Paper | Title | Other Keywords | Page |
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MOPG05 | Transient Studies of the Stripline Kicker for Beam Extraction from CLIC Damping Rings | flattop, impedance, kicker, simulation | 35 |
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Stripline kickers are generally assumed to have equal contributions from the electric and magnetic field to the total deflection angle, for ultra-relativistic beams. Hence parameters of the striplines, such as the characteristic impedance, the field homogeneity and the deflection angle are typically determined by simulating the striplines from an electrostatic perspective. However recent studies show that, when exciting the striplines with a trapezoidal current pulse, the magnetic field changes during the flat-top of the pulse, and this can have a significant effect upon the striplines performances. The transient solver of Opera2D has been used to study the magnetic field, for the striplines to be used for beam extraction from the CLIC damping rings, when exciting the electrodes with a pulse of 1 us flat-top and 100 ns rise and fall times. The time dependence of the characteristic impedance, field homogeneity and deflection angle are presented in this paper. In addition, two solutions are proposed to improve the flatness of the magnitude of the magnetic field throughout the flat-top of the pulse, and the predicted results are reported. | |||
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Poster MOPG05 [1.557 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG05 | ||
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MOPG33 | Design of RISP RFQ Cooler Buncher | ion, emittance, rfq, injection | 115 |
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Under RISP project, wide variety of intense rare isotope ion beams will be provided. An EBIS charge breeder has been designed to charge breed these beams. Its optimum operation requires injection of bunched beam with high quality. An RFQ cooler buncher RFQCB is designed to meet these requirements. To meet the EBIS beam requirements, RFQCB should efficiently accept high intensity continuous beams and deliver to the EBIS bunched beams with small emittance (3 '.mm.mrad), low energy spread (< 10 eV) and short bunch width (2-10 μs). A new design concept to be implemented in this RFQCB have been developed, including a novel injection/extraction electrodes geometry, new RF voltages with frequency up to 10 MHz and amplitude up to 10 kV with improved differential pumping system. Simulations have shown the efficient handling of beam intensities which were never handled so far with improved beam quality. An overview of the RFQCB design concept will be presented. Simulated performance of the device and design of different sub-systems will be discussed. Beam parameters will be measured using Faraday cups and emittance meter. The design of these diagnostics tools will be described as well. | |||
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Poster MOPG33 [1.931 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG33 | ||
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MOPG71 | Polarization Measurement and Modeling of Visible Synchrotron Radiation at Spear3 | polarization, radiation, synchrotron, synchrotron-radiation | 240 |
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Synchrotron radiation from dipole magnets is linearly polarized in the plane of acceleration and evolves toward circular polarization with increasing vertical observation angle. The intensity of the x-y field components can be modeled with Schwinger's theory for the angular-spectral power distribution. Combined with Fresnel's laws for reflection at a mirror surface, it is possible to model field polarization of visible SR light in the laboratory. The polarization can also be measured with a polarizer and quarter wave plate to yield Stokes' parameters S0-S3. In this paper we present measurements and modeling of the visible SPEAR3 SR beam in terms of Stokes' parameters and plot on the results on the Poincaré sphere. | |||
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Poster MOPG71 [1.527 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG71 | ||
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TUPG15 | Intra-Train Position and Angle Stabilisation at ATF Based on Sub-Micron Resolution Stripline Beam Position Monitors | feedback, kicker, monitoring, operation | 348 |
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A low-latency, sub-micron resolution stripline beam position monitoring (BPM) system has been developed and tested with beam at the KEK Accelerator Test Facility (ATF2), where it has been used to drive a beam stabilisation system. The fast analogue front-end signal processor is based on a single-stage radio-frequency down-mixer, with a measured latency of 16 ns and a demonstrated single-pass beam position resolution of below 300 nm using a beam with a bunch charge of approximately 1 nC. The BPM position data are digitised on a digital feedback board which is used to drive a pair of kickers local to the BPMs and nominally orthogonal in phase in closed-loop feedback mode, thus achieving both beam position and angle stabilisation. We report the reduction in jitter as measured at a witness stripline BPM located 30 metres downstream of the feedback system and its propagation to the ATF interaction point. | |||
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Poster TUPG15 [1.393 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG15 | ||
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TUPG44 | Diagnoses and Controls of Single e-Pulse Extraction at LCLS-I for the ESTB Program | kicker, feedback, operation, controls | 445 |
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A pulsed magnet is used to kick single electron bunches into the SLAC A-line from the 120 Hz LCLS-1 bunch train. These single bunches are transported to the End Station Test Beam facility. It is mandated that extraction from the LCLS beam does not disturb the non-kicked pulses. An 8 mrad kick is required to extract a bunch; without compensation the following bunch experiences a 2 urad kick; with compensation this kick is reduced to about 0.1 urad which is well within the jitter level of about 0.3 urad. Electron and photon diagnostics were used to identify problems arising from eddy currents, beam feedback errors, and inadequate monitoring and control protocol. This paper discusses the efforts to diagnose, remedy, and control the pulse snatching. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG44 | ||
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TUPG45 | The CERN Beam Instrumentation Group Offline Analysis Framework | framework, instrumentation, database, software | 449 |
