IPAC2022 - Classification: MC1: Circular and Linear Colliders / A01: Hadron Colliders

Paper	Title	Page
WEPOST003	Implications of the Upgrade II of LHCb on the LHC Insertion Region 8: From Energy Deposition Studies to Mitigation Strategies	1679
	A. Ciccotelli The University of Manchester, Manchester, United Kingdom R.B. Appleby UMAN, Manchester, United Kingdom F. Butin, F. Cerutti, A. Ciccotelli, L.S. Esposito, B. Humann, M. Wehrle CERN, Meyrin, Switzerland B. Humann TU Vienna, Wien, Austria
	Starting from LHC Run3, a first upgrade of the LHCb experiment (Upgrade I) will enable oeration with a significantly increased instantaneous luminosity in the LHC Insertion Region 8 (IR8), up to 2·10³³/(cm² s). Moreover, the proposed second upgrade of the LHCb experiment (Upgrade II) aims at increasing it by an extra factor 7.5 and collecting an integrated luminosity of 400/fb by the end of Run6. Such an ambitious goal poses challenges not only for the detector but also for the accelerator components. Monte Carlo simulations represent a valuable tool to predict the implications of the radiation impact on the machine, especially for future operational scenarios. A detailed IR8 model implemented by means of the FLUKA code is presented in this study. With such a model, we calculated the power density and dose distributions in the superconducting coils of the LHC final focusing quadrupoles (Q1-Q3) and separation dipole (D1) and we highlight a few critical issues calling for mitigation measures. Our study addresses also the recombination dipole (D2) and the suitability of the present TANb absorber, as well as the proton losses in the Dispersion Suppressor (DS) and their implications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST003
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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WEPOST008	Optics Correction Strategy for Run 3 of the LHC	1687
	T.H.B. Persson, F.S. Carlier, A. Costa Ojeda, J. Dilly, V. Ferrentino, E. Fol, H. García Morales, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, F. Soubelet, R. Tomás García, A. Wegscheider, L. van Riesen-Haupt CERN, Meyrin, Switzerland J.F. Cardona UNAL, Bogota D.C, Colombia
	After almost 4 years of shutdown the LHC is again operational in 2022. Experience from the previous Long Shutdown (LS) has shown that the local errors around the triplet magnets changed significantly and it is likely we will again see different errors in 2022. In the LHC there is an interplay between the linear and the nonlinear correction which can make the corrections difficult and time-consuming to find. In this article, we describe the measurements and corrections performed during the commissioning in 2022 in order to control both the linear and the nonlinear optics to high precision.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST008
About •	Received ※ 08 June 2022 — Revised ※ 25 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022
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WEPOST031	RHIC Polarized Proton Operation in Run 22	1765
	V. Schoefer, E.C. Aschenauer, D. Bruno, K.A. Drees, W. Fischer, C.J. Gardner, K. Hock, H. Huang, R.L. Hulsart, C. Liu, Y. Luo, I. Marneris, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, J. Sandberg, W.B. Schmidke, F. Severino, T.C. Shrey, P. Thieberger, J.E. Tuozzolo, M. Valette, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno BNL, Upton, New York, USA
	The Relativistic Heavy Ion Collider (RHIC) Run 22 physics program consisted of collisions with vertically po- larized proton beams at a single collision point (the STAR detector). During initial startup of the collider, power out- ages damaged two of the coils in one of the RHIC helical dipole snake magnets used for polarization preservation in the Blue ring. That snake was reconfigured for use as a partial snake. We will outline some of the remediating mea- sures taken to maximize polarization transmission in this configuration. These measures included changing the col- liding beam energy from 255 GeV to 254.2 GeV to adjust the spin closed orbit at store and adjustment of the field in the other helical dipole in the Blue ring to improve injection spin matching. Later in the run, the primary motor gener- ator for the AGS (the injector to RHIC) failed and a lower voltage backup had to be used, resulting in a period of lower polarization. Other efforts include detailed measurement of the stable spin direction at store and the commissioning of a machine protection relay system to prevent spurious firing of the RHIC abort kickers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST031
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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WEPOPT001	NICA Ion Collider and Plans of Its First Operations	1819
	E. Syresin, O.I. Brovko, A.V. Butenko, A.R. Galimov, E.V. Gorbachev, V. Kekelidze, H.G. Khodzhibagiyan, S.A. Kostromin, V.A. Lebedev, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, G.V. Trubnikov, A. Tuzikov JINR, Dubna, Moscow Region, Russia
	The Nuclotron-based Ion Collider fAcility (NICA) is under assembling in JINR. The NICA goals are providing of colliding beams for studies of hot and dense strongly interacting baryonic matter and spin physics. The heavy ion injection complex of Collider NICA consisting from following accelerators: new acting heavy ion linac HILAC with RFQ and IH DTL sections at energy 3.2 MeV/u, new acting superconducting Booster synchrotron at energy up 600 MeV/u, acting superconducting synchrotron Nuclotron at gold ion energy 3.9 GeV/n, will starts operation with first ion beams in beginning of 2022. The assembling of two Collider storage rings with two interaction points was done in December 2021. The status of acceleration complex NICA and plans of its first operation is under discussion.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT001
About •	Received ※ 30 May 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022
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WEPOPT002	Conception of High Intensive Polarized Proton Beam Formation in NICA Collider	1822
	E. Syresin, A.V. Butenko, S.A. Kostromin, O.S. Kozlov, I.N. Meshkov, A.O. Sidorin, G.V. Trubnikov, A. Tuzikov JINR, Dubna, Moscow Region, Russia Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia S.D. Kolokolchikov, Y. Senichev RAS/INR, Moscow, Russia A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia N.V. Mityanina BINP SB RAS, Novosibirsk, Russia P.R. Zenkevich ITEP, Moscow, Russia
