Safe handling of tubes containing Krypton 85

[Paul Andrews]

A while back we were discussing the B5092A tube (aka 122P224). I knew I had found a document about the safe handling of these tubes, but I couldn’t find it again. Well here it is http://etler.com/docs/bsp-archive/024/024-723-801_I2.pdf

That same directory has other excerpts from 801, most of which seem to concern the safe handling of tubes with various additives such as beryllium oxide in the 416C tube, and radium bromide in tubes like the 346B (replaced with the 346C which only contains Kr85).

Here is a nice excerpt from http://etler.com/docs/bsp-archive/024/024-700-801_I4.pdf regarding sending these tubes by parcel post (no more than six tubes in one package). They say that this has to be stamped on the package:

RADIOACTIVE MATERIAL

GAMMA RADIATION AT SURFACE OF

PARCEL

LESS THAN 10 MILLIROENTGENS FOR 24 HOURS

NO SIGNIFICANT ALPHA, BETA, OR NEUTRON RADIATION

Not sure if I could get that past USPS :)

[Nick Andrews]

Interesting info.  Unless (and even if) those tubes were made in the last couple of years, they'd be undetectable to postal equipment.  If it meets the limits for radiation on the outside of the box, I wouldn't put any such labeling on it.  Those ignorant of the realities of radiation get scared easily, yet willingly spend $12,000 for fancy granite countertops for their house that are most likely much more radioactive.  Not to mention the salt substitute, or the pool salt, etc.  The only one I'd worry about at all in handling are those with radium compounds in them and even then, just don't break it open!

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[Mac Doktor]

On Oct 26, 2020, at 3:05 PM, Nick Andrews <nickja...@gmail.com> wrote:

If it meets the limits for radiation on the outside of the box, I wouldn't put any such labeling on it.  Those ignorant of the realities of radiation get scared easily

Yeah, put NOTHING on the package. I had a friend freak out over a bottle of uranyl acetate he found in a box of stuff he picked up from the sidewalk on a trash night. I tried to explain it to him but he was totally spooked because it had uranium in it.

, yet willingly spend $12,000 for fancy granite countertops for their house that are most likely much more radioactive. 

I tested the new granite kitchen counter at my brother's house. It was only a few counts above background with an LND-712's alpha window resting on it.

Not to mention the salt substitute, or the pool salt, etc.  The only one I'd worry about at all in handling are those with radium compounds in them and even then, just don't break it open!

Be careful with radium dial clocks. They're not sealed. Do NOT take one apart.

This isn't aimed at you, Nick. I know YOU know.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com/

“We’ve arranged a society on science and technology in which nobody understands anything about science and technology, and this combustible mixture of ignorance and power sooner or later is going to blow up in our faces. I mean, who is running the science and technology in a democracy if the people don’t know anything about it.”—Carl Sagan to Charlie Rose, May 27, 1996 (Sagan's last interview)

[Dan Hollis]

On Mon, 26 Oct 2020, Mac Doktor wrote:
>> On Oct 26, 2020, at 3:05 PM, Nick Andrews <nickja...@gmail.com> wrote:
>> , yet willingly spend $12,000 for fancy granite countertops for their house that are most likely much more radioactive.
> I tested the new granite kitchen counter at my brother's house. It was only a few counts above background with an LND-712's alpha window resting on it.

The last granite outdoor benches I tested were 4x background. Pretty neat.

-Dan

[Nick Andrews]

Haha, the radium is the one that makes me nervous.  Tritium, Kr, etc not so much!  Just watched Radioactive on Amazon (I think) about Marie Curie.  A little slow but not bad.

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[Nick Andrews]

Right.  Some are nil, some are screamers.  The ones with bright red colors from Congo and other areas seem to be hotter.  I used to carry my little Polimaster PM1703M to open houses at the annual home builders' show.

[Paul Andrews]

I have a couple of old alarm clocks with radium dials. My Geiger counter goes crazy when it’s next to them.

I also have some Uranium glass glasses and was surprised to get about 20-30 times background off of them.

