Th. Bauer
Utrecht University
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Publication
Featured researches published by Th. Bauer.
Journal of Instrumentation | 2014
R. Arink; A. Pellegrino; S. Bachmann; R. Schwemmer; R. F. Koopman; J. Rovekamp; M. Szczekowski; D. van Eijk; M. Deckenhoff; D. Wiedner; Ch. Linn; A. Bien; T. M. Karbach; F. Schimmel; S. Swientek; J. Spelt; H. Schuylenburg; L. Grillo; W. Hulsbergen; Z. Deng; B. Spaan; M. Nedos; E. Gersabeck; J. Blouw; G. Polok; J. Michalowski; Y. Bagaturia; N. Serra; P. Seyfert; O. van Petten
The LHCb Outer Tracker is a gaseous detector covering an area of 5 x 6 m(2) with 12 double layers of straw tubes. The detector with its services are described together with the commissioning and calibration procedures. Based on data of the first LHC running period from 2010 to 2012, the performance of the readout electronics and the single hit resolution and efficiency are presented. The efficiency to detect a hit in the central half of the straw is estimated to be 99.2%, and the position resolution is determined to be approximately 200 mu m. The Outer Tracker received a dose in the hottest region corresponding to 0.12 C/cm, and no signs of gain deterioration or other ageing effects are observed.
Astronomy and Astrophysics | 2012
J. Abadie; B. Abbott; R. Abbott; T. D. Abbott; M. Abernathy; T. Accadia; F. Acernese; C. Adams; R. Adhikari; C. Affeldt; M. Agathos; P. Ajith; B. Allen; G. Allen; E. Amador Ceron; D. Amariutei; R. Amin; S. Anderson; W. G. Anderson; K. Arai; M. A. Arain; M. C. Araya; S. Aston; P. Astone; D. Atkinson; P. Aufmuth; C. Aulbert; B. E. Aylott; S. Babak; P. Baker
Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipelines ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with similar to 50% or better probability with a few pointings of wide-field telescopes.Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to Oct 20 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipelines ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ~50% or better probability with a few pointings of wide-field telescopes.
Nuclear Physics | 1977
G.D. Alkhazov; Th. Bauer; R. Bertini; L. Bimbot; O. Bing; A. Boudard; G. Bruge; H. Catz; A. Chaumeaux; P. Couvert; J.M. Fontaine; F. Hibou; George Igo; J.C. Lugol; M. Matoba
Abstract Differential cross sections of elastic and inelastic scattering of 1.37 GeV α-particles from 40, 42, 44, 48Ca have been measured. The angular distributions show that the scattering process is quite diffractive. Glaubers nucleus-nucleus scattering theory for elastic scattering has been examined in two approximate ways. The method in which the projectile is assumed not to be excited internally in the course of multiple scattering, reproduces reasonably well the experimental angular distributions. The trend of the root-mean-square radii of the neutron densities of the four calcium isotopes has been found to be in agreement with the recent results from proton scattering measurements at 1.04 GeV.
Physical Review Letters | 2013
Th. Bauer; P. Lunkenheimer; A. Loidl
The slowing down of molecular dynamics when approaching the glass transition generally proceeds much stronger than expected for thermally activated motions. This strange phenomenon can be formally ascribed to a temperature-dependent activation energy E(T). In the present work, via measurements of the third-order nonlinear dielectric susceptibility, we deduce the increase of the number of correlated molecules N(corr) when approaching the glass transition and find a surprisingly simple correlation of E(T) and N(corr)(T). This provides strong evidence that the noncanonical temperature development of glassy dynamics is caused by a temperature-dependent energy barrier arising from the cooperative motion of ever larger numbers of molecules at low temperatures.
Nuclear Physics | 1976
G.D. Alkhazov; Th. Bauer; R. Beurtey; A. Boudard; G. Bruge; A. Chaumeaux; P. Couvert; G. Cvijanovich; H.H. Duhm; J.M. Fontaine; D. Garreta; A.V. Kulikov; D. Legrand; J.C. Lugol; J. Saudinos; J. Thirion; A.A. Vorobyov
Abstract Elastic and inelastic scattering of 1.044 GeV protons have been studied on isotopically enriched even 40, 42, 44, 48 Ca isotopes and 48 Ti. A spin independent Glauber theory analysis of the elastic scattering allowed the extraction of neutron and nuclear matter densities for these targets.
