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Author Fuster-Martinez, N.; Assmann, R.W.; Bruce, R.; Giovannozzi, M.; Hermes, P.; Mereghetti, A.; Mirarchi, D.; Redaelli, S.; Wenninger, J. url  doi
openurl 
  Title Beam-based aperture measurements with movable collimator jaws as performance booster of the CERN Large Hadron Collider Type Journal Article
  Year 2022 Publication (up) European Physical Journal Plus Abbreviated Journal Eur. Phys. J. Plus  
  Volume 137 Issue 3 Pages 305 - 20pp  
  Keywords  
  Abstract The beam aperture of a particle accelerator defines the clearance available for the circulating beams and is a parameter of paramount importance for the accelerator performance. At the CERN Large Hadron Collider (LHC), the knowledge and control of the available aperture is crucial because the nominal proton beams carry an energy of 362 MJ stored in a superconducting environment. Even a tiny fraction of beam losses could quench the superconducting magnets or cause severe material damage. Furthermore, in a circular collider, the performance in terms of peak luminosity depends to a large extent on the aperture of the inner triplet quadrupoles, which are used to focus the beams at the interaction points. In the LHC, this aperture represents the smallest aperture at top-energy with squeezed beams and determines the maximum potential reach of the peak luminosity. Beam-based aperture measurements in these conditions are difficult and challenging. In this paper, we present different methods that have been developed over the years for precise beam-based aperture measurements in the LHC, highlighting applications and results that contributed to boost the operational LHC performance in Run 1 (2010-2013) and Run 2 (2015-2018)  
  Address [Fuster-Martinez, N.] Inst Fis Corpuscular CSIC UV, Valencia, Spain, Email: nuria.fuster@ific.uv.es  
  Corporate Author Thesis  
  Publisher Springer Heidelberg Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2190-5444 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000764734000003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5160  
Permanent link to this record
 

 
Author Martinez-Reviriego, P.; Esperante, D.; Grudiev, A.; Gimeno, B.; Blanch, C.; Gonzalez-Iglesias, D.; Fuster-Martinez, N.; Martin-Luna, P.; Martinez, E.; Menendez, A.; Fuster, J. url  doi
openurl 
  Title Dielectric assist accelerating structures for compact linear accelerators of low energy particles in hadrontherapy treatments Type Journal Article
  Year 2024 Publication (up) Frontiers in Physics Abbreviated Journal Front. Physics  
  Volume 12 Issue Pages 1345237 - 12pp  
  Keywords dielectric assist accelerating (DAA) structures; radio frequency (RF); LINAC; hadrontherapy; standing wave  
  Abstract Dielectric Assist Accelerating (DAA) structures based on ultralow-loss ceramic are being studied as an alternative to conventional disk-loaded copper cavities. This accelerating structure consists of dielectric disks with irises arranged periodically in metallic structures working under the TM02-pi mode. In this paper, the numerical design of an S-band DAA structure for low beta particles, such as protons or carbon ions used for Hadrontherapy treatments, is shown. Four dielectric materials with different permittivity and loss tangent are studied as well as different particle velocities. Through optimization, a design that concentrates most of the RF power in the vacuum space near the beam axis is obtained, leading to a significant reduction of power loss on the metallic walls. This allows to fabricate cavities with an extremely high quality factor, over 100,000, and shunt impedance over 300 M omega/m at room temperature. During the numerical study, the design optimization has been improved by adjusting some of the cell parameters in order to both increase the shunt impedance and reduce the peak electric field in certain locations of the cavity, which can lead to instabilities in its normal functioning.  
  Address [Martinez-Reviriego, Pablo; Esperante, Daniel; Gimeno, Benito; Blanch, Cesar; Gonzalez-Iglesias, Daniel; Fuster-Martinez, Nuria; Martin-Luna, Pablo; Martinez, Eduardo; Menendez, Abraham; Fuster, Juan] CSIC Univ Valencia, Inst Fis Corpuscular IFIC, Paterna, Spain, Email: pablo.martinez.reviriego@ific.uv.es  
  Corporate Author Thesis  
  Publisher Frontiers Media Sa Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2296-424x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001162373700001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5953  
Permanent link to this record
 