On Oct 26, 2020, at 5:38 PM, Nick Andrews <nickja...@gmail.com> wrote:



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[Mac Doktor]

On Oct 26, 2020, at 5:35 PM, Nick Andrews <nickja...@gmail.com> wrote:

Haha, the radium is the one that makes me nervous.  Tritium, Kr, etc not so much!  Just watched Radioactive on Amazon (I think) about Marie Curie.  A little slow but not bad.

I read somewhere that the Curies would go out to their workshop after dark and just stand there watching the entire room glow. There were glowing rings on the shelves where bottles had been sitting at some time in the past, who knows how long ago.

On Oct 26, 2020, at 6:00 PM, Paul Andrews <judg...@gmail.com> wrote:

I have a couple of old alarm clocks with radium dials. My Geiger counter goes crazy when it’s next to them.

I also have some Uranium glass glasses and was surprised to get about 20-30 times background off of them.

What kind of GM tube is in it? My entry-level scintillator gives me a background of ~1150CPM at 900V.

My dad had prostate cancer a while back. They implanted something with a half-life of two or three weeks. I checked him every half-life to confirm that the count had in fact decreased exactly 50%.  8D

Terry Bowman, KA4HJH
"The Mac Doctor"

Q: Should car stereo speakers be pointed to the rear for more thrust or up for more traction?

A. On long trips, the 20- to 30% improvement in gas mileage you might get with speakers pointing to the rear is certainly worthwhile. On the other hand, if you drive on snow or ice, the extra traction of speakers pointing upward gives you added control.

Don Lancaster

[Paul Andrews]

Mine is a GK Mini with a SBM20 tube. Background with it is about 20 CPM.

On Oct 26, 2020, at 6:12 PM, Mac Doktor <themac...@gmail.com> wrote:



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[Nicholas Stock]

I received a box of dekatrons a couple years ago where some of them had radioactive labels on the boxes. Just standard GC10B's, so not sure what the label was warning me of, alas I don't have a geiger counter, but maybe I should get hold of one!

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[Mac Doktor]

> On Oct 26, 2020, at 6:52 PM, Nicholas Stock <nick...@gmail.com> wrote:
>
> I received a box of dekatrons a couple years ago where some of them had radioactive labels on the boxes. Just standard GC10B's, so not sure what the label was warning me of, alas I don't have a geiger counter, but maybe I should get hold of one!

Absolutely. The price of Soviet GM tubes is rising while the quantity available appears to be dropping. Remind you of anything?

Terry Bowman, KA4HJH
"The Mac Doctor"

"There is no Main Street anymore except at Disneyland—and try and buy a gun there"—Hank Hill

[Robert G. Schaffrath]

Back in the late 1970's, I purchased an old ARC-44 radio that came with a warning about Cobalt-60. Seems the 5829/WA and 5787/WA tubes contained Cobalt-60. However, with a half life of 5.3 years, the tubes showed no activity on a Geiger counter. By the time I got the radio as surplus, three half-lives had already passed.

[GastonP]

The source I use to test my Geiger counters (actually just one, and I switch the GM tubes) is a plastic bag with 3 NOS gas lamp mantles. They are quite hot.

I haven't had any luck (or perhaps that was actual luck) trying to detect natural radioactivity at the places I have access to, so every time I take my Geiger counter somewhere, I have to take the mantles too just to show that the counter works.

> What kind of GM tube is in it? My entry-level scintillator gives me a background of ~1150CPM at 900V.

A scintillator? Wow! That's serious stuff! :)

[Nick Andrews]

" A scintillator? Wow! That's serious stuff! :)"

Haha, you just don't have the addiction going strong (yet).  I'm pretty sure I am up over 20 scint probes or parts to make them now, and let's just say quite a few G-M detectors.  And the different types of scint detectors.  You have plastic, NaI, CsI, CZT, BGO, etc.

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[SWISSNIXIE - Jonathan F.]

