hey folks,
i've found some threads about Cadmium here, but that didnt really answer my questions; so i hope you dont mind me asking here.
first of all, Cadmium seems to have the highest neutron cross section of all material that is still sort-of "readily available". thus, it seems like a good material to use for neutron detection with geiger mueller tubes (due to activation).
1st, did anybody try this with just a simple GM tube? i've go at a mica-windowed pancake probe i'd like to use for this experiment.
2nd, is Cadmium really "worth it"? it does have a very high neutron cross section, but the resulting radioisotopes also have very long half lifes. Silver, on the other hand, has a much worse neutron cross section, but therefor, the resulting radioisotopes undergo rapid decay. is Cadmium still superior to Silver, especially when detecting a very low flux of neutrons (two-digit-number of neutrons/second)?
3rd, where could i get a sheet of Cadmium? i know multiple sources for other forms of Cadmium (e.g. i have some thin wire for my element collection), but the idea of melting that into a thin plate at home with no safety equipment doesnt really sound great to me. is there any "industrial appliance" for cadmium sheets (you know, like you can possibly get Be sheets from old x-ray devices)? i e.g. think NiCd accumulators just use powder / crystals of Cd...?
thanks a lot for any info!
- Illy
Cadmium + GM-Tube for Neutron detection?
Re: Cadmium + GM-Tube for Neutron detection?
Illy - try ' morgaine-le-feys-cat ' on ebay - they sometime have Cadmium sheet cheap
330456089754 or 380255016485
330456089754 or 380255016485
Re: Cadmium + GM-Tube for Neutron detection?
Remember cadmium is VERY toxic and must be handled with great caution - that stuff is highly toxic via ingestion so carefully wash hands after handling (use plastic gloves?) and that stuff forms oxides and as such, does generate fine dust that can be deadly to breath (dust/face mask?)) So be careful in a closed room (use a process hood or sealed glove box?) You could coat it in plastic and/or paint it. Always store in a sealable plastic bag and clearly mark it.
To dispose of it is a big problem since it is a high level toxic waste that can not be thrown into the trash - so find out if the company you buy it from will take it back for recycling. I have worked with Cd, Hg and many other toxic heavy materials in labs and have gained great respect for their toxic qualities ... .
By the way, Gadolinium has a much larger neutron capture cross-section and is both readily available and very cheap and no where near as toxic (a few orders of magitude less!) See the MSDS sheet online.
Consider Gd (and it responses to BOTH fast and slow neutrons by way of electron capture followed quickly by X-ray (gamma ray level energy - around 40 keV) emmitance.) That is what my daughter plans on using with her GM, by the way, to detect neutrons. Due to its response, shieldinga GM will be very easy in order to readily filter out false signals.
Still, an interesting idea for slow neutron detection but be very careful - good luck!
To dispose of it is a big problem since it is a high level toxic waste that can not be thrown into the trash - so find out if the company you buy it from will take it back for recycling. I have worked with Cd, Hg and many other toxic heavy materials in labs and have gained great respect for their toxic qualities ... .
By the way, Gadolinium has a much larger neutron capture cross-section and is both readily available and very cheap and no where near as toxic (a few orders of magitude less!) See the MSDS sheet online.
Consider Gd (and it responses to BOTH fast and slow neutrons by way of electron capture followed quickly by X-ray (gamma ray level energy - around 40 keV) emmitance.) That is what my daughter plans on using with her GM, by the way, to detect neutrons. Due to its response, shieldinga GM will be very easy in order to readily filter out false signals.
Still, an interesting idea for slow neutron detection but be very careful - good luck!
Re: Cadmium + GM-Tube for Neutron detection?
John - thanks for the tip, but those are rods... i'd be forced to melt them into sheets, which i dont really want to do, as i dont have proper safety equipment to do so.
Dennis, i do have latex gloves as well as surgical face masks which i'd use, i suppose - that should provide sufficient protection. i'm storing the wire i have in a little plastic tube / plastic bag, too.
in germany, we have places that take toxic waste (batteries, accumulators, energy saving lamps...) for no charge. if i'd ever need to dispose of Hg or Cd, i'd just slip in in there, lol (in a sealed up, marked container). after all, NiCd accumulators contain Cd, and those energy saving lamps contain Hg, so they need to handle and dispose of these materials, anyway.
as for Gadolinum, i thought that'd be quite expensive, and most isotopes produced with neutrons would be, again, stable... with the radioisotope Gd-159 having a pretty long half-life. hmmm. or can you obtain just Gd-158 somehow?
otherwise, it seems very interesting, as it has a reasonable decay-energy, too. i'll look into it, thanks a lot!
Dennis, i do have latex gloves as well as surgical face masks which i'd use, i suppose - that should provide sufficient protection. i'm storing the wire i have in a little plastic tube / plastic bag, too.
in germany, we have places that take toxic waste (batteries, accumulators, energy saving lamps...) for no charge. if i'd ever need to dispose of Hg or Cd, i'd just slip in in there, lol (in a sealed up, marked container). after all, NiCd accumulators contain Cd, and those energy saving lamps contain Hg, so they need to handle and dispose of these materials, anyway.
as for Gadolinum, i thought that'd be quite expensive, and most isotopes produced with neutrons would be, again, stable... with the radioisotope Gd-159 having a pretty long half-life. hmmm. or can you obtain just Gd-158 somehow?
otherwise, it seems very interesting, as it has a reasonable decay-energy, too. i'll look into it, thanks a lot!
