Advanced VIRGO: detector optimization for gravitational waves by inspiralling binaries

For future configurations, we study the relation between the abatement of the noise sources and the Signal to Noise Ratio (SNR) for coalescing binaries. Our aim is not the proposition of a new design, but an indication of where in the bandwidth or for which noise source, a noise reduction would be most efficient. We take VIRGO as the reference for our considerations, solely applicable to the inspiralling phase of a coalescing binary. Thus, only neutron stars and small black holes of few solar masses are encompassed by our analysis. The contributions to the SNR given by final merge and quasi-normal ringing are neglected. It is identified that i) the reduction in the mirror thermal noise band provides the highest gain for the SNR, when the VIRGO bandwidth is divided according to the dominant noises; ii) it exists a specific frequency at which lies the potential largest increment in the SNR, and that the enlargement of the bandwidth, where the noise is reduced, produces a shift of such optimal frequency to higher values; iii) the abatement of the pendulum thermal noise provides the largest, but modest, gain, when noise sources are considered separately. Our recent astrophysical analysis on event rates for neutron stars leads to a detection rate of one every 148 or 125 years for VIRGO and LIGO, respectively, while a recently proposed and improved, but still conservative, VIRGO configuration would provide an increase to 1.5 events per year. Instead, a bi-monthly event rate, similar to advanced LIGO, requires a 16 times gain. We analyse the 3D (pendulum, mirror, shot noises) parameter space showing how such gain could be achieved.Comment: Change of title (Virgo detector optimization for gravitational waves by coalescing binaries) and partially of text. 6 figure

First results of the CUORICINO experiment

Preliminary results on double beta decay (DBD) of 130 Te, obtained in the first run of the CUORICINO experiment are presented. The set-up consists of an array of 62 crystals of TeO 2 operating as bolometers in a deep underground dilution unit at a temperature of about 10 mK. Due to a total mass of about 41 kg, CUORICINO represents by far the most massive running cryogenic mass to search for rare events. The achieved lower limit on the neutrinoless DBD is 5.5⋅10 23 years, that corresponds to a limit on the Majorana effective mass between 0.37 and 1.9 eV. Performances of the detectors together with the sensitivity estimation are discussed

Calibration of a coal thermometer to the range between \'0.3 DEGREES K\' and \'20 DEGREES K\'

Calibração de um termômetro de carvão para o intervalo entre \'0,3 GRAUS K\' e \'20 GRAUS K\'Calibration of a coal thermometer to the range between \'0.3 DEGREES K\' and \'20 DEGREES K\

Observation of an electronic singlet ground state in Au171 Yb

International audienc

THE EXCITON LUMINESCENSE UNDER EXCESS ELECTRON DRIFT THROUGH CONDENSED RARE GASES

$^{a}$E. B. Gordon, V. V. Khmelenko and O. S. Rzhevsky. Chem. Phys. Lett.217(5,6), 605, 1994. $^{b}$A. S. Schussler, J. Burghorn, P. Wyder, et al. Appl. Phys. Lett. 77(18),2786, 2000. $^{c}$E. B. Gordon, A. F. Shestakov. Low Temp. Phys. + 27(9/10), 883, 2001.Author Institution: Institute of Problems of Chemical Physics; Kamerlingh Onnes Lab, Leiden UniversityThe intensive VUV emission under excess electrons drift in high ($(10^{3} V/cm)$ electric fields through condensed heavy rare gas has been $predicted^{a}$ and recently $observed^{b}$. Our $analysis^{c}$ revealed the important role of $(Rg^{\ast})^{-}$ metastable negative ions formation on the electron's energy distribution function and confirmed the possibility to achieve high $(10^{2})$ yield of excitons (and VUV photons) per electron. Such avalanches development has been experimentally observed at 77K in three-electrodes cell, where the photocathode-grid gap, filled by Ar gas $(10^{17} cm^{-3})$, provided the multiplication of seed electrons number via ionization, the Xe crystal was grown between grid and anode, and the seed electrons were created by cathode irradiation by short laser (266 nm) pulse.The same design was used for the realization of effective and powerful UV emission generator in the regime of self-sustained discharge (without laser initiation)