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Author Gonzalez-Iglesias, D.; Esperante, D.; Gimeno, B.; Boronat, M.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J.
Title Analytical RF Pulse Heating Analysis for High Gradient Accelerating Structures Type Journal Article
Year 2021 Publication IEEE Transactions on Nuclear Science Abbreviated Journal IEEE Trans. Nucl. Sci.
Volume (down) 68 Issue 2 Pages 78-91
Keywords RF accelerating structures; RF pulse heating; thermal analysis
Abstract The main aim of this work is to present a simple method, based on analytical expressions, for obtaining the temperature increase due to the Joule effect inside the metallic walls of an RF accelerating component. This technique relies on solving the 1-D heat-transfer equation for a thick wall, considering that the heat sources inside the wall are the ohmic losses produced by the RF electromagnetic fields penetrating the metal with finite electrical conductivity. Furthermore, it is discussed how the theoretical expressions of this method can be applied to obtain an approximation to the temperature increase in realistic 3-D RF accelerating structures, taking as an example the cavity of an RF electron photoinjector and a traveling wave linac cavity. These theoretical results have been benchmarked with numerical simulations carried out with commercial finite-element method (FEM) software, finding good agreement among them. Besides, the advantage of the analytical method with respect to the numerical simulations is evidenced. In particular, the model could be very useful during the design and optimization phase of RF accelerating structures, where many different combinations of parameters must be analyzed in order to obtain the proper working point of the device, allowing to save time and speed up the process. However, it must be mentioned that the method described in this article is intended to provide a quick approximation to the temperature increase in the device, which of course is not as accurate as the proper 3-D numerical simulations of the component.
Address [Gonzalez-Iglesias, D.; Esperante, D.; Gimeno, B.; Boronat, M.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J.] UV, CSIC, Inst Fis Corpuscular IFIC, Valencia 46980, Spain, Email: daniel.gonzalez-iglesias@uv.es
Corporate Author Thesis
Publisher Ieee-Inst Electrical Electronics Engineers Inc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-9499 ISBN Medium
Area Expedition Conference
Notes WOS:000619349900001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4720
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Author Ji, T.; Dong, X.K.; Albaladejo, M.; Du, M.L.; Guo, F.K.; Nieves, J.; Zou, B.S.
Title Understanding the 0(++) and 2(++) charmonium(-like) states near 3.9 GeV Type Journal Article
Year 2023 Publication Science Bulletin Abbreviated Journal Sci. Bull.
Volume (down) 68 Issue 7 Pages 688-697
Keywords Charmonium(-like) states; Hadronic molecules; Heavy quark spin symmetry; Exotic hadrons; Hadron-hadron interactions
Abstract We propose that the X(3915) observed in the J/psi x channel is the same state as the chi(c2)(3930), and the X(3960), observed in the Ds+Ds- channel, is an S-wave Ds+Ds- hadronic molecule. In addition, the J(PC) = 0(++) component in the B+ -> D+D-K+ assigned to the X(3915) in the current Review of Particle Physics has the same origin as the X(3960), which has a mass around 3.94 GeV. To check the proposal, the available data in the D (D) over bar and Ds+Ds- channels from both B decays and gamma gamma fusion reaction are analyzed considering both the D (D) over bar -D-s(D) over bar (s)-D*(D) over bar*-D-s*(D) over bar (s)* coupled channels with 0(++) and a 2(++) state introduced additionally. It is found that all the data in different processes can be simultaneously well reproduced, and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73, 3.94, 3.99 and 4.23 GeV, respectively. The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons.
Address [Ji, Teng; Dong, Xiang-Kun; Guo, Feng-Kun; Zou, Bing-Song] Inst Theoret Phys, Chinese Acad Sci, CAS Key Lab Theoret Phys, Beijing 100190, Peoples R China, Email: jiteng@itp.ac.cn;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2095-9273 ISBN Medium
Area Expedition Conference
Notes WOS:000985290600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5520
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Author Borja-Lloret, M.; Barrientos, L.; Bernabeu, J.; Lacasta, C.; Muñoz, E.; Ros, A.; Roser, J.; Viegas, R.; Llosa, G.
