Publications
173 results found
Araujo H, Howard A, Chauvie S, et al., 2005, Geant4 low energy electromagnetic physics, Pages: 1119-1127
An overview of the Geant4 low-energy electromagnetic physic package is presented. The package includes detailed simulations of the interactions of particles with energies from about 100 eV to 100 GeV. The emphasis is placed on models in which the accurate description of the atomic structure of media is essential. The package encompasses processes based on different approaches: for electrons and photons one set of implementations is based on the exploitation of evaluated data libraries and allows simulating cross section and energy loss of slow particles, another set is based on analytical models deriving from the Penelope code. For hadrons and ions alternative implementations based on Ziegler and ICRU reviews are provided. Charge-dependent effects are taken into account, and precise models for angular distributions are implemented. Geant4 simulation of some effects important for particle detectors are provided only by the low-energy package: nuclear stopping power, fluorescence of the media due to excitation and ionization of atoms, Auger electron production.
Carson M, Araújo HM, Davies JC, et al., 2005, Veto performance for large-scale xenon dark matter detectors, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 548, Pages: 418-426, ISSN: 0168-9002
- Author Web Link
- Cite
- Citations: 10
Dawson JV, Howard AS, Akimov D, et al., 2005, A study of the scintillation induced by alpha particles and gamma rays in liquid xenon in an electric field, Nuclear Instruments & Methods in Physics Research Section A - Accelerators Spectrometers Detectors and Associated Equipment, Vol: 545, Pages: 690-698, ISSN: 0168-9002
Scintillation produced in liquid xenon by alpha particles and gamma rays has been studied as a function of applied electric field. For back scattered gamma rays with energy of about 200 keV, the number of scintillation photons was found to decrease by 64±2% with increasing field strength. Consequently, the pulse shape discrimination power between alpha particles and gamma rays is found to reduce with increasing field, but remaining non-zero at higher fields.
Araujo HM, Kudryavtsev VA, Spooner NJC, et al., 2005, Muon-induced neutron production and detection with GEANT4 and FLUKA, Nuclear Instruments & Methods in Physics Research Section A - Accelerators Spectrometers Detectors and Associated Equipment, Vol: 545, Pages: 398-411, ISSN: 0168-9002
We report on a comparison study of the Monte Carlo packages GEANT4 and FLUKA for simulating neutron production by muons penetrating deep underground. GEANT4 is found to generate fewer neutrons at muon energies above View the MathML source, by at most a factor of 2 in some materials, which we attribute mainly to lower neutron production in hadronic cascades. As a practical case study, the muon-induced neutron background expected in a 250 kg liquid-xenon WIMP dark matter detector was calculated and good agreement was found for the recoil event rates. The detailed model of neutron elastic scattering in GEANT4 was also shown to influence the nuclear recoil spectrum observed in the target, which is presently a shortcoming of FLUKA. We conclude that both packages are suited for this type of simulation, although further improvements are desirable in both cases.
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Limits on WIMP cross-sections from the NAIAD experiment at the boulby underground laboratory, PHYS LETT B, Vol: 616, Pages: 17-24, ISSN: 0370-2693
The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at the Boulby Underground Laboratory (North Yorkshire, UK) ran from 2000 until 2003. A total of 44.9 kg x years of data collected with 2 encapsulated and 4 unencapsulated NaI(Tl) crystals with high light yield were included in the analysis. We present final results of this analysis carried out using pulse shape discrimination. No signal associated with nuclear recoils from WIMP interactions was observed in any run with any crystal. This allowed us to set upper limits on the WIMP-nucleon spin-independent and WIMP-proton spin-dependent cross-sections. The NAIAD experiment has so far imposed the most stringent constraints on the spin-dependent WIMP-proton cross-section. (c) 2005 Elsevier B.V. All rights reserved.
