Paper | Title | Page |
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MOOHC2 | The US Electron Ion Collider Accelerator Designs | 1 |
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With the completion of the National Academies of Sciences Assessment of a US Electron-Ion Collider, the prospects for construction of such a facility have taken a step forward. This paper provides an overview of the two site-specific EIC designs: JLEIC (Jefferson Lab) and eRHIC (BNL) as well as brief overview of ongoing EIC R&D. | ||
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Slides MOOHC2 [14.774 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOOHC2 | |
About • | paper received ※ 29 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019 | |
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MOYBA4 | eRHIC Design Update | 18 |
TUPLO11 | use link to see paper's listing under its alternate paper code | |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The future electron-ion collider (EIC) aims at an electron-proton luminosity of 1033 to 1034 cm-2 sec-1 and a center-of-mass energy range from 20 to 140 GeV. The eRHIC design has been continuously evolving over a couple of years and has reached a considerable level of maturity. The concept is generally conservative with very few risk items which are mitigated in various ways. |
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Slides MOYBA4 [5.466 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA4 | |
About • | paper received ※ 24 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019 | |
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MOYBA6 | Accelerator Performance During the Beam Energy Scan II at RHIC in 2019 | 26 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. RHIC provided Au-Au collisions at beam energies of 9.8, 7.3, 4.59 and 3.85 GeV/nucleon during the first year of the Beam Energy Scan II in 2019. The physics goals at the first two higher beam energies were achieved. At the two lower beam energies, bunched electron beam cooling has been demonstrated successfully. The accelerator performance was improved compared to when RHIC was operated at these energies in earlier years. This article will introduce the challenges to operate RHIC at low energies and the corresponding countermeasures, and review the improvement of accelerator performance during the operation in 2019. |
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Slides MOYBA6 [6.579 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA6 | |
About • | paper received ※ 21 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019 | |
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MOPLM18 | Design of the 2-Stage Laser Transport for the Low Energy RHIC Electron Cooling (LEReC) DC Photogun | 144 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The electron beam for the recently constructed Low Energy RHIC electron Cooler (LEReC) at Brookhaven National Laboratory is generated by a high-power fiber laser illuminating a photocathode. The pointing stability of the low-energy electron beam, which is crucial to maintain within acceptable limits given the long beam transport, is highly dependent on the center-of-mass (CoM) stability of the laser spot on the photocathode. For reasons of accessibility during operations, the laser itself is located outside the accelerator tunnel, leading to the need to propagate the laser beam 34 m via three laser tables to the photocathode. The challenges to achieving the required CoM stability of 10 microns on the photocathode thus requires mitigation of vibrations along the transport and of weather- and season-related environmental effects, while preserving accessibility and diagnostic capabilities with proactive design. After successful commissioning of the full transport in 2018/19, we report on our solutions to these design challenges. LEReC Photocathode DC Gun Beam Test Results - D. Kayran Conference: C18-04-29, p.TUPMF025 Commissioning of Electron Accelerator LEReC for Bunch Beam Cooling - D.Kayran, NAPAC19 |
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Poster MOPLM18 [1.970 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM18 | |
About • | paper received ※ 27 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019 | |
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TUXBB1 |
Beam Instrumentation and Measurement Challenges | |
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Since the inception of particle accelerators about 100 years ago, nearly every field of modern society has benefited from their continued development. Applications include discovery science (identification of basic matter constituents and their interactions), nuclear weapon and energy development, material and biological sciences as well as medical sciences including cancer therapies. Common to all accelerators is the need for accurate and precise measurements of the beam’s properties to optimize accelerator performance. This tutorial will cover select beam instrumentation basics, applications of these for characterizing accelerator performance, then present instrumentation challenges for future particle accelerators. | ||
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Slides TUXBB1 [17.345 MB] | |
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TUZBA1 | Commissioning of the Electron Accelerator LEReC for Bunched Beam Cooling | 330 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The brand-new state of the art electron accelerator, LEReC, was built and commissioned at BNL. LEReC accelerator includes a photocathode DC gun, a laser system, a photocathode delivery system, magnets, beam diagnostics, a SRF booster cavity, and a set of Normal Conducting RF cavities to provide sufficient flexibility to tune the beam in the longitudinal phase space. Electron beam quality suitable for cooling in the Relativistic Heavy Ion Collider (RHIC) was achieved [1], which lead to the first demonstration of bunched beam electron cooling of hadron beams [2]. This presentation will discuss commissioning results, achieved beam parameters and performance of the LEReC systems. [1] D.Kayran et al., First results from Commissioning of LEReC, in Proc of IPAC2019 [2] A.Fedotov et al., First electron cooling of hadron beams using a bunched electron beam, presented at NAPAC2019 |
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Slides TUZBA1 [18.343 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA1 | |
About • | paper received ※ 27 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019 | |