	NICA (Nuclotron-based Ion Collider fAcility) is a new accelerator complex being assembled at JINR to search for the mixed phase of baryonic matter and to investigate the nature of nucleon/particle spin. The polarized proton beams will be operated at the energy range of 5-12.6 GeV, the beam intensity in each ring of 2.2x10¹³ and the luminosity of 1x10³² cm^-2 s^-1. The conception of formation of high intensive proton beams is discussed for two different schemes. In first scheme the protons are injected from Nuclotron to Collider at an energy of 2-2.5 GeV to provide the cooling and the storage at this energy and then they are accelerated up to energy of experiments. In the second scheme the cooling of protons is realized in one from accelerators of the injection chain and the protons are injected from Nuclotron to Collider at energy of experiments, where they are stored up required intensity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT002
About •	Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 12 June 2022
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WEPOPT003	Challenges of Low Energy Hadron Colliders	1825
	G.V. Trubnikov, V.A. Lebedev JINR, Dubna, Moscow Region, Russia A.V. Butenko, S.A. Kostromin, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, E. Syresin, A. Tuzikov JINR/VBLHEP, Dubna, Moscow region, Russia
	NICA collider complex is under construction at JINR. The initial configuration of the collider will perform collisions of fully stripped heavy ions, 209 Bi and others, for a study of phase transition in the quark-gluon plasma in the energy range 1/4.5 GeV/u per beam. Commissioning of the collider injection chain has been recently started. The complex includes 2 linacs, 2 Booster synchrotrons (Booster and Nuclotron to support the beam injection to the collider), and 2 collider rings of 503 m circumference. The design luminosity is ~10²⁷ 1/(cm*s) at 4.5 GeV/u. The heavy ions are generated in the ESIS-type ion source with intensity ~10 9 /pulse. Then they are accelerated into the linac and Booster and directed to stripping target. Next, fully stripped ions are accelerated in the Nuclotron and injected into Collider. The electron and stochastic cooling are used in each of the collider rings to support beam accumulation and to prevent the emittance growth due to intrabeam scattering. Three RF systems are used for longitudinal phase space manipulations. An achievement of design luminosity requires overcoming many technological and beam physics problems which are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT003
About •	Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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WEPOPT004	Acceleration and Crossing of Transition Energy Investigation Using an RF Structure of the Barrier Bucket Type in the NICA Accelerator Complex	1829
	S.D. Kolokolchikov, A.A. Melnikov, Y. Senichev RAS/INR, Moscow, Russia E. Syresin JINR, Dubna, Moscow Region, Russia
	The dynamic of longitudinal motion in Barrier Bucket RF structure is considered. To preserve the stability of the proton beam during the acceleration to the experiment energy it is necessary to cross the transition energy and a rapid jump of transition energy is possible. The influence of the second-order slip factor is taking into account, as well as the space charge effect. The dynamic aperture is investigated for various gradients of focusing quadrupoles and corresponding working points which is necessary for transition crossing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT004
About •	Received ※ 16 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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WEPOPT007	First Interaction Region Local Coupling Corrections in the LHC Run 3	1838
	F. Soubelet, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland Ö. Apsimon, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This research is supported by the LIV. DAT Center for Doctoral Training, STFC and the European Organization for Nuclear Research The successful operation of large scale particle accelerators depends on the precise correction of unavoidable magnetic field or magnet alignment errors present in the machine. During the LHC Run 2, local linear coupling in the interaction regions (IR) was shown to have a significant impact on the beam size, making its proper handling a necessity for Run 3 and the High Luminosity LHC (HL-LHC). A new approach to accurately minimise the local IR linear coupling based on correlated external variables such as the \|C-\| had been proposed, which relies on the application of a rigid waist shift in order to create an asymmetry in the IR optics. In this contribution, preliminary corrections from the 2021 beam test and the early 2022 commissioning are presented, as well as first results of the new method’s experimental configuration tests in the LHC Run 3 commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT007
About •	Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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WEPOPT008	Supervised Machine Learning for Local Coupling Sources Detection in the LHC	1842
SUSPMF001	use link to see paper's listing under its alternate paper code
	F. Soubelet, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland Ö. Apsimon, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This research is supported by the LIV. DAT Center for Doctoral Training, STFC and the European Organization for Nuclear Research Local interaction region (IR) linear coupling in the LHC has been shown to have a negative impact on beam size and luminosity, making its accurate correction for Run 3 and beyond a necessity. In view of determining corrections, supervised machine learning has been applied to the detection of linear coupling sources, showing promising results in simulations. An evaluation of different applied models is given, followed by the presentation of further possible application concepts for linear coupling corrections using machine learning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT008
About •	Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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WEPOPT009	Operational Scenario of First High Luminosity LHC Run	1846
	R. Tomás García, G. Arduini, P. Baudrenghien, R. Bruce, O.S. Brüning, X. Buffat, R. Calaga, F. Cerutti, R. De Maria, J. Dilly, I. Efthymiopoulos, M. Giovannozzi, P.D. Hermes, G. Iadarola, O.R. Jones, S. Kostoglou, E.H. Maclean, N. Mounet, E. Métral, Y. Papaphilippou, S. Redaelli, G. Sterbini, H. Timko, F.F. Van der Veken, J. Wenninger, M. Zerlauth CERN, Meyrin, Switzerland
