Where do you pick up a 1DN5 tube and 1B86 Victoreen geiger element for a portable geiger counter?

I've seen them on eBay.....

Rodney

1U5 should replace a 1DN5.

1B86 have to use WA6VVL suggestion.

WA6VVL, when did you get the call? It would have originally been issued around 1961. Mine is WA6VGE

Hi Norm,
1973....
I was first licensed in '59/'60 with WA6LXW, and after I got married, I let it lapse. 8 yrs later, in Apr. '73, I got my 2nd Novice license WN6VVL and quickly upgraded to Adv w/WA6VVL.
I kept my VVL call after I upgraded to Extra in '92.
Dave

The 1B86 is a small glass Geiger-Müller tube that was used primarily in inexpensive and home-made Geiger counters. The 1B86, a Victoreen type, works at a very low voltage (300 volts), is quite fragile, and is now difficult to find as a separate item. Counters that use it turn up on eBay occasionally, though they are far less common than other types.

I think that the 1B86 was popular briefly, when the voltage source primarily used for GM tubes consisted of one or more 300-volt batteries. This method was quickly displaced by power supplies that stepped up lower battery voltages; and since these supplies could easily achieve the higher voltages (600 to 1,000 volts) for more effective GM tubes, the 1B86 fell by the wayside. I think it had more use in home-built instruments than in the commercial variety.

For a time, compact, low-voltage Russian GM tubes were available on eBay at relatively low prices; but all I can find now is this low voltage (400 volts) pancake tube that should be very sensitive:

http://cgi.ebay.com/PANCAKE-GEIGER-MUELLER-TUBE-2-mica-window_W0QQitemZ390015282726QQihZ026QQcategoryZ53154QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

LND produce a wide variety of GM tubes:

http://www.lndinc.com/products/category/34/

However, while some visually resemble the 1B86, I don’t see any that will work at 300 volts.

One vintage style glass type GM tube, the Raytheon CK1026, is still available at reasonable prices:

http://www.surplussales.com/Tubes-Sock-Acc/geiger.html

Note that the CK1026 requires 900 volts.

The Victoreen VG-18, which was used in the Sylvania U-235 Prospector portable radio/Geiger counter, seems similar in some ways to the 1B86, and requires only 600 volts:

http://www.orau.org/ptp/collection/GMs/victoreenvg18.htm

These turn up on eBay occasionally.

If you are restoring a vintage counter, you will have to patiently search for a suitable GM tube. If you would like to build a counter, you may wish to try a circuit that permits the use of a higher voltage tube. You may prefer to simply purchase and restore one of the many vintage Geiger counters that are listed for sale on eBay. The transistor and later models will often be in working condition as they are. Inverters to replace B-batteries in tube type counters are available from Allyn Goshy:

http://allnilo.com/

Also see the ORAU on-line museum of vintage Geiger counters and tubes:

http://www.orau.org/ptp/collection/surveymeters/surveymeters.htm

http://www.orau.org/ptp/collection/GMs/GMs.htm

ORAU museum index:

http://www.orau.org/ptp/museumdirectory.htm

Hi Philip,
Ahhh, those were the "good ole days"... In the early "prospecting for uranium days", the late 50's and early 60's, there were a gaggle of geiger counter designs using the 1B85 and 1B86 GM tubes: Radio & TV News, Radio-Electronics, Electronics World, Electronics Illustrated, Popular Electronics, etc., and the 1B85 and 1B86 reigned supreme in build-it-yourself geiger counters. The Allied Radio RK-665 used an IB85. Although I sold my geiger counter collection many years ago, I still have a collection of articles from those days. 1B86's occasionally show up on eBay, but they are relatively rare. There were a couple of NOS 1B85's recently sold on eBay. The 1DN5 is available via Antique Electronic Supply for $1.98.
Dave - WA6VVL

The 1B85, an aluminium GM tube, was the type most commonly used in commercial Geiger counters. These readily collapse due to sudden spikes of air pressure (such as shutting a car door with the counter inside) and from handling. 1B85s show up for sale on eBay, as do the counters that employ them, but they are as likely as not to arrive collapsed:

http://www.orau.org/ptp/collection/GMs/victoreen1b85thyrode.htm

The similar 6306, a bismuth tube, is more sensitive and also reinforced:

http://www.orau.org/ptp/collection/GMs/victoreen6306.htm

These are less likely to collapse, but I have seen collapsed specimens.

It is too bad that you sold your Geiger counter collection, Dave. I am sure it contained some interesting instruments. I have put together a reasonable collection of vintage counters and scalers, and have been surprised to find that there quite a few collectors out there lately.

Hi Philip,
My collection consisted of about a dozen counters. Much by accident, the bulk of my collection was mfr'd by Precision Radiation Instruments, from their bottom models, to the "Professional" 107, to an odd type of scaler-type counter which I can't remember the model #, to their scintillation counter. I still have the Victoreen CD set and an Eico 803 for comic relief.. Most of my collection was museum-quality and went to a collector. My collection was mostly found at garage sales and swap meets (pre-eBay).
Dave - WA6VVL

Dave, the Precision line was of high quality. And the 107 and scintillators have the added attraction of subminiature tubes. Your Precision scaler must have been the 118 Royal Scintillator, a rare and valuable unit to-day:

http://www.orau.org/ptp/collection/surveymeters/precisionroyal.htm

There were not very many portable scalers on the market. My collection includes a Hoffman Countmaster—

http://www.orau.org/ptp/collection/surveymeters/hoffman.htm

—and a very elaborate Beckman unit that is not in the ORAU collection.

