Advanced Virgo is the project to upgrade the interferometric gravitational wave detector Virgo, and it foresees the implementation of power and signal non-degenerate recycling cavities. Such cavities ...suppress the build-up of high order modes of the resonating sidebands, with some advantage for the commissioning of the detector and the build-up of the gravitational signal. Here we present the baseline design of the Advanced Virgo non-degenerate recycling cavities, giving some preliminay results of simulations about the tolerances of this design to astigmatism, mirror figure errors and thermal lensing.
We propose a new implementation of a quantum speed meter QND measurement scheme. It employs two independent optical readouts of the interferometer test masses with different values of the bandwidths ...and of the optical circulating power, whose outputs have to be combined by an additional beamsplitter. Signals at the two outputs of the beamsplitter are proportional to the position and the velocity of the test masses, respectively. The influence of the position meter-like back action force associated with the position signal can be cancelled using the EPR approach by measuring the amplitude quadrature of the beamsplitter common output.
•This is an article for the Special Issue in memory of V.B. Braginsky.•We propose a novel and arguably the simplest scheme of a speed meter interferometer.•Speed meters curb quantum noise at low frequencies, boosting the SNR for GW sources.•Combination of readouts of two detectors with distinct bandwidths yields speed signal.•No significant changes of the current GWD infrastructure is necessary for our scheme.
The goals of this study were to determine the CDB-4022 dose-response relationship for induction of acute decreases in testicular
weight and germ cell depopulation in rats; establish the threshold ...dose of CDB-4022 required to induce infertility; and investigate
whether CDB-4022-induced testicular damage could be prevented by a GnRH agonist (Lupron Depot). Reduction of testis weight
and germ cell depopulation were observed 7 days after a single oral dose of 1 mg CDB-4022/kg, whereas 0.5 mg/kg had no observable
effect. These effects were maximal at 12.5 or 25 mg CDB-4022/kg. After a single oral dose of either 2.5 or 5 mg/kg, CDB-4022
induced infertility in five of five treated rats by Week 5, whereas only one of five males was rendered infertile at a dose
of 1 mg/kg. Proven fertile male rats (6/group) were treated with vehicle, CDB-4022 alone (2.5 mg/kg on Day 0), CDB-4022 plus
Lupron Depot (on Weeks â1, 2, 5, and 8), or Lupron Depot alone. Control males demonstrated normal fertility throughout a 32-wk
cohabitation period. Five of six rats were rendered transiently infertile with Lupron Depot alone, but all recovered fertility.
CDB-4022 treatment resulted in infertility in all six rats, and only one of six regained fertility. Combined treatment also
caused infertility in all six rats, but four of six recovered fertility ( P = 0.08 compared to CDB-4022 alone). Testicular weight was decreased in the three treatment groups compared to vehicle controls;
testicular weights were ranked from highest to lowest as follows: vehicle > Lupron Depot > Lupron Depot + CDB-4022 > CDB-4022.
The tubule differentiation index of Lupron Depot-treated rats (96 ± 4%) was not different from vehicle-treated rats (100%).
CDB-4022 treatment decreased the number of differentiating tubules (15 ± 8%). Lupron Depot plus CDB-4022 treatment resulted
in a greater number of differentiating tubules (53 ± 12%) than CDB-4022 alone, but this was still lower than vehicle- or Lupron
Depot-treated rats. These data indicate that 2.5 mg/kg of CDB-4022 was the oral threshold dose that caused testicular damage
rendering the majority of adult male rats permanently infertile within the study interval; 12.5 mg/kg of CDB-4022 induced
maximal testicular damage. Suppression of gonadotropins and/or testosterone production by treatment with Lupron Depot before
and after CDB-4022 prevented the CDB-4022-induced irreversible testicular damage.
The detection of gravitational waves from compact binary mergers by LIGO has opened the era of gravitational wave astronomy, revealing a previously hidden side of the cosmos. To maximize the reach of ...the existing LIGO observatory facilities, we have designed a new instrument able to detect gravitational waves at distances 5 times further away than possible with Advanced LIGO, or at greater than 100 times the event rate. Observations with this new instrument will make possible dramatic steps toward understanding the physics of the nearby Universe, as well as observing the Universe out to cosmological distances by the detection of binary black hole coalescences. This article presents the instrument design and a quantitative analysis of the anticipated noise floor.
Gravitational wave detectors of the advanced generation are expected to be limited in sensitivity by thermal noise of the optics. The reduction of this noise is therefore of high importance for ...future detectors which aim to surpass the sensitivity of the advanced generation. A proposed method for reducing the impact of this noise is to use higher-order Laguerre-Gauss (LG) modes for the readout beam, as opposed to the currently used fundamental mode. We present here a synopsis of the research program undertaken by the University of Birmingham into the suitability of LG mode technology for future gravitational wave detectors. This will cover our previous and current work on this topic, from initial simulations and table-top LG mode experiments up to implementation in a prototype scale suspended cavity and high-power laser bench.
The optical layout of the interferometric gravitational wave detector GEO600 is described in detail. Criteria for the choice of the geometry of this power- and signal recycled interferometer are ...presented, including the beam shape inside the interferometer and the surface figure of the optical components. Light power limits for the present setup are discussed. In addition, the demands for the mode cleaners and their performance are given.
The scanning force microscope (SFM) was used to investigate the temperature dependent micro mechanical properties of polymethylmethacrylate (PMMA) films with a thickness of 35 nm in the range of the ...radius of gyration. Force–distance curves were performed in the glass transition range to create permanent nanometric indentations with maximal forces up to 4 μN. Quantitative measurements of the indentation depth during and after application of the force, hysteresis energy and slope of the loading part are carried out as function of sample temperature and applied force. The glass transition of the polymer film can be clearly identified by the change of the mechanical properties of the polymer. Surprisingly, only a small change of elasticity at the glass transition is observed.
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