Re: positron source inquiry info

[SAFarberMSPH@CS.COM]

From a google search on sodium and positron:


http://www.chem.kent.edu/~rgregory/pals.htm


        22Na sandwiched between thin metal foils or sheets of Kapton is 

employed as the source of positrons.    22Na has a half-life of 2.6 years and 

its predominant mode of decay produces a positron and essentially 

simultaneous emission of a 1.28 MeV gamma photon.  Subsequent annihilation 

produces two 0.51 MeV gamma photons. 

In a message dated 8/1/01 7:10:16 AM Pacific Daylight Time, tjsav@LYCOS.COM 

writes:


Stewart Farber

=====


> I read a brief article in the weekly Scientific American weekly e-mail 
>
> newsletter about scanning positron microscope (SPM).  The microscope uses 
>
> an isotope of sodium as its positron source.  Does anyone know what isotope 
>
> it is and the decay pathway that allows the the release of a positron?  I 
>
> searched the web and came up with zero.