First Magnet Girder Installed in NSLS-II Storage Ring
Supervisor Frank Lincoln explains how the first magnet girder is installed in the storage ring of Brookhaven National Laboratory's National Synchrotron Light Source II (NSLS-II).
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Results for “STORAGE RING”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Progress in EIC Polarization Studies for the Injectors and Storage Ring
We present recent progress in simulations and studies for the EIC’s Electron Storage RING (ESR) and the EIC’s polarized injector the Rapid Cycling Synchrotron.
43 PARTICLE ACCELERATORS↗
Observation of Magnetic Resonances in Electron Clouds in a Positron Storage Ring
The first experimental observation of magnetic resonances in electron clouds is reported. The resonance was observed as a modulation in cloud intensity for uncoated as well as TiN-coated aluminum surfaces in the positron storage ring of the PEP-II collider at SLAC. Electron clouds frequently arise in accelerators of positively charged particles, and severely impact the machines performance. The TiN coating was found to be an effective remedy, reducing the cloud intensity by three orders of magnitude.
43 PARTICLE ACCELERATORS↗
Beam Meassurements Using Visible Synchrotron Light at NSLSII Storage Ring
Visible Synchrotron Light Monitor (SLM) diagnostic beamline has been designed and constructed at NSLS2 storage ring, to characterize the electron beam profile at various machine conditions. Thanks for the excellent alignment, SLM beamline was able to see the first visible light when beam was circulating the ring for the first turn. The beamline has been commissioned for the past year. Besides a normal CCD camera to monitor the beam profile, streak camera and gated camera are used to measure the longitudinal and transverse profile to understand the beam dynamics. Measurement results from these cameras will be present in this paper. A time correlated single photon counting system (TCSPC) has been setup and measures the single bunch purity using visible light, preliminary TCSPC measurement result will be presented as well.
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Particle Accelerator Spin-Transparent Storage Rings for Beyond State-of-the-Art Science
We will describe spin-transparent storage rings that exhibit spin-coherence times of several hours and store a large number of particles and their use in novel applications. For example, these rings can be used to directly measure the electric dipole moment of the electron, relevant to CP violation and matter-antimatter asymmetry in the universe, and to search for dark energy and ultra-light dark matter*. These rings can also serve as a compelling platform for quantum computing. In this presentation, we will describe how spin-transparent rings can be used in conjunction with ion traps to enhance scalability and increase quantum coherence times of ion quantum computing.
Suleiman, R.↗
STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe{sup 7+}
We have measured electron impact ionization for Fe{sup 7+} from the ionization threshold up to 1200 eV. The measurements were performed using the TSR heavy ion storage ring. The ions were stored long enough prior to measurements to remove most metastables, resulting in a beam of 94% ground-level ions. Comparing with the previously recommended atomic data, we find that the Arnaud and Raymond cross section is up to about 40% larger than our measurement, with the largest discrepancies below about 400 eV. The cross section of Dere agrees to within 10%, which is about the magnitude of the experimental uncertainties. The remaining discrepancies between our measurement and the Dere calculations are likely due to shortcomings in the theoretical treatment of the excitation-autoionization contribution.
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Lattice design and optimization for the PEP-X ultra low emittance storage ring at SLAC
SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source. One of the possibilities is a new PEP-X 4.5 GeV storage ring that would be housed in the 2.2 km PEP-II tunnel. The PEP-X is designed to produce photon beams having brightness near 10{sup 22} (ph/s/mm{sup 2}/mrad{sup 2}/0.1% BW) at 10 keV with 3.5 m undulator at beam current of 1.5 A. This report presents an overview of the PEP-X baseline lattice design and describes the lattice optimization procedures in order to maximize the beam dynamic aperture. The complete report of PEP-X baseline design is published in SLAC report.
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Beamline front end for in-vacuum short period undulator at the photon factory storage ring
The straight-section upgrade project of the Photon Factory created four new short straight sections capable of housing in-vacuum short period undulators. The first to fourth short period undulators SGU#17, SGU#03, SGU#01 and SGU#15 were installed at the 2.5-GeV Photon Factory storage ring in 2005, 2006, 2009 and 2013, respectively. The beamline front end for SGU#15 is described in this paper.
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Multi-objective dynamic aperture optimization for storage rings
We report an efficient dynamic aperture (DA) optimization approach using multiobjective genetic algorithm (MOGA), which is driven by nonlinear driving terms computation. It was found that having small low order driving terms is a necessary but insufficient condition of having a decent DA. Then direct DA tracking simulation is implemented among the last generation candidates to select the best solutions. The approach was demonstrated successfully in optimizing NSLS-II storage ring DA.
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Multi-stream instability of a single long electron bunch in a storage ring
A multistream instability is observed experimentally during the longitudinal expansion of an electron beam in a storage ring. The instability is observed when the beam expands in length to several times the circumference of the ring so that portions of the beam overlap. While portions of the beam overlap in physical space, they form multiple streams and remain separate in velocity space. The streams become unstable as their number increases and their separation in velocity decreases. An analytical theory predicts the onset of the instability, in agreement with simulations and measurements, over a wide range of peak line-charge densities (10.3 pC/m–1.8 nC/m) and bunch lengths. Finally, this work extends previous calculations to include the dynamic nonlinear elongation of the bunch, with a given initial length, and defines an onset criterion for the filament velocity separation for the beam to be unstable.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Analysis of Mis-Steered Electron Beam in the NSLS-II Storage Ring
This note reports the analysis of the mis-steered electron in the NSLS-II storage ring for the determination of supplementary shielding. The potential angles and offsets of the mis-steered beam are calculated by implementing the cascaded parameter scan (CPS) along the beam-line. This method is originally developed for the top-off safety analysis, and has been well documented in ref. The basic idea of CPS is to combine the phase space images due to different magnet set-points into one superset, then re-populate virtual particles on a fine grid as the input of the downstream magnet scanning. The purpose of re-population in phase space is to avoid the redundant particle tracking calculation due to the multi-layer overlap of different magnet settings. A parallel python code of implementing the tracking study has been written, and benchmarked with other top-off safety simulators developed in SLAC and LBNL.
