Development of a Tunnel Diode Resonator technique for magnetic measurements in Electrostatic Levitation chamber*

The incorporation of the Tunnel Diode Resonator (TDR) technique into an ElectroStatic Levitation (ESL) apparatus was explored. The TDR technique is known to operate and behave well at low temperatures with careful attention to coil-sample positioning in a dark, shielded environment. With these specifications a frequency resolution of $10^{-9}$ in a few seconds counting time can be achieved.\footnote{C. V. Degrift, ``Tunnel diode oscillator for 0.001 ppm measurements at low temperatures,'' Rev. Sci. Instrum. \textbf{46}, 599 (1975).} Complications arise when this technique is applied in the ESL chamber where a sample of molten metal is levitating less then 10 mm from the coil in a large electrostatic field. We have tested a variety of coils unconventional to TDR; including Helmholtz pairs and Archimedean spiral coils.