Vertical Sensor Thoughts

Date Mon, 28 Oct 2002 231318 EST
Hi all,

I am attaching much the same GIF as before. Earlier, I had suggested making an unstable spring suspension, and using diamagnetic forces on a graphite rod to make it stable. I want to consider another approach. I would make the spring provide a stable suspension of rather short period. Then, instead of using diamagnetic graphite and a quadrupole magnet for adding a restoring force, I would substitute a rod of paramagnetic material for the graphite. This would have the effect of making the natural period controllably longer. I would want a paramagnetic susceptibility similar in magnitude to the negative susceptibility of graphite. I am wondering what would be a suitable material to use. I don't think aluminum is paramagnetic enough. Other elemental metals might be, but I doubt if I could easily obtain a sample in the form of a rod.

Most stainless steels are magnetic. In the past, I have used a particular "nonmagnetic" alloy which is actually paramagnetic. I don't know the composition or where I could get it. Any info and advice you may have would be helpful. Maybe some resin plastic with iron dust mixed in would work?

I looked for some rouge polishing powder I used to have around, but I can't find it. It might be suitably paramagnetic.

I realize that this scheme, as any other one using spring forces, is likely to have pendulum drift and sensitivity to ambient temperature. I am willing to live with that.

Note that using a decentering force to weaken a centering force is not a new idea. A sketch by C. L. Stong is reproduced below.



Final vertical.