Here are a few items from our private collection. These items are not for sale (unless someone makes an offer we can't refuse, of course!), but we thought you'd like a look at them. They fit roughly into a few categories:
Two fairly early portable Geiger Counters, typically used by rockhounds and prospectors looking for the next Uranium mine. The larger meter on the left, "Geiger Counter F-6" was manufactured by Technical Associates in Burbank, California. Built in a one-piece drawn steel case, it has more weather stripping than some other civilian models of its day, but couldn't be considered weatherproof. For batteries, it requires 2 "B" batteries, Eveready No. 467 (NEDA 200), 67 1/2 volts each, plus 4 "D" cells. Note that a "B" battery is not a particular size, just a schematic designation when talking about any high-voltage battery in a vacuum tube circuit. Besides the Geiger tube, this unit uses 4 tubes, 2 ea. 1U4, a 5823, and a 6174. It is operational, except for its Geiger tube (see the Show 'n Tell section). The probe on the TA is a plastic/phenolic to accept beta radiation in addition to gamma. This is the only unit I own with an external speaker. Not sure, but it may have been the model they used in a couple of episodes of the original "Superman" tv series. It certainly "looks" like a Geiger Counter.
On the right is the Hoffman Hunter 223-1, a me-too meter jumping on the prospecting bandwagon. Built in a FOMB (folded-over metal box), and having no weather proofing of any kind, we're not surprised to find it in a fairly corroded condition. However, the internals are still good, except for the aluminum D-cell holders, which were pretty much lost to battery corrosion. The tube and cable assembly is fine (we've tested it on the TA). Like the TA, this one also uses two #467's and 4 D cells. However, in addition, the designers took the easy way out on the plate bias circuit and the unit also needs a 15volt battery which is even harder to find. The probe on this model has a shield which retracts. With the shield covering the tube, the probe is shielded from beta radiation, and reads only gamma.
The standard Victoreen V-715 Survey Meter has been the source of a lot of confusion and a good deal of consumer fraud. This instrument is an ionization-chamber meter, designed for one thing only, helping civilians take cover after a full-blown nuclear attack. It is not a Geiger counter. You couldn't use it to detect minor hazards, or in most cases even serious spills of isotopes from hospitals or nuclear reactors. It's just too insensitive. Most of the potential hazards we now face are not from full-blown thermonuclear attack, but instead from "dirty bombs", loss or spillage of stolen materials from labs or hospitals, poorly shielded x-ray equipment and leakage from waste sites and commercial reactors. Wrong tool. A quick way to identify it is the meter marked in full Rads (not milliRads like Geiger counters) and the lack of an external probe or any place to plug one in. "Survival" shops sell these things for hundreds of dollars, but you can buy them for practically nothing on eBay. I got this one for about $7, I think. By the way, they're not only expensive to get retested and properly calibrated, they're impossible to test yourself, unless you have a really dangerous chunk of something you shouldn't have without a license. There is also a version of this same device with a two-piece case. The bottom part contains the ionization chamber and a long wire, so you can deploy it outside your shelter to get a remote reading.
Here are two variations of the Civil Defense Geiger Counter. Manufactured for many years, by many manufacturers including the model-train people, Lionel, this meter went through many revisions. Each manufacturer was also free to make modifications to its circuitry. As a result, there are pretty much no interchangeable parts between models. These units run only on D batteries, the number of cells required varying from 2 to 5, depending on which version. On the side of each Geiger Counter, opposite the side with the Civil Defense logo, is a metal foil tape with a black spot in the middle, labelled "Operational Check Source". Under the tape is a small radioactive source to allow you to check your meter and see if it's still working. These meters can be fairly sensitive, although not very well calibrated at the lowest radiation levels. At left is a CDV-700 Series 6 manufactured by Anton. At right is a Series 6-B manufactured by Victoreen. These were transistorized units. Victoreen brand Geiger tubes were used in both, and in most of the others of all series.
