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Magnet Photo

Bolometers and the Big Bang Detector Arrays for Next-Generation CMB Experiments

Abstract: Measurements of the Cosmic Microwave Background have provided key cosmological data. Future experiments, however, require orders of magnitude increased sensitivity. After a brief survey of the physics goals and measurement techniques, I will describe monolithically integrated bolometer arrays and a readout system for both temperature anisotropy and polarization experiments. Superconducting transition edge sensors feed SQUID amplifiers through a novel frequency-domain multiplexing network, which reduces the number of wires and thus heat leaks to the 0.25K bolometer cold stage, while achieving the theoretically predicted noise. The talk will illustrate some of the crucial details that lurk behind a deceptively simple concept.
Speaker: Helmuth Spieler - Lawrence Berkeley National Laboratory
Speaker Bio: American born and educated in Germany, Helmuth Spieler returned to the US in 1982 as a staff scientist at LBNL where he is a leading expert in the development of semiconductor detectors, readout electronics and signal-processing techniques. His recent book, Semiconductor Detector Systems, has become an instant classic in the field and he is much sought after as a reviewer and lecturer on both detector technologies and readout electronics. Helmuth currently leads an effort to develop new instrumentation for measuring the cosmic microwave background (CMB), for which significant advances are required to achieve the sensitivity necessary for the next generation of experiments.
Poster Link: Poster
Presentation: Presentation on 1/10/2007 (PDF)