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Search Results: 1 - 10 of 191346 matches for " D. Heinert "
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Potential mechanical loss mechanisms in bulk materials for future gravitational wave detectors
D Heinert,A Grib,K Haughian,J Hough,S Kroker,P Murray,R Nawrodt,S Rowan,C Schwarz,P Seidel,A Tünnermann
Physics , 2010, DOI: 10.1088/1742-6596/228/1/012032
Abstract: Low mechanical loss materials are needed to further decrease thermal noise in upcoming gravitational wave detectors. We present an analysis of the contribution of Akhieser and thermoelastic damping on the experimental results of resonant mechanical loss measurements. The combination of both processes allows the fit of the experimental data of quartz in the low temperature region (10 K to 25 K). A fully anisotropic numerical calculation over a wide temperature range (10 K to 300 K) reveals, that thermoelastic damping is not a dominant noise source in bulk silicon samples. The anisotropic numerical calculation is sucessfully applied to the estimate of thermoelastic noise of an advanced LIGO sized silicon test mass.
Comparison between specific and multiplex reverse transcription-polymerase chain reaction for detection of hepatitis A virus, poliovirus and rotavirus in experimentally seeded oysters
Coelho C,Vinatea CEB,Heinert AP,Sim？es CMO
Memórias do Instituto Oswaldo Cruz , 2003,
Abstract: Outbreaks of gastroenteritis have occurred among consumers of raw or undercooked shellfish harvested from faecally polluted waters. A multiplex reverse transcription-polymerase chain reaction (RT-PCR) was applied for the simultaneous detection of hepatitis A virus (HAV), poliovirus (PV) and simian rotavirus (RV-SA11) and compared with specific primers for each genome sequence. Three amplified DNA products representing HAV (192 bp), PV (394 bp) and RV (278 bp) were identified when positive controls were used. However, when tested on experimentally contaminated raw oysters, this method was not able to detect the three viruses simultaneously. This is probably due to the low concentration of viral RNAs present in oyster extract which were partially lost during the extracts preparation.
Investigation of mechanical losses of thin silicon flexures at low temperatures
R. Nawrodt,C. Schwarz,S. Kroker,I. W. Martin,F. Brückner,L. Cunningham,V. Gro？e,A. Grib,D. Heinert,J. Hough,T. K？sebier,E. B. Kley,R. Neubert,S. Reid,S. Rowan,P. Seidel,M. Thürk,A. Tünnermann
Physics , 2010, DOI: 10.1088/0264-9381/30/11/115008
Abstract: The investigation of the mechanical loss of different silicon flexures in a temperature region from 5 to 300 K is presented. The flexures have been prepared by different fabrication techniques. A lowest mechanical loss of $3\times10^{-8}$ was observed for a 130 $\mu$m thick flexure at around 10 K. While the mechanical loss follows the thermoelastic predictions down to 50 K a difference can be observed at lower temperatures for different surface treatments. This surface loss will be limiting for all applications using silicon based oscillators at low temperatures. The extraction of a surface loss parameter using different results from our measurements and other references is presented. We focused on structures that are relevant for gravitational wave detectors. The surface loss parameter $\alpha_s$ = 0.5 pm was obtained. This reveals that the surface loss of silicon is significantly lower than the surface loss of fused silica.
Comparison between specific and multiplex reverse transcription-polymerase chain reaction for detection of hepatitis A virus, poliovirus and rotavirus in experimentally seeded oysters
Coelho, C;Vinatea, CEB;Heinert, AP;Sim？es, CMO;Barardi, CRM;
Memórias do Instituto Oswaldo Cruz , 2003, DOI: 10.1590/S0074-02762003000400006
Abstract: outbreaks of gastroenteritis have occurred among consumers of raw or undercooked shellfish harvested from faecally polluted waters. a multiplex reverse transcription-polymerase chain reaction (rt-pcr) was applied for the simultaneous detection of hepatitis a virus (hav), poliovirus (pv) and simian rotavirus (rv-sa11) and compared with specific primers for each genome sequence. three amplified dna products representing hav (192 bp), pv (394 bp) and rv (278 bp) were identified when positive controls were used. however, when tested on experimentally contaminated raw oysters, this method was not able to detect the three viruses simultaneously. this is probably due to the low concentration of viral rnas present in oyster extract which were partially lost during the extracts preparation.
