On Sat, 23 Jun 2012 15:22:39 -0700, wrote:

On Sat, 23 Jun 2012 09:09:42 -0700, Jeff Liebermann
wrote:

On Fri, 22 Jun 2012 17:10:12 +0000 (UTC),
wrote:

Why do all the atomic clocks require batteries?

I think you mean WWVB 60KHz clocks. Atomic clocks are cesium and
rubidium standards.

SNIP
Can Americium be used to build an atomic clock?

Probably not. Anything that will vaporize at reasonable temperatures
to form a "fountain" or produces an RF excited gas cell can be used.
Americium-241 is solid and melts at about 2600C:
http://en.wikipedia.org/wiki/Americium
Compare with Cesium-133 boiling at 671C and Rubidium-87 at 688C:
http://en.wikipedia.org/wiki/Caesium
http://en.wikipedia.org/wiki/Rubidium
Actually, it doesn't need to vaporize the entire contents to work.
100C is usually sufficient to create some usable gas. I just wanted
to illustrate the relative difference in temperatures required.

I understand a little
about how cesium and rubidium atoms are used to build atomic clocks
but since Americium is used in many smoke detectors wouldn't that be a
great science fair project or a Maker Faire project?

Ummm... I suggest you read The Radioactive Boy Scout before
proceeding.
http://www.amazon.com/The-Radioactive-Boy-Scout-Backyard/dp/037550351X

The world's first
truly atomic wall clock?

It's closer than you might suspect. See:
http://www.symmetricom.com/media/files/downloads/product-datasheets/DS%5FSA.45sCSAC.pdf
http://tf.nist.gov/timefreq/ofm/smallclock/CSAC.html
It draws only 0.1 watts. I think it's based on Thallium-205, but I'm
not sure. You don't want to know the price.

Of course, I suppose it could be argued that
radium on clock hands qualify the clock as atomic if radioactivity is
the only metric.

That reminds me. To vaporize radioactive materials into a gas is not
exactly a safe thing to do. The slightest leak, and you've zapped the
user. Triple seal the physics package will help, but there's always
going to be someone with a can opener and a product liability attorney
for a brother in law.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558