Re: Cadmium + GM-Tube for Neutron detection?
Don't melt - use a roller mill and produce whatever thickness you want
Re: Cadmium + GM-Tube for Neutron detection?
Hello and I am glad you have what you need to handle it safely.
from the Wiki - "The majority of these (Gd isotopes) have half-lives less than 24.6 seconds(so 53% of Gd are the desired isotopes so no enrichment is needed at all.) Gadolinium isotopes have 4 metastable isomers, with the most stable being 143mGd (T½=110 seconds), 145mGd (T½=85 seconds) and 141mGd (T½=24.5 seconds).
The primary decay mode at atomic masses lower than the most abundant stable isotope, 158Gd, is electron capture. "
This means that once a neutron is absorbed and 53% of the Gd is the correct isotope for what is needed (and with Gd's huge cross section capture probability for both fast or slow neutrons means you will get a huge absorption), resulting in a very powerful 'x-ray' to be emmitted in a very short time.
So the issue of a signal for a decay path will be rather rapid if I understand this data correctly. So if I am reading this wrong (wouldn't be the first time!), I need to know so as not to waste my time. So, please check out this information.
from the Wiki - "The majority of these (Gd isotopes) have half-lives less than 24.6 seconds(so 53% of Gd are the desired isotopes so no enrichment is needed at all.) Gadolinium isotopes have 4 metastable isomers, with the most stable being 143mGd (T½=110 seconds), 145mGd (T½=85 seconds) and 141mGd (T½=24.5 seconds).
The primary decay mode at atomic masses lower than the most abundant stable isotope, 158Gd, is electron capture. "
This means that once a neutron is absorbed and 53% of the Gd is the correct isotope for what is needed (and with Gd's huge cross section capture probability for both fast or slow neutrons means you will get a huge absorption), resulting in a very powerful 'x-ray' to be emmitted in a very short time.
So the issue of a signal for a decay path will be rather rapid if I understand this data correctly. So if I am reading this wrong (wouldn't be the first time!), I need to know so as not to waste my time. So, please check out this information.
-
Carl Willis
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Re: Cadmium + GM-Tube for Neutron detection?
Hi Illy,
I could mail you a small piece of Cd foil if you want it. What are the dimensions of the GM tube? (I'm also curious if you have enough neutrons from somewhere to give you a fair shot at success.)
Regarding your second question, the most important slow-neutron capture reaction on Cd is on Cd-113 to produce stable Cd-114 with the prompt release of about 9 MeV of energy as gamma rays: Cd-113(n,g)Cd-114. The populated states of the Cd-114 nucleus have half-lives of only a few picoseconds at the longest.
http://www.nndc.bnl.gov/chart/getdatase ... CD&unc=nds
To detect neutrons by capture in cadmium, you have to rely on either these gamma rays or on conversion electrons or x-rays. Unfortunately, as a dense metal, cadmium is good at shielding its own radiations, and other ambient sources of gamma and electrons will make such a detection method not particularly selective for neutrons. Cadmium finds applications in neutron detection as a scintillator dopant, for example, but it is not commonly used by hobbyists because of its various challenges I just mentioned. I did once gather prompt neutron-capture gamma spectra from a piece of cadmium (Wood's metal, to be exact) using a scintillation detector, in which some of these known radiations show up, see:
viewtopic.php?f=13&t=5285#p33729
-Carl
I could mail you a small piece of Cd foil if you want it. What are the dimensions of the GM tube? (I'm also curious if you have enough neutrons from somewhere to give you a fair shot at success.)
Regarding your second question, the most important slow-neutron capture reaction on Cd is on Cd-113 to produce stable Cd-114 with the prompt release of about 9 MeV of energy as gamma rays: Cd-113(n,g)Cd-114. The populated states of the Cd-114 nucleus have half-lives of only a few picoseconds at the longest.
http://www.nndc.bnl.gov/chart/getdatase ... CD&unc=nds
To detect neutrons by capture in cadmium, you have to rely on either these gamma rays or on conversion electrons or x-rays. Unfortunately, as a dense metal, cadmium is good at shielding its own radiations, and other ambient sources of gamma and electrons will make such a detection method not particularly selective for neutrons. Cadmium finds applications in neutron detection as a scintillator dopant, for example, but it is not commonly used by hobbyists because of its various challenges I just mentioned. I did once gather prompt neutron-capture gamma spectra from a piece of cadmium (Wood's metal, to be exact) using a scintillation detector, in which some of these known radiations show up, see:
viewtopic.php?f=13&t=5285#p33729
-Carl
-
Carl Willis
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Re: Cadmium + GM-Tube for Neutron detection?
Dennis,
As I recall mentioning on your earlier gadolinium thread, the reaction for which Gd is notable as a neutron detector is Gd-157(n,g)Gd-158 in which the excited nucleus promptly (within 3 ns, see http://www.nndc.bnl.gov/chart/getdatase ... GD&unc=nds) emits gamma rays and some conversion electrons. Neither electron capture nor long-lived (metastable) isomers are part of this process. The capture cross-section is high at low neutron energies and drops at higher energies, making Gd rather ineffective as a fast neutron absorber:
http://www.nndc.bnl.gov/sigma/getPlot.j ... =1&nsub=10
Qualitatively, the challenges of using gadolinium are pretty much the same as those of using cadmium: you have a material that emits prompt radiations that are indistinct from many ambient radiations and are easily self-shielded.