	A new scenario for the first operational run of the HL-LHC era (Run 4) has been recently developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL-LHC design. The operational scenario in terms of beam parameters and machine settings, as well as the different phases, are described here along with the impact of potential delays on key hardware components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT009
About •	Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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WEPOPT010	Progress on Action Phase Jump for LHC Local Optics Correction	1850
	J.F. Cardona, Y. Rodriguez Garcia UNAL, Bogota D.C, Colombia H. García Morales, M. Hofer, E.H. Maclean, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland Y. Rodriguez Garcia UAN, Bogotá D.C., Colombia
	The correction of the local optics at the Interaction Regions of the LHC is crucial to ensure a good performance of the machine. This is even more important for the future LHC upgrade, HL-LHC, where the optics is more sensitive to magnetic errors. For that reason, it is important to explore alternative techniques for local optics corrections. In this paper, we evaluate the performance of the Action Phase Jump method for optics correction in the LHC and the HL-LHC and explore ways to integrate this technique in regular operations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT010
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022
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WEPOPT013	Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC	1862
	C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb₃Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013
About •	Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022
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WEPOPT014	The Effect of a Partially Depleted Halo on the Criticality and Detectability of Fast Failures in the HL-LHC	1866
	C. Hernalsteens, C. Lannoy, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	In the High Luminosity LHC (HL-LHC) era, the bunch intensity will be increased to νm{2.2e11} protons, which is almost twice the nominal LHC intensity. The stored energy in each of the two beams will increase to §I{674}{MJ}. The HL-LHC will feature beams whose transverse halos are partially depleted by means of a hollow electron lens. The reduced stored energy in the beam tails will significantly change the development of losses caused by failures. This paper reports on beam tracking simulations evaluating the effect of a partially depleted halo on the criticality and detection of failures originating from the superconducting magnet protection systems. In addition, the effect of the transverse damper operating as a coherent excitation system leading to orbit excursions on a beam with a partially depleted halo is discussed. The results in terms of time-dependent beam losses are presented. The margins between the failure onset, its detection, and the time to reach critical loss levels, are discussed. The results are extrapolated to failure cases of different origins that induce similar beam loss dynamics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT014
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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WEPOPT015	Study of Hydrodynamic-Tunnelling Effects Induced by High-Energy Proton Beams in Graphite	1870
	C. Wiesner, F. Carra, J. Don, I. Kolthoff, A. Lechner, S.R. Rasile, D. Wollmann CERN, Meyrin, Switzerland
	The design and assessment of machine-protection systems for existing and future high-energy accelerators comprises the study of accidental beam impact on machine elements. In case of a direct impact of a large number of high-energy particle bunches in one location, the damage range in the material is significantly increased due to an effect known as hydrodynamic tunnelling. The effect is caused by the beam-induced reduction of the material density along the beam trajectory, which allows subsequent bunches to penetrate deeper into the target. The assessment of the damage range requires the sequential coupling of an energy-deposition code, like FLUKA, and a hydrodynamic code, like Autodyn. The paper presents the simulations performed for the impact of the nominal LHC beam at 7 TeV on a graphite target. It describes the optimisation of the simulation setup and the required coupling workflow. The resulting energy deposition and the evolution of the target density are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT015
About •	Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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WEPOPT016	Beam-Based Reconstruction of the Shielded Quench-Heater Fields for the LHC Main Dipoles	1874
	L.C. Richtmann, L. Bortot, E. Ravaioli, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	Small orbit oscillations of the circulating particle beams have been observed immediately following quenches in the LHC’s superconducting main dipole magnets. Magnetic fields generated during the discharge into the quench heaters were identified as the cause. Since the resulting, shielded field inside the beam screen cannot be measured in-situ, the time evolution of the field has to be reconstructed from the measured beam excursions. In this paper, the field-reconstruction method using rotation in normalized phase space and the optimized fitting algorithm are described. The resulting rise times and magnetic field levels are presented for quench events that occurred during regular operation as well as for dedicated beam experiments. Finally, different approaches to model the shielding behavior of the beam screen are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT016
About •	Received ※ 16 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022
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WEPOPT019	RHIC Blue Snake Blues	1881
	F. Méot, E.C. Aschenauer, H. Huang, A. Marusic, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, V. Schoefer BNL, Upton, New York, USA
