Imperial College London

ProfessorTimothySumner

Faculty of Natural SciencesDepartment of Physics

Professor of Experimental Astrophysics
 
 
 
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Contact

 

+44 (0)20 7594 7552t.sumner

 
 
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Location

 

1108Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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416 results found

Ni W-T, Bao Y, Dittus H, Huang T, Lammerzahl C, Li G, Luo J, Ma Z-G, Mangin JF, Nie Y-X, Peters A, Ruediger A, Samain E, Schiller S, Shiomi S, Sumner T, Tang C-J, Tao J, Touboul P, Wang H, Wicht A, Wu X-J, Xiong Y, Xu C, Yan J, Yao D-Z, Yeh H-C, Zhang S-L, Zhang Y-Z, Zhou Z-Bet al., 2006, ASTROD I: Mission concept and Venus flybys, 5th IAA International Conference on Low-Cost Planetary Missions, Publisher: PERGAMON-ELSEVIER SCIENCE LTD, Pages: 598-607, ISSN: 0094-5765

Conference paper

Araujo HM, Akimov DY, Alner GJ, Bewick A, Bungau C, Camanzi B, Carson MJ, Chepel V, Chagani H, Davidge D, Davies JC, Daw E, Dawson J, Durkin T, Edwards B, Gamble T, Ghag C, Hollingworth R, Howard AS, Jones WG, Joshi M, Kirkpatrick J, Kovalenko A, Kudryavtsev VA, Lebedenko VN, Lawson T, Lewin JD, Lightfoot P, Lindote A, Liubarsky I, Lopes MI, Luscher R, Majewski P, Mavrokoridis K, McMillan J, Morgan B, Muna D, Murphy AS, Neves F, Nicklin G, Paling S, da Cunha JP, Plank S, Preece R, Quenby JJ, Robinson M, Silva C, Solovov VN, Smith NJT, Smith PF, Spooner NJC, Stekhanov V, Sumner TJ, Tovey DR, Thorne C, Tziaferi E, Walker RJet al., 2006, The ZEPLIN-III dark matter detector: Performance study using an end-to-end simulation tool, Astroparticle Physics, Vol: 26, Pages: 140-153, ISSN: 1873-2852

We present results from a GEANT4-based Monte Carlo tool for end-to-end simulations of the ZEPLIN-III dark matter experiment.ZEPLIN-III is a two-phase detector which measures both the scintillation light and the ionisation charge generated in liquid xenon byinteracting particles and radiation. The software models the instrument response to radioactive backgrounds and calibration sources,including the generation, ray-tracing and detection of the primary and secondary scintillations in liquid and gaseous xenon, and subsequentprocessing by data acquisition electronics. A flexible user interface allows easy modification of detector parameters at run time.Realistic datasets can be produced to help with data analysis, an example of which is the position reconstruction algorithm developedfrom simulated data. We present a range of simulation results confirming the original design sensitivity of a few times 108 pb to theWIMP-nucleon cross-section.

Journal article

Achterberg A, Ackermann M, Adams J, Ahrens J, Andeen K, Atlee DW, Bahcall JN, Bai X, Baret B, Bartelt M, Barwick SW, Bay R, Beattie K, Becka T, Becker JK, Becker K-H, Berghaus P, Berley D, Bernardini E, Bertrand D, Besson DZ, Blaufuss E, Boersma DJ, Bohm C, Boser S, Botner O, Bouchta A, Bouhali O, Braun J, Burgess C, Burgess T, Castermans T, Chirkin D, Clem J, Conrad J, Cooley J, Cowen DF, D'Agostino MV, Davour A, Day CT, De Clercq C, Desiati P, DeYoung T, Diaz-Velez JC, Dreyer J, Duvoort MR, Edwards WR, Ehrlich R, Ekstrom P, Ellsworth RW, Evenson PA, Fadiran O, Fazely AR, Feser T, Filimonov K, Gaisser TK, Gallagher J, Ganugapati R, Geenen H, Gerhardt L, Goldschmidt A, Goodman JA, Gozzini R, Greene MG, Grullon S, Gross A, Gunasingha RM, Gurtner M, Hallgren A, Halzen F, Han K, Hanson K, Hardtke D, Hardtke R, Harenberg T, Hart JE, Hauschildt T, Hays D, Heise J, Helbing K, Hellwig M, Herquet P, Hill GC, Hodges J, Hoffman KD, Hoshina K, Hubert D, Hughey B, Hulth PO, Hultqvist K, Hundertmark S, Huelss J-P, Ishihara A, Jacobsen J, Japaridze GS, Jones A, Joseph JM, Kampert K-H, Karle A, Kawal H, Kelley JL, Kestel M, Klein SR, Klepser S, Kohnen G, Kolanoski H, Koepke L, Krasberg M, Kuehn K, Landsman H, Leich H, Leuthold M, Liubarsky I, Lundberg J, Madsen J, Marciniewski P, Mase K, Matis HS, McCauley T, McParland CP, Meli A, Messarius T, Meszaros P, Minaeva Y, Miocinovic P, Miyamoto H, Mokhtarani A, Montaruli T, Morey A, Morse R, Movit SM, Muenich K, Nahnhauer R, Nam J, Neunhoeffer T, Niessen P, Nygren DR, Ogelman H, Olbrechts P, Olivas A, Patton S, Pena-Garay C, de los Heros CP, Plegsa A, Pieloth D, Pohl AC, Porrata R, Pretz J, Price PB, Przybylski GT, Rawlins K, Razzaque S, Refflinghaus F, Resconi E, Rhode W, Ribordy M, Rizzo A, Robbins S, Rodriguez Martino J, Rott C, Rutledge D, Sander H-G, Schlenstedt S, Schneider D, Schwarz R, Seckel D, Seo SH, Seunarine S, Silvestri A, Smith AJ, Solarz M, Song C, Sopher JE, Spiczak GM, Spiering C, Stamatikos M, Stanev T, Steffen P, Steet al., 2006, Limits on the muon flux from neutralino annihilations at the center of the Earth with AMANDA, ASTROPARTICLE PHYSICS, Vol: 26, Pages: 129-139, ISSN: 0927-6505

