Instructables

Stepper motors for sale

I have a few large stepper motors I pulled out of a liquid sinilation counter. I'm not exactly sure what thier value is, similair motors are priced around 50-60$ new, so offers are welcome. They operate ~6v and have 0.90 degree steps, I believe they are bipolar. I can upload pics if needed.

kelseymh1 year ago
Just out of curiousity, what were you doing with a liquid-scintillator counter? And how come you get to keep the motors you salvaged from it? I ask because SLAC won't let us take components, even from equipment being decommissioned.
martzsam (author)  kelseymh1 year ago
Hehe... I was asked to help disassemble it by an un-named friend who works for a hospital which will also remain without name. They were taking it apart for a radioactive source inside and properly disposed of the rest. Regulations were loosely enforced and I was allowed to snag them before they were destroyed.
Heh :-) Nice score for you!

Do you know if the motors were surveyed by the health-physics folks before you "snagged" them? Depending on what the source was, it is possible for metals in particular to develop induced radioactivity under high-intensity and high-energy irradiation.

I had exactly this experience myself, at a different lab more 15 years ago. I was given a couple of really nice quality rare-earth magnets, for a personal project, from a can full of fragments salvaged from an old fixed-target experiment (the original large magnets had been used for a spin-polarized hydrogen target). The experiment had been surveyd when it was taken off the beamline, but the internal components had not been.

Anyway, I carried my magnets around in my coat pocket for the weekend, and set off the radiation alarm when I came back in the next Monday. The RP folks were very nice when I explained what had happened, surveyed all the remaining magnet pieces, and gave me a couple that weren't hot.
This is generally an issue only with neutron radiation.
Alpha, beta, and gamma, no matter how intense, doesn't
induce radioactivity. On the other hand, physical contamination
with radioactive substance can be a problem. Radium and cobalt 60
are notorious in this respect.

If you suspect any of the above, then a geiger counter is your best friend.
Low-end GCs can be had for under $100 and they're easy to use.
Hey, hey, hey, maybe a topic for a future Instructable.
You're right, generally. Neutrons are extremely nasty, but so are beamlines. Even the electron-positron collider at SLAC, where I worked, produced high-enough energy secondaries (beam losses, bremsstrahlung photons, etc.) to induce secondary radioactivity in the beamline components.

There are a few alpha sources (typically high-end actinides), where the alpha energy is high enough to get past the Coulomb barrier in some targets. Gammas, if you have just exactly the right energy and target, can occasionally (microbarn cross sections) produce excited nuclear states or kick out a proton/neutron.

I just did an I'bles search for "geiger counter" -- there are ten projects to actually build one. I've also seen a couple in MAKE. The G-M tube itself is the most expensive bit; a whole project can run well over $100.
You're right, generally. Neutrons are extremely nasty, but so are beamlines. Even the electron-positron collider at SLAC, where I worked, produced high-enough energy secondaries (beam losses, bremsstrahlung photons, etc.) to induce secondary radioactivity in the beamline components.

There are a few alpha sources (typically high-end actinides), where the alpha energy is high enough to get past the Coulomb barrier in some targets. Gammas, if you have just exactly the right energy and target, can occasionally (microbarn cross sections) produce excited nuclear states or kick out a proton/neutron.

I just did an I'bles search for "geiger counter" -- there are ten projects to actually build one. I've also seen a couple in MAKE. The G-M tube itself is the most expensive bit; a whole project can run well over $100.
martzsam (author)  kelseymh1 year ago
Yeah they made sure it was all safe before getting rid of it. I was stoked to get them but I haven't used them at all' so I figured I would see if somebody here had a need for them.

Maybe I should break out the old Geiger counter just to make sure...
Don't get rid of them! You've built other robotic projects. The best thing you can do with working components is hold onto them (in a clearly labelled box), so you don't have to dump money to get new ones the next time you need them.

Good luck!
martzsam (author)  kelseymh1 year ago
Thanks. I think I will hold onto them.