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| MOPAB112 | Schottky Based Intensity Measurements and Errors Due to Statistical Fluctuations | background, pick-up, instrumentation, diagnostics | 385 |
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| The beam intensities at the Extra Low ENergy Antiproton ring ELENA are too low for standard beam current transformers and, thus, are measured with longitudinal Schottky diagnostics. This method is already successfully used at the Antiproton Decelerator since the commissioning of this machine. The fact that Schottky noise is a statistical phenomenon implies statistical errors of these measurements. Simple analytical formulas describing the statistical error to be expected as a function of the frequency spread of the band considered, the time resolution chosen and the background noise have been derived. On the one hand, low revolution harmonics and, in turn, frequency spread of the band analysed lead to large measurement errors as this situation corresponds to low momentum resolution of the resulting distribution describing the beam. At very large revolution harmonics and, thus, frequency spreads of the band analysed, the measurement error increases again due to additional contributions from the background noise. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB112 | ||
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| MOPAB127 | A New Method for Emittance Reconstruction Using a Scraper in a Dispersive Region of a Low Energy Storage Ring | emittance, simulation, storage-ring, closed-orbit | 429 |
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Funding: Science and Technology Funding Council, UK CERN Beam scraping is a standard method for beam emittance measurements at low energies and will be applied at the Extra Low ENergy Antimatter (ELENA) ring. However, in ELENA, as in many other low energy storage rings, the scraper is located in a position of finite dispersion which poses a unique challenge when reconstructing the emittance from beam intensity data. A new algorithm for ELENA and other machines that use a scraper in a dispersive region has been developed. It combines data obtained by scraping the beam from opposite sides with information on the storage ring lattice. In this contribution, the new algorithm is presented, tested using simulations and compared with alternate methods for emittance reconstruction. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB127 | ||
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| MOPIK127 | FAIR Risk Management as a Proactive Steering Tool for the Large Scale Multi Project | factory, experiment, project-management, ion | 839 |
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| The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar separator, Collector Ring, High Energy Storage Ring), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes the implementation of a progressive risk management methodology based on a comprehensive assessment on work package level. Complexity factors (number of parts, level of state of the art, level of human interfaces, level of operational complexity) and importance factors (safety, cost, schedule, resources) represent the likelihood of risk occurrence and the eventual value at risk. Relative comparison of the normalized factors together with a supplier assessment enables to derive an event based risk register with a standardized evaluation scheme assigning risk and opportunity classes. This contribution demonstrates the full methodology highlighting some typical examples of the FAIR project. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK127 | ||
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| TUPVA134 | Accelerators Validating Antimatter Physics (AVA) | experiment, electron, storage-ring, diagnostics | 2414 |
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Funding: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk'odowska-Curie grant agreement No 721559. Antimatter experiments are at the cutting edge of science. They are, however, very difficult to realize and have been limited by the performance of the only existing facility in the world, the Antiproton Decelerator (AD) at CERN. The Extra Low Energy Antiproton ring (ELENA) will be a critical upgrade to this unique facility and commissioned from autumn 2016. This will significantly enhance the beam quality and enable new experiments. To fully exploit the discovery potential of this facility, advances are urgently required in numerical tools that can adequately model beam transport, life time and interaction, beam diagnostics tools and detectors to characterize the beam's properties, as well as in novel experiments that exploit the enhanced beam quality that ELENA will provide. AVA is a new European research and training initiative between universities, research centers and industry that will carry out R&D into ELENA and related facilities. This contribution gives an overview of the AVA research programme across its three scientific work packages. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA134 | ||
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| WEPVA034 | ELENA - From Installation to Commissioning | injection, experiment, ion, ion-source | 3327 |
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| ELENA (Extra Low ENergy Antiproton ring) is an upgrade project at the CERN AD (Antiproton Decelerator). The smaller ELENA ring will further decelerate 5.3 MeV antiprotons from the AD ring down to 100 keV using electron cooling to obtain good deceleration efficiency and dense beams. An increase of up to two orders of magnitude in trapping efficiency is expected at the AD experiments. This paper will report on the current status of ELENA where beam commissioning of the ring is now taking place. Phase one of the project installation has been completed with ring and injection lines in place, while phase two will finalize the project with installation of 100 keV transfer lines connecting the experiments to ELENA and is planned to take place in 2019/2020. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA034 | ||
