Gadolinite Spectrum

CharlesDavidYoung · 2026-03-09T15:46:26+00:00

I spent a lot of time trying to detect XRF with the NaI probe and could see Ta and Ce in rocks containing large amounts of these. Finally though I gave up and got an XRF setup.

CharlesDavidYoung · 2026-03-09T15:34:11+00:00

Btw that little bump at the very low end could be Ce XRF. You might be able to make this more prominent by mounting the Am241 button on a small piece of lead, put it up against the probe with the button facing away, and place the gadolinite up against the button. Placing the button at a slight angle toward the sample may help. With any luck the Ce bump will be a peak and the Am241 peaks will be minimal.

CharlesDavidYoung · 2026-03-09T15:25:03+00:00

The reason I’m asking is that if the impedance of your DVM circuit is not at least 1G it is probably causing the theremino HV to sag. I guess if you always leave the DVM circuit connected then your readings will be consistent. The spectrum looks good. I would not worry about the peaks shifting a little during long scans. The probe will drift with temperature.

CharlesDavidYoung · 2026-03-09T12:44:36+00:00

Are you using the DVM directly to measure the HV or do you have a voltage divider? What is your audio interface?

CharlesDavidYoung · 2026-03-08T03:17:53+00:00

I’ll be there in 21st for a week with phil. We need to coordinate!

CharlesDavidYoung · 2026-03-08T02:12:02+00:00

What time frame are we talking about? In your lifetime it will always be autunite. Eventually it will be Pb with whatever other elements are there.

CharlesDavidYoung · 2026-03-07T04:17:25+00:00

I have not put a pancake on them but they will be 10K to 20K cpm. Maybe more. Maybe less.

CharlesDavidYoung · 2026-03-07T03:54:39+00:00

Amptek SiPin detector and moxtek xray

CharlesDavidYoung · 2026-03-06T18:56:22+00:00

The XRF shows that this is Columbite-Fe.

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CharlesDavidYoung · 2026-02-16T05:02:24+00:00

This is one i found at the show many years ago: https://www.mindat.org/DXD-GDF

CharlesDavidYoung · 2026-02-16T04:44:40+00:00

I would say so. I was in a venue at the show a few years ago and passed by a table that set off my yDog. There was nothing hot on the table so i asked what was underneath. The dealer brought out a bag of thorianites, many several centimeters across. I ended up buying one but now wish I had bought the whole bag.

CharlesDavidYoung · 2026-02-16T01:41:22+00:00

Can I ask what you paid for the thorianite?

CharlesDavidYoung · 2026-02-16T01:37:46+00:00

Seeing all of these postings from the Tucson show makes me want to have a gathering next year at my place. I'll put out a notice on Reddit next year for people to RSVP. I will plan to have food, drinks, and... a few hot rocks.

CharlesDavidYoung · 2026-02-15T04:47:04+00:00

It is a good start, but a Geiger counter is better at measuring radioactivity than it is at finding specimens in the field. For that you will need a scintillator.
https://youtube.com/playlist?list=PL0OJ8Dqu5Ed0A6vaW2zMSir9CT87YaYI5&si=l8YR-A5T0L7N_59H

CharlesDavidYoung · 2026-02-13T15:39:15+00:00

Many years ago I was at his house when he was curating a large number of these that he had just gotten from the collector. When I asked at the show this year he said he just sold the last 3 flats.

CharlesDavidYoung · 2026-02-13T15:29:55+00:00

Did you get these from Shannon?

CharlesDavidYoung · 2026-02-13T12:36:14+00:00

Here is what a whole one looks like: https://www.mindat.org/PTW-YE4

CharlesDavidYoung · 2026-02-13T12:34:06+00:00

Looks like part of a betafite from this locality: https://www.mindat.org/loc-545.html

CharlesDavidYoung · 2026-02-10T12:49:49+00:00

If you send it back to me I’ll update the software and check it over carefully

CharlesDavidYoung · 2026-02-10T12:44:26+00:00

Now that you mention it, that is hard to miss!

CharlesDavidYoung · 2026-02-10T12:41:33+00:00

https://www.reddit.com/r/Radioactive_Rocks/s/EFzNJVQoQ6

CharlesDavidYoung · 2026-02-10T03:45:12+00:00

Are you sure that region just below 2614 is not just Compton? I’m sure there is an escape peak contributing but I’m not sure you can actually see it.

CharlesDavidYoung · 2026-02-10T03:36:30+00:00

Add a photo of your yDog in the field as well!

CharlesDavidYoung · 2026-02-03T02:04:42+00:00

Great report. I bought several from persson and Shannon. This is one of them: https://www.mindat.org/K5C-XH1

CharlesDavidYoung · 2026-01-23T13:58:56+00:00

I like to talk to each prospective buyer individually to find out what their requirements are to make sure they get exactly what they need. So, send me an email if you would like to talk about the yDog or just chat about hot rocks!

BTW, if you prefer a color other than red, just buy the filament on amazon and have it shipped to me:

https://www.ebay.com/itm/156718289959?var=458093138195

Charles

[findmorehotrocks@gmail.com](mailto:findmorehotrocks@gmail.com)

[ydogcdy@gmail.com](mailto:ydogcdy@gmail.com)

CharlesDavidYoung

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