PSN-L Email List Message

Subject: Re: ebay seismom.?
From: meredithlamb meredithlamb@.............
Date: Sat, 04 May 2002 14:24:05 -0600


Thanks....that all makes sense.  Suspect anyone buying such
would run the risk of the fiber breaking via shipment; even
with/without any fiber tension loosening/tightening mechanical
device.  Interesting gizmo though.


Hammonds wrote:

> Meridith, I think this particular magnetometer has one or more small
> magnets attached to a hair-like quartz fiber held
> vertically and under tension.
> Ambient light (coming in from that long frosted slit on the top and side of
> the instrument) shines on a tiny mirror which
> is also attached to the quartz fiber.  Any perturbation of the magnetic
> field causes the magnet(s) and the mirror to move
> and thus moving the reflected light beam on a scale.  The scale is read
> through the lens at the top of the instrument.
> If the quartz fiber is broken, the instrument is useless.  I haven't found
> a source for them.
> Bob Hammond
> apsn


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