[109464] in Cypherpunks
Re: About Alpha radiation...
daemon@ATHENA.MIT.EDU (Tim May)
Thu Mar 25 02:37:27 1999
In-Reply-To: <199903242230.RAA26438@cti06.citenet.net>
Date: Wed, 24 Mar 1999 22:59:22 -0800
To: cypherpunks@cyberpass.net
From: Tim May <tcmay@got.net>
Reply-To: Tim May <tcmay@got.net>
At 1:38 PM -0800 3/24/99, Jean-Francois Avon wrote:
>Alpha from other sources might be another story, but still, the slightest
>material is enough to shield from alphas. Alphas from Radon, a commonly
>found
>radio-isotope seeping out of concrete in our basements have an Air Mean Range
>of 4.014 cm, (approx 1.58 inches) (figures from Rasetti, P116)
Alpha particles are a known problem with silicon chips. And I ought to know.
>Gammas are high energy photons, just like incredibly short wavelenght radio
>waves or light rays. They are ionizing, which mean that they could change
>the
>conductive state of semiconductors.
Gammas are vastly less ionizing than alphas. In fact, they don't create
_any_ electron-hole pairs along their track length...only when they
eventually interact with a target atom. "All or nothing." By contrast,
alphas are very heavily ionizing, shedding energy through the creation of
electron-hole pairs all along their track.
>Back to silicon chips, unless I misunderstood my physics classes, Alphas
>never
>get there...
Incorrect.
>As far as flipping bits are concerned, X could possibly, Gammas do and
>Cosmics
>too. But don't quote me on that last paragraph... :-)
X-rays don't flip bits, gamma rays don't flip bits. Cosmic rays, which are
high-Z nucleons and mu mesons can and do.
--Tim May
Y2K: Hope for the best, prepare for the worst, enjoy the ride.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May | Crypto Anarchy: encryption, digital money,
ComSec 3DES: 831-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets,
Licensed Ontologist | black markets, collapse of governments.
