[Rockhounds] DIY XRD?

[Pmodreski at aol.com]

Ah, yes, now, let's not throw too much cold water on Kreigh's cool  idea.  
Who knows, "in theory" it might work, but in practice... yeah, the  amount of 
X-rays produced are probably very miniscule, and although in theory  one might 
filter out just one wavelength of X-rays, in practice what one is  starting 
with is probably too spread over a range of X-ray wavelengths, to be  useful.  
And the X-rays are probably emitted in all directions, not focused  
geometrically at all, so by the time one collimated just the ones traveling in a  
particular direction toward the sample, one would again lose 99% of the tiny  amount 
that had been produced...  There was also the caveat in the story,  that the 
X-rays were only detectable when the experiment was done in a vacuum  chamber.
 
I wonder, if a miniscule amount of X-rays are produced in any electrical  
discharge, where high-voltage electrons are hitting something; as in a lightning  
bolt, or even, in a static electricity discharge when you shuffle across the 
rug  and touch your finger to something metal?  Seems like that and the Scotch 
 Tape, are just different versions of the same thing.  That would be even  
the simpler way to generate the X-rays for Kreigh's homemade  
mini-diffractometer!
 
Cheers, and keep at it, Kreigh,
Pete
 
 
In a message dated 10/22/2008 7:49:23 P.M. Mountain Daylight Time,  
Kreigh at tomaszewski.net writes:

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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