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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:20:10 ADT
Mike Rosing (eresrch@msn.fullfeed.com)
Tue, 7 Jul 1998 10:02:42 -0500 (CDT)
> - From the little research I have done so far there seem to be no way of
> influencing the time between hits in any predictable manner.
> Adding/removing sources can increase/decrease the frequency of hits over a
> given time period but the actual time between any two hits is still a
> random event.
I concur.
>
> It would not be that hard to add some sanity checking to the software that
> would detect abnormal fluctuations in the hit rate. I think that it would
> be extremely unlikely that an outside source could influence such a device
> without detection.
I agree completely. That's what makes radioactive sources seems so
secure. You can shield the source from all temperature and RF external
sources. the only thing that could bother it would be a shower of
neutrons, and that would have to be dense enough to kill every living
thing within miles. (note: you can shield a diode too, but it takes
a lot of detection tools to make sure there's no outside influence. If
your pet cat drops dead and you feel sick, chances are you're swimming
in a sea of too much radiation).
> So far this thread seems to be off the cuff discussion on the matter.
> There must be some research papers on this.
Let me know if you find any. If not, maybe I'll write one :-)
The ionization source should be easy to model. Americium is a positron
emmitter, I looked up the data once. I think it's on the order of a 5 MeV
particle. I'm not sure what the range is in the medium that carries it,
so I'd have to guess at the active depth. The size of the source is
known and so is the physical configuration of the chamber. So creating a
model of the current generation shouldn't be too hard. Once I have a
model, comparing it to the real situation should give me a clue as to
what is an outside influence and what is ionization current. With all
the sheilding I've built in, I better not see much outside influence!
(actually, I've set up the power supply to the ion chamber independently
of the rest of the circut. When I turn off that voltage, the signal is
below my ability to measure (< .05 Volts which corresponds to <1 microvolt
at the ion chamber).)
I've heard talk about radioactive sources, and seen the hotbits page, but
I have never seen any papers written about its use for random bits.
That's another reason to *do* it. So far, it hasn't been as easy as the
talk makes it out to be.
Patience, persistence, truth,
Dr. mike
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:20:10 ADT