-Carl
As I recall mentioning on your earlier gadolinium thread, the reaction for which Gd is notable as a neutron detector is Gd-157(n,g)Gd-158 in which the excited nucleus promptly (within 3 ns, see http://www.nndc.bnl.gov/chart/getdatase ... GD&unc=nds) emits gamma rays and some conversion electrons. Neither electron capture nor long-lived (metastable) isomers are part of this process. The capture cross-section is high at low neutron energies and drops at higher energies, making Gd rather ineffective as a fast neutron absorber:
http://www.nndc.bnl.gov/sigma/getPlot.j ... =1&nsub=10
Qualitatively, the challenges of using gadolinium are pretty much the same as those of using cadmium: you have a material that emits prompt radiations that are indistinct from many ambient radiations and are easily self-shielded.
-Carl
Re: Cadmium + GM-Tube for Neutron detection?
thanks everybody for this very interesting discussion!
...and Carl, thanks a lot for the offer on the Cd sheet! i just sent you an email about it.
i am planning to use a pancake probe with it; the window is about 5cm (2in.) in diameter. the neutron flux would be very low, maybe 20-30 n/s.
also, i was focusing more on the emitted electrons rather than the gamma rays, as only 1-2% of those being emitted into the direction of my probe would actually register, right? hmm... or would those high-energy gammas actually have a better detection ratio, as they're more likely to "knock out" electrons from the cathode material due to their energy?
well, maybe i'd indeed have to use my gamma scout rather than the pancake probe, as with the gamma scout, i could compare e.g. hourly counts and thus, compare small fluctuations of recorded gamma background in very long "exposures".
then again, there are so many variables that change, like i suspect the sun to be messing with a current experiment, too. probably all low-flux setups are doomed to fail using my equipment, anyway... hmmmm.
...and Carl, thanks a lot for the offer on the Cd sheet! i just sent you an email about it.
i am planning to use a pancake probe with it; the window is about 5cm (2in.) in diameter. the neutron flux would be very low, maybe 20-30 n/s.
also, i was focusing more on the emitted electrons rather than the gamma rays, as only 1-2% of those being emitted into the direction of my probe would actually register, right? hmm... or would those high-energy gammas actually have a better detection ratio, as they're more likely to "knock out" electrons from the cathode material due to their energy?
well, maybe i'd indeed have to use my gamma scout rather than the pancake probe, as with the gamma scout, i could compare e.g. hourly counts and thus, compare small fluctuations of recorded gamma background in very long "exposures".
then again, there are so many variables that change, like i suspect the sun to be messing with a current experiment, too. probably all low-flux setups are doomed to fail using my equipment, anyway... hmmmm.
-
Doug Coulter
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Re: Cadmium + GM-Tube for Neutron detection?
I have done some work with Cd here -- and what everyone says above is to the point. That stuff rates way high on my "dangerous" list after working with it some. I actually had some catch fire in the melting pot! Lucky I was outdoors and could just run away while holding my breath.
It's very hard to get poisoned by it via ingestion according to the rare metals book -- you puke so fast it's gone again (which lead to the banning of Cd plated parts in food things). At the point that book was written there were no deaths from that source.
But there have been a good many deaths by breathing Cd fumes or compounds, and I knew that, which is why I ran so fast. I'm now the proud owner of about a pound of Cd oxides I've got to figure out how to dispose of.
I tried rolling, hammering, squishing, you name it -- not much effect. Even in a hydraulic press at about 12 tons per half sq inch, barely a dent. My hydraulic log splitter would cut the rods, barely.
Its hardness is about 29 brinnel -- too hard for most to roll, and it work hardens and becomes brittle at room temperature -- which is why sheet is rare and expensive.
The stuff has enough surface tension that you can't easily cast sheet. So I went back to the rare metals books for alloy information, and tried a few of them with the usual suspects (Tin, bisumth, lead, indium). So far, none hold a decent amount of Cd in solid solution, and the ones I've tried all make great big (pretty) crystals of the various components, so there's places of no Cd, and places of all Cd unless you cast pretty thick. And those were for eutectic alloys that have decently low melt points, so the fire danger is a lot less -- you let the Cd dissolve into the already melted other stuff, slowly when making them.
Funny, I didn't notice anyone mentioning that Cd has a very so-so cross section for all neutrons not thermal and below -- you have to moderate to make it useful from almost any neutron source. Apologies if I skimmed too fast. Or anyone saying that it's mainly one of the isotopes that isn't the most common one, that does this neat thing.
I would wonder if boron wouldn't do nearly as well for this, and be easier to handle -- in say paraffin you'd get about the same kind of results, I think and the paraffin would let the gammas out easy.
I found this out when I tried borated paraffin for my first attempt at a directional neutron camera (plastic scintillator/phototube as the final sensor). It wasn't directional anymore as any slow neutron captured in the boron made it count! Duh, I didn't need to stop the ones I didn't want to see, just slow them down so the plastic scint wouldn't detect them -- time for redesign ;~)
It's very hard to get poisoned by it via ingestion according to the rare metals book -- you puke so fast it's gone again (which lead to the banning of Cd plated parts in food things). At the point that book was written there were no deaths from that source.
