray spectro work. Some of the lines sit on top of one another for various elements in XRF and 400ev is a wide line!

NaI is happy with a 10kev line width at 200kev. One needs a Ge-Li detector to get sharp, narrow lines out to 6 mev.

Richard Hull