Joseph F. Keithley Award For Advances in Measurement Science Winner: Joel UllomPrecision Measurements with Superconducting Sensors

Calorimeters are sensors that transduce incident energy to a measurable temperature increase. At operating temperatures approaching absolute zero, the dominant noise source in these devices is the stochastic exchange of energy between the sensor and its surrounding heat bath, and it becomes possible to measure energies and powers with exquisite precision. The use of thermometers and readout elements based on superconducting circuitry has proven particularly powerful. The combination of calorimetry, superconductivity, microfabrication, and advanced cryogenics is enabling a new class of scientific instruments with applications in both basic and applied science. Photon spectrometers based on multiplexed arrays of superconducting transition-edge sensor (TES) microcalorimeters are finding uses in metrology, astrophysics, materials analysis, and nuclear security. Imaging microwave polarimeters based on multiplexed arrays of power-sensing TES microbolometers have become indispensable tools for cosmology. In this talk, I review the principles of TES detectors, describe the synthesis of sensor, readout, and cryogenic technologies that has produced practical instruments based on microcalorimeter arrays, and highlight recent applications and instrument deployments.