Low Temperature Measurement and Servo Control on the Low Temperature Microgravity Physics Facility

The Low Temperature Microgravity Physics Facility (LTMPF) utilizes Germanium Resistance Thermo meters (GRT) and other devices which depend upon precision resistance measurements. The LTMPF will use an implementation of the current switched, sampled DC technique developed under the Station Processor and Electronics Control (SPEC) program. The LTMPF version of the GRT circuit utilizes a 16 bit ADC with oversampling in order to increase the resolution and reduce no ise. Short term noise at the lambda point temperature (2.1768 K) has been measured at better than 4μK/ Science Requirements Envelope Document for LTMPF. GRTs provide the source measuremen for servo control of several stages within the instrument.