eLISA is a space mission designed to measure gravitational radiation over a frequency range of 0.1-100 mHz (European Space Agency LISA Assessment Study Report 2011). It uses laser interferometry to ...measure changes of order in the separation of inertial test masses housed in spacecraft separated by 1 million km. LISA Pathfinder (LPF) is a technology demonstrator mission that will test the key eLISA technologies of inertial test masses monitored by laser interferometry in a drag-free spacecraft. The optical bench that provides the interferometry for LPF must meet a number of stringent requirements: the optical path must be stable at the few level; it must direct the optical beams onto the inertial masses with an accuracy of better than ±25 μm, and it must be robust enough not only to survive launch vibrations but to achieve full performance after launch. In this paper we describe the construction and testing of the flight optical bench for LISA Pathfinder that meets all the design requirements.
The LISA Pathfinder mission Antonucci, F; Armano, M; Audley, H ...
Classical and quantum gravity,
06/2012, Letnik:
29, Številka:
12
Journal Article, Conference Proceeding
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In this paper, we describe the current status of the LISA Pathfinder mission, a precursor mission aimed at demonstrating key technologies for future space-based gravitational wave detectors, like ...LISA. Since much of the flight hardware has already been constructed and tested, we will show that performance measurements and analysis of these flight components lead to an expected performance of the LISA Pathfinder which is a significant improvement over the mission requirements, and which actually reaches the LISA requirements over the entire LISA Pathfinder measurement band.
The Laser Interferometer Space Antenna (LISA) is a joint ESA NASA mission to be launched in 2018. It is an interferometric gravitational wave detector with a measurement band going from 0.1 mHz to 1 ...Hz. The conceptual interferometer design is unique and includes many challenging aspects that must be analysed in terms of their stability in advance to the mission. One of these new features is the so-called back-side fibre link, which connects the two optical benches on-board each spacecraft. In its optical fibre, two frequency shifted laser beams are counter-propagating. LISA will only reach its design sensitivity, if these two beams inside this fibre experience the same pathlength changes down to a level of approximately 1 pm/ in the mHz range. In this paper, we present the construction of a quasi-monolithic interferometer that represents a cutout of the LISA interferometry concerning the back-side fibre link. In order to ensure a high thermal and mechanical stability of the interferometer, the hydroxide-catalysis bonding technique was applied. For the construction of the interferometer, a number of new alignment techniques and solutions were developed that are suitable for LISA prototype experiments.
Hydroxide catalysis bonding of silicon carbide van Veggel, A.A.; van den Ende, D.; Bogenstahl, J. ...
Journal of the European Ceramic Society,
2008, 2008-1-00, 20080101, Letnik:
28, Številka:
1
Journal Article
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For bonding silicon carbide optics, which require extreme stability, hydroxide catalysis bonding is considered Rowan, S., Hough, J. and Elliffe, E.,
Silicon carbide bonding. UK Patent 040
7953.9, ...2004. Please contact Mr. D. Whiteford for further information:
D.Whiteford@admin.gla.ac.uk. This technique is already used for bonding silicate-based materials, like fused silica and Zerodur. In application with silicon carbide, the technique is highly experimental and the aim is to test the strength of the bond with silicon carbide. The silicon carbide is polished to
λ/10 PV flatness and then oxidized at 1100
°C in a wet environment prior to bonding to form a necessary layer of SiO
2 on the surface. The bonding is performed in clean room conditions. After bonding the pieces are sawed into bars to determine the strength in a four-point bending experiment. The oxidization process shows many different color changes indicating thickness variations and contamination of the oxidization process. The bonding has been performed with success. However, these bonds are not resistant against aqueous cooling fluids, which are used during sawing. Several bars have survived the sawing and a maximum strength of 30
N
mm
−2 has been measured.
LISA, the Laser Interferometer Space Antenna, is a proposed ESA/NASA space based gravitational wave detector. In order to help meet the many technological challenges of LISA, the ESA precursor ...mission LISA Pathfinder (LPF) will test some of the key enabling technologies for LISA. LPF however will only go so far, and much work is needed to take LPF technology to a state suitable for LISA. One such area is the use of polarising Mach-Zehnder interferometers. We report on the design and initial construction of an experiment to test the use of such interferometric techniques, as well as suitable component mounting mechanisms.
We analyzed the available LIGO data coincident with GRB 070201, a short- duration, hard-spectrum -ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral arms ...of the Andromeda galaxy (M31). Possible progenitors of such short, hard GRBs include mergers of neutron stars or a neutron star and a black hole, or soft -ray repeater (SGR) flares. These events can be accompanied by gravitational-wave emission. No plausible gravitational-wave candidates were found within a 180 s long window around the time of GRB 070201. This result implies that a compact binary progenitor of GRB 070201, with masses in the range image and image, located in M31 is excluded at >99% confidence. If the GRB 070201 progenitor was not in M31, then we can exclude a binary neutron star merger progenitor with distance image Mpc, assuming random inclination, at 90% confidence. The result also implies that an unmodeled gravitational-wave burst from GRB 070201 most probably emitted less than image (image ergs) in any 100 ms long period within the signal region if the source was in M31 and radiated isotropically at the same frequency as LIGO's peak sensitivity (image Hz). This upper limit does not exclude current models of SGRs at the M31 distance.
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