Geiger Counters Unlikely to Detect Radiation in Food, Water

[flamingdem]

http://www.bloomberg.com/news/2011-04-12/geiger-counters-to-find-radiation-in-meals-may-be-meaningless-.html

Also, some companies claim they are "testing" but the tests are primitive and only for Iodine, not cesium or uranium, etc. This creates a false sense of security. Even UC Berkeley seems to be using one liter samples instead of the 5 kilos recommended, not sure though.

-- snip

Large samples should be tested in laboratory-like settings to obtain results, said Joseph Rotunda, who heads the radiation measurement division at toolmaker Thermo Fisher Scientific Inc. Determining whether food, water or milk is safe also requires expert knowledge and more sophisticated equipment than the typical devices sold online, said Atsushi Katayama, a member of the Japan Society for Analytical Chemistry.

“Just pointing a measuring device at your food before dinner is pretty much meaningless,” said Katayama, who has a doctorate in analytical chemistry from Hokkaido University. “Tap water and fish, for example, require special handling, isolation and concentration to get meaningful readings.”

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A sample for emergency testing should be at least 5 kilograms (11 pounds) or 5 liters (1.3 gallons), according to instructions from Japan’s Ministry of Health, Labour and Welfare. The manual advises against using Geiger-Muller devices, known as Geiger counters, for measurements in food and drink because of their low sensitivity to gamma radiation. MORE AT LINK

[PamW]

1. Geiger counters - why not buggy whips and pay phones?

Geiger Counters Unlikely to Detect Radiation in Food, Water
======================================

I think you'd be hard pressed to find a "Geiger counter" in a modern
nuclear labs.

"Geiger counters" are based on the "Geiger-Muller" tube - just as old radios and
electronics are based on vacuum tube electronics.

Modern radiation detectors are solid state, like the transistors in solid state
electronics.

In fact, solid state radiation detectors are essentially big transistors.

In a transistor, a larger flow of current is controlled by a smaller current applied
to the "control" electrode, like the "gate" of a JFET. ( the other two electrodes are
the source and drain ). When a small current is introduced at the gate, a larger current
flows between source and drain.

In solid state radiation detectors, you have a big transistor without the gate. When
ionizing radiation hits the detector, it liberates electrons. The introduction of those
electrons from the radiation is just like adding electrons via the gate electrode, and
current flows in the transistor.

PamW

[flamingdem]

2. I think the term "dosimeter" is too new for the public still

.. but not for long.