[time-nuts] HP 5071A Electron Multiplier of Cesium Beam Tube

J. Forster jfor at quik.com
Sun Sep 6 19:51:36 UTC 2009


A sugar cube sized chunk of Cs does not really present much of a danger,
unless maybe if you eat it.

MSDS's make no real distinction between small lab quantities of chemicals
and industrial quantities. A 55 gallon drum of Cs whould really merit a
HazMat incident, but not a few grams.

It's quite clear that the HazMat people treat every incident as if it were
a major threat. Recently they closed a major highway near here to
"respond" to a leak of under 15 gallons of Aviation Gas. They had foam
trucks, many fire engines, three helicopters, and who knows how many State
Police cars. Traffic was backed up for many, many miles. Left alone, the
stuff would have evaporated in a half hour or so. A single police car and
some traffic cones would have been more than sufficient.

But, the incident was great publicity for the HazMat folks as most people
lack either the technical knowlege or judgement to separate a real hazard
from a PR exercise. They get credit for "solving the problem" even if
there was really no significant problem to be solved. This makes them
"look good".

FWIW,
-John

==============



>>I'm not so sure. If you cut open the tube and then immediately rinsed the
>>insides with deionized water, then the acid etch, I doubt there'd be much
>>Cs left after 5 minutes. Now there could well be nooks, crannies, or cul
>>de sacs that are all but impossible to wash out. I can certainly believe
>>that.
>
> While you may be able to get away with that in your garage, I can
> certainly see why HP didn't want to do it at work:
>
> From Cs' MSDS:
>
> 	Extinguishing Media: DO NOT USE WATER. Use class D metal
> 		fire agent, dry salt or sand.
>
> 	Special Firefighting Procedures: Firefighters must wear
> 		full face, self-contained breathing apparatus with full
> 		protective clothing to prevent contact with skin and eyes.
> 		Fumes from fire are hazardous.
>
> 	Unusual Fire and Explosion Hazards: DANGEROUS WHEN WET. If
> 		involved in a fire, burning metal may produce
> 		severely corrosive fumes of cesium oxide and
> 		hydroxide. Cesium reacts violently with water,
> 		liberating and igniting hydrogen, perhaps explosively.
> 		Cesium may ignite spontaneously on contact with
> 		air. Pyrophoric metal.
>
> Remember, a spent Ceisium tube has a couple of grams of the stuff
> spread out with a very large surface area.
>
> You won't see me open one...
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by
> incompetence.
>
>





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