Question on Z5660M Tubes- What kind of gas and age survival?

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Dman777

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Jun 7, 2014, 3:12:13 PM6/7/14
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I am about to the trigger and go for a clock kit with Z5660M Tubes unused. They were manufactured in 1985. I know there are a lot variables involved...like the gas used in them. Does anyone know what kind of gas these used? If the tubes from 1985 are good? If they should of aged ok with no issues like cathode poisoning? 

Tidak Ada

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Jun 7, 2014, 4:01:59 PM6/7/14
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eric


From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Dman777
Sent: zaterdag 7 juni 2014 21:12
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Subject: [neonixie-l] Question on Z5660M Tubes- What kind of gas and age survival?

I am about to the trigger and go for a clock kit with Z5660M Tubes unused. They were manufactured in 1985. I know there are a lot variables involved...like the gas used in them. Does anyone know what kind of gas these used? If the tubes from 1985 are good? If they should of aged ok with no issues like cathode poisoning? 

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Dman777

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Jun 7, 2014, 4:07:14 PM6/7/14
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So, the Z5660M's are using neon and argon? How well would those gases retain in glass tubes from 1985? 

Tidak Ada

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Jun 7, 2014, 5:21:31 PM6/7/14
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Please read this thread : [neonixie-l] Cathode poisoning- from being off?


From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Dman777
Sent: zaterdag 7 juni 2014 22:07
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Question on Z5660M Tubes- What kind of gas and age survival?

Dman777

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Jun 7, 2014, 9:24:12 PM6/7/14
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Hmm...ok, I re-read it again for the 3rd time. 


"Many tubes have some radio active material (solid or gas) to enhance the ignition. Depending on the isotope used long storage can half the activity due to natural decay of the isotope (Half life time)"

-Assuming the Penning mixture is neon and argon in the Z5660, are neon and argon considered radio active?

"Some tubes work with a gas mixture containing He or H2. These gases are able to diffuse through the glass. Heavier molecules aren't able to do so. That can influence the ignition in a negative way."

-I am not a chemist, but I assume neon and argon do not apply to this, correct?

Also, since neon and argon weren't mentioned specifically in the other thread...but are implied indirectly from the wiki link on Penning...how would tubes that are Z5660M, which are assumed to contain Penning mixture of neon and argon from the wiki link, hold up in storage from 1985?

Thanks,
-Darin

Nicholas Stock

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Jun 7, 2014, 10:50:13 PM6/7/14
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Darin, I don't mean to be rude, but I think you're over analyzing this somewhat. The gas mixtures are pretty similar throughout most types of nixie tubes (Penning mixtures as Eric pointed out). Nixie tubes have been in storage for decades and still run fine (remarkably). Some tubes fail quickly over time, some don't...it's quite honestly a crapshoot as this is an antiquated technology and there's no knowing how the tubes have been stored (among other variables). However, most tubes will work well for a long time (think years) without any trouble The Z5660's are good quality tubes that should last a long time if they're NOS (new old stock) and heck, perhaps even used ones can last a long time, there really is no definitive lifespan. If you're concerned that about tube failure, then buy a few spares.

Nick


greg...@hotmail.com

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Jun 8, 2014, 2:22:25 AM6/8/14
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Nixie tubes have an internal pressure of about 1/100 atmospheric (basically a vacuum), so I would be more concerned about atmospheric gases, such as oxygen, leaking-in rather than the neon leaking out. I suppose you could buy some spares and store them in a container pressurized with Neon; I wouldn't be surprised if they would last thousands of years under those conditions.. Many of my nixies are 50 years old, and all of them work fine, so I wouldn't worry about gas-retention for  tubes made in the 1980's.

If you are concerned about the radioactive decay of the Krypton-85 (half-life of 10 years), just run the tubes at a higher voltage, with an appropriately upsized series resistor. My anode supplies (+225 to +350VDC) are significantly higher than the ionization voltage (about 170V). Yes, it does waste some energy (about 2.5 watts on my clocks). I'm hoping to fix that on my wristwatch, which reduces the anode supply after ionization to improve battery-life.

Tidak Ada

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Jun 8, 2014, 2:46:22 PM6/8/14
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It is not the outgassing of the neon, argon or what ever other noble gas. It are jus the hydrogen and/or Helium that make the trouble. They are added to improve the ignition.
A higher supply voltage makes in the course of time more serious problems.
 
eric


From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of greg...@hotmail.com
Sent: zondag 8 juni 2014 8:22

To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Question on Z5660M Tubes- What kind of gas and age survival?
Nixie tubes have an internal pressure of about 1/100 atmospheric (basically a vacuum), so I would be more concerned about atmospheric gases, such as oxygen, leaking-in rather than the neon leaking out. I suppose you could buy some spares and store them in a container pressurized with Neon; I wouldn't be surprised if they would last thousands of years under those conditions.. Many of my nixies are 50 years old, and all of them work fine, so I wouldn't worry about gas-retention for  tubes made in the 1980's.

If you are concerned about the radioactive decay of the Krypton-85 (half-life of 10 years), just run the tubes at a higher voltage, with an appropriately upsized series resistor. My anode supplies (+225 to +350VDC) are significantly higher than the ionization voltage (about 170V). Yes, it does waste some energy (about 2.5 watts on my clocks). I'm hoping to fix that on my wristwatch, which reduces the anode supply after ionization to improve battery-life.

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John Rehwinkel

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Jun 8, 2014, 4:02:06 PM6/8/14
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A higher supply voltage makes in the course of time more serious problems.