Journal article

Ni W-T, et al, 2006, ASTROD and ASTROD I: Progress Report, 6th Edoardo Amaldi Conference on Gravitational Waves, Publisher: Institute of Physics Publishing, Pages: 154-160

Conference paper

Grimani C, et al, 2006, SEP flux mapping with PHOEBUS, 6th Edoardo Amaldi Conference on Gravitational Waves, Publisher: Institute of Physics Publishing, Pages: 6-11

Conference paper

Wass PJ, Araújo HA, Davidge D, Howard A, Lee CGY, Rochester GK, Shaul DNA, Sumner TJet al., 2006, Charging of the LISA test masses: Sources, consequences and management, The Tenth Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories, Pages: 2013-2018, ISBN: 9789812566676

© 2005 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. Energetic particle radiation in the form of galactic cosmic rays and solar particles will cause the LISA test masses to become charged. This will give rise to disturbing forces on the test masses through both Lorentz and Couloumb interactions which can translate into acceleration noise, coupling of the spacecraft and test mass motion and coherent signals in the measurement bandwidth. To minimise these effects, the charge management system on LISA will control the amount of charge on the test masses through the photo-electric effect using a system of UV illumination. We present the estimates of the exposure of the spacecraft to energetic particles and the resultant test mass charging rates based on detailed charging simulations using GEANT4. We also describe the system used to measure and manage the charge on the test masses.

Book chapter

Wass PJ, Carbone L, Cavalleri A, Ciani G, Dolesi R, Hueller M, Rochester G, Schulte M, Sumner T, Tombolato D, Trenkel C, Vitale S, Weber Wet al., 2006, Testing of the UV discharge system for LISA pathfinder, 6th International Laser Interferometer Space Antenna, Publisher: AMER INST PHYSICS, Pages: 220-+, ISSN: 0094-243X

Conference paper

Schulte M, Rochester GK, Shaul DNA, Sumner TJ, Trenkel C, Wass PJet al., 2006, The charge-management system on LISA-Pathfinder - Status & outlook for LISA, 6th International Laser Interferometer Space Antenna, Publisher: AMER INST PHYSICS, Pages: 165-+, ISSN: 0094-243X

Conference paper

Alner GJ, Araujo H, Bewick A, Burgos S, Carson MJ, Davies JC, Daw E, Dawson J, Forbes J, Gamble T, Garcia M, Ghag C, Gold M, Hollen S, Hollingworth RJ, Howard AS, Kirkpatrick JA, Kudryavtsev VA, Lawson TB, Lebedenko V, Lewin JD, Lightfoot PK, Liubarsky I, Loomba D, Luscher R, McMillan JE, Morgan B, Muna D, Murphy AS, Nicklin GG, Paling SM, Petkov A, Plank SJS, Preece RM, Quenby JJ, Robinson M, Sanghi N, Smith NJT, Smith PF, Snowden-Ifft DP, Spooner NJC, Sumner TJ, Tovey DR, Turk J, Tzaferi E, Walker RJet al., 2005, The DRIFT-II dark matter detector: Design and commissioning, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 555, Pages: 173-183, ISSN: 0168-9002

Journal article

Lockerbie NA, Sumner TJ, 2005, High precision tests of the Equivalence Principle, Pages: 19-25, ISSN: 0379-6566

This paper reviews experimental measurements of the Equivalence Principle, placing them in an historical context. Emphasis is given to prospective Space-based tests of the Equivalence Principle, where there is real potential for investigation into a region of the appropriate parameter space where the EP may well be violated. The STEP (Satellite Test of the Equivalence Principle) experiment, with a target sensitivity of 10-18 for the Eötvös ratio, η, is used as an exemplar for such experiments, arid is discussed in some detail.