The standard magnetic high-impedance magnetic earphone issued for use with the CDV-700 series. Note the single-contact headphone plug designed to mate with the completely weatherproof jack on the meter. While a good arrangement for weatherproofing, it is horrible for connecting to the wire to the headphone. The spring strain-relief is mostly for show. The least tug on the wire will break the conductor off in its plug.
At left is the Picker model 655-156 Survey Meter, a late-model analog Geiger counter. It uses two Geiger tubes, a large sensitive external one in the probe, and a small one internally for the highest range (up to 2 Rads/hr). This unit is fully operational and still seems pretty close to its correct calibration. Like the Civil Defense meters, it uses a rotatable slotted shield on the probe to be able to select beta or gamma only. Fully weatherproof with an o-ring seal in the cast face plate and a one-piece drawn aluminum case.
At right is a much earlier vacuum tube model, the Detectron model DG-7, which probably belongs in the Early Prospecting category, except for its calibration in mR/hr, and a little more effort in engineering. It uses smaller "B" batteries than the TA and Hoffman, 55 volts each, plus only two D cells. This one was also a victim of the imploding tube problem (see Show 'n Tell).
Meter on Picker 655-156.
Controls on Picker.
Close-up of Detectron DG-7.
Check sources are small amounts of radioactive material used for verifying the function of a Geiger Counter, Scintillator, or other instrument in the field. Below are some common ones which are legal to own without a license.
Old-style gas-lantern mantles used Thorium salts as part of their fluourescent doping to generate a brilliant white light from a gas flame. You can still find some in old stock at some hardware and camping-goods stores. There's also a busy trade in them on eBay. However, beware! These are pretty hot and should be considered mildly dangerous, and most especially the burnt ashes of a mantle already in use. Also, be aware that mantles are no longer being manufactured with Thorium anywhere in the world. Another rare-earth element, Yttrium, was found to work as well in the fluourescent salt doping of silk mantles, and without the radiological hazard. The three packages at top are non-radioactive. The two at bottom can pin the meter on an old Geiger Counter. We use them as a check-source on all items we sell to make sure every item we ship is operational.
A typical radium-dial compass. Unfortunately, with this model, not all the radium paint is under glass! Used to take this thing camping, before I learned how hot it was!
Uranium-oxide (or "Vaseline") glass marbles. Today, vaseline glass is only made from depleted uranium, but older pieces of decorative glassware from the late 19th and early 20th centuries might be quite a bit hotter. A whole handful of these might only have 5% of the beta emissions of a single Thorium-doped gas-lantern mantle, and barely enough gamma to measure. On the other hand, these are still being made. Vaseline glass is interesting in its own right. Clear under incandescent lighting, when exposed to ultraviolet, even daylight or some fluourescent lights, they give off a green glow.
What a difference! The Ecotest Terra weighs less than the probe on TA and will run for several months continuously on 2 AAA batteries, measuring gamma and beta, and is also a digital dosimeter and stand-by radiation alarm! No shoulder-strap required -- just slip it in a pocket! Check for radiation anywhere without anyone knowing what you're doing. Great for prospecting for genuine Depression-era orange Fiestaware at flea markets. Just don't eat off it if you find any!
Eveready 467's in the old style label. Part of a purchase of the old unused stock of a hardware store. Probably not much life left in them, but they're still putting out the right voltage. Price these at Radio Shack if you have nothing else to do. Wow! You'd be far better off buying one of our new digital dosimeters instead.
Notorious Victoreen 1B85 Geiger tube. (These tubes are also interchangeably called GM, Geiger-Mueller, and Geiger-Müller.) Used an organic quenching gas with a relatively short life. Tubes get very erratic near the end of their useful life. Also, between the very thin wall and the relative vacuum these tubes used, they're more than a bit subject to imploding. Geiger Counter afficionados tell stories of putting their working gear in the trunk of their car, slamming the lid, and causing the 1B85 tube to implode! Produced to fill a huge Defense Department contract at the beginning of the Cold War, this model tube was used in a lot of early equipment, most of which is now in need of new tubes.
This probably doesn't belong here, because we actually don't own it, but a friend sent it along and we think it's great! Click on the picture to open a larger view of it in a new window. Memorabilia from the early "Atomic Age"