New developments in accelerator physics have broadened the set of available techniques for manipulating charged-particle beams. Adiabatic trapping and transport of beam in resonance islands has been studied and successfully implemented at the CERN Proton Synchrotron to perform multiturn extraction. Bent crystals have been successfully installed in the CERN Large Hadron Collider, improving the cleaning performance of the collimation system, and at the CERN Super Proton Synchrotron for reducing losses at the extraction septum in the case of slow extraction. In this paper, we discuss the potential of the combined use of resonance islands and bent crystals to devise a novel technique to perform slow extraction in circular hadron accelerators. The proposed approach is promising, particularly for applications with high-intensity beams, as it could dramatically reduce the losses on the extraction devices.
{"title":"Exploring the Potential of Resonance Islands and Bent Crystals for a Novel Slow Extraction from Circular Hadron Accelerators","authors":"D. E. Veres, G. Franchetti, M. Giovannozzi","doi":"arxiv-2409.10928","DOIUrl":"https://doi.org/arxiv-2409.10928","url":null,"abstract":"New developments in accelerator physics have broadened the set of available\u0000techniques for manipulating charged-particle beams. Adiabatic trapping and\u0000transport of beam in resonance islands has been studied and successfully\u0000implemented at the CERN Proton Synchrotron to perform multiturn extraction.\u0000Bent crystals have been successfully installed in the CERN Large Hadron\u0000Collider, improving the cleaning performance of the collimation system, and at\u0000the CERN Super Proton Synchrotron for reducing losses at the extraction septum\u0000in the case of slow extraction. In this paper, we discuss the potential of the\u0000combined use of resonance islands and bent crystals to devise a novel technique\u0000to perform slow extraction in circular hadron accelerators. The proposed\u0000approach is promising, particularly for applications with high-intensity beams,\u0000as it could dramatically reduce the losses on the extraction devices.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142251500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. A. Antipov, V. Gubaidulin, I. Agapov, E. C. Cortes Garcia, A. Gamelin
It is a truth universally acknowledged, that space charge effects in ultrarelativistic electron storage rings are irrelevant due to the steep inverse dependence of their strength on the Lorentz factor. Yet, with the push towards the diffraction limit, the state-of-the-art light sources are approaching the point where their emittance becomes so small that the space charge force can no longer be ignored. In this paper, we demonstrate how space charge effects affect the injection dynamics, dynamical aperture, and collective beam stability on the example of 4th generation light sources PETRA IV and SOLEIL II.
由于空间电荷效应的强度与洛伦兹系数呈陡峭的反比关系，因此在超相对论电子储存环中的空间电荷效应是无关紧要的，这是一个公认的真理。然而，随着衍射极限的推进，最先进的光源正在接近这样一个点：它们的发射率变得如此之小，以至于空间电荷力再也无法被忽视。在本文中，我们以第四代光源 PETRAIV 和 SOLEIL II 为例，展示了空间电荷效应如何影响注入动力学、动态孔径和集束稳定性。
{"title":"Space Charge and Future Light Sources","authors":"S. A. Antipov, V. Gubaidulin, I. Agapov, E. C. Cortes Garcia, A. Gamelin","doi":"arxiv-2409.08637","DOIUrl":"https://doi.org/arxiv-2409.08637","url":null,"abstract":"It is a truth universally acknowledged, that space charge effects in\u0000ultrarelativistic electron storage rings are irrelevant due to the steep\u0000inverse dependence of their strength on the Lorentz factor. Yet, with the push\u0000towards the diffraction limit, the state-of-the-art light sources are\u0000approaching the point where their emittance becomes so small that the space\u0000charge force can no longer be ignored. In this paper, we demonstrate how space\u0000charge effects affect the injection dynamics, dynamical aperture, and\u0000collective beam stability on the example of 4th generation light sources PETRA\u0000IV and SOLEIL II.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142251499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. SolyakFermilab, Batavia, USA, I. GoninFermilab, Batavia, USA, A. SainiFermilab, Batavia, USA, V. YakovlevFermilab, Batavia, USA, C. EdwardsFermilab, Batavia, USA, J. C. ThangarajFermilab, Batavia, USA, R. KostinEuclid Techlabs LLC, C. JingEuclid Techlabs LLC
Compact conductively cooled SRF industrial linacs can provide unique parameters of the electron beam for industrial applications. (up to 10MeV, 1MW). For ERDC project we designed normal conducting RF injector with thermal RF gridded gun integrated in first cell of multi-cell cavities. For design of the RF gun we used MICHELLE software to simulate and optimize parameters of the beam. Output file was converted to ASTRA format and most beam dynamic simulations in multi-cell normal conducting cavity and cryomodule were performed by using ASTRA software. For cross-checking we compare results of MICHELLE and AS-TRA in first few cells. At the end of injector beam reach ~250keV energy which allow to trap bunch in acceleration regime without losses in TESLA like 1.3 GHz cavity. Short solenoid at the end of injector allow to regulate transverse beam size in cryomodule to match beam to extraction system and also reduce charge losses in accelerator.