	Funding: Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Two helical full snakes are used in both Blue and Yellow rings of RHIC collider, in order to preserve beam polarization during acceleration to collision energy and polarization lifetime at store. A snake in RHIC is comprised of four 2.4m long modules, powered by pair. During the startup of RHIC Run 22 in December 2021, two successive power dips have caused the 9 o’clock RHIC BlBrookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.ue ring snake to loose two of its four modules. In spite of this regrettable loss, it has been possible to maintain near 180deg snake precession, by proper powering of the remaining two modules, as well as, by re-tuning the 3 o’clock sister snake, vertical spin precession axis around the ring and spin tune 1/2. Determining these new settings, in order to salvage polarization with the handicapped Blue snake pair, has required series of numerical simulations, a brief overview is given here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT019
About •	Received ※ 03 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 07 July 2022
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WEPOPT020	Modeling RHIC Spin Tilt as Lattice Imperfections	1884
	V.H. Ranjbar, E.C. Aschenauer, H. Huang, A. Marusic, F. Méot, V. Schoefer BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. A tilt in the spin direction from the vertical has been observed for a number of years in the RHIC collider during store. This tilt has been extensively studied by scanning snake strengths, energies and orbital angles during the 2017 polarized proton run. Using a spin transport model, we attempt to model this spin tilt by fitting all the relevant data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT020
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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WEPOPT032	Summary of the 3-year Beam Energy Scan II operation at RHIC	1908
	C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Beam Energy Scan phase II (BES-II) operation in the Relativistic Heavy Ion Collider (RHIC), aiming to explore the phase transition between quark-gluon plasma (QGP) and hadronic gas, exceeded the goal of a four-fold increase in the average luminosity over the range of five gold beam energies (9.8, 7.3, 5.75, 4.59 and 3.85 GeV/nucleon) compared to those achieved during Beam Energy Scan phase I (BES-I). We will present the achievements in BES-II together with a summary of the measures taken to improve RHIC performance in the presence of several beam dynamics effects, and details on improvements made during the operation at 3.85 GeV/nucleon in 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT032
About •	Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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WEPOPT033	Report of RHIC Beam Operation in 2021	1912
	C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The first priority of RHIC operation in 2021 was the Au+Au collisions at 3.85 GeV/nucleon, which is the lowest energy to complete the 3-year Beam Energy Scan II physics program, with RF-based electron cooling. In addition, RHIC also operated for several other physics programs including fixed target experiments, O+O at 100 GeV/nucleon, Au+Au at 8.65 GeV/nucleon, and d+Au at 100 GeV/nucleon. This report presents the operational experience and the results from RHIC operation in 2021. With Au+Au collisions at 3.85 GeV/nucleon reported in a separate report, this paper focuses on the operation conditions for the other programs mentioned above.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT033
About •	Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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WEPOPT058	A Response Matrix Approach to Skew-Sextupole Correction in the LHC at Injection	1987
	E. Waagaard Uppsala University, Uppsala, Sweden E.H. Maclean CERN, Meyrin, Switzerland
	To date, no dedicated attempt has been made to correct skew-sextupole resonances in the LHC at injection. Recently this topic has gained interest however, following the investigation for the emittance growth generation during the LHC energy ramp, due to third order islands. The LHC is equipped with skew-sextupole correctors in the experimental insertions (MCSSX), intended for local compensation at top energy, and with several families of skew sextupole magnets in the arcs (MSS), which are intended for chromatic coupling compensation at top energy but are not optimally placed for resonance compensation. Simulation studies were performed in MAD-X and PTC to assess whether the MSS and MCSSX correctors could be used to compensate skew-sextupole RDTs in the LHC at injection via a response matrix approach, based on measured values at the LHC BPMs. It was found that compensation was viable, but at the cost of significantly increased corrector strength compared to chromatic coupling compensation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT058
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 23 June 2022
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WEPOTK010	The Second Long Shutdown of the LHC and Its Injectors: Feedback from the Accelerator Coordination and Engineering Group	2052
	A.-L. Perrot, M. Bernardini, S. Chemli, J.-P. Corso, J. Coupard, F.B. Dos Santos Pedrosa, J. Etheridge, K. Foraz, S. Grillot, J.M. Jimenez, B. Nicquevert, S. Petit, J.Ph.G.L. Tock, E. Vergara Fernandez CERN, Meyrin, Switzerland
	The operation of the Large Hadron Collider (LHC) at CERN started in September 2008. Every 5 or 6 years, Long Shutdowns (LS) are programmed to execute time-intensive ordinary and extra-ordinary maintenance of the LHC and its injectors. The second LS (LS2) started in December 2018 and was completed end 2020 for the injectors and early 2022 for the LHC. A huge number of maintenance, consolidation and upgrade activities, especially the upgrade of the injectors complex, were performed with challenges at various levels, from technical, to organizational and managerial. This paper presents the applied methodology put in place by the Accelerator Coordination & Engineering (EN-ACE) Group, in charge of the technical coordination of the activities for the interventions and changes to the LHC and its injectors, to ensure that the installation activities are performed safely, meeting the required high level of quality, while optimizing the schedule. It highlights key points of success and lessons learnt in terms of general coordination, quality assurance, configuration and layout management, spatial integration, planning and scheduling, operational safety, logistics and worksite coordination
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK010
About •	Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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Paper

