You will find that natural radioactivity is found not only on Earth
but from extraterrestial roigin as well. There are approximatly 340
nuclides found in nature. More than five dozen of these are
radioactive. All of these elements which have an atomic number more
than 80 possess radioactive isotopes and all isotopes greater than 83
are radioactive.
One source is the Chart of the Nuclides which can be purchased for
$10, including shipping from:
General Electric Company
Production Resources
1080 N. Seventh St.
San Jose, Ca. 95112 - - It is a 55" x 32" wall chart. You can also
purchase a 60 page soft cover booklet from the identical source which
has the same information. The book contains a fold out of the chart.
The chart is similar to the Periodic Table of the Elements, however
the Periodic Table was developed before radioactivity was discovered
and before the isotopic nature of elements was known. The Chart of
the Nuclides contains ALL known radioactive isotopes, including those
natural ones you are asking about.
An online version of the Chart of Nuclides is found here - From
Brookhaven National Laboratory :
( http://www2.bnl.gov/ton/ ) - It includes all the isotopes including
the natural ones you are looking for. Click on "nuclid table" link at
top of the page. You will have to navigate a little bit to use the
chart. An example below.
________________
If you click on Calcium, you will find something like this:
20-Ca
basic
n-XS summary
XS graphs
20-calcium
Naturally occuring isotopes:
Ca-40 ( 96.941% ) Ca-42 ( 0.647% ) Ca-43 ( 0.135% ) Ca-44 (
2.086% ) Ca-46 ( 0.004% ) Ca-48 ( 0.187% , 6E+18 Y )
Isotopes:
Ca-34 Ca-35 Ca-36 Ca-37 Ca-38 Ca-39 Ca-41 Ca-45 Ca-47
Ca-49 Ca-50 Ca-51 Ca-52 Ca-53 Ca-54 Ca-55 Ca-56 Ca-57
If you then select a "natural" isotope, for the example I will use
calcium-48, you will get:
20-Ca-48
basic
n-XS summary
XS graphs
element
20-calcium-48
* Atomic Mass: 47.9525335 +- 0.0000045 amu
* Excess Mass: -44214.742 +- 4.147 keV
* Binding Energy: 415991.169 +- 4.148 keV
* Beta Decay Energy: B- 278.070 +- 5.041 keV
"The 1995 update to the atomic mass evaluation" by G.Audi and
A.H.Wapstra, Nuclear Physics A595 vol. 4 p.409-480, December 25, 1995.
* Atomic Percent Abundance: 0.187%
* Spin: 0+
* Half life: >6E+18 years
* Mode of decay: 2 Beta to Ti-48
o Decay energy: 4.272 MeV
*
Possible parent nuclides:
Beta from K-48 Beta + N from K-49
R.R.Kinsey, et al.,The NUDAT/PCNUDAT Program for Nuclear Data,paper
submitted to the 9 th International Symposium of
Capture-Gamma_raySpectroscopy and Related Topics, Budapest, Hungary,
Octover 1996.Data extracted from NUDAT database (Jan. 14/1999)
___________________
As you can see, the half life information you want is provided along
with a lot of additional information. If you are already familiar
with what the natural isotopes are, you should have no problem. If
you don't already know what they are, this chart will identify them
for you. One stop shopping :)
The sources I used to find this information are:
Radiation Fact Sheets - From the Health Physics Society
( http://www.hps.org/publicinformation/radfactsheets/ ) - this page
provides excellent, but very basic, information about radioactivity in
general.
Natural Radioactivity - From Idaho State University
( http://www.hps.org/publicinformation/radfactsheets/ ) - provides an
overview of radio activity and has a 'short' chart of the most common
natural elements along with half lives.
Search - Google
Terms - natural radiation sources, half life charts, tables +of
isotopes, tables +of natural isotopes
If I may clarify anything before you rate the answer, please let me
know.
Cheers
digsalot |