 
Author Gonzalez-Iglesias, D.; Esperante, D.; Gimeno, B.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J.; Alesini, D. doi  openurl
  Title Analysis of the Multipactor Effect in an RF Electron Gun Photoinjector Type Journal Article
  Year 2023 Publication (up) IEEE Transactions on Electron Devices Abbreviated Journal IEEE Trans. Electron Devices  
  Volume 70 Issue 1 Pages 288-295  
  Keywords Magnetic tunneling; Multipactor effect; photoinjector; RF breakdown; RF gun  
  Abstract The objective of this work is the evaluation of the risk of suffering a multipactor discharge within an RF electron gun photoinjector. Photoinjectors are a type of source for intense electron beams, which are the main electron source for synchrotron light sources, such as free-electron lasers. The analyzed device consists of 1.6 cells and it has been designed to operate at the S-band. Besides, around the RF gun there is an emittance compensation solenoid, whose magnetic field prevents the growth of the electron beam emittance, and thus the degradation of the properties of the beam. The multipactor analysis is based on a set of numerical simulations by tracking the trajectories of the electron cloud in the cells of the device. To reach this aim, an in-house multipactor code was developed. Specifically, two different cases were explored: with the emittance compensation solenoid assumed to be off and with the emittance compensation solenoid in operation. For both the cases, multipactor simulations were carried out exploring different RF electric field amplitudes. Moreover, for a better understanding of the multipactor phenomenon, the resonant trajectories of the electrons and the growth rate of the electrons population are investigated.  
  Address [Gonzalez-Iglesias, D.; Esperante, D.; Gimeno, B.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J.] Univ Valencia, Inst Fis Corpuscular IFIC, CSIC, Paterna 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 0018-9383 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000890813600001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5427  
Permanent link to this record
 

 
Author Martin-Luna, P.; Gimeno, B.; Gonzalez-Iglesias, D.; Esperante, D.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Fuster, J. doi  openurl
  Title On the Magnetic Field of a Finite Solenoid Type Journal Article
  Year 2023 Publication (up) IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.  
  Volume 59 Issue 4 Pages 7000106 - 6pp  
  Keywords Solenoids; Magnetic fields; Integral equations; Magnetostatics; Magnetostatic waves; Particle beams; NASA; Elliptic integrals; finite solenoid; magnetostatics  
  Abstract The magnetostatic field of a finite solenoid with infinitely thin walls carrying a dc current oriented in the azimuthal direction is calculated everywhere in space in terms of complete elliptic integrals by direct integration of the Biot-Savart law. The solution is particularized near the solenoid axis and in the midplane perpendicular to the axis obtaining expressions that agree with some typical approximations that are made in introductory courses of electromagnetism or in the technical literature. The range of validity of these approximations has been studied comparing them with the obtained general expression.  
  Address [Martin-Luna, P.; Gimeno, B.; Gonzalez-Iglesias, D.; Esperante, D.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Fuster, J.] Univ Valencia, Inst Corpuscular Phys IFIC, CSIC, Paterna 46980, Spain, Email: Pablo.Martin@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 0018-9464 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001006992700005 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5552  
Permanent link to this record
 

 
Author Gonzalez-Iglesias, D.; Esperante, D.; Gimeno, B.; Boronat, M.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J. doi  openurl
  Title Analytical RF Pulse Heating Analysis for High Gradient Accelerating Structures Type Journal Article
  Year 2021 Publication (up) IEEE Transactions on Nuclear Science Abbreviated Journal IEEE Trans. Nucl. Sci.  
  Volume 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  
Permanent link to this record
 