Title Influence of the background in Compton camera images for proton therapy treatment monitoring Type Journal Article
Year 2023 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume (down) 68 Issue 14 Pages 144001 - 16pp
Keywords Compton imaging; Compton camera; proton therapy; treatment monitoring; Monte Carlo simulation; image reconstruction; background
Abstract Objective. Background events are one of the most relevant contributions to image degradation in Compton camera imaging for hadron therapy treatment monitoring. A study of the background and its contribution to image degradation is important to define future strategies to reduce the background in the system. Approach. In this simulation study, the percentage of different kinds of events and their contribution to the reconstructed image in a two-layer Compton camera have been evaluated. To this end, GATE v8.2 simulations of a proton beam impinging on a PMMA phantom have been carried out, for different proton beam energies and at different beam intensities. Main results. For a simulated Compton camera made of Lanthanum (III) Bromide monolithic crystals, coincidences caused by neutrons arriving from the phantom are the most common type of background produced by secondary radiations in the Compton camera, causing between 13% and 33% of the detected coincidences, depending on the beam energy. Results also show that random coincidences are a significant cause of image degradation at high beam intensities, and their influence in the reconstructed images is studied for values of the time coincidence windows from 500 ps to 100 ns. Significance. Results indicate the timing capabilities required to retrieve the fall-off position with good precision. Still, the noise observed in the image when no randoms are considered make us consider further background rejection methods.
Address [Borja-Lloret, M.; Barrientos, L.; Bernabeu, J.; Lacasta, C.; Munoz, E.; Ros, A.; Roser, J.; Viegas, R.; Llosa, G.] Inst Fis Corpuscular IFIC, CSIC UV, Valencia, Spain, Email: Marina.Borja@csic.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 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:001022671300001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5571
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Author Vague, J.; Melgarejo, J.C.; Boria, V.E.; Guglielmi, M.; Moreno, R.; Reglero, M.; Mata, R.; Montero, I.; Gonzalez-Iglesias, D.; Gimeno, B.; Gomez, A.; Vegas, A.; Raboso, D.
Title Experimental Validation of Multipactor Effect for Ferrite Materials Used in L- and S-Band Nonreciprocal Microwave Components Type Journal Article
Year 2019 Publication IEEE Transactions on Microwave Theory and Techniques Abbreviated Journal IEEE Trans. Microw. Theory Tech.
Volume (down) 67 Issue 6 Pages 2151-2161
Keywords Ferrites; ferromagnetic resonance; gadolinium-aluminum garnet; Holmium garnet; multipactor; space applications; wideband nonreciprocal devices
Abstract This paper reports on the experimental measurement of power threshold levels for the multipactor effect between samples of ferrite material typically used in the practical implementation of L-and S-band circulators and isolators. For this purposes, a new family of wideband, nonreciprocal rectangular waveguide structures loaded with ferrites has been designed with a full-wave electromagnetic simulation tool. The design also includes the required magnetostatic field biasing circuits. The multipactor breakdown power levels have also been predicted with an accurate electron tracking code using measured values for the secondary electron yield (SEY) coefficient. The measured results agree well with simulations, thereby fully validating the experimental campaign.
Address [Vague, Joaquin; Carlos Melgarejo, Juan; Boria, Vicente E.; Guglielmi, Marco; Reglero, Marta] Univ Politecn Valencia, iTEAM, Dept Comunicac, E-46022 Valencia, Spain, Email: jvague@dcom.upv.es;
Corporate Author Thesis
Publisher Ieee-Inst Electrical Electronics Engineers Inc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-9480 ISBN Medium
Area Expedition Conference
Notes WOS:000470969100006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4056
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Author Zhang, X.; Xiao, Y.T.; Gimeno, B.
