RE: Metastable states

["Fulmer, Philip" <philip.fulmer@cplc.com>]

Greg,

As you know, the metastable states of both Bi-210 and Po-212 do exist;
however, the decay of Pb-210 and Bi-212 do not lead to those metastable
states.  

1.  In the case of Bi-210m, the metastable state is a 9- spin state, and
is produced by a (n, gamma) reaction with Bi-209.  The 9- state is 0.271
MeV above the ground state of Bi-210, and all decays (or at least the
ones I see) of Pb-210 go to either the 0- or 1- states.

2.  In the case of Po-212m, the metastable state is a 16+ spin state at
an energy level of 2.905 MeV above the ground state and is produced by
an (alpha, p) reaction with Bi-209.  All the decays of Bi-212 that I see
go to lower energy spin states.

Interestingly enough, both of these isomers decay by alpha emission.
The gammas listed in the Chart of the Nuclides for these isomers are not
for transitions to the ground state but are for transitions in the
energy states of the daughter following alpha emisssion.  

Regards,

Philip

__________________________
Philip C. Fulmer, PhD, CHP 
Carolina Power & Light Company
Harris Energy and Environmental Center
3932 New Hill-Holleman Road
P. O. Box 327
New Hill, NC 27562-0327
philip.fulmer@cplc.com
(919) 362-3363      

>----------
>From: 	Greg Gibbons[SMTP:gibbgreg@isu.edu]
>Sent: 	Thursday, May 14, 1998 6:53 PM
>To: 	Multiple recipients of list
>Subject: 	Metastable states
>
>Radsafers,
>Does anyone know if the following metastable-state daughters ever result from
>these naturally radioactive decay schemes?
>
>Pb-210 (b-,g) Bi-210m 
>Bi-212 (b-,g) Po-212m
>
>The databases I'm using illustrate that the ground state daughters exist, but
>the metastables are left out in both cases.  Any insight will be appreciated,
>thanks!
>
>Greg Gibbons
>gibbgreg@isu.edu
>