Title

Page

Implications of the Upgrade II of LHCb on the LHC Insertion Region 8: From Energy Deposition Studies to Mitigation Strategies

1679

A. Ciccotelli
The University of Manchester, Manchester, United Kingdom
R.B. Appleby
UMAN, Manchester, United Kingdom
F. Butin, F. Cerutti, A. Ciccotelli, L.S. Esposito, B. Humann, M. Wehrle
CERN, Meyrin, Switzerland
B. Humann
TU Vienna, Wien, Austria

Starting from LHC Run3, a first upgrade of the LHCb experiment (Upgrade I) will enable oeration with a significantly increased instantaneous luminosity in the LHC Insertion Region 8 (IR8), up to 2·10³³/(cm² s). Moreover, the proposed second upgrade of the LHCb experiment (Upgrade II) aims at increasing it by an extra factor 7.5 and collecting an integrated luminosity of 400/fb by the end of Run6. Such an ambitious goal poses challenges not only for the detector but also for the accelerator components. Monte Carlo simulations represent a valuable tool to predict the implications of the radiation impact on the machine, especially for future operational scenarios. A detailed IR8 model implemented by means of the FLUKA code is presented in this study. With such a model, we calculated the power density and dose distributions in the superconducting coils of the LHC final focusing quadrupoles (Q1-Q3) and separation dipole (D1) and we highlight a few critical issues calling for mitigation measures. Our study addresses also the recombination dipole (D2) and the suitability of the present TANb absorber, as well as the proton losses in the Dispersion Suppressor (DS) and their implications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST003

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022

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WEPOST008

Optics Correction Strategy for Run 3 of the LHC

1687

T.H.B. Persson, F.S. Carlier, A. Costa Ojeda, J. Dilly, V. Ferrentino, E. Fol, H. García Morales, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, F. Soubelet, R. Tomás García, A. Wegscheider, L. van Riesen-Haupt
CERN, Meyrin, Switzerland
J.F. Cardona
UNAL, Bogota D.C, Colombia

After almost 4 years of shutdown the LHC is again operational in 2022. Experience from the previous Long Shutdown (LS) has shown that the local errors around the triplet magnets changed significantly and it is likely we will again see different errors in 2022. In the LHC there is an interplay between the linear and the nonlinear correction which can make the corrections difficult and time-consuming to find. In this article, we describe the measurements and corrections performed during the commissioning in 2022 in order to control both the linear and the nonlinear optics to high precision.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST008

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Received ※ 08 June 2022 — Revised ※ 25 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022

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WEPOST031

RHIC Polarized Proton Operation in Run 22

1765

V. Schoefer, E.C. Aschenauer, D. Bruno, K.A. Drees, W. Fischer, C.J. Gardner, K. Hock, H. Huang, R.L. Hulsart, C. Liu, Y. Luo, I. Marneris, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, J. Sandberg, W.B. Schmidke, F. Severino, T.C. Shrey, P. Thieberger, J.E. Tuozzolo, M. Valette, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno
BNL, Upton, New York, USA

The Relativistic Heavy Ion Collider (RHIC) Run 22 physics program consisted of collisions with vertically po- larized proton beams at a single collision point (the STAR detector). During initial startup of the collider, power out- ages damaged two of the coils in one of the RHIC helical dipole snake magnets used for polarization preservation in the Blue ring. That snake was reconfigured for use as a partial snake. We will outline some of the remediating mea- sures taken to maximize polarization transmission in this configuration. These measures included changing the col- liding beam energy from 255 GeV to 254.2 GeV to adjust the spin closed orbit at store and adjustment of the field in the other helical dipole in the Blue ring to improve injection spin matching. Later in the run, the primary motor gener- ator for the AGS (the injector to RHIC) failed and a lower voltage backup had to be used, resulting in a period of lower polarization. Other efforts include detailed measurement of the stable spin direction at store and the commissioning of a machine protection relay system to prevent spurious firing of the RHIC abort kickers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST031

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022

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WEPOPT001

NICA Ion Collider and Plans of Its First Operations

1819

E. Syresin, O.I. Brovko, A.V. Butenko, A.R. Galimov, E.V. Gorbachev, V. Kekelidze, H.G. Khodzhibagiyan, S.A. Kostromin, V.A. Lebedev, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, G.V. Trubnikov, A. Tuzikov
JINR, Dubna, Moscow Region, Russia

The Nuclotron-based Ion Collider fAcility (NICA) is under assembling in JINR. The NICA goals are providing of colliding beams for studies of hot and dense strongly interacting baryonic matter and spin physics. The heavy ion injection complex of Collider NICA consisting from following accelerators: new acting heavy ion linac HILAC with RFQ and IH DTL sections at energy 3.2 MeV/u, new acting superconducting Booster synchrotron at energy up 600 MeV/u, acting superconducting synchrotron Nuclotron at gold ion energy 3.9 GeV/n, will starts operation with first ion beams in beginning of 2022. The assembling of two Collider storage rings with two interaction points was done in December 2021. The status of acceleration complex NICA and plans of its first operation is under discussion.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT001

