A glossary


AURIGA An acronym for the Italian expression: Antenna Ultracriogenica Risonante per l'Indagine Gravitazionale Astronomica (in English: Ultracryogenic Resonant Antenna for the Astronomical Gravitational Investigation).
CASE An acronym for: Computer Aided Software Engineering: a set of utilities/compilers/editors to manipulate a software source code at block-diagram level.
effective mass A mechanical resonator can be treated as a spring-mass system, around its resonance. The effective mass is the mass in the spring-mass system; generallu it is lower that the inertial mass of the  mechanical resonator.
FFT An acronym for: Fast Fourier Transform.An efficient implementation of the Fourier transform in the discrete time domain, with a logarithmic increase of the number of operations per each output sample.
finesse The finesse of a Fabry-Perot cavity is defined as the ratio between the cavity FSR and the cavity linewidth.
FSR An acronym for: Free Spectral Range. The FRS of a Fabry-Perot cavity is the frequency interval between two consecutive peaks of the same electromagnetic mode. If L is the length of the cavity and c the light speed, FSR=c/(2L).
GPS An acronym for: Global Positioning System. It is a method to determine geographical coordinates and local time coordinate on Earth using calibrating signals from a network of satellites. It is based on the knowledge of the orbits of the satellites and the measured phase shifts of their signals at the receiver. The precision of this measure is of ~100m in position and ~1Ás in time.
g.w. A short form for gravitational wave.
IGEC An acronym for: International Gravitational Event Collaboration.
INFN An acronym for the Italian expression: Istituto Nazionale di Fisica Nucleare (in English: National Institute for Nuclear Physics).
IRQ Interrupt Request: the name of an logic signal directed to a specific processor input port which causes the processor to suspend normal instruction execution temporarily and to start executing an interrupt handler routine. 
IVC An acronym for: Internal Vacuum Chamber. It is the vacuum chamber that houses the bar, the readout electronic and the inner thermal shields, inside the AURIGA cryostat.
LNL An acronym for the Italian expression: Laboratori Nazionali di Legnaro (in English: National Laboratories of Legnaro).
mixing chamber It is the last (coldest) stage of the dilution refrigerator where the phase transition of the mixtures 3He-4He occurs. This phenomenon allows the refrigeration 
MXI bus Multisystem eXtension Interface: it is a 8MB/s bus for connection of up to 8 digital devices and expansion boards.
OVC An acronym for: Outer Vacuum Chamber. It is the vacuum chamber that houses the outer aluminum thermal shields, inside the AURIGA cryostat. It provides for the isolation vacuum between the laboratory environment and  the liquid helium vessel.
RS323 port Standard serial communication port for workstations and PC's.
SQUID An acronym for: Superconducting QUantum Interference Device.
Shh Power spectral density of the total noise in terms of g.w. amplitude at the detector input
SNR An acronym for: Signal to Noise Ratio. It is the ratio of the maximum amplitude of a signal and the noise root mean square.
VXI bus The VXI (VME eXtension for Instrumentation) is an enhanced version of VME (Versa Module Eurocard) bus, and is made up of control and syncronization lines between digital boards (with TTL or ECL signals) that are capable of up to 100MB/s data transfer rate and IRQ generation and transmission with a time jitter of 100ns.

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