I'm also owing a few radioactive tube, specifically purchased because they are! ;)
Don't worry about Co-60 and Kr-85 most of them had very few amounts of isotopes in them, and most of them are long gone. For example the  346C Tube nick mentioned, had 4.5uCi of Kr-85 in them when manufactured, this would, if new (manufactured today), be inside a shipping restriction indeed. You can only ship 0.27uCi Kr-85 international. But since Kr-85 has a half life of around 11years most of it will be gone today if the tubes are old. There are also some nixies with Kr-85, but these had lower amounts in them.  Sure there are some "Bad-Boys" out there that still contain significant amounts of isotopes even if they are old. For example usually spark-gap tubes. For example there are some 0B2WA Regulator tubes that have 6uCi of Ra-226. Even if they are around 50 years old, the amount has not dropped significally, since Ra-226 has 1600years of half-life. Technically, they would also be forbidden to ship without proper declaration. But usually everything gets trough just fine, i have purchased a few of them

Also there is nothing to worry about the tubes as long as they are intact and do not break. Actually a very save way to collect radioactive items. Rocks for example are more "dangerous" since small bits and powder can come off.

If someone interested i can show pictures a few tubes ;)

[Leonardo Lisa]

Please show us some pictures of the tubes!

[SWISSNIXIE - Jonathan F.]

So here are four radioactive tubes!
The radiation was measured with Ludlum Model 3 and 44-9 probe. Background is around 50cpm  which is around 15uR/h or 0.15uSv/h. All Values are measured directly on the tube with no distance.

1.) JAN-CADK-4C35A- Hydrogen Thyratron Containing a top of uranium glass    -  Measured 500cpm (150uR/h, 1.5uSv/h)
2.) Western Electric 427A - Voltage Regulator  - Contained 4uCi of Kr-85, Date-code 6639. So after 54years, probably around 0.14uCi left. - Measured only 100cpm (30uR/h, 0.3uSvh)

3.) Western Electric 6141 - Voltage Regulator - Containing Ra-226, found out by my spectroscopy.  Very Hot for that small tube!  - Measured 3500cpm  (1mR/h, 10uSv/h)

4.) Western Electric 1B22 - Military Spark-Gap Radar Modulator - Containing Ra-226.   - Measured 12000cpm  (3.63mR/h, 36uSv/h)

No danger is posed from number 1 and 2, if the 4C35A would break, the uranium isotope would still be contained inside the glass. And for the 427, since Kr85 is a radioactive gas, not a solid element, it would quickly merge with the surrounding air and become neutralized. Surely i wouldn't crack open or break the samples 3 and 4 since Radium is dangerous, even more since its an alpha emitter that could be dangerous when inhaling or ingesting some material.  The biggest "danger" pose this tubes when unknown, for example if someone would dispose a huge amount of 1B22 just to the scrap yard and the radioactive parts would get anywhere. For example, in the USA alot of home smoke detectors use Americum-241 (what an irony ;) ) inside them, which is a radioactive alpha emitter. There is also a disposal problem with those, when just thrown away. Here in Switzerland the government is still cleaning up sites of watch manufacturers that used radium paint for watch hands in the early 1900's.  For collectors of tubes, radioactive ones do not pose a lot of danger, since collectors do not seek to destroy them, or even know about the isotopes inside them. Ive attached a spreadsheet with a list of radioactive tubes (not complete, no warranty) that i found in a radiation related group, sadly i don't know the source. Also there are alot of tubes listed there, that contained radioactive sources only for a certain period, special type or manufacturer. For example 12AT7 is listed there, but only very few of them contain actually the isotopes.

[GastonP]

Interesting list...

Perhaps you could test some AlNiCo speaker drivers to see if they are radioactive too. As the name implies, they used a small percentage of cobalt to enhance the magnetic properties of its permanent magnet. Of course they used natural cobalt (not the artificially enriched Co-60) but there still is the natural percentage of isotopes in the metal.

Gastón

[gregebert]

From an overall toxicity standpoint, I wonder if tubes containing mercury are a greater threat.

