Conveners
Poster Session: Poster Session
- Qing Qin (Institute of High Energy Physics, Chinese Academy of Sciences)
Description
Posters will be hanging in the main workshop hall from 4pm on Tuesday till 12pm on Friday. Posters can be discussed at any time. The time slot allocated to your abstract in the timetable should be ignored.
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Mr Shahnam Gorgi Zadeh (Rostock University (DE))24/09/2019, 16:00
The LHC Injectors Upgrade (LIU) project plans doubling the bunch intensity in the LHC injector chain in order to meet the requirements of the High Luminosity LHC (HL-LHC) project. The longitudinal beam impedance of the Super Proton Synchrotron (SPS), part of the injector of the LHC, is currently one of the limitations in reaching higher beam intensities due to instability issues. In the...
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Patrick Schreiber (Karlsruhe Institute of Technology (KIT))24/09/2019, 16:10
For future synchrotron light sources different acceleration modes are of interest. Therefore various modes are currently being tested at the Karlsruhe Research Accelerator (KARA) including optics for a negative momentum compaction factor. These optics have been calculated and are under commissioning at KARA. Additionally, studies about expected collective effects in this regime are being...
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Vladimir Kornilov (GSI Helmholtzzentrum Darmstadt, Germany)24/09/2019, 16:20
The SIS100 synchrotron, presently under construction in Darmstadt, Germany, will provide high intensity ion beams to the different experiments of FAIR. Numerous types of RF and ramp cycles for the full range of ions are planned for the operation. Here we identify a few reference cycles for the heavy-ion and proton beams and consider the transverse stability along the time scenario of the...
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Andrea Passarelli (Universita e sezione INFN di Napoli (IT))24/09/2019, 16:30
Modern accelerators and light sources often require special treatment of the vacuum chamber surface in order to avoid undesirable effects and to maximize machine performance. Coatings with Amorphous Carbon (a-C) have been extensively tested and used with very effective results since it allows to reduce the secondary electron yield (SEY) of the pipe walls due to electron cloud and to avoid the...
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Ms Olga Tanaka (High Energy Accelerator Research Organization (KEK))24/09/2019, 16:40
When a high intensity charged beam passes through locations with narrow apertures, such as the rod of a collimator, undesirable wake fields can be generated and adversely affect the beam. The Compact ERL at KEK mainly uses five beam collimators (one at the injector line, one at the merger section, and three in the recirculation loop) to remove the beam halo and to localize the beam losses....
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Fatih Yaman (Izmir Institute of Technology (IYTE))24/09/2019, 16:50
Electron clouds are produced by photo-emissions, residual gas ionizations and secondary emissions during positively charged beam circulations in particle accelerators. The interaction between the beam and electron clouds leads to critical instabilities which may cause beam losses, trajectory changes and wake fields. In this study, we investigate electron cloud build-up for CLIC-DR's with 0.5ns...
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Ivan Karpov (CERN)24/09/2019, 17:00
During the filling of the Large Hadron Collider (LHC), it is desirable to keep the rf cavity voltage constant both in amplitude and phase to minimize the emittance blow-up and injection losses. To have a constant voltage and to minimize power consumption, a special beam-loading compensation scheme called half-detuning is used in the LHC, for which the cavity fundamental resonant frequency...
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Markus Schwarz (CERN)24/09/2019, 17:10
The High Luminosity LHC (HL-LHC) requires 2.3e11 protons per bunch (ppb) at LHC injection. For the SPS, the injector to the LHC, this goal requires a doubling of the injected intensity to 2.6e11 ppb. Longitudinal instabilities were observed in the SPS for intensities below the required 2.6e11 ppb. Identifying, and ultimately mitigating, the impedance sources driving the instabilities requires...
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Mr Patrick Kramer (Rheinisch Westfaelische Tech. Hoch. (DE))24/09/2019, 17:20
Beam intensities required by the High-Luminosity (HL-) LHC can presently not be delivered by the CERN SPS, mainly due to beam loading, but also due to a longitudinal multi-bunch instability. This instability is known to be triggered by the third harmonic passband of the 200 MHz multi-cell accelerating structures at an intensity threshold three times below the nominal LHC intensity in the 200...
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Dr Alessandro Citterio (PSI)24/09/2019, 17:30
At the end of 2017, the conceptual design for an upgrade of the Swiss Light Source was finished, promising a 50 fold increase of the brilliance from the current value. From the point of view of collective effects, the main changes in the new design are a reduced chamber size, fully coated with NEG, and operation at small and negative momentum compaction with low synchronous frequency. We give...
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Adrian Oeftiger (GSI)24/09/2019, 17:40
This work presents measurements demonstrating the impact of space charge on the historical vertical SPS instability. The instability has first been encountered as an intensity limit in the SPS Q26 optics. The framework of the fast head-tail instability (or transverse mode coupling instability) describes the behaviour of the found intensity thresholds well. Now, for the first time, we explore...
