Lawrence Livermore National Labs & VSI

A Unique Application of a VSI CYCLOID Rotator

The Letter from Lawrence Livermore National Labs

February 24, 2007
Paul Van Slyke
Van Slyke Instruments
12815 Porcupine Lane
Colorado Springs, CO 80908
Re: Thanks for quick response on Cycloid Auto Rotator
Dear Paul,
A couple of months ago, we inquired about your Cycloid Auto Rotator for a project which was on an extremely tight deadline. We are researchers on a plasma machine called the DIII-D Tokamak which is a "star on earth" - a fusion machine that is being developed as an energy source (it replaces the heat source in an electrical plant which is currently using fossil fuels). We want to Thank You for your quick response and your solid product which enabled us to make a tight deadline.
Roughly once a year, the tokamak (a vacuum vessel about the size of a house) is opened for calibrations for a couple of months. We were calibrating an optical instrument that can measure the electrical current profile of the tokamak plasma. This "Motional Stark Effect" (MSE) diagnostic does very precise measurements of polarized light. Just before starting the calibration, a member of our team came up with a new technique that involved spinning an optic (a large "quarter wave plate") in front of a fixed polarizer - this provides both linearly and circularly polarized light to the system. Unfortunately, we had less than a week to put this system together, and so we started looking for a way to quickly make this polarization generator.
I use one of your off-axis guiders in my (personal) astrophotography endeavors. However, I wasn't up to date on the availability of your Cycloid rotators. One of the members of the team found your Cycloid during a search on the web, and he asked me if I knew anything about Van Slyke Instruments! I called you the next day, and you indicated that this wasn't really made to rotate at 60 rpm, but perhaps we could modify the basic design. (This was Wednesday, and I knew you normally only ship on Friday). We called our purchasing people and asked them to rush the order. You assembled a unit for us and shipped it overnight on Friday - using Fedex as opposed to your normal USPS. You even tested the unit to see how fast it would turn with the existing drive mechanism.
When it arrived, we made a simple modification of the drive mechanism and had the unit running at over 60 rpm in short order. A precision stepping motor was used to keep the rotation speed exact. We started calling this "The Wheel of Fortune" and it was used to successfully calibrate our diagnostic. It rotated at a very precise rate with the stepping motor (we took FFT's of the modulated light).
We want to Thank You for your quick response, your "can do" attitude, and for working with us with a "non-standard" request. The basic strength and quality of your product made it possible for us to modify it for our test.
I'm enclosing a few pictures of the "Wheel of Fortune."
Steve Allen, PhD (pictured above)
Lawrence Livermore National Lab
At General Atomics
San Diego, CA
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