Conference paper

Khan SA, Shafer RA, Benford DJ, Staguhn JG, Chanial P, Le Floc'h E, Babbedge TSR, Farrah D, Moseley SH, Dwek E, Clements DL, Sumner TJ, Ashby MLN, Brand K, Brodwin M, Eisenhardt PR, Elston R, Gonzalez AH, McKenzie E, Murray SSet al., 2005, On the discovery of the first galaxy selected at 350 microns, ASTROPHYSICAL JOURNAL, Vol: 631, Pages: L9-L12, ISSN: 0004-637X

Journal article

Carson M, Araujo HM, Davies JC, Kudryavtsev VA, Robinson M, Spooner N, Sumner Tet 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

Journal article

Dawson JV, Howard AS, Akimov D, Araujo H, Bewick A, Davidge DCR, Jones WG, Joshi M, Lebedenko VN, Liubarsky I, Quenby JJ, Rochester G, Shaul D, Sumner TJ, Walker RJet 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.

Journal article

Araujo HM, Kudryavtsev VA, Spooner NJC, Sumner TJet 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.

Journal article

Alner GJ, Araujo HM, Arnison GJ, Barton JC, Bewick A, Bungau C, Camanzi B, Carson MJ, Davidge D, Davies GJ, Davies JC, Daw E, Dawson JV, Duffy C, Durkin TJ, Gamble T, Hart SP, Hollingworth R, Homer GJ, Howard AS, Ivaniouchenkov I, Jones WG, Joshi MK, Kirkpatrick J, Kudryavtsev VA, Lawson TB, Lebedenko V, Lehner MJ, Lewin JD, Lightfoot PK, Liubarsky I, Luscher R, McMillan JE, Morgan B, Murphy A, Nicklin G, Nickolls A, Paling SM, Preece RM, Quenby JJ, Roberts JW, Robinson M, Smith NJT, Smith PF, Spooner NJC, Sumner TJ, Tovey DR, Tziaferi Eet 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.

Journal article

Alner GJ, Araujo H, Arnison GJ, Barton JC, Bewick A, Bungau C, Camanzi B, Carson MJ, Davidge D, Dawson JV, Davies GJ, Davies JC, Durkin T, Gamble T, Hart SP, Hollingworth RJ, Homer GJ, Howard AS, Ivaniouchenkov I, Jones WG, Joshi MK, Kudryavtsev VA, Lawson TB, Lebedenko V, Lewin JD, Lightfoot PK, Liubarsky I, Lehner MJ, Luscher R, McMillan JE, Morgan B, Nicholls A, Nicklin G, Paling SM, Preece RM, Roberts JW, Robinson M, Quenby JJ, Smith NJT, Smith PF, Spooner NJC, Sumner TJ, Tovey Det 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

Journal article

Anza S, Armano M, Balaguer E, Benedetti M, Boatella C, Bosetti P, Bortoluzzi D, Brandt N, Braxmaier C, Caldwell M, Carbone L, Cavalleri A, Ciccolella A, Cristofolini I, Cruise M, Da Lio M, Danzmann K, Desiderio D, Dolesi R, Dunbar N, Fichter W, Garcia C, Garcia-Berro E, Marin AFG, Gerndt R, Gianolio A, Giardini D, Gruenagel R, Hammesfahr A, Heinzel G, Hough J, Hoyland D, Hueller M, Jennrich O, Johann U, Kemble S, Killow C, Kolbe D, Landgraf M, Lobo A, Lorizzo V, Mance D, Middleton K, Nappo F, Nofrarias M, Racca G, Ramos J, Robertson D, Sallusti M, Sandford M, Sanjuan J, Sarra P, Selig A, Shaul D, Smart D, Smit M, Stagnaro L, Sumner T, Tirabassi C, Tobin S, Vitale S, Wand V, Ward H, Weber WJ, Zweifel Pet al., 2005, The LTP experiment on the LISA Pathfinder mission, 5th International LISA Symposium/38th ESLAB Symposium, Publisher: IOP PUBLISHING LTD, Pages: S125-S138, ISSN: 0264-9381

