Studies and development of a helical resonator for Penning trap application

A high quality factor helical resonator is required for the non-destructive resonant detection of eigen-frequencies of charged particles confined in a Penning trap. A 20 MHz helical resonator has been designed utilizing both the analytical and numerical methods. The performance of the helical resonator has been studied extensively by varying its dimensions and properties of the materials. The design parameters have been optimized and a prototype resonator is fabricated. The important parameters of the resonator like resonance frequency, quality factor, effective inductance and capacitance have been measured. The results obtained from the finite element analysis method are in good agreement with the experimentally measured values. It has been found that the distance between the radiofrequency probe and the open end of the helix plays an important role in maximizing the power coupling between the input and output terminals. Simulation studies have been performed to study the variation of power coupling with the change in the length of the probe and its radial position inside the resonator. The results have been verified experimentally. The maximum power coupling has been obtained by varying the length of the probe, where the resonance frequency and Q-factor were kept nearly same as the unloaded condition. The tank circuit with increased power coupling can be utilized to detect the feeble trap signal with high quality factor.