Aluminum-coated optical fibers as efficient infrared timing fiducial photocathodes for synchronizing x-ray streak cameras

Journal Article · Wed May 15 00:00:00 EDT 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.347631· OSTI ID:5727584

Koch, J A; MacGowan, B J ^[1]

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1. Lawrence Livermore National Laboratory, University of California, P. O. Box 5508, Livermore, California 94550 (US)

The timing fiducial system at the Nova Two-Beam Facility allows time-resolved x-ray and optical streak camera data from laser-produced plasmas to be synchronized to within 30 ps. In this system, an Al-coated optical fiber is inserted into an aperture in the cathode plate of each streak camera. The coating acts as a photocathode for a low-energy pulse of 1{omega} ({lambda} = 1.054 {mu}m) light which is synchronized to the main Nova beam. The use of the fundamental (1{omega}) for this fiducial pulse has been found to offer significant advantages over the use of the 2{omega} second harmonic ({lambda} = 0.53 {mu}m). These advantages include brighter signals, greater reliability, and a higher relative damage threshold, allowing routine use without fiber replacement. The operation of the system is described, and experimental data and interpretations are discussed which suggest that the electron production in the Al film is due to thermionic emission. The results of detailed numerical simulations of the relevant thermal processes, undertaken to model the response of the coated fiber to 1{omega} laser pulses, are also presented, which give qualitative agreement with experimental data. Quantitative discrepancies between the modeling results and the experimental data are discussed, and suggestions for further research are given.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5727584
• Journal Information: Journal of Applied Physics; (USA), Vol. 69:10; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
NOVA FACILITY
PLASMA DIAGNOSTICS
OPTICAL FIBERS
SURFACE COATING
STREAK CAMERAS
TIMING PROPERTIES
ALUMINIUM
DAMAGE
OPERATION
PHOTOCATHODES
CAMERAS
CATHODES
DEPOSITION
ELECTRODES
ELEMENTS
FIBERS
MEASURING INSTRUMENTS
METALS
RADIATION DETECTORS
700102* - Fusion Energy- Plasma Research- Diagnostics
700208 - Fusion Power Plant Technology- Inertial Confinement Technology