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Author Blanes, S.; Casas, F.; Oteo, J.A.; Ros, J.
Title A pedagogical approach to the Magnus expansion Type Journal Article
Year 2010 Publication European Journal of Physics Abbreviated Journal Eur. J. Phys.
Volume 31 Issue 4 Pages 907-918
Keywords
Abstract Time-dependent perturbation theory as a tool to compute approximate solutions of the Schrodinger equation does not preserve unitarity. Here we present, in a simple way, how the Magnus expansion (also known as exponential perturbation theory) provides such unitary approximate solutions. The purpose is to illustrate the importance and consequences of such a property. We suggest that the Magnus expansion may be introduced to students in advanced courses of quantum mechanics.
Address [Blanes, S.] Univ Politecn Valencia, Inst Matemat Multidisciplinar, E-46022 Valencia, Spain, Email: serblaza@imm.upv.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0143-0807 ISBN Medium
Area Expedition Conference
Notes ISI:000279393800024 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 259
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Author Modamio, V.; Valiente-Dobon, J.J.; Jaworski, G.; Huyuk, T.; Triossi, A.; Egea, J.; Di Nitto, A.; Soderstrom, P.A.; Ros, J.A.; de Angelis, G.; de France, G.; Erduran, M.N.; Erturk, S.; Gadea, A.; Gonzalez, V.; Kownacki, J.; Moszynski, M.; Nyberg, J.; Palacz, M.; Sanchis, E.; Wadsworthm, R.
Title Digital pulse-timing technique for the neutron detector array NEDA Type Journal Article
Year 2015 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 775 Issue Pages 71-76
Keywords Digital timing; Constant fraction discriminator; Liquid scintillator; BC501A; Neutron detector; NEDA
Abstract A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in by 5 in BC501A liquict scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CM algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes.
Address [Modamio, V.; Valiente-Dobon, J. J.; Triossi, A.; de Angelis, G.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: victor.modamio@lnl.infn.it
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000348040900011 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2093
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Author Magan, D.L.P.; Caballero, L.; Domingo-Pardo, C.; Agramunt-Ros, J.; Albiol, F.; Casanovas, A.; Gonzalez, A.; Guerrero, C.; Lerendegui-Marco, J.; Tarifeño-Saldivia, A.
Title First tests of the applicability of gamma-ray imaging for background discrimination in time-of-flight neutron capture measurements Type Journal Article
Year 2016 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 823 Issue Pages 107-119
Keywords Neutron capture cross-sections; gamma-ray imaging; Total energy detectors; Pulse-height weighting technique; Time-of-flight method
Abstract In this work we explore for the first time the applicability of using gamma-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr3 scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a Au-197 sample have been carried out at n_TOF, achieving an enhancement of a factor of two in the signal-to-background ratio when selecting only those events coming from the direction of the sample.
Address [Perez Magan, D. L.; Caballero, L.; Domingo-Pardo, C.; Agramunt-Ros, J.; Albiol, F.; Tarifeno-Saldivia, A.] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: domingo@ific.uv.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000374661600015 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2665
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Author Ibanez-Rosello, B.; Bautista-Ballesteros, J.A.; Candela-Juan, C.; Villaescusa, J.I.; Ballester, F.; Vijande, J.; Perez-Calatayud, J.
Title Evaluation of the shielding in a treatment room with an electronic brachytherapy unit Type Journal Article
Year 2017 Publication Journal of Radiological Protection Abbreviated Journal J. Radiol. Prot.
Volume 37 Issue 2 Pages N5-N12
Keywords Esteya; electronic brachytherapy; shielding; radiation protection
Abstract Esteya (R) (Elekta Brachytherapy, Veenendaal, The Netherlands) is an electronic brachytherapy (eBT) system based on a 69.5 kVp x-ray source and a set of collimators of 1 to 3 cm in diameter, used for treating non-melanoma skin cancer lesions. This study aims to estimate room shielding requirements for this unit. The non-primary (scattered and leakage) ambient dose equivalent rates were measured with a Berthold LB-133 monitor (Berthold Technologies, Bad Wildbad, Germany). The latter ranges from 17 mSv h(-1) at 0.25 m distance from the x-ray source to 0.1 mSv h(-1) at 2.5 m. The necessary room shielding was then estimated following US and some European guidelines. The room shielding for all barriers considered was below 2 mmPb. The dose to a companion who, exceptionally, would stay with the patient during all treatment was estimated to be below 1 mSv if a leaded apron is used. In conclusion, Esteya shielding requirements are minimal.
Address [Ibanez-Rosello, Blanca; Ignacio Villaescusa, Juan] La Fe Univ, Radioprotect Dept, E-46026 Valencia, Spain, Email: blanca.ibanez.rosello@gmail.com
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0952-4746 ISBN Medium
Area Expedition Conference
Notes WOS:000413778600001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 3344
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Author Botella-Soler, V.; Oteo, J.A.; Ros, J.
Title Coexistence of periods in a bifurcation Type Journal Article
Year 2012 Publication Chaos, Solitons & Fractals Abbreviated Journal Chaos Solitons Fractals
Volume 45 Issue 5 Pages 681-686
Keywords
Abstract A particular type of order-to-chaos transition mediated by an infinite set of coexisting neutrally stable limit cycles of different periods is studied in the Varley-Gradwell-Hassell population model. We prove by an algebraic method that this kind of transition can only happen for a particular bifurcation parameter value. Previous results on the structure of the attractor at the transition point are here simplified and extended.
Address [Botella-Soler, V.; Oteo, J. A.; Ros, J.] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: vicente.botella@uv.es
Corporate Author Thesis
Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0960-0779 ISBN Medium
Area Expedition Conference
Notes WOS:000303785300014 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1005
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