Title Multipactor Suppression by a Resonant Static Magnetic Field on a Dielectric Surface Type Journal Article
Year 2020 Publication IEEE Transactions on Electron Devices Abbreviated Journal IEEE Trans. Electron Devices
Volume (down) 67 Issue 12 Pages 5723-5728
Keywords Radio frequency; Dielectrics; Magnetic resonance; Discharges (electric); Surface discharges; Surface waves; Electrostatics; Monte Carlo simulation; multipactor discharge; orthogonal waves; resonant static magnetic field; secondary electron yield
Abstract In this article, we study the suppression of the multipactor phenomenon on a dielectric surface by a resonant static magnetic field. A homemade Monte Carlo algorithm is developed for multipactor simulations on a dielectric surface driven by two orthogonal radio frequency (RF) electric field components. When the static magnetic field is perpendicular to the tangential and normal RF electric fields, it is shown that if the normal electric field lags the tangential electric field by pi/2, the superposition of the normal and tangential electric fields will trigger a gyro-acceleration of the electron cloud and restrain the multipactor discharge effectively. By contrast, when the normal electric field is in advance of the tangential electric field by pi/2, the difference between the normal and tangential electric fields drives gyro-motion of the electron cloud. Consequently, two enhanced discharge zones are inevitable. The suppression effects of the resonant static magnetic field that is parallel to the tangential RF electric field or to the normal RF electric field are also presented.
Address [Zhang, Xue; Xiao, Yuting] Xiangtan Univ, Sch Automat & Elect Informat, Xiangtan 411105, Hunan, Peoples R China, Email: zhangxue.iecas@yahoo.com;
Corporate Author Thesis
Publisher Ieee-Inst Electrical Electronics Engineers Inc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-9383 ISBN Medium
Area Expedition Conference
Notes WOS:000594337700064 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4627
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Author Roser, J.; Barrientos, L.; Bernabeu, J.; Borja-Lloret, M.; Muñoz, E.; Ros, A.; Viegas, R.; Llosa, G.
Title Joint image reconstruction algorithm in Compton cameras Type Journal Article
Year 2022 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume (down) 67 Issue 15 Pages 155009 - 15pp
Keywords Compton camera; compton imaging; hadron therapy; image reconstruction; LM-MLEM; Monte Carlo simulations; multi-layer compton telescope
Abstract Objective. To demonstrate the benefits of using an joint image reconstruction algorithm based on the List Mode Maximum Likelihood Expectation Maximization that combines events measured in different channels of information of a Compton camera. Approach. Both simulations and experimental data are employed to show the algorithm performance. Main results. The obtained joint images present improved image quality and yield better estimates of displacements of high-energy gamma-ray emitting sources. The algorithm also provides images that are more stable than any individual channel against the noisy convergence that characterizes Maximum Likelihood based algorithms. Significance. The joint reconstruction algorithm can improve the quality and robustness of Compton camera images. It also has high versatility, as it can be easily adapted to any Compton camera geometry. It is thus expected to represent an important step in the optimization of Compton camera imaging.
Address [Roser, J.; Barrientos, L.; Bernabeu, J.; Borja-Lloret, M.; Munoz, E.; Ros, A.; Viegas, R.; Llosa, G.] CSIC UV, Inst Fis Corpuscular IFIC, Valencia, Spain, Email: Jorge.Roser@ific.uv.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 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:000827830200001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5298
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Author Fujita, Y.; Rubio, B.; Gelletly, W.
Title Spin-isospin excitations probed by strong, weak and electro-magnetic interactions Type Journal Article
Year 2011 Publication Progress in Particle and Nuclear Physics Abbreviated Journal Prog. Part. Nucl. Phys.