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Received ※ 30 May 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022

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WEPOPT002

Conception of High Intensive Polarized Proton Beam Formation in NICA Collider

1822

E. Syresin, A.V. Butenko, S.A. Kostromin, O.S. Kozlov, I.N. Meshkov, A.O. Sidorin, G.V. Trubnikov, A. Tuzikov
JINR, Dubna, Moscow Region, Russia
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
S.D. Kolokolchikov, Y. Senichev
RAS/INR, Moscow, Russia
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
N.V. Mityanina
BINP SB RAS, Novosibirsk, Russia
P.R. Zenkevich
ITEP, Moscow, Russia

NICA (Nuclotron-based Ion Collider fAcility) is a new accelerator complex being assembled at JINR to search for the mixed phase of baryonic matter and to investigate the nature of nucleon/particle spin. The polarized proton beams will be operated at the energy range of 5-12.6 GeV, the beam intensity in each ring of 2.2x10¹³ and the luminosity of 1x10³² cm^-2 s^-1. The conception of formation of high intensive proton beams is discussed for two different schemes. In first scheme the protons are injected from Nuclotron to Collider at an energy of 2-2.5 GeV to provide the cooling and the storage at this energy and then they are accelerated up to energy of experiments. In the second scheme the cooling of protons is realized in one from accelerators of the injection chain and the protons are injected from Nuclotron to Collider at energy of experiments, where they are stored up required intensity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT002

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Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 12 June 2022

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WEPOPT003

Challenges of Low Energy Hadron Colliders

1825

G.V. Trubnikov, V.A. Lebedev
JINR, Dubna, Moscow Region, Russia
A.V. Butenko, S.A. Kostromin, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, E. Syresin, A. Tuzikov
JINR/VBLHEP, Dubna, Moscow region, Russia

NICA collider complex is under construction at JINR. The initial configuration of the collider will perform collisions of fully stripped heavy ions, 209 Bi and others, for a study of phase transition in the quark-gluon plasma in the energy range 1/4.5 GeV/u per beam. Commissioning of the collider injection chain has been recently started. The complex includes 2 linacs, 2 Booster synchrotrons (Booster and Nuclotron to support the beam injection to the collider), and 2 collider rings of 503 m circumference. The design luminosity is ~10²⁷ 1/(cm*s) at 4.5 GeV/u. The heavy ions are generated in the ESIS-type ion source with intensity ~10 9 /pulse. Then they are accelerated into the linac and Booster and directed to stripping target. Next, fully stripped ions are accelerated in the Nuclotron and injected into Collider. The electron and stochastic cooling are used in each of the collider rings to support beam accumulation and to prevent the emittance growth due to intrabeam scattering. Three RF systems are used for longitudinal phase space manipulations. An achievement of design luminosity requires overcoming many technological and beam physics problems which are discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT003

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Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022

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WEPOPT004

Acceleration and Crossing of Transition Energy Investigation Using an RF Structure of the Barrier Bucket Type in the NICA Accelerator Complex

1829

S.D. Kolokolchikov, A.A. Melnikov, Y. Senichev
RAS/INR, Moscow, Russia
E. Syresin
JINR, Dubna, Moscow Region, Russia

The dynamic of longitudinal motion in Barrier Bucket RF structure is considered. To preserve the stability of the proton beam during the acceleration to the experiment energy it is necessary to cross the transition energy and a rapid jump of transition energy is possible. The influence of the second-order slip factor is taking into account, as well as the space charge effect. The dynamic aperture is investigated for various gradients of focusing quadrupoles and corresponding working points which is necessary for transition crossing.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT004

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Received ※ 16 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

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WEPOPT007

First Interaction Region Local Coupling Corrections in the LHC Run 3

1838

F. Soubelet, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland
Ö. Apsimon, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This research is supported by the LIV. DAT Center for Doctoral Training, STFC and the European Organization for Nuclear Research
The successful operation of large scale particle accelerators depends on the precise correction of unavoidable magnetic field or magnet alignment errors present in the machine. During the LHC Run 2, local linear coupling in the interaction regions (IR) was shown to have a significant impact on the beam size, making its proper handling a necessity for Run 3 and the High Luminosity LHC (HL-LHC). A new approach to accurately minimise the local IR linear coupling based on correlated external variables such as the |C-| had been proposed, which relies on the application of a rigid waist shift in order to create an asymmetry in the IR optics. In this contribution, preliminary corrections from the 2021 beam test and the early 2022 commissioning are presented, as well as first results of the new method’s experimental configuration tests in the LHC Run 3 commissioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT007

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Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

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WEPOPT008

Supervised Machine Learning for Local Coupling Sources Detection in the LHC

1842

SUSPMF001

use link to see paper's listing under its alternate paper code

F. Soubelet, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland
Ö. Apsimon, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This research is supported by the LIV. DAT Center for Doctoral Training, STFC and the European Organization for Nuclear Research
Local interaction region (IR) linear coupling in the LHC has been shown to have a negative impact on beam size and luminosity, making its accurate correction for Run 3 and beyond a necessity. In view of determining corrections, supervised machine learning has been applied to the detection of linear coupling sources, showing promising results in simulations. An evaluation of different applied models is given, followed by the presentation of further possible application concepts for linear coupling corrections using machine learning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT008

