Abstract
We show that the energy threshold for nuclear recoils in the XENON10 dark matter search data can be lowered to ~ 1 keV, by using only the ionization signal. In other words, we make no requirement that a valid event contain a primary scintillation signal. We therefore relinquish incident particle type discrimination, which is based on the ratio of ionization to scintillation in liquid xenon. This method compromises the detector's ability to precisely determine the z coordinate of a particle interaction. However, we show for the first time that it is possible to discriminate bulk events from surface events based solely on the ionization signal. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.

Abstract
The extraction efficiency f for the photoelectrons emitted from a CsI photocathode into gaseous Xe-CH4 and Ne-CH4 mixtures is investigated by Monte Carlo simulation. The results are compared with earlier calculations in Ar-CH4 mixtures and in the pure gases Xe, Ar, Ne and CH4. The calculations examine the dependence of f on the density-reduced electric field E/N in the 0.1-40 Td range, on the incident photon energy E-ph in the 6.8-9.8 eV (183-127 nm) VUV range and on the mixture composition. Results calculated for irradiation of the photocathode with a Hg(Ar) lamp are compared with experimental measurements for this lamp. To test the electron scattering cross-sections used in the simulations, electron drift parameters in Xe, Ne and their mixtures with CH4 are also presented and compared with available experimental data.

Abstract
We present optical sensors based on slotted multimode interference waveguides. The sensor can be tuned to highest sensitivity in the refractive index ranges necessary to detect protein-based molecules or other water-soluble chemical or biological materials. The material of choice is low-loss silicon oxynitride (SiON) which is highly stable to the reactivity with biological agents and processing chemicals. Sensors made with this technology are suited to high volume manufacturing. Copyright © 2009 M. Mayeh et al.

Abstract

Abstract

Abstract
A novel self-referencing parameter for electro-optical WDM networks in reflective configuration for remote fiber-optic intensity sensors is reported and experimentally tested. In this configuration electrical delay lines are deployed at the processing unit, instead of long delay fiber coils in each measuring point; providing a more compact sensor-head and an easy-reconfigurable operation point. The measurement parameter is defined as the ratio between voltage values at the reception stage for different electrical phase-shifts and it is analyzed following the Z-transform formalism. Measurements validating the theoretical model are reported and self-referencing and crosstalk properties of the network are analyzed. © 2009 SPIE.