A method of X-ray characterization includes cooling a sample by delivering liquid nitrogen via a pipe to a sample stage of the X-ray diffractometer. The liquid nitrogen is discharged from the pipe to form a coolant stream. The pipe has an outlet to orient a flow of the coolant stream at the sample on the sample stage. The sample includes a substrate and a thin film formed on the substrate. During the cooling, diffraction data of the thin film and diffraction data of the substrate are collected by a detector of the X-ray diffractometer. A temperature of the thin film is determined based on the diffraction data of the substrate and thermal behavior of the substrate as a function of temperature. The thermal behavior of the substrate includes thermal expansion, thermal contraction or both.

A process variable transmitter for sensing a cryogenic temperature in an industrial process includes a cryogenic temperature sensor configured to be thermally coupled to an industrial process. The cryogenic temperature sensor has an electrical resistance which changes in response to changes in a cryogenic temperature and the industrial process is at the cryogenic temperature. Resistance measurement circuitry is electrically coupled to the cryogenic temperature sensor and measures a sensor resistance over a resistance range and responsively provides an output related to temperature based upon the measured resistance. Transmitter output circuitry coupled to the measurement circuitry to transmits information related to the cryogenic temperature to a remote location. The cryogenic temperature sensor comprises a polycrystalline silicon sensor including a dopant such that the cryogenic temperature sensor has an electrical resistance which changes over a cryogenic temperature range which is within the sensor resistance range of the measurement circuitry.