# Purchase uranium ore.

1. May 24, 2005

### theCandyman

Has anyone run across this site before? I found it long ago, but I am not sure why I found it and I just bumped into it again.

http://www.unitednuclear.com/uranium.htm

It is selling uranium ore from ten thousand counts per minute up to five hundred thousand counts per minute. I calculated this to be $$4.5 * 10^{-9}$$ to $$2.25 * 10^{-7}$$ Curies, but that does not seem very high as opposed to what they say on their site ["Low", "Medium", "High" and "Super High Radation Level"]. Is this low number due to it being ore?

Also, under the Radation Measurements part of the site it says they do not measure the alpha emissions, why? It mentions using a "stablized assay meter" instead of a Geiger counter, which I thought was normally used to measure radation, is it not?

Right now, I am just assuming this is a novelty gift group, trying to sell Uranium for inflated prices to unsuspecting buyers who will no doubt store their "Super High" radioactive rock in concrete and lead lined safes and pull out once in a while to impress their friends.

2. May 25, 2005

### Staff: Mentor

Uranium ore has been used in yellow color glass in the past.

The natural U element can be found with about 0.71% U-235 and much of the rest will be U-238 with a trace of U234. Now in the ore, U will be in the form of U3O8, a higher order oxide than the ceramic UO2, or UO3 with other metal oxides like cupruates, vanadates, and non-metal oxides like carbonates, sulfates, and so on.

In ore, the U oxides are few percent. There is a lot of low grade or <1%. One of the highest grades is 13.6% U at Cigar Lake. As a more typical example, Cameco has completed mining at its two open pit mines at Key Lake, where some 24 million pounds of uranium were recovered with an average grade of 1.3 percent U308.

See - http://www.wma-minelife.com/uranium/articles/art316.htm [Broken]

There may also be traces of radionuclides from the decay process in the ore.

Last edited by a moderator: May 2, 2017
3. May 25, 2005

### tehfrr

I’ve picked up a few different radioactive minerals from various different places, with unitednuclear being one of them. They do get some neat stuff in; however, if you really search around you can find better deals. I have a chunk of uranite would easily fit into their "super high" category and I paid like \$65 for it somewhere else.

Also, I don’t think you can convert right from CPM to curies without knowing the efficiency of the detector and the geometry of the setup. The source has isotropic emission (radiation emanates from the source in all directions) so only a certain amount is incident on the detector. Furthermore, gammas can pass right through the detector without interacting.

4. May 26, 2005

### Morbius

tehrr,

The quantity that is convertible to Curies is NOT CPM [ counts per
minute ] but DPM [ disintegrations per minute ].

That quantity is a property of the radioactive material - NOT the
method of detection - so all the issues you bring up above about the
isotropy of the source, and the transparencies to gamma rays are
irrelevant.

Dr. Gregory Greenman
Physicist

5. May 26, 2005

### tehfrr

I see what you are saying, but I was under the impression that if you know the efficiency of the detector, you can relate CPM to DPM, and then convert to curies.

According to Radiation Detection and Instrumentation by Glenn Knoll (3rd ed) you can get the quanta emitted from the source if you know the intrinsic peak efficiency and the geometry of the setup.

$$s = n \frac{4 \pi}{\epsilon_{ip} \Omega}$$
$$\Omega = 2 \pi (1 - \frac{d}{\sqrt{d^2+a^2}})$$

n = number of events recorded
ε = intrinsic peak efficiency
s = number of radiation quanta emitted by source over measurement period
d = source-detector distance (cylindrical detector)
a = detector radius (cylindrical detector)

intrinsic efficiency being [pulses recorded]/[# radiation quanta incident on detector]

6. May 26, 2005

### Morbius

tehrr,

Yes - Curies is measure of the radioactivity of the material - and is
convertible to DPM.

CPM - i.e. what the detector measures can be used to infer the DPM.

But CPM and Curies are not convertible from one to the other.

Dr. Gregory Greenman
Physicist

7. May 26, 2005

### theCandyman

I think tehfrr was trying to tell me that. Thank you for pointing that out tehrff.

8. May 27, 2005

### Staff: Mentor

Counts per unit time can be correlated/converted to disintegrations per unit time (or the actual activity) if one knows the integrated efficiency.

tehfrr provided an example of the spatial/geometric efficiency, but then there are factors like self-shielding within the specimen, scattering, detector dead time, and so on, to consider.