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Beam instrumentation systems at CERN require periodic verifications of both their state and condition. Presently, experts have no generic solution to observe and analyse an instrument's condition and as a result, many ad-hoc Python scripts have been developed to extract historical data from CERN's logging service. Clearly, ad-hoc developments are not desirable for medium/long term maintenance reasons and therefore a generic solution has been developed. In this paper we present the Offline Analysis Framework (OAF), used for automatic report generation based on data from the central logging service. OAF is a Java / Python based tool which allows generic analysis of any instrument's data extracted from the database. In addition to the generic analysis, advanced analysis can also be performed by providing custom Python code. This paper will explain the steps of the analysis, its scope and present the kind of reports that are generated and how instrumentation experts can benefit from it. We will also show how this approach simplifies debugging, allows code re-use and optimises database and CPU resource usage. | |||
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Poster TUPG45 [1.623 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG45 | ||
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TUPG50 | Status of Beam Current Transformer Developments for FAIR | ion, operation, feedback, synchrotron | 461 |
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In view of the upcoming FAIR project (Facility for Antiproton and Ion Research) several long-term development projects had been initiated with regard to diagnostic devices for beam current measurement. The main accelerator of FAIR will be the fast ramped superconducting synchrotron SIS100. Design parameters of SIS100 are acceleration of 2.5·1013 protons/cycle to 29 GeV for the production of antiprotons, as well as acceleration and slow extraction of p to U ions at 109 ions/s in the energy range of 0.4-2.7 GeV/u and extraction times of up to 10 s. For high-intensity operation non-intercepting devices are mandatory, thus the developments presented in this contribution focus on purpose-built beam current transformers. First prototype measurements of a dc current transformer based on a Tunneling Magneto Resistance sensor are presented, as well as recent achievements with a SQUID-based Cryogenic Current Comparator. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG50 | ||
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TUPG68 | Study of the Radiation Damage on a Scintillating Fibers Based Beam Profile Monitor | detector, radiation, factory, proton | 512 |
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The Scintillating Fibers Harp (SFH) monitors are the beam profile detectors used in the High Energy Beam Transfer (HEBT) lines of the CNAO (Centro Nazionale Adroterapia Oncologica, Italy) machine. The use of scintillating fibers coupled with a high-resolution CCD camera makes the detector of simple architecture and with high performances (less than 0.5mm resolution and 50Hz frame rate); on the other hand, fibers radiation damage shall be faced after some years of operation. The damage appears in multiple ways, as efficiency loss in light production, delayed light emission, attenuation length reduction. The work presents measurements and analysis performed to understand the phenomenon, in such a way to deal with it as best as possible. The connection between dose rate, integral dose and damage level is investigated as well as the possible recovery after a period of no irradiation. The influence of the damage effects on profiles reconstruction and beam parameters calculation is studied. Data elaboration is modified in such a way to compensate radiation damage effects and protract the SFH lifetime, before the major intervention of fibers replacement. Methods and results are discussed. | |||
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Poster TUPG68 [1.244 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG68 | ||
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TUPG70 | Test of the Imaging Properties of Inorganic Scintillation Screens Using Fast and Slow Extracted Ion Beams | ion, target, radiation, proton | 516 |
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Funding: Work supported by BMBF, contract number 05P12RDRBJ Inorganic scintillation screens are a common transverse profile diagnostics tool for beams extracted from the heavy ion synchrotron SIS18 at GSI. Detailed investigations concerning light output, profile reproduction and spectral emission were performed for phosphor screens P43 and P46, single crystal YAG:Ce, alumina ceramics and Chromium-doped alumina (Chromox). The screens were irradiated with several ion species from proton to Uranium. The particle energy was 300 MeV/u at intensities in the range from some 106 to 1010 particles per pulse, using either fast extraction (1μsecond duration) or slow extraction (some 100 ms duration). The light output coincides for both extraction types, i.e. no significant saturation was observed. For all materials the optical emission spectrum is independent on the ion species or beam intensities. Radiation hardness tests were performed with up to 1012 accumulated ions: The phosphor P46 as well as YAG:Ce shows no significant decrease of light output, while for P43 and Chromox a decrease by 5 to 15 % was measured. These results will trigger the choice of the standard screens installed at the FAIR facility. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG70 | ||
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WEBL02 | Beam Size Measurements Using Interferometry at LHC | injection, radiation, synchrotron, undulator | 583 |
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During the long LHC shutdown 2013-2014, both the LHC and its injector chain underwent significant upgrades. The most important changes concerned increasing the maximum LHC beam energy from 4TeV to 6.5TeV and reducing the transverse emittance of the beam from the LHC injectors. These upgrades pose challenges to the measurement of the transverse beam size via Synchrotron Radiation (SR) imaging, as the radiation parameters approach the diffraction limit. Optical SR interferometry, widely used in synchrotron light facilities, was considered as an alternative method to measure the 150 'm rms beam size at top energy as it allows measurements below the diffraction limit. A system based on this technique was therefore implemented in the LHC, for the first time on a proton machine. This paper describes the design of the LHC interferometer and its two SR sources (a superconducting undulator at low energy and a bending dipole at high energy), along with the expected performance in terms of beam size measurement as compared to the imaging system. The world's first proton beam interferogram measured at the LHC will be shown and plans to make this an operational monitor will be presented. | |||
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Slides WEBL02 [42.662 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEBL02 | ||
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