Cosmic Rays, other Plasma, and finds

From: Mark Tapley <mtapley_at_swri.edu>
Date: Thu Jan 7 12:06:14 1999

All,
        Right here in Figure 5-6 of NASA's Technical Memorandum 4527,
Natural Orbital Environment Guidelines for Use in Aerospace Vehicle
Development, it shows that the Cosmic Ray environment is actually *less*
severe during a solar Maximum than during a solar Minimum. Note that the
effect only applies to rays with energy lower than appx. 10,000
MeV/nucleon, and these would probably be screened out by the atmosphere
anyway for a surface observer or classic computer. The rays packing more
than 10,000 MeV/nucleon are unaffected by solar max/min.
        I surmise that when the sun is putting out lots and lots of
protons, the extra protons form an additional layer around the inner solar
system and screen out some of the cosmic rays. Of course, this means that
though there are fewer (low-energy) cosmic rays, there are more solar
protons - but their energy distribution falls off rapidly above 10,000
MeV/nucleon (per Figure 5-7c).
        The bottom line is that unless your classic computer is on orbit,
you won't see any particle radiation effects from solar max. Magnetic
storms affecting power distribution grids, particlarly far north, quite
possibly.

        On another topic, I salute Captain Napalm for his multiply-encoded
message. Chuck, I disagree with you with less vehemence than he - I'd
rather see text messages myself - but that was a *hilarious* rejoinder.
Well said, er, shown, er, put.

        On yet another topic: I spotted about a month ago (and finally
found my notes) the following gear at a local electronics shop (A-Tex, near
the airport in San Antonio, Texas).

2 ea. HP 1615 A Logic Analyzer $31
4 ea. HP 1610 B Logic Analyzer $31
1 ea. Tek. 4105 Monitor $10
1 ea. Tek. 4404 Monitor $10
1 ea. Tek. 4025 Terminal $10
1 ea. HP 1611A logic state analyzer $?? (not marked)

        Each unit was about the size of a CRT terminal. The 1611 looked
like it might be an in-circuit emulator for a Z-80 based on some other text
on it. Conditions all unknown, no probes or accessories or manuals.
Outsides were dirty and scarred, with some keycaps gone on the terminal.

A) What are Logic Analyzers? (This is an embarassing question. No need to
coddle me with a long answer, something like "please go *open* the Horowitz
and Hill on your bookshelf" could serve.)
   Anybody know the frequency ranges for these particular units?
   Could I have fun probing the inside of my Rainbow or Mac Plus with them?
   Could I have fun probing My friends' PowerPC computers?
   Are these good prices, assuming they work?

B) What do accessories for the logic analyzers (like probes) cost? Can I
still get manuals? How could I test these in-situ?

C) Is anybody interested enough in any of them to have me pick one up at my
next opportunity and ship it (your expense for shipping, could be some time
before I can get there and they might be gone already, etc. disclaimer etc.)

        Thanks in advance on A) and B), and please contact me seperately on C).
                                                                - Mark
Received on Thu Jan 07 1999 - 12:06:14 GMT