Entwicklung von Kryoelektronik für den Nachweis einzelner Ionen im PENTATRAP Penningfallen-Massenspektrometer

The PENTATRAP experiment located at the Max-Planck-Institut für Kernphysik in Heidelberg deals with the high-precision mass ratio measurement of highly-charged, stable and long-lived ions. For that purpose a setup with five separate Penning traps is used, which allows simultaneous measurements in multiple traps. The Fourier-transform ion cyclotron resonance method is used for the non-destructive determination of the axial frequency of the trapped ions. This method uses the voltage drop over a parallel resonant circuit caused by the image current induced in the trap electrodes. The design, the manufacturing and the test of electronic circuits for the adjustment of the tank circuit’s quality factor was carried out in the context of this bachelor thesis. Several concepts for the discrete and continuous adjustment were created for that. For a realistic simulation of the conditions inside the experiment, these concepts were tested at about 4 K inside a cold head. In the course of those tests a concept with a field effect transistor as variable resistor appeared most suitable, due to the continuous adjustability. Furthermore it showed that the losses in the manufactured boards were strongly limiting the achievable quality factor. With suitable modifications these losses were reduced