Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems
- Advanced Radiographic Technologies, Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1195 (United States)
- National Security Technologies, LLC, P.O. Box 98521, Las Vegas, Nevada 89193 (United States)
- Weizmann Institute of Science, Rehovot, Israel 76100 (Israel)
This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 {mu}m) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ('hotspot') was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm{sup 2}/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.
- OSTI ID:
- 22093694
- Journal Information:
- Review of Scientific Instruments, Vol. 83, Issue 8; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
Similar Records
Apparatus for synthesis of a solar spectrum
Apparatus for synthesis of a solar spectrum
Related Subjects
ACCELEROMETERS
CALIBRATION
CHROMATIC ABERRATIONS
ELECTRON BEAMS
INTERFERENCE
INTERPOLATION
LIGHT SOURCES
LIGHT TRANSMISSION
MONOCHROMATORS
OPTICAL FIBERS
PHOTODETECTORS
PLASMA PRODUCTION
SANDIA NATIONAL LABORATORIES
SPECTRA
SPECTROSCOPY
STREAK CAMERAS
VISIBLE RADIATION