I feel bad, because back in the 1970's, we would find every opportunity to pillage discarded tubes (and light bulbs) so we could pop them in the storm drain. Some tubes even made sparks if thrown hard enough at a concrete wall.

[Robert G. Schaffrath]

My late father was a Professor of Chemistry so I was used to seeing mercury and was educated early on about its dangers. From his collection of elements I have a little 1lb commercial lab bottle of mercury that is almost full whose contents were obtained by him from salvaging loose mercury in the lab over many many years (the bottle had been empty and was reused as a storage container). As it was designed to store mercury, It seals tight so I have no worries about it. Unfortunately the mercury is coated in dull gray oxide.

One thing I have that is very nice is an old glass Honeywell mercury switch that was salvaged from a furnace thermostat back in the 1970's (thermostat was thrown out with regular trash on the curb by a neighbor along with a 10kV transformer - hey, it was the 1970's). It has a rather large quantity of mercury under an inert gas so the mercury stays nice and shiny. My home had one installed too but it was removed 20 or so years ago by the oil company service tech as there was a big push to get rid of all those "dangerous" mercury switches from homes. Sadly I was not around to be able to get it from the installer (probably would not have given it over anyhow). But I at least have one nice one.

[Paolo Cravero]

Hi.

Let me add two pictures and a story.

Lately I picked up locally a bunch of small CRTs (2BP1, that also fit in the vintage tuner currently on eBay, plus a Marantz) and the guy had a few NIB tubes too. I was looking for gas-filled ones and that resulted in a W.E. 6167 dekatron, some 0B2WA and some W.E. 6140/423A. Of particular interest was the 6140 shown in the picture whose box mentions Kr85, but no symbol on the glass.

When I came home I checked with a Geiger counter and SBM-20 probe (hard beta and gamma particles) these tubes and the 6140 from 11/61 shows no action. Same goes for other 6140 except for one, much older from 12/52 marked 423A. Neither the box nor the glass carry any warning sign, but this tube hits >600 CPM vs 40 CPM background when put close to the SBM-20 probe (it's not the right way to measure radiation, but it's cool :) ). There is definitely something else than Kr-85 in there! I have blurred pics of it and it has been stored away from home.

As already mentioned, Nixies did contain Kr-85 and I knew I had one clearly marked. It's a Burroughs Self-Scan display that probably needed some "doping" to handle the almost 1 MHz scan rate. BTW, it contains gas and I might never use it, so if someone wants to experiment with self-scan contact me off the list.

One question for the knowledgeable people in here. I have some Mullard Nixies marked "Kr-0A": has it got something to do with Kr-85? I can't check with the Geiger since my probe does not detect Kr-85 leftovers.

So, if you are on the hunt for active tubes, better look for unmarked pre-1960 editions and carry a Geiger counter with you ;)

Paolo

[gregebert]

Maybe it's Thorium, used in the filaments.

[SWISSNIXIE - Jonathan F.]

Could also be Ra-226 on the 6140

[Paul Andrews]

Finally got an alpha detector for my GK-Mini geiger counter. First picture is a regular nixie tube. Second is one doped with Kr85

[Nicholas Stock]

Still a bit of juice left!

Sent from my iPhone

On Nov 26, 2020, at 07:25, Paul Andrews <pa...@nixies.us> wrote:

Finally got an alpha detector for my GK-Mini geiger counter. First picture is a regular nixie tube. Second is one doped with Kr85

<IMG_5681.JPG>

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<IMG_5683.JPG>

<IMG_5681.JPG>

[Paul Andrews]

And by 'alpha', I meant 'beta'. I actually did mean alpha, but I was wrong. Still my old Geiger/Muller tube couldn't detect anything from these nixies, so at least I can now detect beta particles. Now I need to find an alpha source! Smoke detectors apparently.

[SWISSNIXIE - Jonathan F.]