Volume (down) 66 Issue 3 Pages 549-606
Keywords Gamow-Teller transitions; beta decay; Charge-exchange reactions; Isospin symmetry; High resolution; Proton-rich nuclei
Abstract Gamow-Teller (GT) transitions are the most common weak interaction processes of spin-isospin (sigma tau) type in atomic nuclei. They are of interest not only in nuclear physics but also in astrophysics; they play an important role in supernovae explosions and nucleosynthesis. The direct study of weak decay processes, however, gives relatively limited information about GT transitions and the states excited via GT transitions (GT states); beta decay can only access states at excitation energies lower than the decay Q-value, and neutrino-induced reactions have very small cross-sections. However, one should note that beta decay has a direct access to the absolute GT transition strengths B(GT) from a study of half-lives, Q(beta)-values and branching ratios. They also provide information on GT transitions in nuclei far-from-stability. Studies of M1 gamma transitions provide similar information. In contrast, the complementary charge-exchange (CE) reactions, such as the (p, n) or ((3)He, t) reactions at intermediate beam energies and 0 degrees, can selectively excite GT states up to high excitation energies in the final nucleus. It has been found empirically that there is a close proportionality between the cross-sections at 0 degrees and the transition strengths B(GT) in these CE reactions. Therefore, CE reactions are useful tools to study the relative values of B(GT) strengths up to high excitation energies. In recent ((3)He, t) measurements, one order-of-magnitude improvement in the energy resolution has been achieved. This has made it possible to make one-to-one comparisons of GT transitions studied in CE reactions and beta decays. Thus GT strengths in ((3)He, t) reactions can be normalised by the beta-decay values. In addition, comparisons with closely related M1 transitions studied in gamma decay or electron inelastic scattering [(e, e')1, and furthermore with “spin” M I transitions that can be studied by proton inelastic scattering [(p, p')[ have now been made possible. In these comparisons, the isospin quantum number T and associated symmetry structure in the same mass A nuclei (isobars) play a key role. Isospin symmetry can extend our scope even to the structures of unstable nuclei that are far from reach at present unstable beam factories.
Address [Fujita, Y] Osaka Univ, Dept Phys, Osaka 5600043, Japan, Email: fujita@rcnp.osaka-u.ac.jp
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 0146-6410 ISBN Medium
Area Expedition Conference
Notes WOS:000292473100003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 692
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Author Zhang, X.; Chang, C.; Gimeno, B.
Title Multipactor Analysis in Circular Waveguides Excited by TM01 Mode Type Journal Article
Year 2019 Publication IEEE Transactions on Electron Devices Abbreviated Journal IEEE Trans. Electron Devices
Volume (down) 66 Issue 11 Pages 4943-4951
Keywords Circular waveguide; multipactor; ponderomotive force; TM01 mode
Abstract A series of detailed numerical simulations are used to investigate the properties ofmultipactor breakdown in circularwaveguidespropagating the TM01 mode. AMonte Carlo model is constructed to track the motion of the electrons, study the multipactor scenarios, and predict the multipactor thresholds. The theoretical and numerical analyses indicate that the product of the frequency and the gap (f . D) affects both the intensity of the ponderomotive force and its spatial distribution, which results from the nonuniformity of the radio frequency (RF) field and significantly influences the electrons' trajectoriesandmultipactor trends. The decrease in f . D results in a remarkable enhancement in the magnitude of the ponderomotive force, while the maximal intensity gradually moves toward the half radius R/2 area. Low values of f . D correspond to high ponderomotive potential, which sustains the short-range electrons and triggers the single-sidedmultipactor. In contrast, high values of f . D correspond to low ponderomotive potential, contributing to long-range electrons and exciting the double-sided multipactor. Fitting to the susceptibility diagram produces the border line and a modified f . D threshold of (f . D) th approximate to 338.4 GHz mm, which separates the susceptibility diagram into single-sided, double-sided, andmixed-sided zones. The initial electron energy influences their trajectories at high f . D and low RF power. This effect tends to dominate the multipactor behavior in the mixed-sided region.
Address [Zhang, Xue] Xiangtan Univ, Coll Informat Engn, Xiangtan 411105, Hunan, Peoples R China, Email: zhangxue.iecas@yahoo.com;
Corporate Author Thesis
Publisher Ieee-Inst Electrical Electronics Engineers Inc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-9383 ISBN Medium
Area Expedition Conference
Notes WOS:000494419900066 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4191
Permanent link to this record
 

 
Author Valdes-Cortez, C.; Mansour, I.; Rivard, M.J.; Ballester, F.; Mainegra-Hing, E.; Thomson, R.M.; Vijande, J.