 
Author Liu, S.; Bogard, F.; Cornebise, P.; Faus-Golfe, A.; Fuster-Martinez, N.; Griesmayer, E.; Guler, H.; Kubytskyi, V.; Sylvia, C.; Tauchi, T.; Terunuma, N.; Bambade, P. url  doi
openurl 
  Title In vacuum diamond sensor scanner for beam halo measurements in the beam line at the KEK Accelerator Test Facility Type Journal Article
  Year 2016 Publication (up) Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 832 Issue Pages 231-242  
  Keywords Diamond sensor; Beam halo; ATF2  
  Abstract The investigation of beam halo transverse distributions is important for the understanding of beam losses and the control of backgrounds in Future Linear Colliders (FLC). A novel in vacuum diamond sensor (DSv) scanner with four strips has been designed and developed for the investigation of the beam halo transverse distributions and also for the diagnostics of Compton recoil electrons after the interaction point (IP) of ATF2, a low energy (1.3 GeV) prototype of the final focus system for the ILC and CLIC linear collider projects. Using the DSv, a dynamic range of similar to 10(6) has been successfully demonstrated and confirmed for the first time in simultaneous beam core (similar to 10(6) electrons) and beam halo (similar to 10(3) electrons) measurements at ATF2. This report presents the characterization, performance studies and tests of diamond sensors using an a source, as well as using the electron beams at PHIL, a low energy (<5 MeV) photo-injector at LAL, and at ATF2. First beam halo measurement results using the DSv at ATF2 with different beam intensities and vacuum levels are also presented. Such measurements not only allow one to evaluate the different sources of beam halo generation but also to define the requirements for a suitable collimation system to be installed at ATF2, as well as to optimize its performance during future operation.  
  Address [Liu, S.; Bogard, F.; Cornebise, P.; Faus-Golfe, A.; Guler, H.; Kubytskyi, V.; Sylvia, C.; Bambade, P.] Univ Paris Saclay, Univ Paris 11, CNRS, LAL,IN2P3, Orsay, France, Email: sliu@lal.in2p3.fr  
  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 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000382256400026 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2786  
Permanent link to this record
 

 
Author Gonzalez-Iglesias, D.; Aksoy, A.; Esperante, D.; Gimeno, B.; Latina, A.; Boronat, M.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J. doi  openurl
  Title X-band RF photoinjector design for the CompactLight project Type Journal Article
  Year 2021 Publication (up) Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 1014 Issue Pages 165709 - 10pp  
  Keywords Photoinjector; X-band; Electron sources; Free electron laser; Beam generation  
  Abstract RF photoinjectors have been under development for several decades to provide the high-brightness electron beams required for X-ray Free Electron Lasers. This paper proposes a photoinjector design that meets the Horizon 2020 CompactLight design study requirements. It consists of a 5.6-cell, X-band (12 GHz) RF gun, an emittance-compensating solenoid and two X-band traveling-wave structures that accelerate the beam out of the space-charge-dominated regime. The RF gun is intended to operate with a cathode gradient of 200 MV/m, and the TW structures at a gradient of 65 MV/m. The shape of the gun cavity cells was optimized to reduce the peak electric surface field. An assessment of the gun RF breakdown likelihood is presented as is a multipacting analysis for the gun coaxial coupler. RF pulse heating on the gun inner surfaces is also evaluated and beam dynamics simulations of the 100 MeV photoinjector are summarized.  
  Address [Gonzalez-Iglesias, D.; Esperante, D.; Gimeno, B.; Boronat, M.; Blanch, C.; Fuster-Martinez, N.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster, J.] Univ Valencia Consejo Super Invest Cient, Inst Fis Corpuscular IFIC, Calle Catedrat Jose Beltran 2, Valencia 46980, Spain, Email: daniel.gonzalez-iglesias@uv.es  
  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 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000704382900005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4983  
Permanent link to this record
 

 
Author Fuster-Martinez, N.; Bruce, R.; Hofer, M.; Persson, T.; Redaelli, S.; Tomas, R. doi  openurl
  Title Aperture measurements with ac dipoles and movable collimators in the Large Hadron Collider Type Journal Article
  Year 2022 Publication (up) Physical Review Accelerators and Beams Abbreviated Journal Phys. Rev. Accel. Beams  
  Volume 25 Issue 10 Pages 101002 - 13pp  
  Keywords  
  Abstract This paper presents a first experimental demonstration of a new nondestructive method for aperture measurements based on ac dipoles. In high intensity particle colliders, such as the CERN Large Hadron Collider (LHC), aperture measurements are crucial for a safe operation while optimizing the optics in order to reduce the size of the colliding beams and hence increase the luminosity. In the LHC, this type of measurements became mandatory during beam commissioning and the current method used is based on the destructive blowup of bunches using a transverse damper. The new method presented in this paper uses the ac-dipole excitation to generate adiabatic forced oscillations of the beam in order to create losses to identify the smallest aperture in the machine without blowing up the beam emittance. A precise and tuneable control of the oscillation amplitude enables the beams to be reused for several aperture measurements, as well as for other subsequent commissioning activities. Measurements performed with the new method are presented and compared with the current LHC transverse damper method for two different beam energies and two different operational optics.  
  Address [Fuster-Martinez, N.] CSIC UV, Inst Fis Corpuscular, Valencia 46908, Spain, Email: nuria.fuster@ific.uv.es  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000875736400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5397  
Permanent link to this record
 

