new tensor strainmeter design from NINH China

[Scott DeWolf]

sorry -- i originally sent this a few days ago to the old mailing list address.

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just finished reading a short conference paper, one in a growing catalog of borehole strainmeter articles from the National Institute of Natural Hazards in Beijing, China:

Jiayong Tian, Kanghua Zhang and Lou Jiashu, Next-generation high-resolution borehole tensor strainmeters for the measurement of six strain-components based on fully automated interferometric displacement sensors

the link is to the article on ResearchGate, which is the only source i've found for the pdf and i don't want to mess around with redistributing copyrighted material.

some of us have discussed a similar type of arrangement of interferometric displacement transducers similar to the Sakata Fabry-Perot as described in US Patent US5629757A, but using Michelson interferometers.  this one appears to use commercial Fabry-Perot displacement transducers from attocube systems AG whose collimators are compact enough to embed in a borehole package.  the most interesting part to me is the arrangement of the gauges using the bridges (or whatever they're called) to span the pressure case inner diameter to get all the collimators to fit.

this looks like a prototype with a very simple test of functionality in the lab, but it will be fascinating to see results after it's deployed, mostly to see if the laser is stable enough to record tides in addition to the cycle-per-day temperature changes of its operating environment.

enjoy,

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If we don't succeed we run the risk of failure. -- Dan Quayle

Scott DeWolf, Ph.D.

Associate Research Professor

Clemson University

Clemson, SC  29634-0919

Mobile: (858) 750-5675

sc...@scottdewolf.com

https://www.scottdewolf.com

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