The Virgo status

We propose a modified configuration of an advanced gravitational-wave detector that is a speed meter type interferometer with improved sensitivity with respect to quantum noise. With the addition of polarization controlling components to the output of an arm cavity Michelson interferometer, an orthogonal polarization state of the interferometer can be used to store signal, returning it later with opposite phase to cancel position information below the storage bandwidth of the opposite mode. This modification provides an alternative to an external kilometer scale Fabry-Pérot cavity, as presented in earlier work of Purdue and Chen [P. Purdue and Y. Chen. PRD 66, 122004 (2002)]. The new configuration requires significantly less physical infrastructure to achieve speed meter operation. The quantity of length and alignment degrees of freedom is also reduced. We present theoretical calculations to show that such a speed meter detector is capable of beating the strain sensitivity imposed by the Standard Quantum Limit over a broad range of frequencies for Advanced LIGO-like parameters. The benefits and possible difficulties of implementing such a scheme are outlined. We also present results for tuning of the speed meter by adjusting the degree of polarization coupling, a novel possibility that does not exist in previously proposed designs, showing that there is a smooth transition from speed meter operation to that of a signal recycling Michelson behavior.

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“…LIGO), Virgo and KAGRA [1,9,10]. The configurations explored in this paper are proposed as third generation concepts for these instruments.…”

Section: Gravitational-wave (Gw) Detectors Such As Advanced Ligo Armentioning

confidence: 99%

“…(1). This interferometer configuration is based on the advanced topologies of LIGO, Virgo and KAGRA [1,9,10] but with the addition of a quarterwave plate and output coupling mirror as well as ancillary polarization readout optics. The advanced interferometer configuration (dashed box, Fig.…”

Section: Polarization Configuration Concept and The Mathematical mentioning

confidence: 99%

Polarization speed meter for gravitational-wave detection

et al. 2012

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“…There are currently 6 km scale laser-interferometric gravitational wave (GW) detectors operational in the world: three detectors as part of the LIGO project [1]; a Japanese detector, TAMA 300 [2]; a French-Italian detector, VIRGO [3]; and a British-German collaboration, GEO 600 [4]. Together they form an international network searching for GWs from a variety of sources.…”

Section: Introductionmentioning

confidence: 99%

Charge measurement and mitigation for the main test masses of the GEO 600 gravitational wave observatory

Hewitson

Danzmann

Grote

et al. 2007

Class. Quantum Grav.

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Spurious charging of the test masses in gravitational wave interferometers is a well-known problem. Typically, concern arises due to the possibility of increased thermal noise due to a lowering of the quality factor of modes of the test-mass suspension, or due to the potential for increased displacement noise arising from charge migration on the surface of the test masses. Recent experience gained at the GEO 600 gravitational wave detector has highlighted an additional problem. GEO 600 uses electrostatic actuators to control the longitudinal position of the main test masses. The presence of charge on the test masses is shown to strongly affect the performance of the electrostatic actuators. This paper reports on a measurement scheme whereby the charge state of the GEO 600 test masses can be measured using the electrostatic actuators. The resulting measurements are expressed in terms of an effective bias voltage on the electrostatic actuators. We also describe attempts to remove the charge from the test masses and we show that the use of UV illumination was the most successful. Using UV illumination we were able to discharge and re-charge the test masses.PACS numbers: 95.55.Ym, 04.80.Nn

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“…One of the most exciting classes of gravitational wave (GW) signatures that may be detected by the current array of ground-based laser interferometric GW detectors [1][2][3][4] is unmodelled transient (burst) signals arising from short-lived, violent astronomical events. The search for such signals typically focuses on time scales of the order of a few (or few tens of) milliseconds.…”

Section: Introductionmentioning

confidence: 99%

A statistical veto method employing an amplitude consistency check

Hild

Ajith

Hewitson

et al. 2007

Class. Quantum Grav.

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Statistical veto methods are commonly used to reduce the list of candidate gravitational wave (GW) events which are detected as transient (burst) signals in the main output of GW detectors. If a burst event in the GW channel is coincident with an event in a veto channel (where the veto channel does not contain any GW signal), it is possible to veto the event from the GW channel with a low 'false-veto' rate. Unfortunately, many promising veto channels are interferometer channels which can, at some level, contain traces of any detected GW signal. In this case, the application of a 'standard statistical veto' could have a high false-veto rate. We will present an extension to the standard statistical veto method that includes an 'amplitude consistency check'. This method allows the application of statistical vetoes derived from interferometer channels containing GW information with a low false-veto rate. By applying a statistical veto with an amplitude consistency check to data from the GEO 600 detector, veto efficiencies between 5 and 20%, together with a use-percentage of up to 80%, were obtained. The robustness of this veto method was also confirmed by hardware injections. The burst triggers were generated using the mHACR detection algorithm.

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The Virgo status

Cited by 205 publications

References 7 publications

Polarization speed meter for gravitational-wave detection

Polarization speed meter for gravitational-wave detection

Charge measurement and mitigation for the main test masses of the GEO 600 gravitational wave observatory

A statistical veto method employing an amplitude consistency check

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