Bonjour

Any info about this 4x6 inches 'tube' (6AK5 on side)
Only two connections, top and bottom...no connection between...of course no filament
This is not a vacuum condenser (no plate, just a thin wire running inside from bottom)
Perhaps an 'ionisation room'...but as no 'window' of thin matérial (paper-mica...) useless for 'soft' alpha rays
This can be only used for 'hard' rays gamma...military or medical measurement
A second tube is exactly the same apparence , but with white internal paint...
Last...this tube was received among a lot of British and German WWII tubes (this is not a proof against a 'mixed' affair)

Any idea is welcome
F2FO

Never saw anything like this before. I'm as curious as you are.



Larry

It might be a T-R tube from a radar set.

With only two connections , its a diode or spark gap ( breaks down at a certain voltage ) enchanced with radioactive gas , doesn't look like any TR cell i've seen .

Looks like a T/R from a radar set either german ,or british.Sprman : )

Quite sure it is not a TR tube.. the size is much big than classic TR for waveguide or coaxial (British CV43)
More, if this one was on an early 'low frequency' radar (100-200 Mcs) two possibilities
1) mount in a resonant cavity, with power coupled by some hairpin, the shape of the glass bulb is not easy to match...
and the internal 'paint' (graphit - aquadag) will be destroyed by sucessive RF pulses, many kw traveling across the paint...
2) if the tube is directly connected to RF by the two connection, the bottom wire will not resist to the current as only (about) 0,05 diam.
One friend says something about HV régulator (gaseous discharge) but not on low voltage (VR150 - 0B2..) but more high as Victoreen
tubes for regulation of Geiger mullard tubes around 500 volts.....from memory I think that these tubes are always of small size..?...

Nevertheless, thanks or your interest
F2FO

These images may give a hint to what you have.

I'd guess a voltage regulator for several kV. If you have a vacuum test coil you can apply it to the small electrode and see if the gas inside glows.

If it is a tr tube, with a keep alive, it certainly will glow a bit but if HV is used a limiter resistor
will be needed or it will be destroyed.

thanks for your suggestions...in particular about old radar TR
the second drawing is exactly the inside of a CV43 (left picture)and we see that the spark will be located between the cones
samething for the TH3127 (right picture) of the French CFTH company...in this, the gap between cones is variable , turning the top knob
as a Jennings vacuum condenser...in center a little 1B40 for coacial near 1000 Mcs
The first drawing is very interesting and quite the same as my tube, except that there is no gap between plates..because no plates here
Ater a very careful look, I can see that the center wire is ended with half a dozen o VERY fine wires (0.01 or less) bended 90° for a lenght of about 1/2 inch...so thin wires can not resist to the current of a classic TR
From this discovery I made some test for a possible HV regulator...with voltage up to 5000 volts (7000 peak when AC) and a lot of resistor in serie...quite nothing across, just very few microampères in AC...after some hesitation, I take my chance...just the secondary of the transformer, the tube, the AC microammeter all three in serie...NO resistor.... result 20 microamperes under 5000 VAC..and if I am not wrong 250 megohms of 'resistor', or the same as a 13 picofarad in place of the tube (here the AC is 50 Cs)...but i think no gas inside the tube
At the moment I do not see a sure reply...
F2FO

Bonjour/bonsoir, Oldiesfan!

As you state, the big tube pictured has an internal conductive coating, one that appears similar to Aquadag used inside CRTs as an accelerator or anode. More likely this is a detector of some sort. I recall that Philips and Amperex made odd devices having generally similar appearance, and apologise that I have no literature from the 1950s or '60s covering their industrial product lines and cannot now spare the time to hunt for any. Might also be Soviet. (Am supposed to be writing something else,now, more profitable but not nearly so much fun as goofing off here on ARF... )

However, this thread is a sort of industrial archaeology, and a good one to pursue to its conclusion.

A question: Does the small tip-off shown at the upper left also serve to mount a contact pin of any sort? I can't discern any, but it would be very helpful to know if any sort of (third) electrode exists. If it did, I'm sure you would have described that in detail. I assume it is just the usual pumping tip-off. Another question: Is there any silvering or other type of coating anywhere inside the larger section, especially in a circumferential ring or band?

The OP's HV tests are the most logical exploration, but possibly not conclusive that there is no gas inside. If a much higher voltage low-current RF source, such as an old Oudin coil or a Tesla Coil, is brought near, that should make the tube glow inside. Might be necessary to do it in darkness after setting up. (Caution - Years ago I burned a conical crater deep into a finger when holding a bottle near a small 250W Tesla - the sparks jumped the glass, and I dropped the mystery tube - No joy, no tube, no answers, and a nasty burn that took months to heal up, and left some nerve damage. Ahhh, but it must have been fun, by definition, non? ) The color of any internal glow, if discovered, will be of great interest.
---
For proponents of the T-R tube explanation, which the OP already handled spot-on:
F2FO stated thathis mystery bottle has a conductive 'dag-like coating, which excludes all possiblity of T-R use. Likewise, his observations of its size and geometry seem to exclude anything save P-band as a possibility, and regardless, it isn't any traditional sort of T-R tube.
The photos of actual T-R tubes provided by other ARF poster above are excellent illustrations of all this. F2FO's tube is nothing of the kind! [The fine wires inside his tube seem to be discharge points of a wholly different sort, perhaps the anode srtucture./i] }

The device shown may be a vacuum photodiode or soft radiation detector of some sort. What is it? What does it detect? I don't know yet, but it seems increasingly clear what it's not.