Title A study of Type B uncertainties associated with the photoelectric effect in low-energy Monte Carlo simulations Type Journal Article
Year 2021 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume (down) 66 Issue 10 Pages 105014 - 14pp
Keywords Monte Carlo simulations; brachytherapy; low energy physics; photoelectric effect
Abstract Purpose. To estimate Type B uncertainties in absorbed-dose calculations arising from the different implementations in current state-of-the-art Monte Carlo (MC) codes of low-energy photon cross-sections (<200 keV). Methods. MC simulations are carried out using three codes widely used in the low-energy domain: PENELOPE-2018, EGSnrc, and MCNP. Three dosimetry-relevant quantities are considered: mass energy-absorption coefficients for water, air, graphite, and their respective ratios; absorbed dose; and photon-fluence spectra. The absorbed dose and the photon-fluence spectra are scored in a spherical water phantom of 15 cm radius. Benchmark simulations using similar cross-sections have been performed. The differences observed between these quantities when different cross-sections are considered are taken to be a good estimator for the corresponding Type B uncertainties. Results. A conservative Type B uncertainty for the absorbed dose (k = 2) of 1.2%-1.7% (<50 keV), 0.6%-1.2% (50-100 keV), and 0.3% (100-200 keV) is estimated. The photon-fluence spectrum does not present clinically relevant differences that merit considering additional Type B uncertainties except for energies below 25 keV, where a Type B uncertainty of 0.5% is obtained. Below 30 keV, mass energy-absorption coefficients show Type B uncertainties (k = 2) of about 1.5% (water and air), and 2% (graphite), diminishing in all materials for larger energies and reaching values about 1% (40-50 keV) and 0.5% (50-75 keV). With respect to their ratios, the only significant Type B uncertainties are observed in the case of the water-to-graphite ratio for energies below 30 keV, being about 0.7% (k = 2). Conclusions. In contrast with the intermediate (about 500 keV) or high (about 1 MeV) energy domains, Type B uncertainties due to the different cross-sections implementation cannot be considered subdominant with respect to Type A uncertainties or even to other sources of Type B uncertainties (tally volume averaging, manufacturing tolerances, etc). Therefore, the values reported here should be accommodated within the uncertainty budget in low-energy photon dosimetry studies.
Address [Valdes-Cortez, Christian; Ballester, Facundo; Vijande, Javier] Univ Valencia UV, Dept Fis Atom Mol & Nucl, Burjassot, Spain, Email: javier.vijande@uv.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 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:000655291500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4847
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Author LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J.
Title Evidence of a J/psi Lambda structure and observation of excited Xi(-) states in the Xi(-)(b) -> J/psi Lambda K- decay Type Journal Article
Year 2021 Publication Science Bulletin Abbreviated Journal Sci. Bull.
Volume (down) 66 Issue 13 Pages 1278-1287
Keywords QCD; Exotics; Pentaquark; Spectroscopy; Quarkonium; Particle and resonance production
Abstract First evidence of a structure in the J/psi Lambda invariant mass distribution is obtained from an amplitude analysis of Xi(-)(b) -> J/psi Lambda K- decays. The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1r including systematic uncertainties and lookelsewhere effect. Its mass and width are determined to be 4458.8 +/- 2.9(-1.1)(+4.7) MeV and 17.3 +/- 6.5(-5.7)(+8.0) MeV, respectively, where the quoted uncertainties are statistical and systematic. The structure is also consistent with being due to two resonances. In addition, the narrow excited Xi(-) states, Xi(-)(1690) and Xi(-)(1820)(-), are seen for the first time in a Xi(-)(b) decay, and their masses and widths are measured with improved precision. The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb(-1), collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV.
Address [Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2095-9273 ISBN Medium
Area Expedition Conference
Notes WOS:000668689800009 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4888
Permanent link to this record