Item

Abstract

The TrapRemi experiment combines a reaction microscope with an electrostatic ion trap for a kinematically
complete observation of molecular processes in molecular ions. This thesis describes the made
improvements to the experimental setup as well as the characterisation measurements. The main focus
laid on the generation and storing of ion bunches.
A functioning method was found for pulsing the ion beam. The characterisation of the pulses yielded
a sufficiently homogeneous transversal profile and a relatively rectangular longitudinal profile.
The pickup electrode signal was proven to be suitable for the estimation of the order of magnitude
of the stored ion number.
A certain ion trap configuration was found that results in a so called self-bunching mode: the stored
ions synchronise their movement through the Coulomb interaction and the bunch preserves its form over
a longer time period as in the common dispersive mode. The width of the bunch stays constant within
the estimated errors over 70ms and increases marginally afterwards in the self-bunching mode.
The electrostatic Zajfman trap of the TrapRemi can be used as a time-of-flight mass spectrometer.
The self-bunching mode increases the precision of this application. The relative frequency resolution was
estimated to be of the order of 10⁻³ ... 10⁻⁴.
The not compensated earth magnetic field reduces the acceptance of the ion trap. Nevertheless, a simulation
has shown that this impact is tolerable in reaction microscope experiments with the ions with a
mass of at least 40 a.m.u.
An over-exponential loss of the stored ions was observed. This leads to a conclusion that neutralisation
and scatterinng on the residual gas are not the dominating loss mechanisms. For a more precise
identification of the loss mechanisms further measurements of the stored ion number should be carried
out. This is, however, not necasssary for the intended reaction microscope experiments.