Gensheng Wang

Materials Science Division, Argonne

Absorber Coupled TES Bolometer For Cosmic Microwave Background Polarization Anisotropy Measurements

Superconducting Transition Edge Sensor (TES) bolometers are sensitive receivers at millimeter and submillimeter wavelengths. A TES operated with negative electro-thermal feedback has a fast response time and a noise level below the photon counting noise. Therefore, TES bolometers, with appropriate optical coupling, have the desired performance to conduct sensitive observations of the Cosmic Microwave Background (CMB) radiation. The frontier of CMB research is to detect or to constrain CMB B-mode polarization induced by inflationary gravitational waves at the very beginning of the universe. Furthermore, polarization measurements of dusty high red-shift galaxies and of the gas and dust in the local universe at millimeter and sub-millimeter wavelengths have their own interest in astrophysics. Such measurements are used to investigate the magnetic field believed to be critical in the process of star formation.

I will start with the technical requirements of CMB B-mode measurement, review the TES technology in astrophysical instrumentation, and report the development of an absorber coupled TES bolometric polarimeter, which consists of an absorptive metal grid and a Mo/Au bi-layer TES on a suspended silicon nitride membrane disk. And I will have a general discussion of the TES detector applications and possible scientific impacts at Argonne Lab in high-energy resolution electron and X-ray spectroscopy in last part of my presentation.

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