Search found 101 matches

by Geoff
30 Oct 2019, 13:49
Forum: Spectrum
Topic: Apatite
Replies: 7
Views: 332

Re: Apatite

Incorporation of rare earth elements (lanthanides and actinides) in minerals is an interesting subject. I’ve dug up crystals of anatase, simple TiO2, with a significant amount of uranium incorporated in them. To the point that it doesn’t look like anatase at all. F3C381C6-9658-429E-8510-80D87E4F11D6...
by Geoff
24 Oct 2019, 04:36
Forum: General discussion
Topic: Visual effect of long term radiation exposure on the acrylic glass of a watch
Replies: 7
Views: 225

Re: Visual effect of long term radiation exposure on the acrylic glass of a watch

I don't know enough about the chemistry of plastics to comment on what's happening in the watch glass, but I do know that radiation plays a large part in the color of gemstones/minerals. Ionization can alter color centers in minerals changing their color. this is often the case with smoky quartz and...
by Geoff
22 Oct 2019, 07:36
Forum: General discussion
Topic: Minimal set of suggested sources for calibration
Replies: 4
Views: 138

Re: Minimal set of suggested sources for calibration

I use 22Na, 226Ra, and 241Am for calibration. I have other disk sources, but for calibration I find that my homemade 226Ra and 241Am cover a wide enough range that I don't need much else. I use the 22Na 1274keV peak for my maximum. I'm not sure about the tolerance of the disk sources, I use a pulser...
by Geoff
14 Oct 2019, 08:41
Forum: General discussion
Topic: Geiger Müller tubes on flights
Replies: 11
Views: 470

Re: Geiger Müller tubes on flights

I'm not sure if it would be safe as I've never done it. I've only taken scintillation detectors when travelling. However, living in Alaska required the majority of my mail to come by air and I've had three different thin window GM tubes sent to me without issue. None of them were in pressurized pack...
by Geoff
04 Oct 2019, 08:12
Forum: General discussion
Topic: activating gold
Replies: 3
Views: 170

Re: activating gold

One Pyrotronics F3/5A has as much americium as ~90 modern smoke alarms.
by Geoff
21 Aug 2019, 15:16
Forum: Resources
Topic: Radioactive Minerals
Replies: 6
Views: 425

Re: Radioactive Minerals

0.085 mR/hr on my calibrated Ludlum model 18 including background.
37ABA289-6F7C-4494-A798-5AA3F8862450.jpeg
by Geoff
17 Aug 2019, 03:43
Forum: Resources
Topic: Radioactive Minerals
Replies: 6
Views: 425

Re: Radioactive Minerals

Radioactive minerals on mindat you say? My photo gallery can be found at https://www.mindat.org/gallery-21211.html As for radian barite, minerals tend to be pretty old. I have a huge sample from the Czech Republic but it’s not very strong. Most of the radium has already decayed to lead making it mor...
by Geoff
04 Aug 2019, 00:47
Forum: Spectrum
Topic: Will the real K-40 please stand up (please stand up, please stand up)
Replies: 12
Views: 616

Re: Will the real K-40 please stand up (please stand up, please stand up)

That bump should be there. It’s likely 125 keV. You can see there are more peaks to a 241Am spectrum hidden by the 59 keV in my discussion on energy attenuation:

viewtopic.php?f=5&t=384&p=1822#p1822
by Geoff
05 Apr 2019, 04:04
Forum: Software
Topic: PRA 22 Hold on to your seats..
Replies: 7
Views: 1155

Re: PRA 22 Hold on to your seats..

Interesting, I'm excited to try the sum quantity setting.
by Geoff
02 Apr 2019, 11:25
Forum: Spectrum
Topic: New lutetium source
Replies: 1
Views: 401

New lutetium source

David Hamric has a web shop called metallium where he sells custom minted element coins. I recently added a 26th to my collection, lutetium. The coins are about the size of an American cent and are absolutely beautiful.