c160-3ay@ucbzooey.BERKELEY.EDU (Ranjit Bhatnagar) (10/08/85)
***
Sorry I didn't F)ollowup to the previous message- my machine doesn't support
that.
I was just reading about Marie Curie in the book From X-Rays to Quarks:
Modern Physicists and their discoveries by Emilio Segre and...
"The Curies themselves investigated whether heating or cooling a sample
would increase or decrease its radioactivity-- chemistry suggested
such an experiment-- but nothing happened. They also tried to compress
their sample, but nothing they did would alter its radioactivity. It
was a great mystery. In fact, the decay rate of radioactive elements
was not altered until after World War II, and then by subtle chemical
influences in which C. Wiegand and I used the understanding of the
nucleus accumulated over the previous decade."
I don't know WHY temperature does not alter radioactivity- but it was
interesting to read about it, especially in historical perspective.
(By the way, I recommend this book, if you're interested in the history
of physics- it's not comprehensive but it is fun to read. There is a
sequel, 'From Falling Bodies to Radio Waves.' Published by W.H.Freeman.
....Ranjitmikes@AMES-NAS.ARPA (10/11/85)
From: mikes@AMES-NAS.ARPA (Peter Mikes) I find it rather natural that temperature would not affect radioctivity - after all - if you imagine hotter material as bouncing atoms - then at any reasonable temperature only outer electron shells get deformed on each collision. There is no effect on the nucleus ( appart fom the broadening of lines due to the Doepler shift) and so no effect on the radioctivity. What I find strange is the other half of the statement - namely that they ( Segre and Wiegand) eventually did that - that they changet the decay rates - by what effect? Would somebody please explain what they did? . :q . :wq :q .
sukenick@ccnysci.UUCP (10/15/85)
[[[[((((<<<<*>>>>))))]]]] > mikes@AMES-NAS.ARPA >From: mikes@AMES-NAS.ARPA (Peter Mikes) > > I find it rather natural that temperature would not affect radioctivity >- after all - if you imagine hotter material as bouncing atoms - then > at any reasonable temperature only outer electron shells get deformed > on each collision. There is no effect on the nucleus ( appart fom the > broadening of lines due to the Doepler shift) and so no effect on the > radioctivity. Sounds reasonable, but I have a question which relates to this: Does the temperature of a plasma of radioactive atoms have any effect on the radioactivity (half-life)? (a plasma is at a temperature such that the electron shells are stripped off - so in this case, 'collisions' disturb the nucleus) (My guess is no - but I may be wrong) -GDS
ethan@utastro.UUCP (Ethan Vishniac) (10/19/85)
> >From: mikes@AMES-NAS.ARPA (Peter Mikes) > > > > I find it rather natural that temperature would not affect radioctivity > >- after all - if you imagine hotter material as bouncing atoms - then > > at any reasonable temperature only outer electron shells get deformed > > on each collision. There is no effect on the nucleus ( appart fom the > > broadening of lines due to the Doepler shift) and so no effect on the > > radioctivity. > > Sounds reasonable, but I have a question which relates to this: > Does the temperature of a plasma of radioactive atoms > have any effect on the radioactivity (half-life)? > (a plasma is at a temperature such that the electron shells are stripped > off - so in this case, 'collisions' disturb the nucleus) > (My guess is no - but I may be wrong) > > -GDS Atoms that decay by capturing an electron can be affected by their environment because anything that affects the electron orbitals can (theoretically) affect the capture rate. In practice you need to have such a strong environmental effect that the lowest energy level orbit is strongly perturbed, not an easy thing to do. The only way to affect other decays,i.e. beta or alpha emmission, is to reduce the phase space open to decay products. This would require a degenerate sea of electrons or alpha particles extending up to quite high levels. In practice I don't think this is achievable in a terrestrial environment. Neutron stars are made of neutrons that are stabilized in this way against beta decay. -- "Superior firepower is an Ethan Vishniac important asset when {charm,ut-sally,ut-ngp,noao}!utastro!ethan entering into ethan@astro.UTEXAS.EDU negotiations" Department of Astronomy University of Texas