 
Author Andrews, H.L.; Taheri, F.B.; Barros, J.; Bartolini, R.; Bharadwaj, V.; Clarke, C.; Delerue, N.; Doucas, G.; Fuster-Martinez, N.; Vieille-Grosjean, M.; Konoplev, I.V.; Labat, M.; Le Corre, S.; Perry, C.; Reichold, A.; Stevenson, S. doi  openurl
  Title Reconstruction of the time profile of 20.35 GeV, subpicosecond long electron bunches by means of coherent Smith-Purcell radiation Type Journal Article
  Year 2014 Publication (up) Physical Review Special Topics-Accelerators and Beams Abbreviated Journal Phys. Rev. Spec. Top.-Accel. Beams  
  Volume 17 Issue 5 Pages 052802 - 13pp  
  Keywords  
  Abstract We have used coherent Smith-Purcell radiation (cSPr) in order to determine the temporal profile of sub-ps long electron bunches at the Facility for Advanced Accelerator Experimental Tests, at SLAC. The measurements reported here were carried out in June 2012 and April 2013. The rms values for the bunch length varied between 356 to 604 fs, depending on the accelerator settings. The resolution of the system was limited by the range of detectable wavelengths which was, in turn, determined by the choice of the grating periods used in these experiments and the achievable beam-grating separation. The paper gives the details of the various steps in the reconstruction of the time profile and discusses possible improvements to the resolution. We also present initial measurements of the polarization properties of cSPr and of the background radiation.  
  Address [Andrews, H. L.] LANL, Los Alamos, NM 87545 USA, Email: g.doucas@physics.ox.ac.uk  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1098-4402 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000336654500006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1808  
Permanent link to this record
 

 
Author Gonzalez-Iglesias, D.; Gimeno, B.; Esperante, D.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster-Martinez, N.; Blanch, C.; Martinez, E.; Menendez, A.; Fuster, J.; Grudiev, A. url  doi
openurl 
  Title Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures Type Journal Article
  Year 2024 Publication (up) Results in Physics Abbreviated Journal Results Phys.  
  Volume 56 Issue Pages 107245 - 12pp  
  Keywords Multipactor; Dielectric accelerating structures; RF particle accelerators; Plasma discharge  
  Abstract The objective of this work is the evaluation of the risk of suffering a multipactor discharge in an S-band dielectric-assist accelerating (DAA) structure for a compact low-energy linear particle accelerator dedicated to hadrontherapy treatments. A DAA structure consists of ultra-low loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure, with the advantage of having an extremely high quality factor and very high shunt impedance at room temperature, and it is therefore proposed as a potential alternative to conventional disk-loaded copper structures. However, it has been observed that these structures suffer from multipactor discharges. In fact, multipactor is one of the main problems of these devices, as it limits the maximum accelerating gradient. Because of this, the analysis of multipactor risk in the early design steps of DAA cavities is crucial to ensure the correct performance of the device after fabrication. In this paper, we present a comprehensive and detailed study of multipactor in our DAA design through numerical simulations performed with an in-house developed code based on the Monte-Carlo method. The phenomenology of the multipactor (resonant electron trajectories, electron flight time between impacts, etc.) is described in detail for different values of the accelerating gradient. It has been found that in these structures an ultra-fast non-resonant multipactor appears, which is different from the types of multipactor theoretically studied in the scientific literature. In addition, the effect of several low electron emission coatings on the multipactor threshold is investigated. Furthermore, a novel design based on the modification of the DAA cell geometry for multipactor mitigation is introduced, which shows a significant increase in the accelerating gradient handling capabilities of our prototype.  
  Address [Gonzalez-Iglesias, Daniel; Gimeno, Benito; Esperante, Daniel; Martinez-Reviriego, Pablo; Martin-Luna, Pablo; Fuster-Martinez, Nuria; Blanch, Cesar; Martinez, Eduardo; Menendez, Abraham; Fuster, Juan] CSIC UV, Inst Fis Corpuscular IF, c Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: daniel.gonzalez-iglesias@uv.es  
  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 2211-3797 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001133850600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5866  
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