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Proceedings Paper

3ω beam-timing diagnostic for the OMEGA laser facility
Author(s): J. Katz; W. R. Donaldson; R. Huff; E. M. Hill; J. H. Kelly; J. Kwiatkowski; R. B. Brannon
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Paper Abstract

The Omega Laser Facility at the University of Rochester’s Laboratory for Laser Energetics is a 60-beam system used for inertial confinement fusion experiments. Uniform drive of the target surface requires precise beam timing to achieve accurate power balance. A new diagnostic has been implemented for measuring the relative beam-to-beam arrival time of each of the 60 beamlines. A 900-μm spherical diffuser placed at the target chamber center serves as a quasi-isotropic scattering source that allows a fixed optical detector to view light from any individual beamline. During a beam-timing run, the OMEGA laser is configured to generate frequency-tripled, 351-nm ultraviolet (UV) pulses with energies of ~50 pJ at a repetition rate of 5 Hz. Light from the scattering target is optically relayed to a fast photomultiplier tube and recorded on a digital oscilloscope. A portion of the original infrared (IR) seed pulse is fiber optically delivered to the beam-timing oscilloscope and recorded using a photodiode. By recording the scattered UV pulse and the IR seed on the same oscilloscope trace, a jitter-free measurement of the beam’s arrival time can be made. Discrepancies in beam timing are corrected by adjusting the total optical path length of the beamlines. Typical variation in the measured arrival times of all 60 OMEGA beams after adjustment is <5 ps root mean square

Paper Details

Date Published: 31 August 2015
PDF: 5 pages
Proc. SPIE 9591, Target Diagnostics Physics and Engineering for Inertial Confinement Fusion IV, 95910A (31 August 2015); doi: 10.1117/12.2189394
Show Author Affiliations
J. Katz, Univ. of Rochester (United States)
W. R. Donaldson, Univ. of Rochester (United States)
R. Huff, Univ. of Rochester (United States)
E. M. Hill, Univ. of Rochester (United States)
J. H. Kelly, Univ. of Rochester (United States)
J. Kwiatkowski, Univ. of Rochester (United States)
R. B. Brannon, Univ. of Rochester (United States)

Published in SPIE Proceedings Vol. 9591:
Target Diagnostics Physics and Engineering for Inertial Confinement Fusion IV
Jeffrey A. Koch; Gary P. Grim, Editor(s)

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