Alner GJ, Araujo H, Arnison GJ, et al., 2005, First limits on nuclear recoil events from the ZEPLIN I galactic dark matter detector, ASTROPARTICLE PHYSICS, Vol: 23, Pages: 444-462, ISSN: 0927-6505
- Author Web Link
- Cite
- Citations: 100
Wass PJ, Araújo HM, Shaul DNA, et al., 2005, Test-mass charging simulations for the LISA Pathfinder mission, 5th International LISA Symposium/38th ESLAB Symposium, Publisher: IOP PUBLISHING LTD, Pages: S311-S317, ISSN: 0264-9381
- Author Web Link
- Cite
- Citations: 39
Shaul DNA, Araújo HM, Rochester GK, et al., 2005, Evaluation of disturbances due to test mass charging for LISA, 5th International LISA Symposium/38th ESLAB Symposium, Publisher: IOP PUBLISHING LTD, Pages: S297-S309, ISSN: 0264-9381
- Author Web Link
- Cite
- Citations: 33
Alner GJ, Araujo H, Arnison GJ, et al., 2005, Nuclear recoil limits from the ZEPLIN I liquid xenon WIMP dark matter detector, 6th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCI LTD, Pages: 245-249, ISSN: 1387-6473
- Author Web Link
- Cite
- Citations: 2
CARSON MJ, DAVIES JC, KUDRYAVTSEV VA, et al., 2005, VETO PERFORMANCE FOR LARGE-SCALE XENON DARK MATTER DETECTORS, Proceedings of the Fifth International Workshop, Publisher: WORLD SCIENTIFIC
Walker R J, el at, 2005, THUMPER: a 200-µm photometer for ground-based astronomy, Millimeter and Submillimeter Detectors for Astronomy, Publisher: International Society for Optical Engineering, Pages: 563-573
Araujo HM, Wass P, Shaul D, et al., 2005, Detailed calculation of test-mass charging in the LISA mission, Astroparticle Physics, Vol: 22, Pages: 451-469, ISSN: 1873-2852
The electrostatic charging of the LISA test masses due to exposure of the spacecraft to energetic particles in the space environment has implications in the design and operation of the gravitational inertial sensors and can affect the quality of the science data. Robust predictions of charging rates and associated stochastic fluctuations are therefore required for the exposure scenarios expected throughout the mission. We report on detailed charging simulations with the Geant4 toolkit, using comprehensive geometry and physics models, for Galactic cosmic-ray protons and helium nuclei. These predict positive charging rates of 50+e/s (elementary charges per second) for solar minimum conditions, decreasing by half at solar maximum, and current fluctuations of up to 30+e/s/Hz1/2. Charging from sporadic solar events involving energetic protons was also investigated. Using an event-size distribution model, we conclude that their impact on the LISA science data is manageable. Several physical processes hitherto unexplored as potential charging mechanisms have also been assessed. Significantly, the kinetic emission of very low-energy secondary electrons due to bombardment of the inertial sensors by primary cosmic rays and their secondaries can produce charging currents comparable with the Monte Carlo rates.
Shaul DNA, Sumner TJ, Rochester GK, 2005, Coherent Fourier components in the LISA measurement bandwidth from test mass charging: Estimates and suppression, INTERNATIONAL JOURNAL OF MODERN PHYSICS D, Vol: 14, Pages: 51-71, ISSN: 0218-2718
- Author Web Link
- Cite
- Citations: 13
Araujo HM, 2005, The ZEPLIN III dark matter detector, New York, ieee international conference on dielectric liquids JUN 26-JUL 01, 2005 Coimbra, PORTUGAL, Publisher: Ieee, Pages: 305-308
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Limits on wimp cross-sections from the NAIAD experiment at Boulby, Singapore, 5th international workshop on the identification of dark matter, 6 - 10 September 2004, Edinburgh, SCOTLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 224-229
Araujo HM, Kudryavtsev VA, 2005, Muon-induced neutron production and detection with GEANT4 and FLUKA, Singapore, 5th international workshop on the identification of dark matter, Edinburgh, Scotland, 6 - 10 September 2004, Publisher: World Scientific, Pages: 499-504
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Zeplin I: first limits on nuclear recoil rate, Singapore, 5th international workshop on the identification of dark matter, 6 - 10 September 2004, Edinburgh, SCOTLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 218-223
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Limits on wimp cross-sections from the NAIAD experiment at Boulby, Singapore, 5th international workshop on the identification of dark matter, 6 - 10 September 2004, Edinburgh, SCOTLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 224-229
Alner GJ, Araujo H, Ayad R, et al., 2004, The DRIFT-I dark matter detector at Boulby:: design, installation and operation, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 535, Pages: 644-655, ISSN: 0168-9002
- Author Web Link
- Cite
- Citations: 35
Alner GJ, Araujo H, Ayad R, et al., 2004, The DRIFT-I dark matter detector at Boulby: Design, installation and operation, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol: 535, Pages: 644-655, ISSN: 0168-9002
DRIFT-I, the first full-scale gaseous dark matter detector, has recently been installed at ∼1100 m depth at the Boulby Underground Laboratory, UK. The DRIFT concept offers high background discrimination and sensitivity to the direction of WIMP-induced nuclear recoils, the latter being of particular importance in the search for evidence of WIMPs in our galaxy, In this paper we discuss the design of the DRIFT-I detector and its installation and operation at Boulby. We also present results of early engineering runs and outline plans for the future. © 2004 Elsevier B.V. All rights reserved.
