Abstract
Experimental measurements of the extraction efficiency f of the UV-induced photoelectrons emitted from a CsI photocathode into gas mixtures of Ne with CH4, CF4, CO2 and N-2 are presented; they are compared with model-simulation results. Backscattering of low-energy photoelectrons emitted into noble gas is significantly reduced by the admixture of molecular gases, with direct impact on the effective quantum efficiency. Data are provided on the dependence of f on the type and concentration of the molecular gas in the mixtures and on the electric field.

Abstract
XENON10 is an experiment designed to directly detect particle dark matter. It is a dual phase (liquid/gas) xenon time-projection chamber with 3D position imaging. Particle interactions generate a primary scintillation signal (S1) and ionization signal (S2), which are both functions of the deposited recoil energy and the incident particle type. We present a new precision measurement of the relative scintillation yield L(eff) and the absolute ionization yield 2, for nuclear recoils in xenon. A dark matter particle is expected to deposit energy by scattering from a xenon nucleus. Knowledge of L(eff) is therefore crucial for establishing the energy threshold of the experiment; this in turn determines the sensitivity to particle dark matter. Our L(eff) measurement is in agreement with recent theoretical predictions above 15 keV nuclear recoil energy, and the energy threshold of the measurement is similar to 4 keV. A knowledge of the ionization yield 2(y) is necessary to establish the trigger threshold of the experiment. The ionization yield 2(y) is measured in two ways, both in agreement with previous measurements and with a factor of 10 lower energy threshold.

Abstract
The transmission efficiency of photoelectrons emitted from CsI photocathodes operated in Ar-CH4 and Xe-CH4 mixtures is experimentally investigated and compared to Monte Carlo simulation results: the ratio between the number of photoelectrons collected in the gas media and in vacuum is determined as a function of the pressure-reduced electric field E/p at the photocathode surface, for irradiation with the VUV photons from an Hg(Ar) lamp. The addition of a small percentage of CH4 to At and Xe results in a significant increase of the photoelectron transmission, in particular for electric fields below E/p similar to 1 V cm(-1) Torr(-1). Below E/p similar to 0.5 V cm(-1) Torr(-1) the transmission efficiency f in Ar-CH4 Mixtures reaches values higher than in pure CH4, going through a maximum in the range of 10-30% CH4. The addition of 5% and 20% CH4 to Xe increases f by a factor of about 2 and 3, respectively, when compared to pure Xe.

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Abstract
The study of the strain and temperature characteristics of a sensing head based on a four-hole suspended-core fibre in a Sagnac interferometric configuration is reported. It is shown that, for the case of using an uncoated suspended-core fibre, a relatively large strain sensitivity is obtained (similar or equal to 1.94 pm/mu epsilon), while the temperature sensitivity is small (similar or equal to 0.29 pm/degrees C), pointing to a temperature-independent strain sensor. When the fibre is coated, the strain sensitivity remains essentially the same, while the temperature sensitivity becomes much larger and with a value that changes with the localisation of the temperature variation range.