But there have been a good many deaths by breathing Cd fumes or compounds, and I knew that, which is why I ran so fast. I'm now the proud owner of about a pound of Cd oxides I've got to figure out how to dispose of.
I tried rolling, hammering, squishing, you name it -- not much effect. Even in a hydraulic press at about 12 tons per half sq inch, barely a dent. My hydraulic log splitter would cut the rods, barely.
Its hardness is about 29 brinnel -- too hard for most to roll, and it work hardens and becomes brittle at room temperature -- which is why sheet is rare and expensive.
The stuff has enough surface tension that you can't easily cast sheet. So I went back to the rare metals books for alloy information, and tried a few of them with the usual suspects (Tin, bisumth, lead, indium). So far, none hold a decent amount of Cd in solid solution, and the ones I've tried all make great big (pretty) crystals of the various components, so there's places of no Cd, and places of all Cd unless you cast pretty thick. And those were for eutectic alloys that have decently low melt points, so the fire danger is a lot less -- you let the Cd dissolve into the already melted other stuff, slowly when making them.
Funny, I didn't notice anyone mentioning that Cd has a very so-so cross section for all neutrons not thermal and below -- you have to moderate to make it useful from almost any neutron source. Apologies if I skimmed too fast. Or anyone saying that it's mainly one of the isotopes that isn't the most common one, that does this neat thing.
I would wonder if boron wouldn't do nearly as well for this, and be easier to handle -- in say paraffin you'd get about the same kind of results, I think and the paraffin would let the gammas out easy.
I found this out when I tried borated paraffin for my first attempt at a directional neutron camera (plastic scintillator/phototube as the final sensor). It wasn't directional anymore as any slow neutron captured in the boron made it count! Duh, I didn't need to stop the ones I didn't want to see, just slow them down so the plastic scint wouldn't detect them -- time for redesign ;~)
Why guess when you can know? Measure!
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Richard Hull
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Re: Cadmium + GM-Tube for Neutron detection?
I handle cadmium regularly with my bare hands. (I make a lot of homebrew low melting alloys and cadmium is almost always a part of the melt.) No real issues here. I have posted on all this cadmium related info in other postings in the past, of course. One thread I started and posted in from 2006 gave a lot of info.
viewtopic.php?f=2&t=868&hilit=Cadmium#p6397
Again, never melt cadmium. I would rather, bare handed, scoop up 10 lbs of cadmium flake, than melt one ounce of bulk metal. Cadmium's vapor pressure is through the roof at its melting point and its boiling point is close at hand after melting. This is where cadmium kills easily and without warning. Lots of deaths have been reported in industrial and melt accidents.
In alloy melts, I wear a special respirator with a filter rated for heavy metals fumes and, as noted in my earlier posts, allow the cadmium to be the last to be dropped into the melt where it is dissolved and not melted, as such.
I have had little trouble rolling pure cadmium it into small sheets provided you don't go too thin and work harden it into splitting. For my money, cadmium has little use in most any form in what we are doing.
A simple washing of the hands is all that is needed. However, each to his own amount of safety nerding.
Now that the commies are gone, we gotta' find a whole new bunch of boogey men to keep us sufficiently fearful. Fortunately, we are still free enough to choose our own boogey men for ourselves. It remains gratifying and proven fact that, in the end, we all die from something.
Richard Hull
viewtopic.php?f=2&t=868&hilit=Cadmium#p6397
Again, never melt cadmium. I would rather, bare handed, scoop up 10 lbs of cadmium flake, than melt one ounce of bulk metal. Cadmium's vapor pressure is through the roof at its melting point and its boiling point is close at hand after melting. This is where cadmium kills easily and without warning. Lots of deaths have been reported in industrial and melt accidents.
In alloy melts, I wear a special respirator with a filter rated for heavy metals fumes and, as noted in my earlier posts, allow the cadmium to be the last to be dropped into the melt where it is dissolved and not melted, as such.
I have had little trouble rolling pure cadmium it into small sheets provided you don't go too thin and work harden it into splitting. For my money, cadmium has little use in most any form in what we are doing.
A simple washing of the hands is all that is needed. However, each to his own amount of safety nerding.
Now that the commies are gone, we gotta' find a whole new bunch of boogey men to keep us sufficiently fearful. Fortunately, we are still free enough to choose our own boogey men for ourselves. It remains gratifying and proven fact that, in the end, we all die from something.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Re: Cadmium + GM-Tube for Neutron detection?
Doug,
thanks for the info on casting and all that - hmm, i'm confused now, lol.
seems like there are lots of different opinions around now.
as for Praffin - or more like, H - i believe the neutron cross section of H for CAPTURE of thermal neutrons is incredibly BAD, so it cannot easily be activated - however, it has a very good SCATTERING cross section, so it can be used to slow down neutrons very well (so it's a good moderator).
Cd, on the other hand, has an incredibly good "capture rate", so it can easily be "activated".
i also believe that any isotope of a nuclide has the same neutron cross section - but the resulting isotopes can be "better or worse" for ones means, especially when it comes to radioisotopes... regarding to half life, decay modes, decay energies, etc..
i'm not 100% sure about this, though, but it just seems logical to me. could anybody please confirm / correct that statement? i'd like to know for sure.
