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General Science / Could beams of neutrons be used to find gold?

« on: 26/09/2012 23:14:57 »

Is there any safe way to produce a collumated high energy neutron flux?

If there is, I have an idea for a specialized gold metal detector.

Imagine if you will, a gold metal detector designed to find only gold using radiation. This gold metal detector would not use a standard search coil such as used in normal metal detectors. Instead, the search coil would be replaced with a device that could produce safe, local, collumated high energy neutron flux that could penetrate the ground and transmutate natural gold into radioactive Au198, which could then be detected with a standard radiation detector using a discriminator window around the Au198 energy level. Au198 has a short half life of about 2 and a half days, so it wouldn't take long for the radioactive gold to become safe enough to market. The nice thing about this gold detector would be that it would not detect anything but gold. No more digging up aluminum beer cans, hot rocks and pull tabs. NORM may be a problem if Au198 energy level is similar in strength to Thorium, Potassium or natural Uranium but these might be rejected through the use of clever analysis of multiple discriminator windows.

Sadly, the only way I'm aware of to produce such a neutron flux also produces a deadly massive fireball.

Any thoughts?

2

Physics, Astronomy & Cosmology / Calculating radiation sigma levels

« on: 22/08/2012 20:43:44 »

I hope I put this in the right place.

I'm no mathematician or nuclear engineer, so please bare with me. Am I calculating this right?

 
Let's say, for example, a radiation monitor has an average background of 1872 CPS. During a scan the maximum count is say 2143 CPS. How much of a sigma increase is that?

Is this correct? :

Delta = MaxScan - AverageBkg = 2143-1872 = 271
Sigma = Delta/SQRT(AverageBkg) = 271/SQRT(1872) = 6.263 sigma increase

Searching the internet for a confirmation of this calculation gets over my head rather quickly. If the above calculation is wrong, could someone please tell me what the proper process is without getting all long haired about it?

Thanks much!

3

Geek Speak / Borland C++ builder log() bug?

« on: 21/08/2012 23:47:04 »

It appears that Borland C++ compiler (version 6) has a bug with the log() function.

For example, a compiled application using log(15) returns 2.708. My calculator and OpenOffice agree that log(15) = 1.706

Anyone else encounter this? I fought this problem almost all day thinking I was doing something wrong!!!

4

Geology, Palaeontology & Archaeology / Gold nuggets formed by water action?

« on: 16/08/2012 21:37:55 »

I found this following quote on a wikipedia article on gold.

"Such free gold is always richer at the surface of gold-bearing veins[clarification needed] owing to the oxidation of accompanying minerals followed by weathering, and washing of the dust into streams and rivers, where it collects and can be welded by water action to form nuggets."

Wikipedia article on gold : http://en.wikipedia.org/wiki/Gold

My question is, Really? Water action can weld gold fragments into nuggets? I find this a little hard to believe. If it was possible, I'm picturing the so called "nuggets" to be very crumbly with a grainy look to them. Has such a thing been found or proven to be true?

I feel like keeping this piece of information in the same place I keep other nonsense such as "diamonds were formed from coal".