Looking for a low temp actuator or motor

[Orson1981]

I just thought I would throw this out there, see if anyone knows of some good products or neat tricks.

We are building a probe to be used with some DC SQUIDs that are going to be operating at low temp (~4 - 40K). For part of the design we want some sort of actuator or motor that would allow us to make contact with the sides of the chamber, probably somewhere on the order of a cm of displacement.

We have thought about using piezoelectric materials, but what I've seen so far only seems to have a displacement of a couple microns. Even wedged against the base of the material this would produce a cm of displacement.

We have also thought that there maybe a sort of pneumatic device that could do this, something designed for low tempurature, but, thus far I haven't been able to find anything.

Finally we thought of perhaps using some kind of magnetic device, but decieded to rule this out for fear of screwing up the readings from the SQUIDs.

Mostly we are looking for a product to buy, since we are going to be overloaded with building this probe and the machine to go with it, but, all ideas or suggestions are welcome

 

[berkeman]

You mentioned piezos, which made me think of linear piezo motors, which can do cm displacements. Don't know if they can work down at that low of a temperature, though:

http://www.physikinstrumente.com/en/products/piezo_motor/linear_motor_introduction.php

Maybe they could do a special version for low-temp...

 

[ZapperZ]

I just thought I would throw this out there, see if anyone knows of some good products or neat tricks.

We are building a probe to be used with some DC SQUIDs that are going to be operating at low temp (~4 - 40K). For part of the design we want some sort of actuator or motor that would allow us to make contact with the sides of the chamber, probably somewhere on the order of a cm of displacement.

We have thought about using piezoelectric materials, but what I've seen so far only seems to have a displacement of a couple microns. Even wedged against the base of the material this would produce a cm of displacement.

We have also thought that there maybe a sort of pneumatic device that could do this, something designed for low tempurature, but, thus far I haven't been able to find anything.

Finally we thought of perhaps using some kind of magnetic device, but decieded to rule this out for fear of screwing up the readings from the SQUIDs.

Mostly we are looking for a product to buy, since we are going to be overloaded with building this probe and the machine to go with it, but, all ideas or suggestions are welcome

Try looking at Kurt Lesker. They have quite a range of linear actuator. I should know. I bought one from them. :)

Zz.

 

[f95toli]

But do they work at low temperatures?
Complicated mechanical parts tend to be very unreliable at low temperatures. Even simple things like needle-valves, heat-switches etc can cause all sorts of problems (I know, I have spent a LOT of time troubleshooting mechanical parts, they tend to be the least reliable parts on the dilution fridges, ADRs etc that I use). I have never even heard of a motor that worked well at low temperatures. Kurt Lesker is a good source for vacuum parts, but I doubt their products work well at 4K.

Your best bet is to contact a company that specializes in this type of equipment. Do NOT try to design something yourself unless you know what you are doing, you will inevitably end up spending months trying to get it to work.
The "obvious" supplier for something like this would be Janis. You can also try Oxford Instruments but they will probably just try to sell you a complete system.
There are also some smaller companies that you can try, such as Ice Oxford, CMR, Chase Cryogenics etc.

 

[Orson1981]

Thanks everyone for the suggestions!

My natural insticnt is to always want to build everything from scratch, even after the guy with the letters "d" "r" in front of his name tells me not to... Though here I would have to agree, going through a supplier seems like the best idea.

I'll keep you updated on what the suppliers say, and if anyone has anyother suggestions, keep em coming.

 

[f95toli]

Thanks everyone for the suggestions!

My natural insticnt is to always want to build everything from scratch, even after the guy with the letters "d" "r" in front of his name tells me not to...

Well yes, but remember that they guy in question might have earned those letters by-among other things- spending a LOT of time trying to get needle valves etc to work
Practical cryogenics is a craft, the only way to learn it is by working on real equipment together with more experienced colleagues.

Send me a PM if you need more help.