Re: Re[2]: Cloud Chamber

["Ron L. Kathren" <rkathren@beta.tricity.wsu.edu>]

Actually, Am-241 emits a number of different alphas, although the yield 
is small for most.  In any event, you are correct in that there are 2 
major groups, but the energy dirrecence between them is less than 1% and 
so should not be detectable by cloud chamber techniques.  An excellent 
source of alphas is uranium, and uranium compounds can be purchased in 
small quantities from chemical supply houses.  This will, of course, be 
depleted U containing approximately 0.2% of the 235 isotope.

Good luck with your endeavor.

On Wed, 11 Jan 1995, Potter, Charles wrote:

>      Am-241 is a good alpha source, however, it does emit two different 
>      energy alpha particles.  There are two excellent sources of alphas.  
>      One is Gd-142, which is difficult to obtain because, I understand, 
>      plating of Gd is difficult.  The second is Po-210 which can be very 
>      easily made in a laboratory.  This is done by diluting Pb-210 solution 
>      with dilute HCL, pouring it into a vessel with a copper disc (masked, 
>      except for the desired source area) and agitating for a few hours.  I 
>      used this type of source in my Ph.D. research with very good results.
>      
>      Gus Potter
>      Sandia National Laboratories
>      PO Box 5800, MS1095
>      Albuquerque, NM 87185
>      (505) 844-2750
>      CAPOTTE@sandia.gov
>      
>      
> ______________________________ Reply Separator _________________________________
> Subject: Re: Cloud Chamber
> Author:  radsafe@romulus.ehs.uiuc.edu at ccsmtp 
> Date:    1/10/95 6:39 AM
>      
>      
>                       RE>>Cloud Chamber                            1/10/95
> The kit sounds great but it sounds like the only thing you really need from 
> them is the source.  If you want the source to be more familiar, you could 
> always take an air sample in the basement of your building before class.  I 
> would imagine you could get sufficient radon progeny to conduct your 
> experiment.
>      
> Rob Forrest 
>      
> -------------------------------------- 
> Date: 1/10/95 7:11 AM
> To: ROB FORREST
> From: radsafe@romulus.ehs.uiuc.edu
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> From: bkolb@arinc.com
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> Subject: Re: Cloud Chamber
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>      
> David Bromwich writes:
> >I saw something in a physics journal 10 (or was it 20 ) years ago 
> >describing a simple cloud chamber for demonstrating the range of 
> >alpha particles in air.  I think it used methanol and dry ice,    
> >producing a supersaturated methanol atmosphere.  I intend to use the 
> >amerecium source from a smoke detector, to make the source feel 
> >familiar to my students.
>      
> There is an inexpensive kit (under $30US) made by The Science
> Source in New England and available from the Fisher Scientific Educational 
> catalog.  It consists of a flat plastic jar, a styrofoam block, a 0.1 uCi 
> Pb-210 source and instructions (total value other than the source is less 
> than a dollar).  You supply the dry-ice and alcohol.  You place a piece of 
> blotting paper in the plastic jar (actually a plastic cylinder about 5cm 
> tall), soak it with alcohol, and put the lid on.  Place the jar on dry-ice, 
> which in turn, is resting on the styrofoam block.  Just at the moment when 
> a mist start to form in the jar, remove it from the dry-ice -- otherwise 
> you get freezing and have to start over with fresh alcohol.  This takes a 
> little practice.  It's at that point you will be able to get alpha and beta 
> tracks in the mist.  Put the jar back on the dry-ice and repeat.  I don't 
> think you will have good luck with an Americium source due to the high 
> emission rate and the inability to deionize this type of chamber quickly. 
> You are better off with a very weak source.
>      
> Good luck.
>      
> bill
> bkolb@arinc.com
>      
>      
>      
>      
> 
>