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Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022

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WEPOPT009

Operational Scenario of First High Luminosity LHC Run

1846

R. Tomás García, G. Arduini, P. Baudrenghien, R. Bruce, O.S. Brüning, X. Buffat, R. Calaga, F. Cerutti, R. De Maria, J. Dilly, I. Efthymiopoulos, M. Giovannozzi, P.D. Hermes, G. Iadarola, O.R. Jones, S. Kostoglou, E.H. Maclean, N. Mounet, E. Métral, Y. Papaphilippou, S. Redaelli, G. Sterbini, H. Timko, F.F. Van der Veken, J. Wenninger, M. Zerlauth
CERN, Meyrin, Switzerland

A new scenario for the first operational run of the HL-LHC era (Run 4) has been recently developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL-LHC design. The operational scenario in terms of beam parameters and machine settings, as well as the different phases, are described here along with the impact of potential delays on key hardware components.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT009

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Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022

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WEPOPT010

Progress on Action Phase Jump for LHC Local Optics Correction

1850

J.F. Cardona, Y. Rodriguez Garcia
UNAL, Bogota D.C, Colombia
H. García Morales, M. Hofer, E.H. Maclean, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland
Y. Rodriguez Garcia
UAN, Bogotá D.C., Colombia

The correction of the local optics at the Interaction Regions of the LHC is crucial to ensure a good performance of the machine. This is even more important for the future LHC upgrade, HL-LHC, where the optics is more sensitive to magnetic errors. For that reason, it is important to explore alternative techniques for local optics corrections. In this paper, we evaluate the performance of the Action Phase Jump method for optics correction in the LHC and the HL-LHC and explore ways to integrate this technique in regular operations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT010

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022

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WEPOPT013

Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC

1862

C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb₃Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013

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Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022

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WEPOPT014

The Effect of a Partially Depleted Halo on the Criticality and Detectability of Fast Failures in the HL-LHC

1866

C. Hernalsteens, C. Lannoy, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

In the High Luminosity LHC (HL-LHC) era, the bunch intensity will be increased to νm{2.2e11} protons, which is almost twice the nominal LHC intensity. The stored energy in each of the two beams will increase to §I{674}{MJ}. The HL-LHC will feature beams whose transverse halos are partially depleted by means of a hollow electron lens. The reduced stored energy in the beam tails will significantly change the development of losses caused by failures. This paper reports on beam tracking simulations evaluating the effect of a partially depleted halo on the criticality and detection of failures originating from the superconducting magnet protection systems. In addition, the effect of the transverse damper operating as a coherent excitation system leading to orbit excursions on a beam with a partially depleted halo is discussed. The results in terms of time-dependent beam losses are presented. The margins between the failure onset, its detection, and the time to reach critical loss levels, are discussed. The results are extrapolated to failure cases of different origins that induce similar beam loss dynamics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT014

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

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WEPOPT015

Study of Hydrodynamic-Tunnelling Effects Induced by High-Energy Proton Beams in Graphite

1870

C. Wiesner, F. Carra, J. Don, I. Kolthoff, A. Lechner, S.R. Rasile, D. Wollmann
CERN, Meyrin, Switzerland

The design and assessment of machine-protection systems for existing and future high-energy accelerators comprises the study of accidental beam impact on machine elements. In case of a direct impact of a large number of high-energy particle bunches in one location, the damage range in the material is significantly increased due to an effect known as hydrodynamic tunnelling. The effect is caused by the beam-induced reduction of the material density along the beam trajectory, which allows subsequent bunches to penetrate deeper into the target. The assessment of the damage range requires the sequential coupling of an energy-deposition code, like FLUKA, and a hydrodynamic code, like Autodyn. The paper presents the simulations performed for the impact of the nominal LHC beam at 7 TeV on a graphite target. It describes the optimisation of the simulation setup and the required coupling workflow. The resulting energy deposition and the evolution of the target density are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT015

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Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022

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WEPOPT016

Beam-Based Reconstruction of the Shielded Quench-Heater Fields for the LHC Main Dipoles

1874

L.C. Richtmann, L. Bortot, E. Ravaioli, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

Small orbit oscillations of the circulating particle beams have been observed immediately following quenches in the LHC’s superconducting main dipole magnets. Magnetic fields generated during the discharge into the quench heaters were identified as the cause. Since the resulting, shielded field inside the beam screen cannot be measured in-situ, the time evolution of the field has to be reconstructed from the measured beam excursions. In this paper, the field-reconstruction method using rotation in normalized phase space and the optimized fitting algorithm are described. The resulting rise times and magnetic field levels are presented for quench events that occurred during regular operation as well as for dedicated beam experiments. Finally, different approaches to model the shielding behavior of the beam screen are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT016

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Received ※ 16 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022

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WEPOPT019

RHIC Blue Snake Blues

1881

F. Méot, E.C. Aschenauer, H. Huang, A. Marusic, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, V. Schoefer
BNL, Upton, New York, USA

