Victoreen 440 Survey Meter

[Richard Hull]

The two to three times background refers to a counter at point blank range on a medium sized sample of the material.

A light dusting here and there on a garage floor would not impact background one bit, if the counter is placed at chest height off the floor.

The inverse square law protects nicely, even from dangerously lethal sources. Cerium oxide, even heavily thorium contaminated material is not worth honorable mention in the hazards class, provided no large quantity is ingested.

Richard Hull

[guest]

You guys talking about Cerium Oxide thorium contamination got me wondering about the thoriated tungsten electrodes used in tig welding. I have often wondered if this posed any health threat to people who do a lot of tig welding. (Aside from breathing fumes from welding and being exposed to UV light and large emag fields.) I do know that a new type of electrode (.5% Lanthanated, which is much more expensive) is now avialable to replace the thoriated electrodes.

[Richard Hull]

I do a bit of TIG welding on the side in my lab for friends to make a few extra bucks to feed back into my projects and, personally, prefer only the thoriated electrodes. (1-2%)

I am sure I am not exposed to the level of a welder on the line 8 hours per day, but am sure that the levels I receive are minimal. The new lanthanided electrodes are, I am sure much safer rad wise, but how much safer toxicity wise. Many of the lanthanides long term health risks are still unknown as only in the last decade have rare earths become un-rare.

A number of my books list the hazards of a number of the rare earths as "un-classified" as regards hazards, stating that studies are either conflicting or have not developed a body of work from which specific conclusions can be made.

You can be sure that when something is made safer, it is almost always more expensive and usually doesn't work as well.

Richard Hull