| Paper | Title | Page |
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| MOPOPT047 | Experimental Demonstration of Machine Learning Application in LHC Optics Commissioning | 359 |
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| Recently, we conducted successful studies on the suitability of machine learning (ML) methods for optics measurements and corrections, incorporating novel ML-based methods for local optics corrections and reconstruction of optics functions. After performing extensive verifications on simulations and past measurement data, the newly developed techniques became operational in the LHC commissioning 2022. We present the experimental results obtained with the ML-based methods and discuss future improvements. Besides, we also report on improving the Beam Position Monitor (BPM) diagnostics with the help of the anomaly detection technique capable to identify malfunctioning BPMs along with their possible fault causes. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT047 | |
| About • | Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022 | |
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| WEPOST008 | Optics Correction Strategy for Run 3 of the LHC | 1687 |
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| 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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| WEPOPT009 | Operational Scenario of First High Luminosity LHC Run | 1846 |
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| 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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| WEPOPT059 | Corrections of Systematic Normal Decapole Field Errors in the HL-LHC Separation/Recombination Dipoles | 1991 |
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Funding: This work has been supported by the HiLumi Project and been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Re-search. Magnetic measurements revealed that the normal decapole (b5) errors of the recombination dipoles (D2) could have a systematic component of up to 11 units. Based on previous studies, it was predicted that the current corrections would not be able to compensate this, thereby leading to a degradation of the dynamic aperture by about 0.5 - 1 ’. On the other hand, the separation dipole D1 is expected to have a systematic b5 component of 6-7 units and its contribution to the resonance driving terms will partly compensate the effect of D2, due to the opposite field strength of the main component. Simulations were performed with the HL-LHC V1.4 lattice to test these concerns and to verify the compensation assumption. In addition, various normal decapole resonance driving terms were examined for correction, the results of which are presented in this contribution. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT059 | |
| About • | Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022 | |
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| WEPOPT060 | Controlling Landau Damping via Feed-Down From High-Order Correctors in the LHC and HL-LHC | 1995 |
| SUSPMF005 | use link to see paper's listing under its alternate paper code | |
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Funding: This work has been supported by the HiLumi Project and been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Re-search. Amplitude detuning measurements in the LHC have shown that a significant amount of detuning is generated in Beam 1 via feed-down from decapole and dodecapole field errors in the triplets of the experiment insertion regions, while in Beam 2 this detuning is negligible. In this study, we investigate the cause of this behavior and we attempt to find corrections that use the feed-down from the nonlinear correctors in the insertion region for amplitude detuning. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT060 | |
| About • | Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022 | |
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| WEPOPT061 | A Flexible Nonlinear Resonance Driving Term Based Correction Algorithm with Feed-Down | 1999 |
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Funding: This work has been supported by the HiLumi Project and been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Re-search. The optics in the insertion regions of the LHC and its upgrade project the High Luminosity LHC are very sensitive to local magnetic errors, due to the extremely high beta-functions. In collision optics, the non-zero closed orbit in the same region leads to a "feed-down" of high-order errors to lower orders, causing additional effects detrimental to beam lifetime. An extension to the well-established method for correcting these errors by locally suppressing resonance driving terms has been undertaken, not only taking this feed-down into account, but also adding the possibility of utilizing it such that the powering of higher-order correctors will compensate for lower order errors. Existing correction schemes have also operated on the assumption of (anti-)symmetric beta-functions of the optics in the two rings. This assumption can fail for a multitude of reasons, such as inherently asymmetric optics and unevenly distributed errors. In this respect, an extension of this correction scheme has been developed, removing the need for symmetry by operating on the two separate optics of the beams simultaneously. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT061 | |
| About • | Received ※ 07 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022 | |
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