🚀 go-pugleaf

In article <Bx8CGq.HsK@news.iastate.edu>, fils@iastate.edu (Douglas R Fils) writes...
>sci.physics
>	While reviewing my 300 level quantum bokk I came upon a
>section that hadn't impressed me as much as it does now.  It's
>in reference to possibility of doubly magic nuclei at Z=114
>and N=184 (Shell model) or perhaps more accurately, Z=110
>and N=184 (Collective model prediction) with decay on the order
>of 10^8 years via alpha or spontaneoius fission.
> 
>	Has anyone got any good references or heard anything about
>this subject?

Funny, I was just telling this story to my new officemate.  As you
correctly point out, there are supposed to be two islands of stability
in the (Z,A) plane which would allow the existence of "superheavy"
nuclei.  Their discovery would be (a) a tremendous boost to the
nuclear model builders and (b) a great playground for studying nuclear
properties under extreme conditions.  

The basic way you look for these guys is to collide very heavy nuclei
together at low energy - just enough to overcome the mutual coulomb
repulsion - to make them "kiss."  Some of them should fuse to form
the superheavy nucleus you want to study.  The superheavy will be in
an excited, unstable state, and you should be able to detect its presence
from the new unique set of spectral lines or decay fragements that
you capture in your detector as it de-excites.

People have mounted many experimental searches with no success.  The
current belief is that it is an experimental problem.  The islands of 
stability are very shallow - the nuclei are bound, but only with very
little net binding energy, making their production a tricky process.

People are still working on the problem, albeit not with the zeal that
the field once had.  There is at least one guy here at LBL we has recently
worked on refined mass calculations for superheavies, and there still
is experimental interest as well.  New facilities are probably required,
with high intensity heavy ions at low energy.  There are no such facilities
on the drawing board, at least that I know of in this country.  Europe has
been doing somewhat better at supporting such work, Germany in particular.

Any nuclear physics book will discuss this topic.  Segre's book is a 
good place to start.  For modern history, you will have to look for conference
proceedings and that kind of thing.

-Scott
--------------------
Scott I. Chase			"It is not a simple life to be a single cell,
SICHASE@CSA2.LBL.GOV		 although I have no right to say so, having
				 been a single cell so long ago myself that I 
				 have no memory at all of that stage of my 
				 life." - Lewis Thomas