| Autor: |
L.R. Veeser, J.C. Cochrane, R.R. Bartsch, L.J. Tabaka, R.E. Chrien, L.D. Looney, J.L. Stokes, B.R. Marshall, P.J. Forman, B. Warthen, W. Broste |
| Rok vydání: |
2002 |
| Předmět: |
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| Zdroj: |
Digest of Technical Papers. Tenth IEEE International Pulsed Power Conference. |
| Popis: |
The authors measure the current on the Los Alamos pulsed power machine, Pegasus II, using the Faraday rotation technique in a twisted, low-birefringence optical fiber. This technique yields results which are reproducible to within about 1%. When comparing their results with data from a Rogowski loop and from B-dot loop detectors, they find discrepancies larger than the uncertainties in the measurements. They have calibrated their system in three different ways: (1) the Pegasus II experiment was driven into a shorted load in a ring-down test to measure the load inductance. The measured Faraday data were fitted to a damped sinusoidal equation and compared with current calculated from the measured voltage and capacitance; (2) a single capacitor drove about 3 kA of current into a 403 turn solenoid coil. A Pearson transformer calibrated to about 1% measured the current supplied to the coil and the Faraday data were compared with the Pearson data; and (3) on a separate machine, a calibrated Rogowski coil provided direct comparison with fiber optic Faraday measurements. The Verdet constant has been measured for bulk silica glass at a wavelength of 633 nm by several researchers. The authors extrapolated these averaged results of 4.61 radians/MA to their wavelength of 830 nm and corrected it for the 4% germania dopant in the glass from which their optical fiber was fabricated. They obtained results from all three methods consistent with a Verdet constant 6% smaller than the extrapolated value. They are continuing to investigate this discrepancy and are working with NIST to measure the Verdet constant in their glass at 830 nm. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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