Araújo HM, Bewick A, Davidge D, et al., 2004, Low-temperature study of 35 photomultiplier tubes for the ZEPLIN III experiment, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 521, Pages: 407-415, ISSN: 0168-9002
- Author Web Link
- Cite
- Citations: 21
Shaul DNA, Sumner TJ, Araujo HM, et al., 2004, Unwanted, coherent signals in the LISA bandwidth due to test mass charging, 5th Edoardo Amaldi Conference on Gravitational Waves, Publisher: IOP PUBLISHING LTD, Pages: S647-S651, ISSN: 0264-9381
- Author Web Link
- Cite
- Citations: 16
Sumner T, Araújo H, Davidge D, et al., 2004, Description of charging/discharging processes of the LISA sensors, 5th Edoardo Amaldi Conference on Gravitational Waves, Publisher: IOP PUBLISHING LTD, Pages: S597-S602, ISSN: 0264-9381
- Author Web Link
- Cite
- Citations: 29
Araujo HM, Wass P, Shaul D, et al., 2004, New estimates of test-mass charging in the LISA mission, Bellingham, Conference on gravitational wave and particle astrophysics detectors, Glasgow, Scotland, 23 - 24 June 2004, Publisher: SPIE - International Society for Optical Engineering, Pages: 174-182
Araujo H, Wass P, Howard A, et al., 2004, Space science simulations using GEANT4: test-mass charging in the LISA and LISA pathfinder space missions, SEPTIMESS final report to ESA, Contract number 16339/02/NL/FM
Araujo HM, Wass P, Shaul D, et al., 2004, New estimates of test-mass charging in the LISA mission, Bellingham, Conference on gravitational wave and particle astrophysics detectors, Glasgow, Scotland, 23 - 24 June 2004, Publisher: SPIE - International Society for Optical Engineering, Pages: 174-182
Ahmed B, Alner GJ, Araujo H, et al., 2003, The NAIAD experiment for WIMP searches at Boulby mine and recent results, Astroparticle Physics, Vol: 19, Pages: 691-702, ISSN: 1873-2852
The NAIAD experiment (NaI Advanced Detector) for weakly interacting massive particle (WIMP) dark mattersearches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulatedNaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6kg year exposure) have been used to set upper limits on the WIMP–nucleon spin-independent and WIMP–protonspin-dependent cross-sections. Pulse shape analysis has been applied to discriminate between nuclear recoils, as may becaused by WIMP interactions, and electron recoils due to gamma background. Various calibrations of crystals arepresented.
Howard AS, Araujo H, 2003, Simulation and analysis for astroparticle experiments, 8th Topical Seminar on Innovative Particle and Radiation Detectors, Publisher: ELSEVIER SCIENCE BV, Pages: 320-326, ISSN: 0920-5632
- Author Web Link
- Cite
- Citations: 2
Agostinelli S, Allison J, Amako K, et al., 2003, GEANT4-a simulation toolkit, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 506, Pages: 250-303, ISSN: 0168-9002
- Author Web Link
- Cite
- Citations: 16088
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.