Search results for "linear accelerators"
showing 8 items of 8 documents
Space charge and microbunching studies for the injection arc of MESA
2018
For intense electron bunches traversing through bends, as for example the recirculation arcs of an ERL, space charge (SC) may result in beam phase space deterioration. SC modifies the electron transverse dynamics in dispersive regions along the beam line and causes emittance growth for mismatched beams or for specific phase advances. On the other hand, longitudinal space charge together with dispersion can lead to the microbunching instability. The present study focuses on the 180° low energy (5 MeV) injection arc lattice for the multi-turn Mainz Energy-recovering Superconducting Accelerator (MESA), which should deliver a CW beam at 10⁵ MeV for physics experiments with an internal target. W…
Present status and first results of the final focus beam line at the KEK Accelerator Test Facility
2011
ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.
Precision luminosity measurements at LHCb
2014
Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves sig…
Signal integrity studies at optical multiplexer board for TileCal system
2007
6 pages.-- ISI Article Identifier: 000253651800006
High-Gradient issues in S-band RF Acceleration Structure for Hadrontherapy accelerators and Radio Frequency Quadrupoles
2020
La investigación de estructuras de microondas de alto gradiente en aceleradores lineales es un tema clave en instalaciones de física de altas energías, y en particular en sistemas de física médica basados en hadronterapia. Esta Tesis Doctoral se centra en el estudio de los problemas que surgen al emplear sistemas de alto gradiente en estructuras aceleradoras de radiofrecuencia no superconductoras. Uno de los efectos que aparecen durante la operación de alta potencia en estos sistemas son los arcos de vacío de RF, llamados breakdown. Esto ocurre debido a los altos campos electromagnéticos de RF que aparecen en las estructuras aceleradoras. Tales eventos tienen un impacto en el rendimiento de…
Innovative remotely-controlled bending device for thin silicon and germanium crystals
2020
Steering of negatively charged particle beams below 1 GeV has demonstrated to be possible with thin bent silicon and germanium crystals. A newly designed mechanical holder was used for bending crystals, since it allows a remotely-controlled adjustment of crystal bending and compensation of unwanted torsion. Bent crystals were installed and tested at the MAMI Mainz MIcrotron to achieve steering of 0.855-GeV electrons at different bending radii. We report the description and characterization of the innovative bending device developed at INFN Laboratori Nazionali di Legnaro (LNL).
Monte Carlo simulations of high-energy electron beams : model validation and dose calculations
2017
Komponenttisäteilytykseen valjastetusta Varian Clinac 2100 C/D -lineaarikiihdyttimestä luotiin Monte Carlo -menetelmiä hyödyntävä simulaatiomalli. Malli luotiin aineen ja säteilyn vuorovaikutuksien laskennalliseen mallintamiseen tarkoitettua Geant4 -ohjelmointityökalupakettia käyttäen. Mallin kyky ennustaa mittaustuloksia kiihdyttimen tuottamasta 20 MeV:in elektronisuihkusta todennettiin laskettuja ja mitattuja tuloksia vertailemalla, ja mallin jatkokehityksen kannalta tärkeimmät toimenpiteet määriteltiin. Lisäksi arvioitiin mallin ennustamaa absorpoitunutta annosta vesi- ja piifantomeissa, sekä laskettiin viitearvo absorpoituneen annoksen ja elektronivuon suhteelle. Lasketut annosprofiilit…
Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operation.
2012
Linac4 accelerator of Centre Européen de Recherches Nucléaires is under construction and a RFdriven H− ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible after extended opera…