PSN-L Email List Message

Subject: Re: wonderful invention of R. V. Jones
From: John Lahr johnjan@........
Date: Tue, 26 Feb 2008 08:03:12 -0800

Hi Randall,

This sounds very intriguing, but it's frustrating that the cost of 
joining IOP is not
published on the web site and must be obtained by sending them an 
E-mail message!

I hate systems like that, because it's one more probable source of 
future junk mail.


At 04:54 AM 2/26/2008, you wrote:
>With the attention so frequently given to optical-type detectors, I 
>am surprised that nobody
>has yet (to my knowledge) mentioned what I believe to be the most 
>clever invention of them
>The great R. V. Jones, who is best known and quoted in seismology 
>for his work with
>capacitive sensors, while at Aberdeen invented a modified optical 
>lever that uses Ronchi
>rulings.  Ronchi is in this modern era largely unknown, but his 
>contributions in the field of
>figure-testing of optical components was of truly great 
>significance.  Those who want to
>study Jones' system can download the following paper:
>What is most remarkable about the coarse gratings (Ronchi rulings) 
>used for this work is that
>they work with ordinary (non-monochromatic) light from an 
>incandescent bulb.  I have for
>about two decades demonstrated to students the physics of this 
>remakable system by means of a
>spherical mirror in which the white light bulb/grating combination 
>is situated at the center
>of curvature.
>     To those who are impressed by observing displacements as small 
> as a nanometer, consider
>the following:  In the 1960 paper referenced above, Jones claims a 
>resolution of 0.1 nrad!
>It should be noted that this device is not a simple (standard) 
>optical lever where one
>typically is limited to tenths of a microradian;  Jones combined 
>Ronchi rulings with the
>optical lever to produce a whole new concept--much better for 
>seismic purposes, if anybody
>wants to try it.  In my case--so much of interest, limited time left 
>to pursue them!


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