The transistor version of the Victoreen CDV-700 is still usable to-day, as is. For years, Victoreen made commercial counters on the same essential design. The earlier version with subminiature tubes has three or four little condensers that are invariably leaky by now, and which prevent proper operation.

Hi Philip,
My CD-700 is Model 6b mfr'd in Dec.'66. It has been at least 15 yrs since I fired it up. Following your links, my scaler-type counter was the Hoffman "Countmaster". It's hard to confuse the "Countmaster" with anything else. I had several radioactive sources at the time to calibrate these things, but as so often happened, I loaned them out, and by the time I got around to using them, I had forgotten who I loaned them out to!!! Darn!!! The CD-700 has a source taped against the side of the case, but like I said, I haven't fired that up in a long time. The major reason I kept the CD-700 was BECAUSE it was solid-state with a very good design and that the GM tube was made by the wheelbarrow full, so easy to replace. In the beginning, using the various articles I had, I managed to build some homebrew counters using the lower voltage 1B86, but they were nothing to write home about - especially compared to the commercial stuff that was actually cheaper than "rolling your own"!! Thanks for renewing my interest in these.
Dave - WA6VVL

Dave,

It is remarkable how regularly vintage Geiger counter and scintillators turn up on eBay. I think you could re-build your collection with relative ease.

One would not think there would be a field of collectors for these instruments, but there is! There are two reasonably useful Geiger counter forums:

http://tech.groups.yahoo.com/group/CDV700CLUB/?v=1&t=search&ch=web&pub=groups&sec=group&slk=2

http://tech.groups.yahoo.com/group/GeigerCounterEnthusiasts/?v=1&t=search&ch=web&pub=groups&sec=group&slk=1

--Philip

I suspect there are a bunch of us interested in old Geiger counters, but there doesn't seem to be a forum for them that I have found.

I have a 1950's Atomic Research 521 counter which originally used a 1B85 tube. Naturally, the tube is crushed. Via a flea market I bought a nice stainless Hoffman probe with a sliding window, and the intact tube inside is a 6530.

So far I have been unable to locate data on the 6530. Does anyone know if the 6530 would sub for the 1B85 in this application?

I've got one of each of the CDV-700's by all the manufacturers.

That being said, I also have an ENI that's been modded and upgraded by GeoElectronics (see the Yahoo forums mentioned above) to a Leni (Lionel ENI). I think just last month, after selling his 800th unit he's given it up.

See here for more:

http://airraidsirens.com/forums/viewtopic.php?p=50170&sid=65eeb8330bbe98a697b1eb14f58a8bd9

The 1B85 and 6530 are both designed for a 900V supply, so that seems like a reasonable sub.
Dave - WA6VVL

Geoff, I have seen the 6530 only in Hoffman Countmaster portable Geiger counter/scalers. This means it certainly does work at 900 volts as Dave states, and it will electrically interchange with the 1B85, though it is of physically smaller diameter. It should work well in your Atomic Research counter, though it is hard to know how close the calibration would be.

Mort, have you all of the tube type CDV-700s? A tube type Victoreen CDV-700 was the first Geiger counter I owned, decades ago. These Victoreens with subminiature tubes turn up on eBay every so often. The CDV-700 line appears to have been based on the Nuclear Measurements GS-3, which has cylindrical subminiature tubes and a long glass GM tube:

http://www.orau.org/ptp/collection/surveymeters/nucmeasgs3.htm

The Nuclear Measurements CDV-700 Model 1 looks the same, except painted yellow and with a shorter GM tube and probe that no longer fits as well in the carrying handle. Victoreen took over for the Model 2, which has flat Raytheon subminiature tubes and a slightly different circuit (a dual tube permitted the elimination of one physical tube), but is otherwise extremely similar.

CDV-700 line:

http://www.orau.org/ptp/collection/civildefense/cdv700.htm

I have never been able to get a look inside an International Pump Model 3, the last of the vacuum tube type CDV-700s.

The CDV-700 Models 1 and 2 are, ironically, far more compact than the later transistor models.

The ORAU (Oak Ridge Associated Universities) museum site is a wonderful resource, and I have noted that they continue to acquire instruments for the collection. It is a shame that they do not present photographs of the chassis, often the most interesting part of the design.

Thanks, Philip and Dave. I will start work on swapping the probes as soon as I put together a DC-DC converter to replace the original B batteries.

The military PDR-27 counters seem to be regulars on eBay, although I see that many of them have repair "issues." Somewhere along the years the military converted many of the older models to use a DC-DC converter so that the B batteries could be done away with. Fair Radio Sales did have the assorted G-M tubes for these, but they seemed a bit pricey, and they are not physical substitutes for the 1B85 anyway.

For those just getting started in this area of interest, I would recommend a rather "antique" Howard Sams book entitled Atomic Radiation Detection and Measurement, by Harold S. Renne. Sams book ADR-1, first printing 1955. This is an interesting book which has schematics and descriptions of many of the popular counters of the day, with photos and theory sections. The book is a paperback and shows up cheaply on eBay and ABE Books every once in awhile. Anyone with an interest in collecting old counters would probably want a copy.

One shortcoming of the book is that it doesn't have a list of specifications of the assorted G-M tubes available at the time, which I would think would only have consumed a few pages.

Has anybody located a 1B86 Victoreen GM tube?

There are at least two Geiger counter websites:

GeigerCounterEnthusiasts@yahoogroups.com

and CDV 700 club

-Dennis