Re: W. on the Environment

[Dan Minette]

----- Original Message -----
From: Charlie Bell <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, May 20, 2001 4:27 AM
Subject: RE: W. on the Environment



>
> Anyone have to hand exacly how radioactive potassium is, and which
isotopes?
>
> Charlie
>
>

K40 is the radioactive isotope of potassium.  It has a half life of
1.277E+9 years and a relative abundance of   0.0117%. It produces a 1.46 Mev
gamma in 11% of its decays.  1 g of potassium will emit approximately 3 of
these gammas every second.

(For those who want to double check my math, I assumed 1 K atom has a mass
of 40 amu or 40*1.66e-24 g, the probability of decay in one second is
1.7e-17, the relative abundance is 0.000117, and the branching ratio is
0.11.)

Dan M.