Interesting document on Krypton-doped nixies,,,

[Nick]

Bell Systems Practice document #024-723-801-I2, February 1983

This covered tubes such as the 122P224 / B-5092A which had a tiny amount of Kr85 added - half life is just under 11 years, so these tubes now only have an even more minuscule amount left (if any)...

Nick

[Dalibor Farný]

Interesting, do You know which nixie tubes were doped with radioactive krypton?

I like especially the "content" section which occupies a quarter of one page ;-)

Dalibor

2014-02-06 10:44 GMT+01:00 Nick <nick@...t>:
> Bell Systems Practice document #024-723-801-I2, February 1983
>

> Nick

--
Dalibor Farny
----------------------------------------
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http://www.daliborfarny.com
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[Nick]

The one I mentioned in the OP (122P224 / B-5092A) is the most common one found.

I've attached Burroughs Bulletin N101 from November 1968,  which has a section on issues surrounding ionisation. A good read.

Nick

[GastonP]

Interesting... so if we happen to break about 750 nixie tubes in the same normal size room, we should have absorbed the equivalent of one week occupationally allowed radiation dose.

They don't say anything on how to feel or what to do if we happen to do that now ;)

Gastón

On Thursday, February 6, 2014 6:44:35 AM UTC-3, Nick wrote:

Bell Systems Practice document #024-723-801-I2, February 1983

[petehand]

Hivac used to add a little to some of their tubes - I learned this 40 years ago from one of their R&D engineers. Actually I wasn't sure if it was Kr85 or Radon, but radon has a shorter half life.

As a practical matter, when I made my trigger clock with over a hundred Hivac XC17 trigger tubes, some of them stubbornly refused to strike unless they were brightly illuminated, preferably with UV. It made it pretty useless, as it would run all day and then at dusk the rings would stop counting and stick. I guess the tubes were between a 1/16 life and a 1/32 life by the time I got them.

[Nick]

Some time ago I was playing with XC18s (aka CV2486 - bought a large number many years ago when they were very cheap) - they have a similar problem so I experimented with uranium marbles and UV LEDs...

I wasn't very "quantitative", but from a qualitative standpoint, the marbles made no difference and at that time so-called "UV" LEDs didn't seem to have much UV content - more just purple...

Maybe things have improved since then and UV LEDs are a possible answer. All you need is a good source of high energy photons to initiate ionisation...

Nick

[Tidak Ada]

Nick, may be you find useful UV LED's here:  [  http://www.roithner-laser.com/ ] However, consider the price rises exponential with the inverse of the wave length  of the UV.

Does ordinary black light work?  Or aquarium water sterilization lamps, but use the latter only in a light tight case

Another source could be a mercury rectifier with an open system like 866's, but the power consumption of the tube make makes them valueless.

 

eric

---

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Nick
Sent: maandag 10 februari 2014 11:11
To: neoni...@googlegroups.com
Subject: [neonixie-l] Re: Interesting document on Krypton-doped nixies,,,

Some time ago I was playing with XC18s (bought a large number many years ago when they were very cheap) - they have a similar problem so I experimented with uranium marbles and UV LEDs...

I wasn't very "quantitative", but from a qualitative standpoint, the marbles made no difference and at that time so-called "UV" LEDs didn't seem to have much UV content - more just purple...

Maybe things have improved since then and UV LEDs are a possible answer. All you need is a good source of high energy photons to initiate ionisation...

Nick

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[NeonJohn]

Those UV LEDs generate a LOT of UV. I use one as a color tester for my
neon shop (most colors of neon tubing look white when off). Glad you
didn't hurt your eyes. Problem is, the glass is opaque to UV.

If you don't mind spending the money you can reactivate the tubes. One
can buy a microcurie of Cs-137 without a license. It can be had epoxied
to the head of a pin. 1uCi is more than enough to strike a couple of
tubes. Position the source in an inconspicuous place between two tubes
and it'll work for both of them. Cs-137 emits a good healthy 661keV
gamma ray that will easily penetrate the glass and cause bunches of
secondary electrons.

I just tried this using a 30 year old source (down to half a uCi) on a
flickering neon bulb on some old test equipment. I just held the source
against the plastic lens and the lamp glow went steady.

The only downside is that a pin source will run you about $60. If
anyone is interested in this route, I'll dig up some names of some
suppliers.