Funding: Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Two helical full snakes are used in both Blue and Yellow rings of RHIC collider, in order to preserve beam polarization during acceleration to collision energy and polarization lifetime at store. A snake in RHIC is comprised of four 2.4m long modules, powered by pair. During the startup of RHIC Run 22 in December 2021, two successive power dips have caused the 9 o’clock RHIC BlBrookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.ue ring snake to loose two of its four modules. In spite of this regrettable loss, it has been possible to maintain near 180deg snake precession, by proper powering of the remaining two modules, as well as, by re-tuning the 3 o’clock sister snake, vertical spin precession axis around the ring and spin tune 1/2. Determining these new settings, in order to salvage polarization with the handicapped Blue snake pair, has required series of numerical simulations, a brief overview is given here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT019

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Received ※ 03 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 07 July 2022

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WEPOPT020

Modeling RHIC Spin Tilt as Lattice Imperfections

1884

V.H. Ranjbar, E.C. Aschenauer, H. Huang, A. Marusic, F. Méot, V. Schoefer
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A tilt in the spin direction from the vertical has been observed for a number of years in the RHIC collider during store. This tilt has been extensively studied by scanning snake strengths, energies and orbital angles during the 2017 polarized proton run. Using a spin transport model, we attempt to model this spin tilt by fitting all the relevant data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT020

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022

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WEPOPT032

Summary of the 3-year Beam Energy Scan II operation at RHIC

1908

C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam Energy Scan phase II (BES-II) operation in the Relativistic Heavy Ion Collider (RHIC), aiming to explore the phase transition between quark-gluon plasma (QGP) and hadronic gas, exceeded the goal of a four-fold increase in the average luminosity over the range of five gold beam energies (9.8, 7.3, 5.75, 4.59 and 3.85 GeV/nucleon) compared to those achieved during Beam Energy Scan phase I (BES-I). We will present the achievements in BES-II together with a summary of the measures taken to improve RHIC performance in the presence of several beam dynamics effects, and details on improvements made during the operation at 3.85 GeV/nucleon in 2021.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT032

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Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022

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WEPOPT033

Report of RHIC Beam Operation in 2021

1912

C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The first priority of RHIC operation in 2021 was the Au+Au collisions at 3.85 GeV/nucleon, which is the lowest energy to complete the 3-year Beam Energy Scan II physics program, with RF-based electron cooling. In addition, RHIC also operated for several other physics programs including fixed target experiments, O+O at 100 GeV/nucleon, Au+Au at 8.65 GeV/nucleon, and d+Au at 100 GeV/nucleon. This report presents the operational experience and the results from RHIC operation in 2021. With Au+Au collisions at 3.85 GeV/nucleon reported in a separate report, this paper focuses on the operation conditions for the other programs mentioned above.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT033

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Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022

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WEPOPT058

A Response Matrix Approach to Skew-Sextupole Correction in the LHC at Injection

1987

E. Waagaard
Uppsala University, Uppsala, Sweden
E.H. Maclean
CERN, Meyrin, Switzerland

To date, no dedicated attempt has been made to correct skew-sextupole resonances in the LHC at injection. Recently this topic has gained interest however, following the investigation for the emittance growth generation during the LHC energy ramp, due to third order islands. The LHC is equipped with skew-sextupole correctors in the experimental insertions (MCSSX), intended for local compensation at top energy, and with several families of skew sextupole magnets in the arcs (MSS), which are intended for chromatic coupling compensation at top energy but are not optimally placed for resonance compensation. Simulation studies were performed in MAD-X and PTC to assess whether the MSS and MCSSX correctors could be used to compensate skew-sextupole RDTs in the LHC at injection via a response matrix approach, based on measured values at the LHC BPMs. It was found that compensation was viable, but at the cost of significantly increased corrector strength compared to chromatic coupling compensation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT058

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 23 June 2022

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WEPOTK010

The Second Long Shutdown of the LHC and Its Injectors: Feedback from the Accelerator Coordination and Engineering Group

2052

A.-L. Perrot, M. Bernardini, S. Chemli, J.-P. Corso, J. Coupard, F.B. Dos Santos Pedrosa, J. Etheridge, K. Foraz, S. Grillot, J.M. Jimenez, B. Nicquevert, S. Petit, J.Ph.G.L. Tock, E. Vergara Fernandez
CERN, Meyrin, Switzerland

The operation of the Large Hadron Collider (LHC) at CERN started in September 2008. Every 5 or 6 years, Long Shutdowns (LS) are programmed to execute time-intensive ordinary and extra-ordinary maintenance of the LHC and its injectors. The second LS (LS2) started in December 2018 and was completed end 2020 for the injectors and early 2022 for the LHC. A huge number of maintenance, consolidation and upgrade activities, especially the upgrade of the injectors complex, were performed with challenges at various levels, from technical, to organizational and managerial. This paper presents the applied methodology put in place by the Accelerator Coordination & Engineering (EN-ACE) Group, in charge of the technical coordination of the activities for the interventions and changes to the LHC and its injectors, to ensure that the installation activities are performed safely, meeting the required high level of quality, while optimizing the schedule. It highlights key points of success and lessons learnt in terms of general coordination, quality assurance, configuration and layout management, spatial integration, planning and scheduling, operational safety, logistics and worksite coordination

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK010

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Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022

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