I don't think so.  The efficiency is lower, of course, but the conditions on the tube are
pretty much the same once it's on (the anode resistor drops more voltage, the tube's
maintaining voltage and current are the same).  The only difference to the tube is that
it ionizes faster, as far as I can figure, and I don't see a damage mechanism there.

- John

Nick

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Jun 8, 2014, 4:06:38 PM6/8/14
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Has anyone got any PROOF that hydrogen or helium were added to these tubes, or indeed any nixies.

There are hydrogen filled dekatrons - i.e. special "fast" dekatrons, but nixies?

Tube types, datasheets?

Nick

greg...@hotmail.com

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Jun 8, 2014, 10:43:25 PM6/8/14
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Ebay has a lot of inexpensive spectroscopes; you can have a look at what your tubes produce. I might even give it a try for my own amusement

GastonP

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Jun 9, 2014, 10:35:22 AM6/9/14
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I don't think there would be any need to add helium, hydrogen, or even krypton-85 to *indicator* tubes.

The reason those gases were used in dekatrons or trigger tubes was to get more speed or reliable triggering, which of course is not needed at all in indicator tube.

Also the mixture in voltage regulator or reference tubes sets up the sustaining voltage, but again, they are *not* intended for display, regardless of the use they are given sometimes nowadays.

Most certainly all of the indicators use either pure neon or a simple Ne-Ar Penning mixture, with the "modern" addition of Hg to get extended life.

Gastón

John Rehwinkel

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Jun 9, 2014, 11:38:02 AM6/9/14
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I don't think there would be any need to add helium, hydrogen, or even krypton-85 to *indicator* tubes.

Helium and hydrogen no, but some 5092s had Kr85 for rapid ionization for multiplexed use. Discussion on this list from 2010:


- John

Dieter Waechter

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Jun 9, 2014, 11:56:55 AM6/9/14
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You all surely know the problem, that if a standard Nixie tube is off for a longer time, say 1 hour, and switched on at night, it takes some time (0.1 ... 3 seconds) until the glowing comes up.
Does anyone know a method to speed up the ignition in this condition?
I have found out that:
- higher voltage does not make a change
- higher target current does not make a change
- slew rate of the switch (means a sharp pulse) does not make a change
It looks like nothing helps to make it glow immediately.
All the best
Dieter
 
 
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Sent: Monday, June 09, 2014 5:37 PM
Subject: Re: [neonixie-l] Question on Z5660M Tubes- What kind of gas and age survival?

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David Forbes

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Jun 9, 2014, 12:19:43 PM6/9/14
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Dieter,

It needs a trigger event to start some ionization. I think that a blue
or UV LED will do the trick. Have not tried this myself.
--
David Forbes, Tucson AZ

Dieter Waechter

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Jun 9, 2014, 12:25:28 PM6/9/14
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Thank you David,
At my clocks with blue floor lighting the blue LEDs are on, but tubes stay
off.
So blue LEDs do not help I think (I remember the electron volts are too low,
am I right?)
I think I have some IR-LEDs laying around and test that this night to see
what happens.
Dieter


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From: "David Forbes" <dfo...@dakotacom.net>
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Sent: Monday, June 09, 2014 6:19 PM
Subject: Re: [neonixie-l] Question on Z5660M Tubes- What kind of gas and age
survival?


David Forbes

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Jun 9, 2014, 12:30:34 PM6/9/14
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Dieter,

Another idea is to use a decimal point, if the tube has one, as a
secondary anode for a very high voltage trigger pulse. This would work
similar to the xenon flash tubes in cameras.


On 6/9/14 8:56 AM, Dieter Waechter wrote:

Dieter Waechter

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Jun 9, 2014, 12:37:30 PM6/9/14
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Thanks, I understand. Well I don't have a very high voltage in the Clocks...
but it is a method - yes.
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Nick

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Jun 9, 2014, 12:49:09 PM6/9/14
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More recently, a posting about the details of handling Kr doped tubes...


The tubes had 0.5 μCi (micro-Curies) of 85Kr (half-life is 10.7 years) - a tiny amount. Generally, 1milli-Curie ingested will be fatal - so that's about 2,000 5092A nixie tubes when they were "hot" off the press - today, assuming the tube was made in 1970 (the 122P224 tubes I have are dated around there), that original 0.5 μCi would have decayed down to 0.028 μCi (overwhelmingly by β (beta) decay at 687 keV), i.e. only 5.7% of the original radioactivity remains (see http://www.radprocalculator.com/Decay.aspx or http://ordose.ornl.gov/decay.cfm)

1 μCi = 3.7 × 104 disintegrations per second.

Decent UV light (shorter wavelength = higher energy) certainly helps striking, IME. In the absence of daylight, you need something to kick the ionisation off - Panaplex devices had a keep-alive cathode to help, as do a lot of cold-cathode trigger tubes...

FWIW, UV light around 400nm produces photons with an energy of about 3eV or 0.003keV, rather less than the β particles from 85Kr...

Nick

Tidak Ada

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Jun 9, 2014, 3:25:17 PM6/9/14
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IR will do nothing. The energy per photon is to low.
However, UV contains more energy per photon an even more the shorter the
wave length is.
An ordinary ('blacklight') LED is insufficient in case of hard ignition.
Better to het short wave UV LEDs. Disadvantage is that the price raises
exponentially to the reduction factor of the wavelength.
Look here for prices and purchase: [ http://www.roithner-laser.com/ ]

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