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TUPLH24 | Performance of CeC PoP Accelerator | 526 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Coherent electron cooling experiment is aimed for demonstration of the proof-of-principle demonstration of reduction energy spread of a single hadron bunch circulating in RHIC. The electron beam should have the required parameters and its orbit and energy should be matched to the hadron beam. In this paper we present the achieved electron beam parameters including emittance, energy spread, and other critical indicators. The operational issues as well as future plans are also discussed. |
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Poster TUPLH24 [11.180 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH24 | |
About • | paper received ※ 29 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019 | |
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TUPLO03 | RHIC Beam Abort System Upgrade Options | 536 |
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Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. The RHIC ion (polarized proton) beam intensity has increased to 4x (1.1x) of the original design specifications. In 2013 proton beam currents overcame the eddy current reduction design features in the RHIC beam abort system kicker magnets causing ferrite heating and resulting in a reduction of the kicker strength. In 2014, the abort kicker ferrites were changed, the eddy current reduction design was upgraded, and an active ferrite cooling loop installed to prevent heating. For ions the beam dump vacuum window was changed from stainless steel to a titanium alloy and the adjacent beam diffuser block carbon material was changed to allow for higher ion intensities. A thicker beam pipe was installed to prevent secondaries from quenching the adjacent superconducting quadrupole. With these upgrades there is at least a factor 2 of safety margin for the demonstrated intensities to date. For a further increase in the intensity for RHIC and eRHIC we evaluate upgrade options for the beam abort system. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO03 | |
About • | paper received ※ 26 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019 | |
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TUPLO05 | Fixed Target Operation at RHIC in 2019 | 542 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. RHIC operated in fixed target mode at beam energies 4.59, 7.3, and 31.2 GeV/nucleon in 2019 as a part of the Beam Energy Scan II program. To scrape beam halo effectively at the fixed target which is 2.05 m away from the center of the STAR detectors, lattice design with relative large beta function at STAR was implemented at the two lower energies. The kickers of the base-band tune (BBQ) measurement system were engaged to dilute the beam transversely to maintain the event rate except for 31.2 GeV/nucleon. In addition, beam orbit control, tune and chromaticity adjustments were used to level the event rate. This paper will review the operational experience of RHIC in fixed target mode at various energies. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO05 | |
About • | paper received ※ 21 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019 | |
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THYBA6 | Active Pointing Stabilization Techniques Applied to the Low Energy RHIC Electron Cooling Laser Transport at BNL | 938 |
MOPLM22 | use link to see paper's listing under its alternate paper code | |
SUPLH07 | use link to see paper's listing under its alternate paper code | |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The electron beam for the Low Energy RHIC electron Cooler (LEReC) at Brookhaven National Laboratory (BNL) is generated by a high-power fiber laser illuminating a photocathode. The pointing stability of the electron beam, which is crucial given its long transport, is highly dependent on the center-of-mass (CoM) stability of the laser spot on the photocathode. For reasons of accessibility during operations, the laser is located outside the accelerator tunnel, and the laser beam is propagated over a total distance of 34 m via three laser tables to the photocathode. The challenges to achieving the required CoM stability of 10 microns RMS on the photocathode include mitigation of the effects of vibrations along the transport and of weather- and season-related environmental effects, while preserving accessibility and diagnostic capabilities. Due to the insufficiency of infrastructure alone in overcoming these challenges, two active laser transport stabilization systems aimed at addressing specific types of position instability were installed during the 2018 Shutdown. After successful commissioning of the full transport in 2018/19, we report on our solutions to these design challenges. |
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Slides THYBA6 [3.426 MB] | |
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Poster THYBA6 [1.299 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THYBA6 | |
About • | paper received ※ 27 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019 | |
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THZBA5 | First Electron Cooling of Hadron Beams Using a Bunched Electron Beam | 957 |
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Funding: Work supported by the U.S. Department of Energy. The Low Energy RHIC electron Cooler (LEReC) was recently constructed and commissioned at BNL. The LEReC is the first electron cooler based on the RF acceleration of electron bunches (previous electron coolers all used DC beams). Bunched electron beams are necessary for cooling hadron beams at high energies. The challenges of such an approach include generation of electron beams suitable for cooling, delivery of electron beams of the required quality to the cooling sections without degradation of beam emittances and energy spread, achieving required small angles between electrons and ions in the cooling sections, precise energy matching between the two beams, high-current operation of the electron accelerator, as well as several physics effects related to bunched beam cooling. Following successful commissioning of the electron accelerator in 2018, the focus of the LEReC project in 2019 was on establishing electron-ion interactions and demonstration of cooling process using electron energy of 1.6MeV (ion energy of 3.85GeV/n), which is the lowest energy of interest. Here we report on the first demonstration of Au ion cooling in RHIC using this new approach. |
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Slides THZBA5 [16.417 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA5 | |
About • | paper received ※ 16 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019 | |
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