Ultrasensitive Superconducting Cold-Electron Bolometer Coupled to Multi-frequency Phased Antenna Array for Polarization Detection of the Cosmic Microwave Background
Examensarbete för masterexamen
We describe the design and simulation of a novel dual-polarized multi-frequency singlepixel for next-generation Cosmic Microwave Background (CMB) polarization detection. The pixel consists of a phased array of planar antennas known as slot antennas coupled to millimeter-wave cryogenic detector by superconducting transmission lines. The pixel separates the incoming radiation into two linear polarizations with high polarization purity and operates at two frequencies (75 GHz and 105 GHz) as well. This completely lithographed planar technology will enable us to squeeze the size of the focal plane to avoid aberration problems. This will also enable us to realize bolometer arrays with thousands of pixels needed to meet the sensitivity requirements of future CMB polarization experiments and to achieve better resolutions and higher scan speeds. Having multiple frequencies is important to differentiate the CMB from the galactic foreground contamination. Those goals are difficult to achieve with the current technology which uses feed horn for each pixel. The detector is a superconducting Cold Electron Bolometer (CEB), which have several advantages over current technologies. The main component of the CEB is a Normal- Insulator-Superconductor (NIS) tunnel junction, which acts as a thermometer. The CEB could implement an additional spectral filtering feature, which obviates the need for external filters. This technology is a candidate for use in the European Space Agency (ESA) Cosmic Vision Program (2015-2025) to detect the B-mode of the CMB, which will be considered as an indirect detection of the gravitational waves that followed the Big Bang.
Nanovetenskap och nanoteknik , Fysik , Nanoscience & Nanotechnology , Physical Sciences