[en] The first adaptive optics system for laser beam geometrical fluctuations correction, based on interferometric detection of aberrations, is presented. The bandwidth of the resulting feed-back is of several hundreds Hz and the residual fluctuations, measured on the error signal, are better than what can be obtained by typical Shack-Hartmann technique, encouraging for use in long baseline interferometers for GW detection

[en] In this paper, we analyse the application of an optical readout system to the gravitational reference sensor of LISA. The goal is not the replacement of the capacitive sensor with an optical one, but the integration of the optical sensor in the present design of LISA. The main motivation is the implementation of a back-up solution, so that there is a significant risk reduction for the mission in case the main sensor fails for some reason. Furthermore, an optical system is potentially more sensitive than the capacitive one for some degrees of freedom. In this paper, we report some preliminary experimental results on the sensitivity of the sensor and describe a possible set-up for the implementation according to the present design of the gravitational reference sensor

[en] The user interface is a crucial service to guarantee the Grid accessibility. The goal to achieve, is the implementation of an environment able to hide the grid complexity and offer a familiar interface to the final user. Currently many graphical interfaces have been proposed to simplify the grid access, but the GUI approach appears not very congenital to UNIX developers and users accustomed to work with command line interface. In 2004 the GridShell project proposed an extension of popular UNIX shells such as TCSH and BASH with features supporting Grid computing. Starting from the ideas included in GridShell, we propose IGSH (INFN-GRID SHELL) a new login shell for the INFN-GRID middleware, that interact with the Resource Broker services and integrates in a 'naturally way' the grid functionality with a familiar interface. The architecture of IGSH is very simple, it consist of a software layer on the top of the INFN-GRID middleware layer. When some operation is performed by the user, IGSH takes in charge to parse the syntax and translate it in the correspondents INFN-GRID commands according to some semantic rules specified in the next sections. The final user interacts with the underlying distributed infrastructure by using IGSH instead of his default login shell, with the sensation to work on a local machine.

[en] We present an optical readout system for the LISA gravitational reference sensor. Some estimations of the most relevant sources of noise are given showing that the required sensitivity can be reached with such a type of detector. Preliminary results with a bench-top experiment are also reported; a sensitivity of 10^-8 m Hz^-1/2 at 1 mHz and better than the specification of 10^-9 m Hz^-1/2 above 10 mHz has been measured. The sensitivity is probably limited, at low frequency, by drifts in the experimental set-up. A more compact and stable set-up is presently under design that should allow the demonstration of the required sensitivity down to 1 mHz

[en] A numerical procedure for noise recognition and uncoupling is described. The procedure is applied to a Michelson interferometer and is effective in seismic and acoustic noise uncoupling from the output signal of the interferometer. Due to the low data flow coming from the instrumentation this uncoupling can be performed in real time and it is useful as a data quality procedure for interferometer data output

[en] We present the results of an adaptive optics prototype system used to test the feasibility of active control for corrections of geometrical fluctuations of a gravitational wave interferometer's input laser beam. It is shown that the efficiency of the system in correcting fluctuations extends up to 80 Hz unity gain frequency and that the upper limit of reintroduced noise is within the Virgo interferometer requirements

[en] We present an adaptive optics (AO) system for the control of geometrical fluctuations in a laser beam based on the interferometric detection of phase front. By comparison with the usual Shack-Hartman-based AO system, we show that this technique is of particular interest when high sensitivity and high band-pass are required for correction of small perturbations such as, for instance, the control of the input beam of gravitational waves interferometric detectors

[en] Archimedes is an INFN-funded pathfinder experiment aimed at verifying the feasibility of measuring the interaction of vacuum fluctuations with gravity. The final experiment will measure the force exerted by the gravitational field on a Casimir cavity whose vacuum energy is modulated with a superconductive transition, by using a balance as a small force detector. Archimedes is two-year project devoted to test the most critical experimental aspects, in particular the balance resonance frequency and quality factor, the thermal modulation efficiency and the superconductive sample realization. - Highlights: • Weight of the vacuum. • Superconductive stacks studies. • Thermal behavior studies at cryogenic temperatures.

[en] An RPC carpet covering ∼ 10⁴ m² (ARGO-YBJ experiment) will be installed in the YangBaJing Laboratory (Tibet, P.R. China) at an altitude of 4300 m a.s.l.. A test-module of ∼ 50 m² has been put in operation in this laboratory and about 10⁶ air shower events have been collected. The carpet capability of reconstructing the shower features is presented

[en] The use of non-Gaussian flat laser beams is currently under study to reduce the thermoelastic noise in the advanced gravitational wave interferometers. In this work we present a system based on two deformable mirrors to transform a Gaussian beam in a non-Gaussian flat beam. We use an approximated representation of flat beam based on the usual Hermite-Gaussian modes which is particularly useful when the flat beam is generated by using deformable mirrors. This system can be used either for flat beams generation or for beam matching in the mexican-hat mirrors Fabry-Perot cavities proposed for next generation of gravitational wave interferometers