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Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project
Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction and rf cavity straight sections. An overview of progress in these areas is presented.
Stillwell, B.↗
STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT SINGLE AND DOUBLE IONIZATION OF Fe{sup 13+} AND SINGLE IONIZATION OF Fe{sup 16+} AND Fe{sup 17+}
We report measurements of electron impact ionization for Fe{sup 13+}, Fe{sup 16+}, and Fe{sup 17+} over collision energies from below threshold to above 3000 eV. The ions were recirculated using an ion storage ring. Data were collected after a sufficiently long time that essentially all the ions had relaxed radiatively to their ground state. For single ionization of Fe{sup 13+}, we find that previous single pass experiments are more than 40% larger than our results. Compared to our work, the theoretical cross section recommended by Arnaud and Raymond is more than 30% larger, while that of Dere is about 20% greater. Much of the discrepancy with Dere is due to the theory overestimating the contribution of excitation-autoionization via n = 2 excitations. Double ionization of Fe{sup 13+} is dominated by direct ionization of an inner shell electron accompanied by autoionization of a second electron. Our results for single ionization of Fe{sup 16+} and Fe{sup 17+} agree with theoretical calculations to within the experimental uncertainties.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Mass Measurements of Proton-rich Nuclides at the Cooler Storage Ring at IMP
Recent results and progress of mass measurements of proton-rich nuclei using isochronous mass spectrometry (IMS) are reported. The nuclei under investigation were produced via fragmentation of relativistic energy heavy ions of {sup 78}Kr and {sup 58}Ni. After in-flight separation by the fragment separator RIBLL-2, the nuclei were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of the revolution times. The impact of these measurements on the stellar nucleosynthesis in the rp-process is discussed.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Beam Dynamics Simulations of Transient Beam Loading Effects in the 10GeV EIC Electron Storage Ring
We report on beam dynamics studies of transient beam loading effects in the 10 GeV EIC electron storage ring [1]. The studies are carried out with time-dependent Vlasov-Fokker-Planck simulations performed with the parallel, particle tracking code SPACE [2], which allows to follow self-consistently the dynamics of h bunches, where h in the number of RF buckets, in arbitrary multi-bunch configurations. The specific goal of the numerical simulations is to determine stable RF cavity settings under heavy beam loading. We also study the option to operate with a passive, third-harmonic cavity (3HC) system for bunch lengthening, addressing both stability and the performance limitation due to a gap in the uniform filling pattern for ion clearing.
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Conceptual Design of the Electron-Ion Collider (EIC) Electron Storage Ring (ESR) Beam Abort Systems
Two beam abort system candidates of the Electron-Ion Collier (EIC) Electron Storage Ring (ESR) are devised and discussed. The proposed candidates are based on an existing Lambertson magnet in RHIC inventory, or a brand-new Septum magnet. A comprehensive comparison is provided in this article in support of the Record of Decision.
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Muon loss rates from betatron resonances at the Muon g – 2 Storage Ring at Fermilab
The Muon g–2 Experiment at Fermilab (E989) is directed toward measuring the muon magnetic anomaly, a μ = (g–2)/2, with total statistical and systematic errors of 0.14 ppm. Here, this new measurement will serve as strong probe of effects of as yet undiscovered particles beyond the Standard Model (SM), and perhaps validate or disprove other theoretical models beyond the SM. Of special interest is the reduction of muon losses from the storage ring to achieve the precision needed at the Muon g–2 Experiment.
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STORAGE RING CROSS-SECTION MEASUREMENTS FOR ELECTRON IMPACT SINGLE AND DOUBLE IONIZATION OF Fe{sup 9+} AND SINGLE IONIZATION OF Fe{sup 10+}
We have measured electron impact ionization from the ground state of Fe{sup 9+} and Fe{sup 10+} over the relative electron-ion collision energy ranges 200-1900 eV and 250-1800 eV, respectively. The ions were confined in an ion storage ring long enough for essentially all metastable levels to radiatively relax to the ground state. For single ionization, we find a number of discrepancies between the existing theoretical cross sections and our results. The calculations appear to neglect some excitation-autoionization (EA) channels, particularly from n = 3 to n' excitations, which are important near threshold, and those from n = 2 {yields} 3 excitations, which contribute at about 650 eV. Conversely, at higher energies the calculations appear to overestimate the importance of EA channels due to excitation into levels where n {>=} 4. The resulting experimental rate coefficients agree with the most recent theory for Fe{sup 9+} to within 16% and for Fe{sup 10+} to within 19% at temperatures where these ions are predicted to form in collisional ionization equilibrium. We have also measured double ionization of Fe{sup 9+} forming Fe{sup 11+} in the energy range 450-3000 eV and found that although there is an appreciable cross section for direct double ionization, the dominant mechanism appears to be through direct ionization of an inner shell electron producing an excited state that subsequently stabilizes through autoionization.
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