Let this quest for ancient knowledge continue! Knowing the correct answer to this question would delight many of us. Thanks for posting the problem here. [i]Now, back to the saltmine, selling heartbeats for money...

73,

John

F2FO states: "A second tube is exactly the same apparence , but with white internal paint..."

Re-reading that original post makes me wonder if both the black and white tubes could possibly have been used together, perhaps as differential detectors, one to establish background count, while the other did the detection work. But what is it they detected?

If the white coating inside the other tube can be identified, that should be the key clue neded to solve the mystery. Does it fluoresce under UV light? Under HV? Probably not, especially if it is some odd photocathode. Is it granular or of a fine structure without any roughness? Does it have any internal metallic contact or ring that is distinct from the internal structure of the black tube?

Perhaps a photo of the two tubes side by side might be instructive. Likewise anything more on the internal electrode brush or pin-wheel structure (~ as I infer it) would be helpful.


To me, this really is one of the best mystery tubes ever submitted in this forum!


73,
John

It is possible that matching tubes were an TR and an ATR. The one thing about that era of UHF
radar was, as the TR tube grew older, the gas ionization voltage rose, placing the input of the
receiver at more risk.

The ATR didn't worry about higher let through because it wasn't protecting a dainty little crystal
in the mixing cavity.

If the TR and ATR were interchangeable, dodgy TRs could work for a while as ATRs, so they swapped then
when spares were few.

All this stuff goes back to the British labs when they invented radar.

Now the 'twins' tubes...the top tip-off is the remains of the exhaust pipe...no electrical connection...internal paint is 'white milk' color ..no metal flashed anywhere (silver..magnesium) these are not photo cell: no window usable for light input...no trace of a metal used in photo cell (cesium)
In the tubes we can have vacuum - air - another gas..If vacuum I know few uses without a filament emitting electrons ..mainly photo cell (see above), the first generation of X Rays, clearly not the case, ..for a possible 'spark' use with the size of glass need an enormous potential...and destruct the tiny wires
With air inside, we can detect 'hard rays' like the radiation detector of the picture...around 1970, in the 'Radio Sirplus' from the 1960's French Army,...two types, the one (picture) with a 600 cubic centimeters volume, another with only 50 CC..ranging from 10 milli Rad to up...(lethal..) ...a CK5886 electrometer tube...ONLY 220 volts between 'aquadag' in the plastic dome and a center rod...plus a lot o resustor ranging from 1000 Megohms to 1000000 Megohms (yes one million megohms) as ionisation current is in nanoampères
In this situation, internal 'paint' can be of relativaly high resistance, looking to the rest o circuits...(white unknown paint)
Another gaz.?. filling the volume with a gas of high atomic number (krypton) the sensitivity increase...
A question...the discharge points 'our tiny wires) can help the discharge.??
Again...I am sure of...nothing

73 F2FO

sorry for the missing picture

F2FO

Do you have access to an low power X-Ray machine? If you could get a radiograph of the shape of the
electrodes it might help.

As to the gas mixture, after a spark-over, the recovery time is the thing that is important.


Alan Douglas suggested a glow test. If variable DC was used, with a series resistor 1 megohm,
(voltage limit 1 kV) you could do a plot I/ E .

I can not have a test with x rays...but this is not very important as there is NO electrodes inside, only the 'aquadag' paint and the thin wire in center...(a look is possible from th botton of bulb)
After a test with DC ranging up 1000 volts: NO any current (and glow...) no current on a sensitive microammeter...
But a gas can be present in a 'tube' without any current up to many many kilovolrs on electrodes ...
In the 'T discharge tube' of the picture, when at ambiant air pressure we can apply 50,000 volts between plates ...no current
If we use a vacuum pump to decrease the pressure to 5 torrs, a noticeable current (10 mA or more) is present with only 1500 volts on plates, with a very good glow...this is the case for others gas ...
With a lower pressure, the current decrease until he stop (around 0.001 torr) ...now, with a very good vacuum and very high voltage we can have some sort of 'antique' X rays tube
Now if we return to normal pressure of air, and have a source of X rays or gamma rays, we can detect a very very low current, with only 500 or 1000 volts on electrodes ....preferably with the position of the 'ionisation room' above...
finally, current across the tube, or NO current across the tube is not an indication of what is inside...except (in my hope...) in the case of a 'possible'...ionisation room
Again thanks for your interest
73 F2FO

It is too big for RF (VHF or above), and the lead inductances are too great.

I vote for an early type of trigatron, which is used to fire a pulse modulator for radar.

http://www.electricstuff.co.uk/pulse.html#trigatron

Pete

The fact that there are two identical tubes suggests a comparative test: either some sort of laboratory demonstration, or a developmental test of the white coating (to see if it behaved the same as the well-known aquadag?). The white coating might also be fluorescent.

Not a trigatron...I have a CV100 trigatron, and inside, looking across the net i can see the two 'front to front' electrodes for the discharge of strong current ...the current is so strong that the tube has a net in case of explosion...more, in a trigatron, there is a third electrode for triggering the pulse across ... in my tube no electrode as common, only aquadag paint and a thin wire unable to accept high current

Speaking of 'Radar' family..I see that Alan Douglas live in cape cod...in Ridenour MIT book on radar, there is a picture of cape cod on screen of a 3cm early radar...
Possibly a fluorescent question...why not... has someone an answer...?.

73 F2FO