Hi Meredith,

  Your setup reminds me of an experiment of mine I performed over two years 
ago. Like you, I used 3 Nd rectangular magnets and a pyrographite slab. I added 
2 cube magnets near the ends to get a stable period. I put a 0.004" thick 
aluminum damping vane on top of the pyrographite. A small lens was mounted in the 
damping vane as part of a planned optical pickoff. The magnetic field for 
damping was furnished by four cube magnets on top of the structure.

  I never made the optical pickoff to complete the sensor, because tilt tests 
disclosed that the motion of the graphite was somewhat "sticky". I think 
small variations in the levitating magnetic fields are responsible. I tried thin 
iron shims in order to homogenize the field, but then the field was too weak to 
support levitation. It is my belief that iron pole pieces are necessary for 
the successful implementation of a diamagnetic seismometer/tiltmeter.

  Paramagnetism of the aluminum vane was a minor problem also.

Cheers,

Bob


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Check out AOL's list of 2007's 
hottest products.

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Hi Meredith,



  Your setup reminds me of an experiment of mine I performed over two y=
ears ago. Like you, I used 3 Nd rectangular magnets and a pyrographite slab.=
 I added 2 cube magnets near the ends to get a stable period. I put a 0.004"=
 thick aluminum damping vane on top of the pyrographite. A small lens was mo=
unted in the damping vane as part of a planned optical pickoff. The magnetic=
 field for damping was furnished by four cube magnets on top of the structur=
e.



  I never made the optical pickoff to complete the sensor, because tilt=
 tests disclosed that the motion of the graphite was somewhat "sticky". I th=
ink small variations in the levitating magnetic fields are responsible. I tr=
ied thin iron shims in order to homogenize the field, but then the field was=
 too weak to support levitation. It is my belief that iron pole pieces are n=
ecessary for the successful implementation of a diamagnetic seismometer/tilt=
meter.



  Paramagnetism of the aluminum vane was a minor problem also.



Cheers,



Bob


**************************************
Check out AO=
L's list of 2007's hottest products.
(http://money.aol.com/special/hot-pr=
oducts-2007?NCID=3Daoltop00030000000001)