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| WEPVA103 | Renovation of CERN Antiproton Production Target Area and Associated Design, Testing and R&D Activities | target, operation, proton, simulation | 3506 |
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| In the Antiproton Decelerator (AD) Target Area antiprotons are produced by the collisions of 26 GeV/c proton beam with a fixed target. They are then collected by a 400 kA pulsed magnetic horn, momentum selected and injected into the AD facility. The area has been in operation since the 80s, keeping most of the equipment dating back to this period. A major upgrade is foreseen during the CERN's Long Shutdown 2 to guarantee the next decades of antiproton physics. Among other R&D activities, three main systems are within the scope of this upgrade; (i) a new antiproton target design, pressurized-air-cooled and with a new core configuration based on the results from the HiRadMat27 experiment. (ii) Manufacturing of a set of new magnetic horns and testing them using a dedicated test bench replicating the real horn setup. (iii) Design of new target and horn's trolleys, which are responsible for their positioning as well as providing an efficient long term maintenance giving the high radioactivity of the area. This paper presents an overview of these and other critical activities associated to the renovation of the target area, including status and direction of the new proposed designs. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA103 | ||
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| THPAB098 | Test Setup for Automated Barrier Bucket Signal Generation | cavity, operation, controls, synchrotron | 3948 |
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Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) under the project 05P15RDRBA. For sophisticated beam manipulation several ring accelerators at FAIR and GSI like the main synchrotron SIS100 and the ESR will be equipped with barrier bucket systems. Hence, the associated LLRF has to be applicable to different RF systems, with respect to the cavity layout and the power amplifier used, as well as to variable repetition rates and amplitudes. Since already the first barrier bucket pulse of a long sequence has to meet certain minimum demands, an open-loop control on the basis of calibration data is foreseen. Closed-loop control is required to improve the signal quality during a sequence of pulses and to adapt to changing conditions like temperature drifts. A test setup was realized that allows controlling the signal generator, reading out the oscilloscope as well as processing the collected data. Frequency and time domain methods can be implemented to approach the dynamics of the RF system successively and under operating conditions, i.e. generating single sine pulses. The setup and first results from measurements are presented as a step towards automated acquisition of calibration data and iterative improvement of the same. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB098 | ||
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| THPIK092 | Considerations on the Effect of Magnet Yoke Dilution on Remanent Field at ELENA | quadrupole, simulation, dipole, multipole | 4299 |
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The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron constructed at CERN to decelerate antiprotons down to 100 keV and, thus, operated at very low magnetic fields. The CERN magnet group has carried out extensive investigations on accelerator magnets for very low fields, comprising theoretical studies and the construction of several prototype magnets, to ensure that the required field quality can be reached at these very low fields. In the course of this work, experimental investigations [1] led to the initially unexpected observation that dilution of the yoke, i.e. alternating laminations made of electric steel with thicker non-magnetic stainless steel laminations, increases the remnant field. An explanation for this behaviour has already been anticipated in a previous paper [2]. Here, we treat this specific topic in analytical detail. We come to the conclusion that magnet yoke thinning in most practical situations does not improve the field quality at very low field levels, but rather enhances the impact from hysteresis and remanence effects.
[1] L.Fiscarelli, Magnetic measurements on the quadrupoles prototypes for ELENA (PXMQNLGNAP), CERN internal report. [2] D. Schoerling, Case Study of a Magnetic System for low-Energy Machines, PRAB 19, 082401 (2016). |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK092 | ||
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| THPIK093 | Blow-Up Due to Intra Beam Scattering during Deceleration in ELENA | emittance, simulation, scattering, electron | 4303 |
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| Intra Beam Scattering (IBS) is expected to be the main performance limitation of the Extra Low Energy Antiproton ring (ELENA), a small synchrotron equipped with electron cooling under construction at CERN to decelerate antiprotons from 5.3 MeV to 100 keV. Thus, the duration of the ramps must not be too long to avoid excessive blow up due to IBS. On the other hand, the bending magnets are C-shaped and the vacuum chambers are without insulated junctions, which are difficult for fully baked machines; thus, the ramps must not be too short. The evolution of transverse and longitudinal emittances along the ramps have been estimated assuming that IBS is the main phenomenon leading to blow-up. The blow-up due to IBS found along the ramps have been found to be acceptable. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK093 | ||
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