Development and Characterization of a Cryogenic Tuned Amplifier for Penning Trap Applications

A two-stage tuned amplifier has been developed and characterised for operation at cryogenic temperatures for Penning Trap application. Two pHEMT devices were tested at 300 K, 77 K and 4.2 K for their DC and AC characteristics. The developed amplifier has shown an amplification of 40 dB at a quiescent power consumption of ~ 1 mW at liquid helium temperature. Considering the feeble intensity of the image charge signal from Penning trap, the input impedance of the first stage amplifier is kept high whereas the output impedance of the second stage is kept 50 Ω for impedance matching with the transmission line. The bandwidth was ~ 200 kHz with the centre frequency around 40 MHz to match with the axial frequency of the electrons confined in the Penning trap. The amplifier was tested at 5 T magnetic field and it showed similar performance as in no field condition. The signal of trapped electrons, in a Penning trap at 4.2 K, was detected using this amplifier through the resonance absorption technique, confirming its suitability for the system.