John

On 02/10/2014 05:10 AM, Nick wrote:
> Some time ago I was playing with XC18s (bought a large number many years
> ago when they were very cheap) - they have a similar problem so I
> experimented with uranium marbles and UV LEDs...
>
> I wasn't very "quantitative", but from a qualitative standpoint, the
> marbles made no difference and at that time so-called "UV" LEDs didn't seem
> to have much UV content - more just purple...
>
> Maybe things have improved since then and UV LEDs are a possible answer.
> All you need is a good source of high energy photons to initiate
> ionisation...
>
> Nick
>

--

John DeArmond
Tellico Plains, Occupied TN
http://www.fluxeon.com <-- THE source for induction heaters
http://www.neon-john.com <-- email from here
http://www.johndearmond.com <-- Best damned Blog on the net
PGP key: wwwkeys.pgp.net: BCB68D77

[John Rehwinkel]

> Hivac used to add a little to some of their tubes - I learned this 40 years ago from one of their R&D engineers. Actually I wasn't sure if it was Kr85 or Radon, but radon has a shorter half life.

Somehow I doubt it was radon, which has a half-life on the order of 4 days. Kr85 has a half life of around 10 years. I suppose you could mean radium, which was used in a variety of tubes, but the most common isotope (Ra226) has a half life of 1600 years or so.

- John

[John Rehwinkel]

> Some time ago I was playing with XC18s (bought a large number many years ago when they were very cheap) - they have a similar problem so I experimented with uranium marbles and UV LEDs...
>
> I wasn't very "quantitative", but from a qualitative standpoint, the marbles made no difference and at that time so-called "UV" LEDs didn't seem to have much UV content - more just purple...
>
> Maybe things have improved since then and UV LEDs are a possible answer. All you need is a good source of high energy photons to initiate ionisation...

Ordinary common high-intensity blue LEDs seem to work well. One thing that might be worth trying is finding an LED that emits photons in one of the neon absorption bands.

- John

[Kent Stevens]

Could Americium-241 be used from an old smoke detector since it emits both Alpha and low level Gamma?

Kent Stevens

> On Feb 10, 2014, at 6:45 AM, NeonJohn <j...@neon-john.com> wrote:
>
> Those UV LEDs generate a LOT of UV. I use one as a color tester for my
> neon shop (most colors of neon tubing look white when off). Glad you
> didn't hurt your eyes. Problem is, the glass is opaque to UV.
>
> If you don't mind spending the money you can reactivate the tubes. One
> can buy a microcurie of Cs-137 without a license. It can be had epoxied
> to the head of a pin. 1uCi is more than enough to strike a couple of
> tubes. Position the source in an inconspicuous place between two tubes
> and it'll work for both of them. Cs-137 emits a good healthy 661keV
> gamma ray that will easily penetrate the glass and cause bunches of
> secondary electrons.
>
> I just tried this using a 30 year old source (down to half a uCi) on a
> flickering neon bulb on some old test equipment. I just held the source
> against the plastic lens and the lamp glow went steady.
>
> The only downside is that a pin source will run you about $60. If
> anyone is interested in this route, I'll dig up some names of some
> suppliers.
>
> John
>
>
>> On 02/10/2014 05:10 AM, Nick wrote:

>> Some time ago I was playing with XC18s (bought a large number many years
>> ago when they were very cheap) - they have a similar problem so I
>> experimented with uranium marbles and UV LEDs...
>>
>> I wasn't very "quantitative", but from a qualitative standpoint, the
>> marbles made no difference and at that time so-called "UV" LEDs didn't seem
>> to have much UV content - more just purple...
>>
>> Maybe things have improved since then and UV LEDs are a possible answer.
>> All you need is a good source of high energy photons to initiate
>> ionisation...
>>

>> Nick
>
> --
> John DeArmond
> Tellico Plains, Occupied TN
> http://www.fluxeon.com <-- THE source for induction heaters
> http://www.neon-john.com <-- email from here
> http://www.johndearmond.com <-- Best damned Blog on the net
> PGP key: wwwkeys.pgp.net: BCB68D77
>

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[Tidak Ada]

But Ra228 will be more efficient in this case, for it is a ß-radiator.
However, it only has an half life of 69 months.

-----Original Message-----
From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On
Behalf Of John Rehwinkel
Sent: maandag 10 februari 2014 15:16
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Re: Interesting document on Krypton-doped
nixies,,,

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[Tidak Ada]

Tha absorption spectrum is the negative of the emissinon spectrum as far I
remember.

eric

-----Original Message-----
From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On
Behalf Of John Rehwinkel
Sent: maandag 10 februari 2014 15:19
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Re: Interesting document on Krypton-doped
nixies,,,

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[NeonJohn]

On 02/10/2014 09:30 AM, Kent Stevens wrote:
> Could Americium-241 be used from an old smoke detector since it emits both Alpha and low level Gamma?

