Principle and definition
A fast ion beam crosses at right angle, first a carbon foil and secondly
a laser beam (fig. 1). After the foil, most of the excited levels of many
different ionisations stage are populated. The intense laser beam is tuned
to a specific transition wavelength and during the interaction, the two
levels of the transitions are coupled. This effect could be quantified by
measuring the change of intensity induced by the laser pumping.
The laser-effect is defined as:
Where 
and 
are the line intensities measured with and without
the laser beam. The laser effect is usually expressed in %.
Experimental arrangement
BFL effect on Deuterium as a function of the dye laser wavelength
Laser arrangement for intracavity ion beam excitation
The fiber optics light captor head is movable and can be tilted
- By moving the head downstream from the foil it is possible to record
decay curves and measure atomic lifetimes.
- By tilting the head, the light emitted by the fast moving ions is Doppler
shifted away from the laser wavelength so that the measurement of the "Laser
effect" is not disturbed by the scattered light of the intense laser
beam.
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