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Analysis of Soviet smoke detector plutonium

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Re: Analysis of Soviet smoke detector plutonium

#21

Post by Reason077 »

anfractuosity wrote: post #19
Reason077 wrote: post #18

Modern smoke detectors seem to have done away with ionization in favour of optical technology, and so no longer contain radioactive materials. Bad news for mad scientists!

Are you sure about that, I thought ones with Americium were more sensitive? I'm pretty sure you can still get both. Edit: Seems I'm not right regarding sensitivity, wiki says: "Ionization detectors are more sensitive to the flaming stage of fires than optical detectors, while optical detectors are more sensitive to fires in the early smouldering stage" Wow it also says: "Where an ionizing smoke detector has been the…

Less sensitivity (or rather, being able to have a higher threshold for sounding the alarm) is actually a good feature for general domestic applications.

You don't really want the thing going off every time someone burns a bit of toast or it just becomes an annoyance, and therefore at risk or being removed or disabled.

Re: Analysis of Soviet smoke detector plutonium

#22

Post by anfractuosity »

Reason077 wrote: post #21
anfractuosity wrote: post #19

Earlier quoted context omitted.

Are you sure about that, I thought ones with Americium were more sensitive? I'm pretty sure you can still get both. Edit: Seems I'm not right regarding sensitivity, wiki says: "Ionization detectors are more sensitive to the flaming stage of fires than optical detectors, while optical detectors are more sensitive to fires in the early smouldering stage" Wow it also says: "Where an ionizing smoke detector has been the…

Less sensitivity (or rather, being able to have a higher threshold for sounding the alarm) is actually a good feature for general domestic applications. You don't really want the thing going off every time someone burns a bit of toast or it just becomes an annoyance, and therefore at risk or being removed or disabled.

Yeah that's true, I guess personally though I'd rather put up with some false positive alarms from toast etc.

Re: Analysis of Soviet smoke detector plutonium

#23

Post by vixen99 »

gumby wrote: post #11

Hey kids, if you plan to play with Pu, what the author fails to mention is that it is not only radioactive but actually poisonous (chemically) as well. On the other hand, another little known fact is that you can weld it, which isn't true of all metals.

Unthinking, I'd always gone for Ralph Nader's 'the most toxic substance known to mankind'. http://atomicinsights.com/how-deadly-plutonium/ tells a different story. Point being - 'During the Manhattan Project in 1944 and 1945, 26 men accidentally ingested plutonium in quantities that far exceeded what is now considered to be a lethal dose. Since there has been a consistent interest in the health effects of this brand new substance (first discovered by Glenn Seaborg’s team at the University of California in 1940), these men were closely tracked for medical studies. Forty Years Later As of 1987, more than four decades later, only four of the workers had died and only one death was caused by cancer. The expected number of deaths in a random sample of men the age of those in the group is 10. The expected number of deaths from cancer in a similar group is between two and three.'. On the other hand, better play safe!

Re: Analysis of Soviet smoke detector plutonium

#24

Post by jsingleton »

Reason077 wrote: post #18

Modern smoke detectors seem to have done away with ionization in favour of optical technology, and so no longer contain radioactive materials. Bad news for mad scientists!

You can get both. I recently bought a twin pack containing one of each. The optical one is marketed as "toast proof" so you can put it near the kitchen and the alpha source one is claimed to be more sensitive.

Radioactive ones are usually cheaper but come with plenty of warnings about not disassembling or ingesting the source. Best to have a mix spread around the home. It's also well worth having a CO alarm if you have non-electric heating/cooking.

Re: Analysis of Soviet smoke detector plutonium

#25

Post by wycx »

URSpider94 wrote: post #13
lokedhs wrote: post #12

Earlier quoted context omitted.

Although the author is a professional nuclear engineer, I do agree with you on the quality of the writing.

