Thin-Film Thermometer and Heater Design for the Detection and Generation of Second Sound Shock Pulses

Abstract

Using a known heater design, and a common type of pencil lead graphite in a novel thermometer design, second sound shock (SSS) pulses comparable to those of previous researchers were successfully transmitted and received in a 1.7 K He II bath. Two sample traces of SSS pulses are presented. Extensive design requirements are outlined for highspeed thin-film thermometers and heaters used to transmit and receive SSS pulses. The heater and thermometer can be described by lumped parameter first order ordinary differential equations for the thermal case because their Biot numbers are less than 0.1 in the presented design. Also, their thermal time constants are minimized. However, the heater and thermometer can be described by lumped parameter first order ordinary differential equations also for the electrical case because they are embedded in an electronic instrumentation system. The time constants in both cases must be considered with respect to the required minimum pulse duration to arrive at a correct design for the heater and thermometer.