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Registered Member #1630
Joined: Sat Aug 09 2008, 11:36AM
Location: Seoul Korea
Posts: 115
c4r0 wrote ...
Seoul_lasers wrote ...
c4r0 wrote ...
My counters based on SBM-20 g-m tube easily detects x-rays generated by x-ray tube powered from 50kV. I'm sure that measurement is much lower than it should be, however it detects this radiation. SBM-20 is designed for measuring radiation >100keV.
Medical x-ray machines usually uses 1-2mm Alluminium for filtering, but it's not so necessary until you're not going to x-ray yourself :)
Umm, they usually use lead lining around the tube for filtering. Beryllium is also sometimes used as well as it has a high atomic number. You can seriouly burn yourself with homemade X-rays. ( just like a very bad sunburn) I'd advise you BE CAREFUL. 50Kv-60Kv is more often the range for a dental x-ray machine. To really see if you have X-rays use a ZnS (Ag) screen below the tube. it will glow green then the power has been turned on. I have seen small radiotube X-ray machines make some impressive X-ray pictures.
I know that there is that lead filter, and i always unwind it off the g-m tube. By the way it's not lead actually becouse i've checked if its good for x-ray tube shielding and its not, about 0.5mm of this metal attenuates just like 2mm of Al.
You wrote that I should use an intensifying screen for detection. Well, in my case the screen glows only in the main x-ray beam so you would say that its ok and safe? My geiger counters are going mad even 5 meters behind the tube (not in front) becouse of scattered radiation and imperfect tube shielding (it can't be perfect). Also while turning anode voltage up the g-m counters laying 1m from the tube starts to tick at significantly lower voltage than the screen placed 5cm from the tube starts to glow visibly. So in my opinion geiger counter is much better for safety radiation detection. Ofcourse it's sensitivity should be checked first.
Oh, no.. of course USE a Geiger counter for safety you must do this!! I ment to say have the screen to make sure you tube is emitting properly. 2) BE extremely careful with the metal around the tube, there were some tubes that used Be foil and acciental exposure to it gives you Beryllium lung eventually. IT could be Sn but most likely NOT Aluminum. -- just be careful. In the orginal build your own xray machine document it suggested making a lead pig to house the tube in. This allowed X-rays out of a single opening. Do you have any old fishing weights?
Registered Member #1134
Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351
Dr. Meh wrote ...
Does that mean the Slab is radioactive?
Probably! I have made several trips now to the Dalbeattie area, and the area has significantly elevated radiation levels. Any rock outcrops in the area containing mineral veins, will almost certainly have some measurable activity, although only a few, are significant enough for collection, or extraction. I found an outcrop of Haematite (iron ore) that contains a significant amount of Uranium mineralization.
Registered Member #1630
Joined: Sat Aug 09 2008, 11:36AM
Location: Seoul Korea
Posts: 115
hydraliskdragon wrote ...
OT but since you guys were talking about it, I throw this out.
Is there any regions close from my city Calgary/Canada that has pitchblende or other radioactive minerals?
I know that the Lake Athabasca is rich in uranium ores but its 1000km drive...
You should check with Minfile project. There is an Alberta based version I think. Having been a collector of minerals past and present I can tell you that there are indeed uranium deposits around Alberta. Athabasca. Drumheller there is some U associated with fossilized wood. (apparently it is pretty common) and it is usually Carnotite and or Tyuyamunite. look for yellow stains on the wood. YOu should easily get a few 1000s CPM from a medium chunk of wood.
Here in BC we have at least 10-12 areas (1 on Quadra Island) that contains U or a mix of High grade U and Th. The most active being in the clearwater area (foghorn mtn). There is quite also quite a bit in the Okanagan valley as well.
btw- Quadra island was a bit of a fluke, and no more was found . BUT I went to the site (Radium Senator) about 4 years ago and little did I discover that there is some high counts 100s of CPM in the same area. hmm. Also people have reported some serious health effects from drinking the water on the island. (Notably Cancer). On Quadra this could be from naturally occurring Hg, As, Sb, Te or U disolved in the water from semi Alkaline conditions.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
Some places actually have warning signs advising people not to pick up the "hot rocks".. mostly because this is not a good idea. The problem is that fossils can be radioactive enough to affect some laptops and there are a couple of documented cases.
A while back they had a serious problem with radioactive lightning conductors, and they occasionally show up then HAZMAT gets called in to deal with the resulting mess.
Registered Member #59353
Joined: Sun Apr 17 2016, 02:08PM
Location: France
Posts: 84
hello,
it reminds Chernobyl, to evacuate wastes from the reactors on the roof before putting the sarcophagus, the Russians had used robots, but they all broke down because of a strong radiation, the liquidators have therefore taken over every 30 seconds, 1minutes.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
Note, modern laptops can be badly affected by sustained radiation even at low levels. Seems that some components can be affected in the DDR2/3 chips and low density ones (ie 2GB DDR3) can be quite sensitive. I think its due to the refresh being marginal on a lot of them, so even a few lost electrons can cause a SEU that cascades into a BSOD if it happens frequently enough on a critical process.
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Making a Geiger-Müller Counter