Birefringence Measurements on Crystalline Silicon
Christoph Krüger,Daniel Heinert,Alexander Khalaidovski,Jessica Steinlechner,Ronny Nawrodt,Roman Schnabel,Harald Lück
Physics , 2015, DOI: 10.1088/0264-9381/33/1/015012
Abstract: Crystalline silicon has been proposed as a new test mass material in third generation gravitational wave detectors such as the Einstein Telescope (ET). Birefringence can reduce the interferometric contrast and can produce dynamical disturbances in interferometers. In this work we use the method of polarisation-dependent resonance frequency analysis of Fabry-Perot-cavities containing silicon as a birefringent medium. Our measurements show a birefringence of silicon along the (111) axis of the order of $\Delta\, n \approx 10^{-7}$ at a laser wavelength of 1550nm and room temperature. A model is presented that explains the results of different settings of our measurements as a superposition of elastic strains caused by external stresses in the sample and plastic strains possibly generated during the production process. An application of our theory on the proposed ET test mass geometry suggests no critical effect on birefringence due to elastic strains.
Reduction of coating thermal noise by using an etalon
Kentaro Somiya,Daniel Heinert,Alexey G. Gurkovsky,Stefan Hild,Ronny Nawrodt,Sergey P. Vyatchanin
Physics , 2011, DOI: 10.1016/j.physleta.2011.02.009
Abstract: Reduction of coating thermal noise is a key issue in precise measurements with an optical interferometer. A good example of such a measurement device is a gravitational-wave detector, where each mirror is coated by a few tens of quarter-wavelength dielectric layers to achieve high reflectivity while the thermal-noise level increases with the number of layers. One way to realize the reduction of coating thermal noise, recently proposed by Khalili, is the mechanical separation of the first few layers from the rest so that a major part of the fluctuations contributes only little to the phase shift of the reflected light. Using an etalon, a Fabry-Perot optical resonator of a monolithic cavity, with a few coating layers on the front and significantly more on the back surface is a way to realize such a system without too much complexity, and in this paper we perform a thermal-noise analysis of an etalon using the Fluctuation-dissipation theorem with probes on both sides of a finite-size cylindrical mirror.
High-sensitivity tool for studying phonon related mechanical losses in low loss materials
Daniel Heinert,Anja Zimmer,Ronny Nawrodt,Torsten Koettig,Christian Schwarz,Matthias Hudl,Wolfgang Vodel,Andreas Tünnermann,Paul Seidel
Physics , 2007, DOI: 10.1088/1742-6596/92/1/012183
Abstract: Fundamental mechanical loss mechanisms exist even in very pure materials, for instance, due to the interactions of excited acoustic waves with thermal phonons. A reduction of these losses in a certain frequency range is desired in high precision instruments like gravitational wave detectors. Systematic analyses of the mechanical losses in those low loss materials are essential for this aim, performed in a highly sensitive experimental set-up. Our novel method of mechanical spectroscopy, cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectroscopy), is well suited to systematically determine losses at the resonant frequencies of the samples of less than 10^(-9) in the wide temperature range from 5 to 300 K. A high precision set-up in a specially built cryostat allows contactless excitation and readout of the oscillations of the sample. The experimental set-up and measuring procedure are described. Limitations to our experiment due to external loss mechanisms are analysed. The influence of the suspension system as well as the sample preparation is explained.
Mechanical losses in low loss materials studied by Cryogenic Resonant Acoustic spectroscopy of bulk materials (CRA spectroscopy)
Anja Zimmer,Ronny Nawrodt,Daniel Heinert,Christian Schwarz,Matthias Hudl,Torsten Koettig,Wolfgang Vodel,Andreas Tünnermann,Paul Seidel
Physics , 2007, DOI: 10.1088/1742-6596/92/1/012095
Abstract: Mechanical losses of crystalline silicon and calcium fluoride have been analyzed in the temperature range from 5 to 300 K by our novel mechanical spectroscopy method, cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectrocopy). The focus lies on the interpretation of the measured data according to phonon-phonon interactions and defect induced losses in consideration of the excited mode shape.
