High Cryogenic Temperatures Research Articles

Coupled Resonator Calorimeter for Particle Detection

We describe a novel coupled microwave dielectric resonator system (an unusual form of parametric amplifier), which is under development, aimed at realizing a high-resolution single X-ray photon energy detector. Unlike other high-resolution detectors, it operates at a relatively high cryogenic temperature in the range of 7-30 K. Construction of the cooler system and thermal characterization system is completed. All aspects of the novel calorimeter performance have been evaluated, including demonstration of single-particle detection, the required rapid thermal time constant of a coupled resonator, a high df/dT response, and promising development of a low-noise microwave detection system.

Towards an Absolute Determination of the Particle Energy Thermalized in Bolometers

We describe a procedure to derive the absolute energy thermalized in the bolometer’s target after a particle interaction. It relies on the comparison of the theoretical responsivity in stationary regime (deduced from the I–V curves) and the area of the pulse. Full thermalization in metals is addressed at high cryogenic temperatures (over 400 mK). Taking them as reference materials when glued to a target, they can be used to estimate the thermalization efficiency of particles in dielectrics and superconductors.