I haven't tried it but I would expect it to work fine. The alpha
particles should slam into the glass and generate enough Bremsstrahlung
X-rays to do the job.

I'm not a safety nazi and I love experimenting with radiation and
radioactive materials. However I do have to urge some caution here.
Am-241 in the body is a bone seeker and a powerful carcinogen. The
isotope is "bonded" (I use that term loosely) to the ion chamber
electrode by a few microns of gold, thin enough to allow the alphas out
but thick enough to contain most of the material itself.

Some Am escapes the gold coating through recoil from the disintegration
of other atoms nearby. So in a detector that is more than a few years
old there will be some loose Am around the emitter.

Also, the gold film can be breached by the mere swipe of a finger across
the surface.

Bottom line: it's easy to loose the stuff and it's quite dangerous once
loosed. If you don't have an alpha-sensitive survey meter please be
very careful. Wear gloves and preferably a respirator. Lay down a
sheet of poly on your work surface and when you're finished, carefully
roll it up and toss it in the trash.

I have processed a large number of detectors to recover the Am so I
speak from experience. I use a wet process but still I use gloves and a
HEPA respirator. I've never found any contamination in the respirator
filter but I still wear it just in case.

John

[NeonJohn]

On 02/10/2014 09:32 AM, Tidak Ada wrote:
> But Ra228 will be more efficient in this case, for it is a ß-radiator.
> However, it only has an half life of 69 months.

Actually no. Ra-226 in equilibrium with its decay chain is an
"everything emitter". It was widely used in tubes such as radar T/R
switchs before cheaper and cleaner isotopes became available. The most
common is Ni-63 with a 100 year half-life. I have a 1st Gulf War
vintage nerve gas detector that uses Ni-63 and of course the venerable
Krytron. I've never heard of it being used in a display tube. Kr-85,
being a gas, is much easier to license and handle than any solid isotope.

[andybiker]

Just an idea, what about an old watch/clock face with glow-in-the-dark paint on it?
I have an old (ww2 german aircraft) clock that I took to work to check on a geiger counter.
My boss insisted I take it straight back home after seeing if showing 100 counts-per-second.
I think the radioactivity from the original paint should have been easily stopped by a piece of paper but apparently 
it decays into other elements that do not.
A piece of paper made no difference. a 40mm thick catalogue made some difference, a sheet of aluminium made some difference.
I think it must be giving off a fair cocktail of alpha, beta and gamma.

[GastonP]

Did any of you try with good old Thorium?

I have been playing with some gas lamp mantles, the retail item that contains more Thorium, and they emit a very happy dose of alpha and beta particles. Way more than what you get from uranium marbles.

[NeonJohn]

On 02/10/2014 10:15 PM, GastonP wrote:
> Did any of you try with good old Thorium?
> I have been playing with some gas lamp mantles, the retail item that
> contains more Thorium, and they emit a very happy dose of alpha and beta
> particles. Way more than what you get from uranium marbles.

Might work. I'd ash several, mix the ash with some epoxy or RTV and
apply to the back of a tube.

Coleman caved to the radiophobes several years ago and removed the
thorium. The only one I know of that still contains Th is this one:

http://www.neon-john.com/Nuke/century_mantle.jpg

The "made in India" and the radioactive material warning are the clues.
Last time I checked these were still available at Wallyworld.

[petehand]

I notice in the Burroughs Bulletin N101 Nick posted that the block diagram on page 2 shows a core memory! Reference in the text to the "recirculation loop" leaves no doubt. I'm curious to know if anyone has ever seen a Nixie instrument with a core memory? Presumably they must have existed sometime, somewhere, but I would have thought the cost - together with the "recirculation loop" and write electronics - would be substantially more than a few BCD to decimal decoders, even in the days before TTL.

I do recall, however, that one of the Anita nixie calculators had a magnetic memory - a torsion delay line. It was kind of like a clock spring made out of stiff wire. An actuator would twist it at one end and the torsion wave would go round all the coils and appear at the other end some milliseconds later, where it was sensed and fed back to the beginning. So you could store data in it, like a very fast tape loop.

[Quixotic Nixotic]

On 18 Apr 2014, at 09:52, petehand wrote:

I notice in the Burroughs Bulletin N101 Nick posted that the block diagram on page 2 shows a core memory! Reference in the text to the "recirculation loop" leaves no doubt. I'm curious to know if anyone has ever seen a Nixie instrument with a core memory? Presumably they must have existed sometime, somewhere, but I would have thought the cost - together with the "recirculation loop" and write electronics - would be substantially more than a few BCD to decimal decoders, even in the days before TTL.

