[Rockhounds] DIY XRD?

[Kreigh Tomaszewski]

Bryan,

The Bragg Equation requires the wavelength. Coherent x-rays from an 
incoherent source are fairly easy to produce using a small aperture 
monochromator. That problem was solved about a hundred years ago.

I agree that the real problem is the energy. There has to be enough at 
some wavelength to produce a detectable beam out of the filtered 
source. I assume there is enough since they were able to x-ray a 
finger, but it might require a slower scan than a commercial unit; it 
is easy to make x-ray detection cumulative.

How long will a roll of tape last? How many times can it be reused? I 
would be really happy to be able to get an analysis for the cost of a 
roll of tape.

Kreigh




On Wednesday, Oct 22, 2008, at 20:58 America/Detroit, J Bryan Kramer 
wrote:

> Doesn't x-ray energy/wavelength make a difference for x-ray 
> diffraction? I
> read that scotch tape article and it didn't sound like you could 
> control
> much beyond being able to produce some sort of x-rays in bursts.
>
> BK
>
> On Wed, Oct 22, 2008 at 20:44, Kreigh Tomaszewski 
> <Kreigh at tomaszewski.net>wrote:
>
>> I've often wished I could move a lab into my basement and do x-ray 
>> analysis
>> of minerals, but cost makes it just a dream.
>>
>> Now it has been discovered that unrolling scotch take in a vacuum 
>> produces
>> x-rays.
>>
>> http://news.yahoo.com/s/ap/20081022/ap_on_sc/sci_scotch_tape_surprise
>>
>> Using a roll of tape, a small motor to unwind it, and a vacuum pump, 
>> to
>> produce a source of x-rays turns the dream into a possible do it 
>> yourself
>> project.
>>
>> The database for comparison against known minerals is available at 
>> places
>> such as http://rruff.geo.arizona.edu/AMS/amcsd.php. The rest of the
>> details are relatively trivial once you have a source of x-rays.
>>        
>> http://productsearch.machinedesign.com/mdproducts/x_ray_diffraction
>>
>> Anybody interested in a science project?
>>
>> Kreigh
>>
>>
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>
>
>
> -- 
>
>
> "The thunderbolt falls on an inch of ground; but the light of it fills 
> the
> horizon."
>
>                        Ralph Waldo Emerson
>
> J Bryan Krämer
> North Florida, USA
> photos at:
> http://pbase.com/photoburner
>
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