Paper | Title | Page |
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MOPAB003 | Machine Learning Analysis of Electron Cooler Operation for RHIC | 45 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. A regression machine learning algorithm was applied to analyze the operation data of RHIC with electron cooler LEReC during the 2020 physics run. After constructing a black-box surrogate model from the XGBoost algorithm and plotting their partial dependency plots for different operation parameters, we can find the effects of an individual parameter on the RHIC luminosity and optimize it accordingly offline. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB003 | |
About • | paper received ※ 14 May 2021 paper accepted ※ 25 May 2021 issue date ※ 11 August 2021 | |
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MOPAB009 | Review of the Fixed Target Operation at RHIC in 2020 | 69 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. As part of the Beam Energy Scan (BES) physics program, RHIC operated in Fixed Target mode at various beam energies in 2020. The fixed target experiment, achieved by scraping the beam halo of the circulating beam on a gold ring inserted in the beam pipe upstream of the experimental detectors, extends the range of the center-of-mass energy for BES. The machine configuration, control of rates, and results of the fixed target experiment operation in 2020 will be presented in this report. |
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Poster MOPAB009 [2.913 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB009 | |
About • | paper received ※ 16 May 2021 paper accepted ※ 17 August 2021 issue date ※ 23 August 2021 | |
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MOPAB010 | RHIC Beam Energy Scan Operation with Electron Cooling in 2020 | 72 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. RHIC provided Au-Au collisions at beam energies of 5.75 and 4.59 GeV/nucleon for the physics program in 2020 as a part of the Beam Energy Scan II experiment. The operational experience at these energies will be reported with emphasis on their unique features. These unique features include the addition of a third harmonic RF system to enable a large longitudinal acceptance at 5.75 GeV/nucleon, the application of additional lower frequency cavities for alleviating space charge effects, and the world-first operation of cooling with an RF-accelerated bunched electron beam. |
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Poster MOPAB010 [3.523 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB010 | |
About • | paper received ※ 17 May 2021 paper accepted ※ 29 July 2021 issue date ※ 10 August 2021 | |
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TUXA04 | Coherent Excitations and Circular Attractors in Cooled Ion Bunches | 1279 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy In electron coolers, under certain conditions, a mismatch in either gamma-factors or trajectory angles between an electron and an ion beam can cause the formation of a circular attractor in the ion beam phase space. This leads to coherent excitations of the ions with a small synchrotron or betatron amplitude and results in unusual beam dynamics, including bifurcations. In this paper, we consider the effect of coherent excitations and discuss its implications both for Low Energy RHIC Electron Cooler (LEReC) and for high energy electron coolers proposed for the Electron-Ion Collider (EIC). |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA04 | |
About • | paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 11 August 2021 | |
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WEXA02 | Operational Electron Cooling in the Relativistic Heavy Ion Collider | 2516 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. Since the invention of the electron cooling technique its application to cool hadron beams in colliders was considered for numerous accelerator physics projects worldwide. However, achieving the required high-brightness electron beams of required quality and cooling of ion beams in collisions was deemed to be challenging. An electron cooling of ion beams employing a high-energy approach with RF-accelerated electron bunches was recently successfully implemented at BNL. It was used to cool ion beams in both collider rings with ion beams in collision. Electron cooling in RHIC became fully operational during the 2020 physics run and led to substantial improvements in luminosity. This presentation will discuss implementation, optimization and challenges of electron cooling for colliding ion beams in RHIC. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA02 | |
About • | paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 31 August 2021 | |
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WEPAB004 | Electron-Ion Luminosity Maximization in the EIC | 2582 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The electron-ion luminosity in EIC has a number of limits, including the ion intensity available from the injectors, the total ion beam current, the electron bunch intensity, the total electron current, the synchrotron radiation power, the beam-beam effect, the achievable beta functions at the interaction points (IPs), the maximum angular spreads at the IP, the ion emittances reachable with stochastic or strong cooling, the ratio of horizontal to vertical emittance, and space charge effects. We map the e-A luminosity over the center-of-mass energy range for some ions ranging from deuterons to uranium ions. For e-Au collisions the present design provides for electron-nucleon (e-Au) peak luminosities of 1.7x1033 cm-2s−1 with stochastic cooling, and 4.7x1033 cm-2s−1 with strong hadron cooling. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB004 | |
About • | paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 20 August 2021 | |
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WEPAB005 | Design Status Update of the Electron-Ion Collider | 2585 |
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Funding: Work supported by BSA, LLC under Contract No. DE-SC0012704, by JSA, LLC under Contract No. DE-AC05-06OR23177, and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy. The design of the electron-ion collider EIC to be constructed at Brookhaven National Laboratory has been continuously evolving towards a realistic and robust design that meets all the requirements set forth by the nuclear physics community in the White Paper. Over the past year activities have been focused on maturing the design, and on developing alternatives to mitigate risk. These include improvements of the interaction region design as well as modifications of the hadron ring vacuum system to accommodate the high average and peak beam currents. Beam dynamics studies have been performed to determine and optimize the dynamic aperture in the two collider rings and the beam-beam performance. We will present the EIC design with a focus on recent developments. |
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Poster WEPAB005 [2.095 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB005 | |
About • | paper received ※ 14 May 2021 paper accepted ※ 22 June 2021 issue date ※ 16 August 2021 | |
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