I didn't look at his bio, but I assumed that he must do something in the field in his day job -- it would be really hard to stockpile this much knowledge from scratch, even with the help of the Internet ... Nonetheless, he did this with the gamma spectrometer in his spare room ...

Note that a high purity Germanium detector requires LN cooling to operate, and judging by the size of the dewar on his detector, would need filling maybe once a week to keep it cool all the time.

That is a bit onerous if you only play with it every now and then and don't have a 20000 L LN tank in your backyard.

Re: Analysis of Soviet smoke detector plutonium

#27

Post by reitanqild »

anfractuosity wrote: post #17
gumby wrote: post #11

Hey kids, if you plan to play with Pu, what the author fails to mention is that it is not only radioactive but actually poisonous (chemically) as well. On the other hand, another little known fact is that you can weld it, which isn't true of all metals.

That's interesting with respect to welding. I just assumed all metals could be welded, do you know the reason why some can't out of interest. Also is plutonium welded for any application, out of curiosity?

I just assumed all metals could be welded, do you know the reason why some can't out of interest.

Not a welder but spent some time in farming school and on farms:

IIRC Not even all steel can be welded (i.e. at least not in a practical way using standard tools.)

Re: Analysis of Soviet smoke detector plutonium

#28

Post by petee »

anfractuosity wrote: post #17
gumby wrote: post #11

Hey kids, if you plan to play with Pu, what the author fails to mention is that it is not only radioactive but actually poisonous (chemically) as well. On the other hand, another little known fact is that you can weld it, which isn't true of all metals.

That's interesting with respect to welding. I just assumed all metals could be welded, do you know the reason why some can't out of interest. Also is plutonium welded for any application, out of curiosity?

One reason certain metals can't be welded is how their crystalline structure is altered by the process, creating a weak or brittle weld/HAZ (heat affected zone: weaker metal surrounding the weld/filler metal altered by heat)

Some metals also have difficult or impossible cooling rates - welding stainless to carbon steel will make a weak weld that is almost guaranteed to crack while cooling because one metal cools and contracts much faster than the other.

The topic is fairly complex, but there is a good textbook/reference for welders put out by the Lincoln Arc Welding Foundation called "Metals and How To Weld Them" that goes deep on structure and metallurgy, in a readable way.

Re: Analysis of Soviet smoke detector plutonium

#29

Post by petee »

seesomesense wrote: post #16
mmmBacon wrote: post #8

Reminds me of David Hahn, a kid who tried to make a breeder reactor in a garden shed. He massed Americium from smoke detectors in an attempt to make Plutonium. https://en.m.wikipedia.org/wiki/David_Hahn

https://en.wikipedia.org/wiki/David_Hahn#Death

Probably important to highlight that he was 39 when he died...

I always admired his passion, but puzzled at his stubborn lack of safety precautions.

Re: Analysis of Soviet smoke detector plutonium

#30

Post by dboreham »

vixen99 wrote: post #23
gumby wrote: post #11

Hey kids, if you plan to play with Pu, what the author fails to mention is that it is not only radioactive but actually poisonous (chemically) as well. On the other hand, another little known fact is that you can weld it, which isn't true of all metals.

Unthinking, I'd always gone for Ralph Nader's 'the most toxic substance known to mankind'. http://atomicinsights.com/how-deadly-plutonium/ tells a different story. Point being - 'During the Manhattan Project in 1944 and 1945, 26 men accidentally ingested plutonium in quantities that far exceeded what is now considered to be a lethal dose. Since there has been a consistent interest in the health effects of this brand…

Not sure they "discovered". Strictly speaking the Berkeley team first isolated, or produced Pu. Its theoretical existence had been known for a while prior (which is why they were trying to produce it). I mean, it wasn't that they were walking around and picked up and chunk and wondered what they had discovered. The project was entirely for the purpose of producing something every Nuclear Physicist knew must exist. They succeeded in making a small piece, which nobody had done successfully before.
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