Calculation of thermal noise in grating reflectors
Daniel Heinert,Stefanie Kroker,Daniel Friedrich,Stefan Hild,Ernst-Bernhard Kley,Sean Leavey,Iain W. Martin,Ronny Nawrodt,Andreas Tünnermann,Sergey P. Vyatchanin,Kazuhiro Yamamoto
Physics , 2013, DOI: 10.1103/PhysRevD.88.042001
Abstract: Grating reflectors have been repeatedly discussed to improve the noise performance of metrological applications due to the reduction or absence of any coating material. So far, however, no quantitative estimate on the thermal noise of these reflective structures exists. In this work we present a theoretical calculation of a grating reflector's noise. We further apply it to a proposed 3rd generation gravitational wave detector. Depending on the grating geometry, the grating material and the temperature we obtain a thermal noise decrease by up to a factor of ten compared to conventional dielectric mirrors. Thus the use of grating reflectors can substantially improve the noise performance in metrological applications.
Scientific Objectives of Einstein Telescope
B. Sathyaprakash,M. Abernathy,F. Acernese,P. Ajith,B. Allen,P. Amaro-Seoane,N. Andersson,S. Aoudia,K. Arun,P. Astone,B. Krishnan,L. Barack,F. Barone,B. Barr,M. Barsuglia,M. Bassan,R. Bassiri,M. Beker,N. Beveridge,M. Bizouard,C. Bond,S. Bose,L. Bosi,S. Braccini,C. Bradaschia,M. Britzger,F. Brueckner,T. Bulik,H. J. Bulten,O. Burmeister,E. Calloni,P. Campsie,L. Carbone,G. Cella,E. Chalkley,E. Chassande-Mottin,S. Chelkowski,A. Chincarini,A. Di. Cintio,J. Clark,E. Coccia,C. N. Colacino,J. Colas,A. Colla,A. Corsi,A. Cumming,L. Cunningham,E. Cuoco,S. Danilishin,K. Danzmann,E. Daw,R. De. Salvo,W. Del. Pozzo,T. Dent,R. De. Rosa,L. Di. Fiore,M. Di. Paolo. Emilio,A. Di. Virgilio,A. Dietz,M. Doets,J. Dueck,M. Edwards,V. Fafone,S. Fairhurst,P. Falferi,M. Favata,V. Ferrari,F. Ferrini,F. Fidecaro,R. Flaminio,J. Franc,F. Frasconi,A. Freise,D. Friedrich,P. Fulda,J. Gair,M. Galimberti,G. Gemme,E. Genin,A. Gennai,A. Giazotto,K. Glampedakis,S. Gossan,R. Gouaty,C. Graef,W. Graham,M. Granata,H. Grote,G. Guidi,J. Hallam,G. Hammond,M. Hannam,J. Harms,K. Haughian,I. Hawke,D. Heinert,M. Hendry,I. Heng,E. Hennes,S. Hild,J. Hough,D. Huet,S. Husa,S. Huttner,B. Iyer,D. I. Jones,G. Jones,I. Kamaretsos,C. Kant Mishra,F. Kawazoe,F. Khalili,B. Kley,K. Kokeyama,K. Kokkotas,S. Kroker,R. Kumar,K. Kuroda,B. Lagrange,N. Lastzka,T. G. F. Li,M. Lorenzini,G. Losurdo,H. Lück,E. Majorana,V. Malvezzi,I. Mandel,V. Mandic,S. Marka,F. Marin,F. Marion,J. Marque,I. Martin,D. Mc. Leod,D. Mckechan,M. Mehmet,C. Michel
Physics , 2012, DOI: 10.1088/0264-9381/29/12/124013
Abstract: The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.
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