Richard,
thanks a lot for both the heads up and clarification. does that go for any heavy metal, then? are they all harmless to handle bare-handed, unless in a compound? hmmm.
i feel reassured about not melting Cd, though, that's for sure. i certainly wont do that. seems like another thing heavy metals have in common: the vapors are insanely toxic.
well, still, i'm rather "safe than sorry", even though it sometimes means being a bit too paranoid. but yeah, it's true - as for the MSDS, even NaCl sounds scary.
- Illy
thanks for the info on casting and all that - hmm, i'm confused now, lol.
seems like there are lots of different opinions around now.
as for Praffin - or more like, H - i believe the neutron cross section of H for CAPTURE of thermal neutrons is incredibly BAD, so it cannot easily be activated - however, it has a very good SCATTERING cross section, so it can be used to slow down neutrons very well (so it's a good moderator).
Cd, on the other hand, has an incredibly good "capture rate", so it can easily be "activated".
i also believe that any isotope of a nuclide has the same neutron cross section - but the resulting isotopes can be "better or worse" for ones means, especially when it comes to radioisotopes... regarding to half life, decay modes, decay energies, etc..
i'm not 100% sure about this, though, but it just seems logical to me. could anybody please confirm / correct that statement? i'd like to know for sure.
Richard,
thanks a lot for both the heads up and clarification. does that go for any heavy metal, then? are they all harmless to handle bare-handed, unless in a compound? hmmm.
i feel reassured about not melting Cd, though, that's for sure. i certainly wont do that. seems like another thing heavy metals have in common: the vapors are insanely toxic.
well, still, i'm rather "safe than sorry", even though it sometimes means being a bit too paranoid. but yeah, it's true - as for the MSDS, even NaCl sounds scary.
- Illy
Re: Cadmium + GM-Tube for Neutron detection?
d'oh, i actually think i messed up something there.
i've been thinking about this yesterday evening when i was supposed to sleep but couldnt switch my brain off, once again.
initially, i was thinking about how at least the atomic number does not seem to be relevant for the neutron cross section, as the listed elements with high cross sections dont seem to be related in their atomic number - take e.g. Hg vs. B, both with a relatively high thermal neutron capture cross section. so i was quick to assume that the size of the nucleus / the contained number of hadrons does not matter.
uranium 235 easily fissions, uranium 238 hardly ever fissions, so that's that.
...but then, as i went to bed, it came to mind how fast neutrons are much more likely to transmutate U-238, that's why they use fast breeders, right?
also, deuterium seems to be a better moderator (because of less neutron absorption if i remember right) than protium, so there does seem to be a difference between the different isotopes.
hmmm....
i've been thinking about this yesterday evening when i was supposed to sleep but couldnt switch my brain off, once again.
initially, i was thinking about how at least the atomic number does not seem to be relevant for the neutron cross section, as the listed elements with high cross sections dont seem to be related in their atomic number - take e.g. Hg vs. B, both with a relatively high thermal neutron capture cross section. so i was quick to assume that the size of the nucleus / the contained number of hadrons does not matter.
uranium 235 easily fissions, uranium 238 hardly ever fissions, so that's that.
...but then, as i went to bed, it came to mind how fast neutrons are much more likely to transmutate U-238, that's why they use fast breeders, right?
also, deuterium seems to be a better moderator (because of less neutron absorption if i remember right) than protium, so there does seem to be a difference between the different isotopes.
hmmm....
Re: Cadmium + GM-Tube for Neutron detection?
Richard,
Yes, you are correct - an extreme poison like Cd is nothing to fear in of itself but possible ingestion or breathing is another matter and you are welcome (and should) handle it in your own way and I will concur - but Cd is not safe no matter what you say and please don't make fun of me for pointing out standard safety methods that all professionals that handle Cd use in companies, schools and Gov. What you choose or not to do is correct for you but to publicly belittle standard and known safety techniques for an extreme poison is not what this forum is about.
For instance -your use of a respirator is both very smart and following good SOP but fumes of melted Cd can get onto surfaces nearby and when you are not aware, you could pick these up. Not as likely but possible, so most places require fume hoods for melting Cd. Maybe a bit over the top, and maybe not. Without testing the safety level of the hazzard it is not known and for a poison like Cd, not knowing could kill you ... .
If your blood tests prove your system is clear, I think for you, your procedures are excellent but please don’t tell others that Cd is safe to handle by not following well established procedures (even if they work for you) – to each their own but when you enter a public forum, you have a responsibility not to encourage dangerous behavior that could lead to great harm and even death. Like 220 volt AC is very safe to work on even if you touch the wires (I have - no harm; not fun but will not kill you) but if I was grounded ... a very different matter; so, I would never tell people 220 three phase is safe to work on even when hot ... hold it! Didn't I just do that ... darn, I mean, oh well, don't pay any attention to the fool behind the curtain - no matter, while true about 220, this would be foolish for most people and could prove very deadly.
Finally, you are also very correct that we all die of something and my hope is to put it off as long as possible (not if I ever work on 220 like that again!) ... well, maybe I shouldn't be building a ES Accelerator ... but fun some times wins out over good sense.
Richard Hull wrote:
> I handle cadmium regularly with my bare hands. (I make a lot of homebrew low melting alloys and cadmium is almost always a part of the melt.) No real issues here. I have posted on all this cadmium related info in other postings in the past, of course. One thread I started and posted in from 2006 gave a lot of info.
