Jump to: navigation, search

Sensors operating at temperatures near 100 mK bring exquisite sensitivity to a startlingly broad range of applications. These sensors often consist of thin superconducting films that are electrically biased in the superconducting-to-normal transition where their resistance is a strong function of temperature and hence deposited energy or power. Devices designed for gamma-ray and alpha-particle spectroscopy are able to measure the energy of single 5 MeV events with resolving powers greater than 5,000, perhaps the highest resolving power ever achieved in an energy-dispersive measurement. These devices provide new capabilities in the arena of nuclear forensics, treaty verification, and nuclear materials accounting. Kilopixel arrays of transition-edge sensors are also being used in contemporary probes of the cosmic microwave background such as ACTPol and SPTPol. Despite significant differences between these applications, the sensing elements are remarkably similar. I will review transition-edge sensor development at NIST and discuss a range of applications including submillimeter and millimeter-wave astronomy, as well as emerging applications that include nuclear materials analysis, time-resolved X-ray spectroscopy, and synchrotron science.

Abstract TBA

Isolated rotating neutron stars are gradually spinning down to lower frequencies because of the emission of magnetic dipole radiation and a wind of electron-positron pairs. This spin-down compresses the matter inside of such neutron stars monotonically to higher densities, leading to changes in the global properties and the hadronic core compositions of such objects. In particular, spin-down may drive rotation-driven phase transitions in the cores of rotating neutron stars, which is the key topic of this talk. First, the structure and stability of rotating neutron stars will be discussed. This is followed by an overview of the different types of phase transitions that may be triggered by stellar spin-down. Finally, astrophysical signatures by means of which such phase transitions may register themselves observationally will be discussed.