The ABC facility includes a two-beam neodymium-phosphate glass laser
associated with the related experimental area. This installation became
operative in May 1988. The design performances are 100 J/beam (bandwidth
0.15 THz) of focusable radiation at the fundamental wavelength (1.054 micron)
for a FWHM pulse duration of about 2 nanosecond with a 2 ns foot (foot
energy 1% of the total). Different choices of this parameter are easily
available by properly operating the first electro-optical shutter used
to form the pulse. The available second harmonic converters allow the target
irradiation also at the wavelengths 0.527 micron.
A glimpse of the ABC facility
The final optics in the ABC installation.
Two arrays of negative square lenses with random thickness can be inserted
to produce near-field ISI smoothing at the focus of the
two F/1 aspherical lenses (b)
The measured energy density profile, at full
laser power, without arrays (a) and with arrays (b).
The distributions are respectively characterized by a flat-top with modulations
of about 6% in amplitude (a) and by a 400x400 micron plateau (b).
The measurements were made on the spot magnified images produced by one
of the F/1 focusing lenses. Calibrated N/P Polaroid plates were used as
recording media, by exploiting their two-photon absorption.
Measured energy density distribution on a smoothed
ABC beam. Cross sections (c) and Fourier modes (d)
The irradiation scheme in the ABC facility / The
layout of some routinary diagnostics
Inertial Confinement Physics & Technology