>
> viewtopic.php?f=2&t=868&hilit=Cadmium#p6397
>
> Again, never melt cadmium. I would rather, bare handed, scoop up 10 lbs of cadmium flake, than melt one ounce of bulk metal. Cadmium's vapor pressure is through the roof at its melting point and its boiling point is close at hand after melting. This is where cadmium kills easily and without warning. Lots of deaths have been reported in industrial and melt accidents.
>
> In alloy melts, I wear a special respirator with a filter rated for heavy metals fumes and, as noted in my earlier posts, allow the cadmium to be the last to be dropped into the melt where it is dissolved and not melted, as such.
>
> I have had little trouble rolling pure cadmium it into small sheets provided you don't go too thin and work harden it into splitting. For my money, cadmium has little use in most any form in what we are doing.
>
> A simple washing of the hands is all that is needed. However, each to his own amount of safety nerding.
>
> Now that the commies are gone, we gotta' find a whole new bunch of boogey men to keep us sufficiently fearful. Fortunately, we are still free enough to choose our own boogey men for ourselves. It remains gratifying and proven fact that, in the end, we all die from something.
>
> Richard Hull
Yes, you are correct - an extreme poison like Cd is nothing to fear in of itself but possible ingestion or breathing is another matter and you are welcome (and should) handle it in your own way and I will concur - but Cd is not safe no matter what you say and please don't make fun of me for pointing out standard safety methods that all professionals that handle Cd use in companies, schools and Gov. What you choose or not to do is correct for you but to publicly belittle standard and known safety techniques for an extreme poison is not what this forum is about.
For instance -your use of a respirator is both very smart and following good SOP but fumes of melted Cd can get onto surfaces nearby and when you are not aware, you could pick these up. Not as likely but possible, so most places require fume hoods for melting Cd. Maybe a bit over the top, and maybe not. Without testing the safety level of the hazzard it is not known and for a poison like Cd, not knowing could kill you ... .
If your blood tests prove your system is clear, I think for you, your procedures are excellent but please don’t tell others that Cd is safe to handle by not following well established procedures (even if they work for you) – to each their own but when you enter a public forum, you have a responsibility not to encourage dangerous behavior that could lead to great harm and even death. Like 220 volt AC is very safe to work on even if you touch the wires (I have - no harm; not fun but will not kill you) but if I was grounded ... a very different matter; so, I would never tell people 220 three phase is safe to work on even when hot ... hold it! Didn't I just do that ... darn, I mean, oh well, don't pay any attention to the fool behind the curtain - no matter, while true about 220, this would be foolish for most people and could prove very deadly.
Finally, you are also very correct that we all die of something and my hope is to put it off as long as possible (not if I ever work on 220 like that again!) ... well, maybe I shouldn't be building a ES Accelerator ... but fun some times wins out over good sense.
Richard Hull wrote:
> I handle cadmium regularly with my bare hands. (I make a lot of homebrew low melting alloys and cadmium is almost always a part of the melt.) No real issues here. I have posted on all this cadmium related info in other postings in the past, of course. One thread I started and posted in from 2006 gave a lot of info.
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> viewtopic.php?f=2&t=868&hilit=Cadmium#p6397
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> Again, never melt cadmium. I would rather, bare handed, scoop up 10 lbs of cadmium flake, than melt one ounce of bulk metal. Cadmium's vapor pressure is through the roof at its melting point and its boiling point is close at hand after melting. This is where cadmium kills easily and without warning. Lots of deaths have been reported in industrial and melt accidents.
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> In alloy melts, I wear a special respirator with a filter rated for heavy metals fumes and, as noted in my earlier posts, allow the cadmium to be the last to be dropped into the melt where it is dissolved and not melted, as such.
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> I have had little trouble rolling pure cadmium it into small sheets provided you don't go too thin and work harden it into splitting. For my money, cadmium has little use in most any form in what we are doing.
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> A simple washing of the hands is all that is needed. However, each to his own amount of safety nerding.
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> Now that the commies are gone, we gotta' find a whole new bunch of boogey men to keep us sufficiently fearful. Fortunately, we are still free enough to choose our own boogey men for ourselves. It remains gratifying and proven fact that, in the end, we all die from something.
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> Richard Hull
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Richard Hull
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Re: Cadmium + GM-Tube for Neutron detection?
Dennis,
I never made fun of any standard or accepted procedures for workers or industry. I fear you over reacted out of fear. A casual to almost "never user" is not a worker in the cadmium industry or a worker in a side industry where cadium is encountered frequently. That would be a totally different matter.
I clearly stated that you or anyone may do as they wish in regards to handling the material safely. I also clearly stated that I never melt cadmium and admonished anyone from ever doing it.
I worry that some must think that I handle tonnage of this stuff. I do not. I handle it on occasion and far more than most anyone here would work with it and for some years now.
I understand vapor pressure charts. The need for working out of doors, etc.
I will not do any sort of battle over safety nazism vs. lassiez faire attitudes nor be part of such long running arguments that are really, in the end, a personal choice. We are not watched by thought and safety police yet in our private lives. Let us not turn this into a pissing match. Let the folks read the MSDS and involve themselves to the degree they wish to become involved and with what safety measures they choose to take as we have both state our case.
Illy,
You are quite aware, as you note in you classic Technicium, "I am radioactive" video, "radioactivity is highly over rated". Also, as you note, the MSDS sheets are pretty much fear factor forms designed to be a "cover your ass" form for any number of things. As such, they must be read by the private individual totally differently than an ISO certified employer. This is so the ridiculous might be overlooked and only the sublime truth be followed. This is true for all things with MSDS sheets and again is a personal decision in the private sector while a cover your ass, absolute and inviolate mandate in the ISO certification world.