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Alexandre Lasheen (CERN)24/09/2019, 17:50
Longitudinal instabilities in the CERN PS are an important limitation in the framework of the LHC Injector Upgrade project to reach the expected beam intensity and longitudinal emittance at PS extraction. The observed instabilities include dipolar and quadrupolar coupled-bunch instabilities, as well as uncontrolled longitudinal emittance blow-up with protons. A microwave instability develops...
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Mauro Migliorati (Sapienza Universita e INFN, Roma I (IT))24/09/2019, 18:00
Two Vlasov solvers for the longitudinal and transverse planes are used to study the frequency shift of coherent oscillation modes and possible mode-coupling instability in case of a broad-band resonator impedance model. In parallel to this approach, a new method to study the coherent frequency shift from the results of simulation codes is presented. Comparisons between the two methods are...
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Miriam Brosi (Karlsruhe Institute of Technology)24/09/2019, 18:10
At KARA, the Karlsruhe Research Accelerator of the Karlsruhe Institute of Technology synchrotron, the so-called short-bunch operation mode allows the reduction of the bunch length down to a few picoseconds. The microbunching instability resulting from the high degree of longitudinal compression leads to fluctuations in the emitted terahertz radiation. For highly compressed bunches at KARA, the...
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Lorenzo Teofili (Sapienza Universita e INFN, Roma I (IT))24/09/2019, 18:20
The High Luminosity Large Hadron Collider (HL-LHC) Project at CERN calls for increasing beam brightness and intensity.
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In this framework, it is crucial to reduce the electromagnetic coupling between the particle beams and the surrounding environment (by means of the concepts of wakefield and impedance) in order to minimize undesired effects as beam instabilities and RF-heating.
In the past... -
chao li (IHEP)24/09/2019, 18:30
The beam-ion interaction is one of the critical issues leading to beam phase space distortion, emittance growth and collective instability in electron rings, especially at the first beam commissioning state. To have a clear picture on the evolution of beam and ion in the rings with various filling patterns and different type of gas, a multi-ion multi-beam code model is developed to depict the...
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Mr Chuntao Lin (Institute of High Energy Physics)24/09/2019, 18:40
In recent years, strong-strong simulations and following theoretical analysis has shown a novel strong coherent head-tail type instability induced by the beam-beam interaction in case of large Piwinski angle The width of stable working point limited by the instability is very narrow when we try to reach the beam-beam limit at CEPC. In this paper the chromaticity is considered, the luminosity...
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Yuting Wang (IHEP, CAS)24/09/2019, 18:50
Within the ultrarelativistic limit, the impedance is investigated for the elliptical beam pipe with finite thickness. Fielding matching method is used to determine the electromagnetic fields in different layers. Additionally, numerical results are given to show the behavior of the longitudinal and transverse wake function or its corresponding impedance. The transverse tune shifts induced by...
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Dr Haisheng Xu (IHEP)24/09/2019, 19:00
The on-axis swap-out injection is a promising injection scheme for the ultra-low emittance storage rings with generally small dynamic apertures. However, previous studies show that the initial mis-match in longitudinal phase space may lead to collective effects, such as transverse oscillations, emittance growth, and even particle loss before approaching the equilibrium state after injection,...
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Robert Williamson (STFC)24/09/2019, 19:10
ISIS is the pulsed spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Operation centres on a rapid cycling proton synchrotron (RCS) which accelerates 3e13 protons per pulse from 70 MeV to 800 MeV at 50 Hz, delivering a mean beam power of 0.2 MW.
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Research and development at ISIS are focused on key aspects of high intensity operation with a view to increasing... -
Danilo Quartullo (Sapienza Universita e INFN, Roma I (IT))24/09/2019, 19:20
The CERN FCC-ee top-up booster synchrotron will accelerate electrons and positrons from an injection energy of 20 GeV up to an extraction energy between 45.6 GeV and 182.5 GeV depending on the operation mode. These accelerated beams will be used for the initial filling of the high-luminosity FCC-ee collider and for keeping the beam current constant over time using continuous top-up injection....
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Mr Vadim Gubaidulin (TU Darmstadt)24/09/2019, 19:30
Electron lenses are one of the ways to provide incoherent betatron tune spread for Landau damping of transverse coherent beam instabilities. We investigated the effect of transverse electron beam profile size and shape for Landau damping with electron lens. Another point of interests is Landau damping provided by a pulsed electron lens with homogeneous transverse beam profile. This type of...
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maria rosaria masullo (infn)24/09/2019, 19:40
Resistive-wall impedance constitutes a significant percentage of the total beam-coupling impedance budget of an accelerator. A number of different reduction techniques have been proposed during the years depending on the specific applications, ranging from higher order modes damping to solutions entailing high electrical-conductivity coatings of the pipe. This paper investigates the use of...
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Dr Thomas Guenzel (CELLS/ALBA synchrotron, Cerdanyola de Valles, Spain)24/09/2019, 19:50
Based on the recent work of R. Lindberg on transverse collective instabilities (PRAB 19, 124402,(2016)) it was observed that if the ratio of quadrupolar to dipolar impedance is equal to -1, there is no TMC-instability. This relationship is actually fulfilled by horizontal resistive wall impedance. "Headtail" simulations were carried out to check if this formal observation could be confirmed....
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