RE: San Diego Union Aricle

["Marco Caceci" <chemitech@chemitech.com>]

The article reports users are upset at high false alarm rate. 

This is relevant.

In developing radiation detectors and alarms, specmanship galore

abounds: of course you get false alarms if you trigger at 2.83 sigmas

over background. But triggering at six sigmas raises your lowest

detectable amount, that does not look good on the specs sheet.

IMHO users do not need digital displays or trembling needles or one ton

of scintillator: if you have a 1 Ci Cs137 source passing by, any cheap

GM will do.

In the portal business I saw reported here that users recommend setting

alarms at 100% over background. What use is it then being able to detect

at 2% thresholds?

Of course the game consists in setting tough specifications in the

requisitions, to keep competitors out (must detect 1 uCi... at 1 m... in

1 sec... at 60 mph... and tell you what it is... and broadcast to a

satellite... and store... and count the neutrons too...): but by the

time a product is made that meets all these specs... lo and behold!,

it's too expensive, we'll wait and buy next year...



Marco



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