In reply to Eric Walker's message of Wed, 4 Dec 2013 21:06:24 -0800: Hi, [snip] >I wrote: > >On Wed, Dec 4, 2013 at 11:36 AM, <[email protected]> wrote: >> >> Surely that depends on the distribution of the radioisotope within the >>> metal? >>> Since you created this hypothetical substance, it's up to you to say >>> whether or >>> not that's the case. ;) >>> >> >> No doubt. :) But for my hypothetical substance, I will choose a >> realistic substance -- an ampule of ordinary cesium (pure but not enriched >> in any way). How do we know that any of the gammas emitted by an ampule >> originate from within the bulk of the cesium rather than being limited to >> the surface? >> > >It occurs to me that earlier I had hypothesized a pure gamma emitter (such >a thing may not exist, and even if any do, there may be no metals among >them).
There are a few pure gamma emitters, e.g. Hf178m. However it's not difficult to screen out the particle emissions from mixed emitters, and furthermore, if a spectral analysis of the gamma radiation is done, the intensity of gammas with a specific energy can be monitored. (Try Googling gamma spectrometry as a starting point.) [snip] Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
