Berlin 2001 – scientific programme
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P: Plasmaphysik
P 3: Dense Plasmas
P 3.4: Talk
Tuesday, April 3, 2001, 17:15–17:30, 2053
Photoneutron production with table-top TW lasers — •Stefan Düsterer1, Rolf Behrens2, Christian Ziener1, Heinrich Schwoerer1, and Roland Sauerbrey1 — 1Inst. für Optik und Quantenelektronik, Uni Jena — 2Physikalisch-Technische Bundesanstalt, Braunschweig
We report on the photofission of nuclei with a TW
Ti:sapphire laser. For the first time nuclei were split by
the use of a table-top laser system.
Extremely hot plasma (Thot ∼ 500keV) is created when
an intensive femtosecond laser pulse (5 × 1018
W cm−2) interacts with a solid high Z target.
Electrons are accelerated by the laser within this plasma
to energies of several MeV. They emit high energetic
bremsstrahlung when they interact with the surrounding
matter. X-rays with energies above the fission threshold of
1.67 MeV initiate the photofission of Be resulting in two alpha
particles and a
neutron: 9Be → 2 α + n. The neutrons were
detected by another
nuclear reaction. Gold nuclei were activated by
197Au + n →
198Au. The subsequent γ-decay of the 198Au was
measured and showed that about 100 neutrons were produced per laser
shot.
The production of neutrons with a compact table-top laser
system enables medical applications. The needs and demands
of radiology and their feasibility will be discussed.