RESUMEN
GroundBIRD is a ground-based telescope for measuring the polarization of cosmic microwave background radiation, and it is soon to be operational at the Teide Observatory. The GroundBIRD telescope employs Mizuguchi-Dragone dual reflectors and 161 kinetic inductance detectors coupled with single polarization antennas as photon detectors. We present the results of our optical simulation on the pointing direction, stray light response, and influence of the blackbody radiation from the baffle. We also find that the power of the baffle radiation incident on the detectors is reduced by 99.95% when corrugated feed horns are coupled to the detectors.
RESUMEN
We present an efficient fluorescence detector in the visible region of the spectrum with a photon detection dynamic range over 10 (6) photons/s made of a temperature-stabilized Si-based multi-pixel photon counter at temperature down to 5 degrees C. We show that effective cooling of the device by means of a compact thermo-electric cooler brings several advantages, such as high gain, low dark noise rate, and thus high signal-to-noise ratio in the efficient fluorescence detection at 398.9 nm from the (1)S(0) ? (1)P(1) transition of the ytterbium atoms in an effusive atomic beam. We present also a comparison of the fluorescence detection efficiencies between the device and a side-on photo-multiplier tube with known gain positioned at the symmetric location from the ytterbium atomic beam.
