Victoreen 440 Survey Meter

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Victoreen 440 Survey Meter

Post by guest »

I just stumbled across a Victoreen 440 Ionization chamber survey meter while looking for something else altogether (isn't that how it always happens?). It looks more or less ok, except for corrosion in the battery chamber (nothing unusual there). Does anyone have a manual for this beast? It looks worth restoring.
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Re: Victoreen 440 Survey Meter

Post by guest »

Late breaking news - By scraping the battery contacts, I have now rendered my Victoreen 440 at least partly functional. There appears to be some intermittent problems in the wire harness as well. Each wire goes to a push-on contact on the board edge, sort of like a poor man's edge connector. Of course, with this sort of setup, there are ample opportunities for intermittents due to wire breakage and contact oxidation. If all else fails, I can just solder the offending wire to the appropriate land on the printed circuit board. Some frustrated technician has aready done that with a couple of the wires...
Jon Rosenstiel
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Re: Victoreen 440 Survey Meter

Post by Jon Rosenstiel »

I just picked up a similar unit at a hamfest a couple of weeks back, it's a model 440RF/A. From what I can determine that particular model has been in production for quite some time. The last calibration done on the one I have was in 1989. I found some information here. http://www.surveymeters.com/products_440rfd.html
The unit I bought uses 4 "D" cells and one 22.5V, (Eveready #412), battery. The newest one uses 9V batteries.
I did get the unit to work after asking Richard Hull his opinion on the correct voltage for the "bias" battery, (It was 22.5V). The unit reads about 4mR/hr when a lantern mantle is held against the mylar window. I plan to test it further with my home-brew x-ray tube.

My unit doesn't have any push on contacts, (it could have been already modified as it appears to have been worked on quite a bit)!
guest

Re: Victoreen 440 Survey Meter

Post by guest »

Mine is ancient history - no microprocessor, runs off 4 "D" cells. Serial number is in the hundreds, so it probably dates from the early to mid sixties, especially judging from the date codes on the caps. I'm rather divided as to whether the polarized caps are electrolytics or tantalums, but it's probably a good idea to swap them out whatever the case (when I get the time).
Tom Dressel
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Re: Victoreen 440 Survey Meter

Post by Tom Dressel »

Just what is the story on radioactive lantern mantles. I vaguely remember hearing about this, but I cant remember the details

Tom
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Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by guest »

At one time, lamp mantles incorporated some thoria as well as a few other metal oxides, so they were somewhat radioactive. Apparently, the thoria has been phased out of domestically made lamp mantles, but may still be in foreign-made product. I have some of these radioactive mantles, and they barely twitch the needle on my RO-3 survey meter.
guest

Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by guest »

Hi Richard, I have a couple of pounds of cerium oxide for polishing glass, bought from a lapidary shop.I understand thorium is a contaminant in this material, just how dangerous is the stuff anyway?
guest

Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by guest »

I'd tend to doubt there is enough thorium in the cerium oxide to amount to a real hazard, but the only way to really tell would be to use a survey meter of some sort. You'll need to get one anyway, sooner or later... You might also want to put a pile of the stuff on top of a piece of sheet film (say Tri-X or HP-5 + or some X-ray film)wrapped in light tight paper to see if it darkens it after a few hours of exposure.
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Richard Hull
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Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by Richard Hull »

I have used and seen a lot of cerium oxide over the years, being an old ex-glass pusher (ATM). The stuff varies from lot to lot depending upon source and price. Expensive cerium oxide used in the pro-polishing industry is usually highly refined and the thorium has been removed along with other natural RE tramp contaminants. Older batches and some very cheap batches are usually just RE oxides directly reduced from Misch metal with is often 75% CexOx and can contain up to 3-5% thorium. This is just enough to indicate 2x-3X or more above background. I wouldn't sweat it though.
Ultra nice Cex0x which is hydrated and very pure is green-gray. De-hydrated Misch material with thorium is often a tan color. This later material is more often found used by rock hounds in tumblers and for rapid gem polishing.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
guest

Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by guest »

Hi Richard Hester and Hull, I bought the cerium oxide to make a scope mirror with, it is the tan material...I wasn't aware there were any other kinds out there but I have slopped a lot of it all over the garage floor over the years. It'll be the first thing I look at when I obtain a detector of some kind. Two to three times background is ok i guess but it shows how easy it is to contaminate an area unwittingly.
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Richard Hull
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Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by 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
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
guest

Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by 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.
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Richard Hull
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Re: Victoreen 440 Survey Meter/Lamp Mantles

Post by 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
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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