Radioactive decay of Ag to form -> Cd and Pd

[Caustic]

I was reading about a neutron capture experiment http://www.dartmouth.edu/~physics/labs/p1/lab4.pdf

Silver was placed in a paraffin block with Americrum (as an alpha source) and Beryllium to produce neutrons. The paraffin was supposed to slow down the neutrons or "thermalize" them so they can be captured.

According to this lab, Ag when bombarded with slow neutrons will capture them and then decay to eaither Cd or Pd depending on the isotope of Ag.

So my question is how long would you have to expose the Ag to the neutrons to convert a majority of it to Cd and Pd? And once converted can these elements be seperated?

 

Basicially i want to know if i can make a valuable element from a cheap one by bombarding it with neutrons.

[budullewraagh]

with resources available to you, youd have a difficult time.

 

familiar with schrodinger's cat?

 

think along those lines, but with quite a few variables....and if you don't have an ultracentrifuge, add a bunch more variables. probability states that you cannot possibly do it:\

[Gilded]

"with resources available to you, youd have a difficult time."

 

Yeah. Nucleosynthesis is no easy task if you want to make visible amounts of stuff. That's way artificially made gold costs MUCH with a big M.

[budullewraagh]

actually, if i ever can make a neutron gun i'll try nucleosynthesizing some wp out of 2 micron al

[Gilded]

"actually, if i ever can make a neutron gun i'll try nucleosynthesizing some wp out of 2 micron al"

 

You mean powder? Thin target plates (even nanoplates) are usually the best for this kind of experiments.

[budullewraagh]

yeah but i want really finely divided wp if you follow ;p

[Gilded]

Rofl. Have fun trying it. )

[budullewraagh]

oh i will...the wp would instantly oxidize yielding enough heat energy to oxidize the al, certainly. thus i'd need to do this in a completely pure inert atmosphere

[YT2095]

Budl, have you seen the anti-static bags computer parts come in, the sort that look silvery, I`m sure thay cant be more than a few microns thick of Al as you can see through them, it might be worth a try?

[budullewraagh]

haha, maybe i'll try that. thing is i need to make a neutron gun first...which isn't happening. i could probably find a way to get the beryllium, but it could be difficult (and no im not paying $20/gram on unitednuclear) but i have a number of associates who work in labs, some nuclear, some not. problem is i need a good alpha source which could be tricky. plus then i need to make sure the atmosphere this is in is totally inert without the slightest impurity, lest the entire mixture oxidizes rapidly

[YT2095]

get some Argon from a Welding shop then, you can buy spare Regulators for the bottle too

[budullewraagh]

could be potentially difficult to flush ALL the O2/N2 etc out of the reaction vessel tho

[Gilded]

Beryllium is easy to get. The only thing that provides a challenge is pure polonium metal. Melt some beryllium and polonium together and you got yourself one serious neutron source.

[YT2095]

Budl

 

maybe the Hypothermia silver foil type plastic blankets may work too?

 

as for the Argon, exploit gas weight at RTP, flush it that way

[Gilded]

I wonder if a silver target is the best way to actually see the outcome of the bombardment at some point.

[budullewraagh]

good call, yt

 

Beryllium is easy to get.

but overly expensive from most sources

[Gilded]

"but overly expensive from most sources"

 

I'd say the 20 bucks for 1g they got at UN is a bit over the the top. The 12$ for a 1g pearl or 25$ for a 5g pearl that they got at Metallium Inc. is starting to sound pretty good though.

[swansont]

I was reading about a neutron capture experiment http://www.dartmouth.edu/~physics/labs/p1/lab4.pdf

Silver was placed in a paraffin block with Americrum (as an alpha source) and Beryllium to produce neutrons. The paraffin was supposed to slow down the neutrons or "thermalize" them so they can be captured.

According to this lab' date=' Ag when bombarded with slow neutrons will capture them and then decay to eaither Cd or Pd depending on the isotope of Ag.

So my question is how long would you have to expose the Ag to the neutrons to convert a majority of it to Cd and Pd? And once converted can these elements be seperated?

 

Basicially i want to know if i can make a valuable element from a cheap one by bombarding it with neutrons.[/quote']

 

If you had a 1 Ci source (which is really, really radioactive) you get 3.7 x 10¹⁰ decays per second. And suppose you had a 100% conversion to neutrons (instead of the small solid angle you'd have in reality) in your beam. Assume all of the neutrons are captured by the Ag - none leak out (unlikely), none absorbed by undesired nuclei,and no reduction in cross section as the target nuclei are depleted (which would give you an exponential decrease in reaction rate) To get one gram of your metal will take on the order of 10¹⁰-10¹¹ seconds, because Avogadro's number is 6.02 x 10²³. There are ~ 3.15 x 10⁷ seconds in a year. So it'll be a while - 300 years under the ideal conditions I described.

[Gilded]

"So it'll be a while - 300 years under the ideal conditions I described."

 

Somehow I thought it was going to take a while. ) Even with good cyclotrons, creating a gram of, let's say, gold is not an easy task (as I said). Btw swansont, do even physicists in the U.S. still use curies in experiment calculations? Do they even encourage you to use Bq?

[swansont]

do even physicists in the U.S. still use curies in experiment calculations? Do they even encourage you to use Bq?

 

I used Ci when I was teaching for the Navy. Since then, I've been doing mostly atomic physics, so it really hasn't come up a whole lot. Besides, a Bq is a dps, so it's pretty boring and useless. (it reminds me of a government program, for some reason)

 

 

I did get mixed up with the whole Sievert vs REM thing, but avoided it mainly by staying away from the hot spots when I was at TRIUMF. Zero dose is zero dose, no matter what the scale...

[Gilded]

"Besides, a Bq is a dps, so it's pretty boring and useless."

 

But it impresses people more when you say "freaking 37 gigabecquerels!" than "1 curie".

 

"I did get mixed up with the whole Sievert vs REM thing, but avoided it mainly by staying away from the hot spots when I was at TRIUMF. Zero dose is zero dose, no matter what the scale..."

 

You're quite right about that. Did you have the simple... err, things that become darker when they get ionized, eventually becoming black and telling you you're not going to do any work around ionizing radiation for a while?

[jdurg]

Those good ol' radiation badges. My dad works at a nuclear power plant, so he has to carry one of those around. I was thinking of taking it while he's asleep and putting it next to my rubidium and potassium samples, as well as my rock of pitchblende. lol. Then I realized that he'd be forced to stay home for a good long while. Suddenly the humor in that joke was lost. heh.

[Gilded]

"Then I realized that he'd be forced to stay home for a good long while."

 

Yeah, here it's a max of 100mSv divided in a period of five years, and 50mSv is the max for one single year. I recall it being quite a similar amount in every country where these levels are even supervised.

[swansont]

You're quite right about that. Did you have the simple... err, things that become darker when they get ionized, eventually becoming black and telling you you're not going to do any work around ionizing radiation for a while?

 

We had a gamma/beta badge and a neutron badge (later combined into one) that we had on whenever we were inside the fence that cordoned off the cyclotron. Those were turned in when you left and swapped out periodically (monthly?) to be read. I never had occasion to see anything turn black, though.

 

When we were running a radioactive beam into our lab, we had the pencil-shaped dosimeters that we could read ourselves, to measure current dose. I also used a digital dosimeter that beeped as it counted each 0.1 mSv when we were running an experiment with a large background.

[Gilded]

Good to see you have proper dosimeters. My dad used to have those too when he did PET-research.