Conference paper

Shaul DNA, Araujo HM, Rochester GK, Sumner TJ, Wass PJet 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

Conference paper

Wass PJ, Araujo HM, Shaul DNA, Sumner TJet 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

Conference paper

Alner GJ, Atac M, Bewick A, Bungau C, Camanzi B, Carson MJ, Ghag C, Chen Y, Cline DB, Davidge D, Davis J, Daw E, Dawson JV, Durkin TJ, Ferbel T, Gamble T, Gao J, Howard AS, Jones WG, Joshi MK, Kudryavtsev VA, Lawson TB, Lebedenko V, Lewin JD, Lightfoot PK, Liubarsky I, Luscher R, McMillan JE, Morgan B, Murphy AS, Paling SM, Preece RM, Quenby JJ, Robinson M, Schroeder U, Sergiampietri F, Skulski W, Smith NJT, Smith P, Smith PF, Spooner NJC, Sumner TJ, Toke J, Tovey D, Walker R, Wang H, White JT, Wolfs F, Yang Xet al., 2005, Status of the ZEPLIN II experiment, 6th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCI LTD, Pages: 259-263, ISSN: 1387-6473

Conference paper

Alner GJ, Araujo H, Arnison GJ, Barton JC, Bewick A, Bungau C, Camanzi B, Carson MJ, Davidge D, Dawson JV, Davies GJ, Davies JC, Durkin T, Gamble T, Hart SP, Hollingworth RJ, Homer GJ, Howard AS, Ivaniouchenkov I, Jones WG, Joshi MK, Kudryavtsev VA, Lawson TB, Lebedenko V, Lewin JD, Lightfoot PK, Liubarsky I, Lehner MJ, Luscher R, McMillan JE, Morgan B, Nicholls A, Nicklin G, Paling SM, Preece RM, Roberts JW, Robinson M, Quenby JJ, Smith NJT, Smith PF, Spooner NJC, Sumner TJ, Tovey DRet 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

Conference paper

Sumner TJ, 2005, The ZEPLIN III dark matter project, 6th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCI LTD, Pages: 277-281, ISSN: 1387-6473

Conference paper

Khan SA, Benford DJ, Clements DL, Shafer RA, Sumner TJet al., 2005, Resolving IRAS 09111-1007 at 350 mu m: a different path to ULIRG formation?, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 359, Pages: L10-L14, ISSN: 0035-8711

Journal article

Sumner T, 2005, Direct dark matter searches - DRIFT and ZEPLIN

© Copiright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. Three new direct dark matter detection experiments are nearing operations within our collaboration. DRIFT II is a next generation modular gas time projection chamber designed to demonstrate directionality with a scalable technology. The first module of this is operational in our underground laboratory at Boulby. ZEPLINs II and III are next generation liquid time projection chambers offering simultaneous measurement of scintillation and charge from liquid xenon. These two instruments will provide sensitivities into the 10−8 pb range. ZEPLIN II is just beginning science operations underground at Boulby. ZEPLIN III is in a final assembly in a surface laboratory. Our programme status will be presented.

Conference paper

Dittus H, Turyshev SG, Lämmerzahl C, Theil S, Foerstner R, Johann U, Ertmer W, Rasel E, Dachwald B, Seboldt W, Hehl FW, Kiefer C, Blome HJ, Kunz J, Giulini D, Bingham R, Kent B, Sumner TJ, Bertolami O, Páramos J, Rosales JL, Christophe B, Foulon B, Touboul P, Bouyer P, Reynaud S, Brillet A, Bondu F, Samain E, De Matos CJ, Erd C, Grenouilleau JC, Izzo D, Rathke A, Anderson JD, Asmar SW, Lau EE, Nieto MM, Mashhoon Bet al., 2005, A mission to explore the Pioneer anomaly, Pages: 3-10, ISSN: 0379-6566