arXiv: Nuclear Experiment | 2013
R. Aaij; B. Adeva; M. Adinolfi; C. Adrover; A. Affolder; Z. Ajaltouni; J. Albrecht; F. Alessio; M. Alexander; S. Ali; G. Alkhazov; P. Alvarez Cartelle; A. A. Alves; S. Amato; S. Amerio; Y. Amhis; L. Anderlini; J. Anderson; R. Andreassen; J. E. Andrews; R. B. Appleby; O. Aquines Gutierrez; F. Archilli; A. Artamonov; M. Artuso; E. Aslanides; G. Auriemma; M. Baalouch; S. Bachmann; J. J. Back
A bstractThe production of J/ψ mesons with rapidity 1.5 < y < 4.0 or −5.0 < y < −2.5 and transverse momentum pT< 14 GeV/c is studied with the LHCb detector in proton-lead collisions at a nucleon-nucleon centre-of-mass energy
Physical Review Letters | 2013
Th. Bauer; P. Lunkenheimer; S. Kastner; A. Loidl
\sqrt{{{s_{NN }}}}
Journal of Chemical Physics | 2014
Per Sillrén; Aleksandar Matic; Maths Karlsson; Michael Marek Koza; Marco Maccarini; Peter Fouquet; M. Götz; Th. Bauer; R. Gulich; P. Lunkenheimer; A. Loidl; Johan Mattsson; C. Gainaru; E. Vynokur; S. Schildmann; S. Bauer; Roland Böhmer
= 5TeV. The J/ψ mesons are reconstructed using the dimuon decay mode. The analysis is based on a data sample corresponding to an integrated luminosity of about 1.6 nb−1. For the first time the nuclear modification factor and forward-backward production ratio are determined separately for prompt J/ψ mesons and J/ψ from b-hadron decays. Clear suppression of prompt J/ψ production with respect to proton-proton collisions at large rapidity is observed, while the production of J/ψ from b-hadron decays is less suppressed. These results show good agreement with available theoretical predictions. The measurement shows that cold nuclear matter effects are important for interpretations of the related quark-gluon plasma signatures in heavy-ion collisions.
Nuclear Physics | 1976
A. Chaumeaux; G. Bruge; Th. Bauer; R. Bertini; A. Boudard; H. Catz; P. Couvert; H.H. Duhm; J.M. Fontaine; D. Garreta; J.C. Lugol; V. Layly; R. Schaeffer
We present nonlinear dielectric measurements of glass-forming glycerol and propylene carbonate applying electrical fields up to 671 kV/cm. The measurements extend to sufficiently high frequencies to allow for the investigation of the nonlinear behavior in the regime of the so-far mysterious excess wing, showing up in the loss spectra of many glass formers as a second power law at high frequencies. Surprisingly, we find a complete lack of nonlinear behavior in the excess wing, in marked contrast to the α relaxation where, in agreement with previous reports, a strong increase of dielectric constant and loss is found.
Nuclear Physics | 1995
A. Zondervan; L.J. de Bever; E. Jans; J. Konijn; M. Kruijer; J. J. M. Steijger; J.L. Visschers; P.J. Countryman; W.H.A. Hesselink; N. Kalantar-Nayestanaki; L.J.H.M. Kester; J.H. Mitchell; A. Pellegrino; J. R. Calarco; F.W. Hersman; Mark Bancroft Leuschner; Timothy Smith; Th. Bauer; M.W. Kelder; C. Giusti; F.D. Pacati; Jan Ryckebusch; Marc Vanderhaeghen
Liquid monohydroxy alcohols exhibit unusual dynamics related to their hydrogen bonding induced structures. The connection between structure and dynamics is studied for liquid 1-propanol using quasi-elastic neutron scattering, combining time-of-flight and neutron spin-echo techniques, with a focus on the dynamics at length scales corresponding to the main peak and the pre-peak of the structure factor. At the main peak, the structural relaxation times are probed. These correspond well to mechanical relaxation times calculated from literature data. At the pre-peak, corresponding to length scales related to H-bonded structures, the relaxation times are almost an order of magnitude longer. According to previous work [C. Gainaru, R. Meier, S. Schildmann, C. Lederle, W. Hiller, E. Rössler, and R. Böhmer, Phys. Rev. Lett. 105, 258303 (2010)] this time scale difference is connected to the average size of H-bonded clusters. The relation between the relaxation times from neutron scattering and those determined from dielectric spectroscopy is discussed on the basis of broad-band permittivity data of 1-propanol. Moreover, in 1-propanol the dielectric relaxation strength as well as the near-infrared absorbance reveal anomalous behavior below ambient temperature. A corresponding feature could not be found in the polyalcohols propylene glycol and glycerol.