I advise against using smoke detectors. To detect heir alpha radiation, you would have to disassemble the source until you get to the radioactive isotope plated strip - or button - element. This is sort of not allowed, and also can be very dangerous if you scratch off radioactive material. From outside the detector you can only detect the Gammas from the Am-241 Also Quantities are sort of really high in these devices, depending on make and model (1-100 uCi Am-241). If you really want to have alpha radiation, i would purchase a Po-210 source from here:
https://www.spectrumtechniques.com/products/sources/disk-sources-and-source-sets/

They are like 60$, safe and legal to handle. Only disadvantage is short half life of 138 days.

You also can find high power Po-210 sources here: https://www.imagesco.com/geiger/radioactive-sources.html

[Grahame]

Would just a chunk of granite (or a granite kitchen worktop if you have one) be good as a cheap starting point?

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[GastonP]

An old gas lamp mantle is good enough for the purpose, as its main emission is alpha particles. It must be an old one because those ones use thorium oxide to get its distinctive bright, while new ones don't use thorium. I keep 3 of them, which I got from a local auction site, in a small ziploc bag that saves me from touching the mantles themselves.

[Nick Andrews]

The source in a US market ionization smoke detector is very small, under 1 uCi and Am-241.  The material is plated on a small ~1/4" button and typically sealed.  They are pretty safe and you could most likely eat it without any issues.  However, it is technically illegal to remove the source and use it for other purposes.  You could open it up for cleaning and calibration purposes...  The ones with higher amounts which are less safe are the old Pyrotronics F5 smoke detectors often sold on ebay for $100+.  Those contain multiple sources which in some vintages are known to shed material and contaminate things.

Po-210 is also used in industrial and photographic dust removal products.  Check out the Staticmaster brushes for removing dust from film negatives.

For legal, exempt quantity sources, direct purchase from Spectrum Techniques is the best, as they are pretty much the only manufacturer around and all the others buy from them. In fact, your source will be shipped directly from them to you no matter who you buy it from.

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[alb.001 alb.001]

I have a few as well in the original packaging.   I find them at flea markets and antique shows. All of the sellers are unaware of their radioactivity.  I paid $2 for each. I have also found some old pharmaceutical products such as corrosive sublimate pills ( contain mercuric salts ) which were used to make disinfectant solutions.  Also dangerous and never packaged in anything resembling child-resistant and very poisonous.   I buy them to protect the public who might buy them as a curiosity and not be aware of the danger they pose.

Pharma Phil

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[Paul Andrews]

I have an old gas lamp mantle. Very active, but apparently not alpha - interposing a piece of paper (as has been suggested) has no effect at all.

On Dec 2, 2020, at 11:11 AM, alb.001 alb.001 <alb...@sympatico.ca> wrote:



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[SWISSNIXIE - Jonathan F.]

Mantles contain alpha emitting isotopes, but are a bad example for testing tubes for alpha sensitivity. Here you can see a comparison of tubes
https://sites.google.com/site/diygeigercounter/technical/gm-tubes-supported

The last chart shows almost identical counts for the mantle on the SMB-20 (gamma tube) and the SBT-11A (alpha tube) i think that's the one Paul uses.

[Mac Doktor]

On Dec 2, 2020, at 2:51 PM, SWISSNIXIE - Jonathan F. <jfre...@gmail.com> wrote:

The last chart shows almost identical counts for the mantle on the SMB-20 (gamma tube) and the SBT-11A (alpha tube) i think that's the one Paul uses.

Thorium is a good beta source. That's why the SBM-20 works so well.

There was a discussion about alpha windows on the GeigerCounters list a while back. The SBT-11/A has a window that's thicker than a "true" alpha tube. The larger Soviet "alpha" tubes with multiple anodes use a rather thick material that you can actually touch without popping it like a soap bubble.

As for smoke detectors, it is in fact illegal to open one up and use it as a source—in the US, anyway. At the same time it's legal to throw one in the trash so it can be crushed by a bulldozer while it's being buried in a landfill. This makes no sense, of course.

I have a couple that I use as alpha sources all the time. You can come to my house and confiscate them if you like. I can get more quite easily.