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Abstract:
In a supersonic gas jet, gas is expanded adiabatically through a nozzle from a high
pressure reservoir (~bar) into a low pressure region (~103 - 104 mbar). In
doing so the free enthalpy of the gas is (partially) transformed into directed motion.
Supersonic jets find use in momentum spectroscopy experiments like for example
reaction microscopes.
In the course of this bachelor thesis the operation of a supersonic jet using iodine
as target gas was characterized. The target density as well as target temperature
are studied as function of the essential operation parameters (temperature of iodine
reservoir, type of carrier gas and back pressure). It could be shown that highest
iodine target density was achieved for low back pressures p0 = 1 - 2 bar and high
reservoir temperatures T0 > 100 °C. By rising the back pressure p0, a decrease in
the gas particles’ temperature T// along the jet propagation direction was observed.
Contrary to the expectations, no significant enhancement in T// with rising reservoir
temperature T0 was found.
By performing short-time IR/XUV pump-probe experiments on dissociation dynamics
of iodine at FLASH, we found iodine ions up to I6+ at 88 eV photon energy. A
dependence of the yield as well as the angular distribution of the ions as function of
the delay between IR and FEL pulse was observed.