I do recall, however, that one of the Anita nixie calculators had a magnetic memory - a torsion delay line. It was kind of like a clock spring made out of stiff wire. An actuator would twist it at one end and the torsion wave would go round all the coils and appear at the other end some milliseconds later, where it was sensed and fed back to the beginning. So you could store data in it, like a very fast tape loop.

Seeburg jukeboxes from the 1950s have core memory they call 'Tormat' units to store the selections. There must be many thousands of these still happily working away today in people's homes, but alas Seeburg never used nixie displays.

I still have an Anita 1011 if anyone is interested in it as a project and I am open to sensible offers. It has its original soft plastic dust cover and a manual for a slightly different model. It was fully working when it was sent to me, but in spite of it arriving to me in a large box of stryrene peanuts I think it had a shock in transit and something got dislodged, as the brittle plastic push button lamp switch on the back was shattered on arrival.

I acquired it from a man whose mother had died. She worked in the accounts department at the Morris Cowley motor works and used it until her retirement, when she was allowed to take it home with her. I still have the contact details of the person I bought it from if anyone wanted more details of its history.

Shipping to US would probably be expensive as it weighs 15 lbs. It is in the UK. Below is the actual item.

I opened it to replace the on-off switch and all the boards seem to be seated properly, but it is not displaying 000s as per the picture above before I bought it, but 999s. Definitely life in it, but I don't want to fiddle and make a mess of it, it is too rare for that. I have not pulled boards out or anything. At the very least if anyone bought this they would get 10 nixies and I think 5 of the very earliest ics.

If nobody wants this item, what do they think I should do with it?

Lots more about this model here: http://www.vintagecalculators.com/html/anita_1011.html

John S

[John Rehwinkel]

> I do recall, however, that one of the Anita nixie calculators had a magnetic memory - a torsion delay line. It was kind of like a clock spring made out of stiff wire. An actuator would twist it at one end and the torsion wave would go round all the coils and appear at the other end some milliseconds later, where it was sensed and fed back to the beginning. So you could store data in it, like a very fast tape loop.

I had a couple of calculators that used that kind of memory. One was a Singer/Frieden, I forget the make of the other one. They also used CRTs for display, with some clever logic to vector-trace seven segment digits onto the screen. They both showed a 3-level stack. Nifty devices, until my sister threw them out.

I also had a nixie calculator. It was made back in the days when calculators were really expensive, so it had one "math box", and four terminals. It could only make one calculation at a time, but since calculators spend most of their time waiting, this was apparently not much of a problem. It had a bunch of digits, Each terminal had 13 CD66 nixies for the display and a neon bulb for the - sign. It had old-style diode "ROM", with boards covered with arrays of diodes in various patterns. It died when a power supply capacitor failed, making all the nixie displays strobe with an interesting rolling effect as the power line frequency beat with the multiplex frequency. I was young and poor, and stripped the poor thing for parts. I still have one of the display boards, minus one of its CD66 nixies.

- John

[Cqr]

Were the CRT calculators Busicom?
One of those was the first thing I ever programmed... Punch cards with an instruction rate of ten per second!
I seem to recall it had a magnetostrictive coil memory, an acoustic delay line using wire that behaves like piezo electric stuff does but with magnetism instead.

Cheers,
Robin.

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[John Rehwinkel]

> Were the CRT calculators Busicom?

No, one was a Singer/Frieden, the other was something else (but I don’t think it was Busicom).

> One of those was the first thing I ever programmed... Punch cards with an instruction rate of ten per second!

These weren’t programmable, just add, subtract, multiple, divide, maybe a couple of other things.

> I seem to recall it had a magnetostrictive coil memory, an acoustic delay line using wire that behaves like piezo electric stuff does but with magnetism instead.

That could be - I remember the big coil of wire in the base, but didn’t know enough in those days to tell the difference between magnetostrictive and torsion memory.

- Cheers,
John

[P.Berk]

I have a Wang Engineering calculator about 1968 with desktop keyboard and Nixie display with electronics in a small suitcase which sat under the desk and a printer which did spark-erosion on aluminized paper. Core plane memory allows a program to be halted at the end of the work day when the system is powered off. Next day when you turn it back on, a lamp illuminates to indicate that it is still running the program !  No instant results when you hit execute back then.

Phil B.

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