The Pioneer 10 and 11 spacecraft yielded the most precise navigation in deep space to date. These spacecraft had exceptional acceleration sensitivity. However, analysis of their radio-metric tracking data has consistently indicated that at heliocentric distances of ∼20-70 astronomical units, the orbit determinations indicated the presence of a small, anomalous, Doppler frequency drift. The drift is a blue-shift, uniformly changing with a rate of ∼ (5.99 ± 0.01) × 10-9 Hz s-1, which can be interpreted as a constant sunward acceleration of each particular spacecraft of aP = (8.74 ± 1.33) × 10-10 ms -2(Anderson et al. 1998; Turyshev et al. 1999; Anderson et al. 2002a). The nature of this anomaly remains unexplained. This signal has become known as the Pioneer anomaly. The inability to explain the anomalous behavior of the Pioneers with conventional physics has contributed to growing discussion about its origin. There is now an increasing number of proposals that attempt to explain the anomaly outside conventional physics. This progress emphasizes the need for a new experiment to explore the detected signal. Furthermore, the recent extensive efforts led to the conclusion that only a dedicated experiment could ultimately determine the nature of the found signal. We discuss the Pioneer anomaly and present the next steps towards an understanding of its origin. We specificallyfocus on the development of a mission to explore the Pioneer Anomaly in a dedicated experiment conducted in deep space. This joint European-US mission is motivated by the desire to better understand the laws of fundamental physics as they affect dynamics in the solar system. The mission could lead to a major discovery in the 21st century and, with readily available technologies, it could be flown well within the Cosmic Vision time frame.

Conference paper

Turyshev SG, Dittus H, Lämmerzahl C, Theil S, Ertmer W, Rasel E, Foerstner R, Johann U, Klioner S, Soffel M, Dachwald B, Seboldt W, Perlick V, Sandford MCW, Bingham R, Kent B, Sumner TJ, Bertolami O, Páramos J, Christophe B, Foulon B, Touboul P, Bouyer P, Damour T, Salomon C, Reynaud S, Brillet A, Bondu F, Mangin JF, Samain E, Bertotti B, Iess L, Erd C, Grenouilleau JC, Izzo D, Rathke A, Asmar SW, Colavita M, Gürsel Y, Hemmati H, Shao M, Williams JG, Nordtvedt KL, Shapiro I, Reasenberg R, Drever RWP, Degnan J, Plowman JE, Hellings R, Murphy TWet al., 2005, Fundamental physics with the laser astrometric test of relativity, Pages: 11-18, ISSN: 0379-6566

The Laser Astrometric Test Of Relativity (LATOR) is a European-U.S. Michelson-Morley-type experiment designed to test the tensor metric nature of gravitation - the fundamental postulate of Einstein's theory of general relativity. By using a combination of independent timeseries of highly accurate gravitational deflection of light in the immediate proximity to the Sun along with measurements of the Shapiro time delay on the interplanetary scales (to a precision respectively better than 10-13 radians and 1 cm), LATOR will significantly improve our knowledge of relativistic gravity. The primary mission objective is to i) measure the key post-Newtonian Eddington parameter 7 with accuracy of a part in 109. (1 - γ) is a direct measure for presence of a new interaction in gravitational theory, and, in its search, LATOR goes a factor 30,000 beyond the present best result, Cassini's 2003 test. Other mission objectives include: ii) first measurement of gravity's non-linear effects on light to ∼0.01% accuracy; including both the traditional Eddington β parameter and also the spatial metric's 2nd order potential contribution(never been measured before); iii) direct measurement of the solar quadrupole moment J2 (currently unavailable) to accuracy of a part in 200 of its expected size; iv) direct measurement of the "frame-dragging" effect on light by the Sun's rotational gravitomagnetic field to one percent accuracy. LATOR's primary measurement pushes to unprecedented accuracy the search for cosmologically relevant scalar-tensor theories of gravity by looking for a remnant scalar field in today's solar system. The key element of LATOR is a geometric redundancy provided by the laser ranging and long-baseline optical interferometry. LATOR is envisaged as a partnership between European and US institutions and with clear areas of responsibility between the space agencies: NASA provides the deep space mission components, while optical infrastructure on the ISS

Conference paper

Sumner TJ, 2005, Advances in Space Research: Preface, ISSN: 0273-1177

Conference paper

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

Journal article

Araujo HM, Wass P, Shaul D, Rochester G, Sumner TJet 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.

Journal article

Alner GJ, Araujo HM, Arnison GJ, Barton JC, Bewick A, Bungau C, Camanzi B, Carson MJ, Davidge D, Daw E, Dawson JV, Davies GJ, Davies JC, Duffy C, Durkin TJ, Gamble T, Hart SP, Hollingworth RJ, Homer GJ, Howard AS, Ivaniouchenkov I, Jones WG, Joshi MK, Kirkpatrick J, Kudryavtsev VA, Lawson TB, Lebedenko V, Lehner MJ, Lewin JD, Lightfoot PK, Liubarsky I, Luscher R, McMillan JE, Morgan B, Murphy A, Nicholls A, Nicklin G, Paling SM, Preece RM, Quenby JJ, Roberts JW, Robinson M, Smith NJT, Smith PF, Spooner NJC, Sumner TJ, Tovey DR, Tziaferi Eet 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

Conference paper

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