Countless millions are not poisoned daily by radiation, cadmium or anyhting else and it is not because they have or have not read the MSDS sheets, while some microscopic number number each year are killed, worldwide, both having read and having not read the MSDS sheet. All interactions with natural and manmade things must be metered and measured by reading coupled with physical knowledge based on real experience and a real understanding of the material science.
Radiation overexposure to a worker, while sad, is a work hazard that daily trails behind and hangs over the head of the worker who has chosen to be involved in the work. The same with cadmium. Day in and day out exposure to cadmium in most any form requires protection similar to the radiation worker and for the same reasons. For the private individual, handling small amounts of bulk metal in solid, ponderable form only once or very rarely, few of the heavy metals worker precautions need apply. Just wash up really well or wear gloves, as you wish.
If you are super jittery then wear gloves, evacuate your neighbors and wash for 4 hours with a wire brush. Better still, never, ever come within 100 meters of a known quantity of cadmium, uranium, or whatever you might fear like death itself. As it turns out, most stuff is highly over rated.
Richard Hull
I never made fun of any standard or accepted procedures for workers or industry. I fear you over reacted out of fear. A casual to almost "never user" is not a worker in the cadmium industry or a worker in a side industry where cadium is encountered frequently. That would be a totally different matter.
I clearly stated that you or anyone may do as they wish in regards to handling the material safely. I also clearly stated that I never melt cadmium and admonished anyone from ever doing it.
I worry that some must think that I handle tonnage of this stuff. I do not. I handle it on occasion and far more than most anyone here would work with it and for some years now.
I understand vapor pressure charts. The need for working out of doors, etc.
I will not do any sort of battle over safety nazism vs. lassiez faire attitudes nor be part of such long running arguments that are really, in the end, a personal choice. We are not watched by thought and safety police yet in our private lives. Let us not turn this into a pissing match. Let the folks read the MSDS and involve themselves to the degree they wish to become involved and with what safety measures they choose to take as we have both state our case.
Illy,
You are quite aware, as you note in you classic Technicium, "I am radioactive" video, "radioactivity is highly over rated". Also, as you note, the MSDS sheets are pretty much fear factor forms designed to be a "cover your ass" form for any number of things. As such, they must be read by the private individual totally differently than an ISO certified employer. This is so the ridiculous might be overlooked and only the sublime truth be followed. This is true for all things with MSDS sheets and again is a personal decision in the private sector while a cover your ass, absolute and inviolate mandate in the ISO certification world.
Countless millions are not poisoned daily by radiation, cadmium or anyhting else and it is not because they have or have not read the MSDS sheets, while some microscopic number number each year are killed, worldwide, both having read and having not read the MSDS sheet. All interactions with natural and manmade things must be metered and measured by reading coupled with physical knowledge based on real experience and a real understanding of the material science.
Radiation overexposure to a worker, while sad, is a work hazard that daily trails behind and hangs over the head of the worker who has chosen to be involved in the work. The same with cadmium. Day in and day out exposure to cadmium in most any form requires protection similar to the radiation worker and for the same reasons. For the private individual, handling small amounts of bulk metal in solid, ponderable form only once or very rarely, few of the heavy metals worker precautions need apply. Just wash up really well or wear gloves, as you wish.
If you are super jittery then wear gloves, evacuate your neighbors and wash for 4 hours with a wire brush. Better still, never, ever come within 100 meters of a known quantity of cadmium, uranium, or whatever you might fear like death itself. As it turns out, most stuff is highly over rated.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Re: Cadmium + GM-Tube for Neutron detection?
Richard,
yeah, that makes sense. however, i also go by the quote "nothing in life is to be feared - it is only to be understood" (marie curie). that also means if i dont fully grasp something, i may still be a bit too paranoid of it - but it's better to be too paranoid than to be too careless.
anyway, i'd like to know your *personal* opinion on heavy metals in general; would you say that any of them are safe to handle with bare hands as long as in elemental form and no fumes / vapors are inhaled?
i mean, i've handled mercury with bare hands, too (it feels awesome!), but i also know that dimethyl mercury would kill me in the worst kind of way if it got even onto my _gloved_ hand for a short amount of time. however, there seem to be different "scares" for different elements around. some people called me "nuts" for touching beryllium, too, but afaik, it's only a real danger when inhaled / ground up. i've ground up some uranium to see the difference in activity with all the "freed" alphas and all, but i'd personally never grind up beryllium. i agree it's all a personal choice (as long as you dont have pets or family which you'd put in harms way, as that'd be irresponsible indeed), but i still highly value different opinions, but i wont blindly follow them.
yeah, that makes sense. however, i also go by the quote "nothing in life is to be feared - it is only to be understood" (marie curie). that also means if i dont fully grasp something, i may still be a bit too paranoid of it - but it's better to be too paranoid than to be too careless.
anyway, i'd like to know your *personal* opinion on heavy metals in general; would you say that any of them are safe to handle with bare hands as long as in elemental form and no fumes / vapors are inhaled?
i mean, i've handled mercury with bare hands, too (it feels awesome!), but i also know that dimethyl mercury would kill me in the worst kind of way if it got even onto my _gloved_ hand for a short amount of time. however, there seem to be different "scares" for different elements around. some people called me "nuts" for touching beryllium, too, but afaik, it's only a real danger when inhaled / ground up. i've ground up some uranium to see the difference in activity with all the "freed" alphas and all, but i'd personally never grind up beryllium. i agree it's all a personal choice (as long as you dont have pets or family which you'd put in harms way, as that'd be irresponsible indeed), but i still highly value different opinions, but i wont blindly follow them.
