Showing papers by "Sae Woo Nam published in 1997"
TL;DR: In this paper, the authors present an experiment to search for WIMPs in the galactic halo using terrestrial detectors based on cooled germanium and silicon detectors in a shielded low-background cryostat.
Abstract: We are conducting an experiment to search for WIMPs, or weakly-interacting massive particles, in the galactic halo using terrestrial detectors. This generic class of hypothetical particles, whose properties are similar to those predicted by extensions of the standard model of particle physics, could comprise the cold component of non-baryonic dark matter. We describe our experiment, which is based on cooled germanium and silicon detectors in a shielded low-background cryostat. The detectors achieve a high degree of background rejection through the simultaneous measurement of the energy in phonons and ionization. Using exposures on the order of one kilogram-day from initial runs of our experiment, we have achieved (preliminary) upper limits on the WIMP-nucleon cross section that are comparable to much longer runs of other experiments.
6 citations
01 Jan 1997
TL;DR: In this article, a quasiparticle-trap assisted Electrothermal feedback Transition Edge Sensor (QET) was proposed for a high-bandwidth SQUID readout.
Abstract: We have demonstrated a new type of phonon sensor for cryogenic particle detectors with a high-bandwidth SQUID readout. Our Quasiparticle-trap assisted Electrothermal feedback Transition edge sensor (QET) utilizes aluminum quasiparticle traps attached to a tungsten superconducting transition edge sensor patterned on a silicon substrate. The tungsten lines are voltage biased and self-regulate in the transition region. Phonons from particle interactions in the silicon deposit energy into the aluminum fins by creating quasiparticles. The quasiparticles are trapped into the tungsten and cause its electrical resistance to increase. The resulting decrease in current through the sensor is measured with a DC SQUID array. We have been abIe to demonstrate xy- position resolution of -0.3 mm for 6 keV X-rays from an 55Fe source in a 2 cm x 2 cm x 4 mm (4g) detector. We dcscribe our optimizations of the sensor design for improved energy and position resolution. By simultaneously measuring the ionization yield we have d emonstrated discrimination between electron and nuclear recoil events in a l0Og Si detector for the CDMS (Cryogenic Dark Matter Search) experiment.
TL;DR: In this article, a quasiparticle-trap assisted Electrothermal feedback Transition Edge Sensor (QET) was proposed for the detection of particle interactions in the silicon substrate.
Abstract: We have demonstrated a new type of phonon sensor for cryogenic particle detectors with high-bandwidth SQUID readout. Our Quasiparticle-trap assisted Electrothermal feedback Transition edge sensor (QET) utilizes aluminum quasiparticle traps attached to a tungsten superconducting transition edge sensor patterned on a silicon substrate. The tungsten lines are voltage biased and self-regulate in the transition region. Phonons from particle interactions in the silicon deposit energy into the creating quasiparticles. The quasiparticles are trapped into the tungsten and cause its electrical resistance to increase. The resulting decrease in current through the sensor is measured with a DC SQUID array. We have been able to demonstrate xy-position resolution of /spl sim/0.3 mm for 6 keV X-rays from an /sup 55/Fe source in a 2 cm/spl times/2 cm/spl times/4 mm (4 g) detector. We describe our optimizations of the sensor design for improved energy and position. By simultaneously measuring the ionization yield we have demonstrated discrimination between electron and nuclear recoil events in a 100 g Si detector for the CDMS (Cryogenic Dark Matter Search) experiment.