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Richard Hull
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Re: Cadmium + GM-Tube for Neutron detection?
It sounds like you have a good grip on things and have the right attitude related to truly lethal stuff. Lead, cadmium, antimony, beryllium, uranium, thorium, the rare earths, and most industrial metals all are ok to handle in ponderable massive form with the bare hands. Just wash before eating. Compounds, especially water soluables, as you note, can be very nasty. About the only metal I will not handle directly that is in massive ponderable form is Thallium, I have several pounds of the stuff and it spalls its own oxide a little too easily for my tastes. (Not atmosphere friendly, sort of like europium, lanthanum or cerium in that regard.) It melts and handles about like lead in other respects though. Once a useful and highly effective rat poison, thallium has been relegated to only limited uses now.
When I was a kid, we used to bare hand rub loads of mercury into pennies to try and pass them off as dimes. One kid's dad had pounds of th' stuff! We used to love to destroy aluminum with it by rubbing it into that metal as well. So far, none of us kids in my group as a youth are drooling or mad as a hatter. All are still alive and I am going out to dinner this evening with two of them! Also we got the full load of radioactive fallout from bomb testing. Richmond and the east coast got loads of it in the 50's We were outside all the time. No daytime TV or computers or gameboys, just baseball, cowboys and indians, army, bike riding etc. Lots of exercise in a rad laden environment.
Again, acute but rare single or limited exposure to something folks run kicking, crying and screaming from today....check the MSDS sheets or consult any news media freak out related to mercury or rad stuff for more real info. You get what I mean.
As you said, it is all in knowledge at the core level, reason and logic followed up by a personal decision.
Remember, eat healthy, get plenty of exercise and, still, die anyway.
Richard Hull
When I was a kid, we used to bare hand rub loads of mercury into pennies to try and pass them off as dimes. One kid's dad had pounds of th' stuff! We used to love to destroy aluminum with it by rubbing it into that metal as well. So far, none of us kids in my group as a youth are drooling or mad as a hatter. All are still alive and I am going out to dinner this evening with two of them! Also we got the full load of radioactive fallout from bomb testing. Richmond and the east coast got loads of it in the 50's We were outside all the time. No daytime TV or computers or gameboys, just baseball, cowboys and indians, army, bike riding etc. Lots of exercise in a rad laden environment.
Again, acute but rare single or limited exposure to something folks run kicking, crying and screaming from today....check the MSDS sheets or consult any news media freak out related to mercury or rad stuff for more real info. You get what I mean.
As you said, it is all in knowledge at the core level, reason and logic followed up by a personal decision.
Remember, eat healthy, get plenty of exercise and, still, die anyway.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Re: Cadmium + GM-Tube for Neutron detection?
Richard,
well, i dont yet have any of the elements you mentioned at the end of your first paragraph - my element collection is lacking a lot of items.
i usually just pick up stuff "on the fly" regarding to chemistry - that is, when i need it, e.g. when about to come in contact with a nuclide.
...and yes, i'm careful with compounds. like i keep the uranyl nitrate i produced for a youtube demonstration in a sealed jar. however, compounds sometimes just happen without expecting it... recently, i was checking up if my gallium had liquefied due to the high ambient temperature. i wanted to take a comparison photo with mercury from my periodic table... and noticed it had turned golden. just great - not only does iodine readily sublimate, but it also diffuses through plastic test tubes. it then sneaked into the Hg sample tube and started attacking it to form mercury iodide. oh, those damn halogens. (picture attached; Hg, HgI2 / Hg2I2 (?), Ga, I)
edit: i believe it was I as it left brown stains and a nice smell of electronics all over, too - plus it is the only halogen in the collection.
well, i dont yet have any of the elements you mentioned at the end of your first paragraph - my element collection is lacking a lot of items.
i usually just pick up stuff "on the fly" regarding to chemistry - that is, when i need it, e.g. when about to come in contact with a nuclide.
...and yes, i'm careful with compounds. like i keep the uranyl nitrate i produced for a youtube demonstration in a sealed jar. however, compounds sometimes just happen without expecting it... recently, i was checking up if my gallium had liquefied due to the high ambient temperature. i wanted to take a comparison photo with mercury from my periodic table... and noticed it had turned golden. just great - not only does iodine readily sublimate, but it also diffuses through plastic test tubes. it then sneaked into the Hg sample tube and started attacking it to form mercury iodide. oh, those damn halogens. (picture attached; Hg, HgI2 / Hg2I2 (?), Ga, I)
edit: i believe it was I as it left brown stains and a nice smell of electronics all over, too - plus it is the only halogen in the collection.
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Joe Jarski
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Re: Cadmium + GM-Tube for Neutron detection?
I'm not really equipped to discuss whether the dangers of Cd are overblown or not, but it is still common practice today for aerospace fasteners to be Cd plated and they are not labeled as being hazardous or requiring special handling precautions. On the other hand, Cd has been phased out by zinc for most every other fastener outside of the aerospace industry.