{"title":"Beam Dynamics simulations for ERDC project -- SRF linac for industrial use","authors":"N. SolyakFermilab, Batavia, USA, I. GoninFermilab, Batavia, USA, A. SainiFermilab, Batavia, USA, V. YakovlevFermilab, Batavia, USA, C. EdwardsFermilab, Batavia, USA, J. C. ThangarajFermilab, Batavia, USA, R. KostinEuclid Techlabs LLC, C. JingEuclid Techlabs LLC","doi":"arxiv-2409.07561","DOIUrl":"https://doi.org/arxiv-2409.07561","url":null,"abstract":"Compact conductively cooled SRF industrial linacs can provide unique\u0000parameters of the electron beam for industrial applications. (up to 10MeV,\u00001MW). For ERDC project we designed normal conducting RF injector with thermal\u0000RF gridded gun integrated in first cell of multi-cell cavities. For design of\u0000the RF gun we used MICHELLE software to simulate and optimize parameters of the\u0000beam. Output file was converted to ASTRA format and most beam dynamic\u0000simulations in multi-cell normal conducting cavity and cryomodule were\u0000performed by using ASTRA software. For cross-checking we compare results of\u0000MICHELLE and AS-TRA in first few cells. At the end of injector beam reach\u0000~250keV energy which allow to trap bunch in acceleration regime without losses\u0000in TESLA like 1.3 GHz cavity. Short solenoid at the end of injector allow to\u0000regulate transverse beam size in cryomodule to match beam to extraction system\u0000and also reduce charge losses in accelerator.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. WallbankFermi National Accelerator Laboratory, J. JarvisFermi National Accelerator Laboratory
Optical Stochastic Cooling (OSC) is a state-of-the-art beam cooling technology first demonstrated in 2021 at the IOTA storage ring at Fermilab's FAST facility. A second phase of the research program is planned to run in early 2025 and will incorporate an optical amplifier to enable significantly increased cooling rates and greater operational flexibility. In addition to beam cooling, an OSC system can be configured to enable advanced control over the phase space of the beam. An example operational mode could enable crystallization, where the particles in a bunch are locked into a self-reinforcing, regular microstructure at the OSC fundamental wavelength; we refer to this as Optical Stochastic Crystallization (OSX). OSX represents a new path toward Steady-State Microbunching (SSMB), which may enable light sources combining the high brightness of a free-electron laser with the high repetition rate of a storage ring. Such a source has applications from the terahertz to the extreme ultraviolet (EUV), including high-power EUV generation for semiconductor lithography. This contribution will discuss the status of the OSC experimental program and its potential to achieve the first demonstration of SSMB during the upcoming experimental run.
{"title":"Realizing Steady-State Microbunching with Optical Stochastic Crystallization","authors":"M. WallbankFermi National Accelerator Laboratory, J. JarvisFermi National Accelerator Laboratory","doi":"arxiv-2409.06619","DOIUrl":"https://doi.org/arxiv-2409.06619","url":null,"abstract":"Optical Stochastic Cooling (OSC) is a state-of-the-art beam cooling\u0000technology first demonstrated in 2021 at the IOTA storage ring at Fermilab's\u0000FAST facility. A second phase of the research program is planned to run in\u0000early 2025 and will incorporate an optical amplifier to enable significantly\u0000increased cooling rates and greater operational flexibility. In addition to\u0000beam cooling, an OSC system can be configured to enable advanced control over\u0000the phase space of the beam. An example operational mode could enable\u0000crystallization, where the particles in a bunch are locked into a\u0000self-reinforcing, regular microstructure at the OSC fundamental wavelength; we\u0000refer to this as Optical Stochastic Crystallization (OSX). OSX represents a new\u0000path toward Steady-State Microbunching (SSMB), which may enable light sources\u0000combining the high brightness of a free-electron laser with the high repetition\u0000rate of a storage ring. Such a source has applications from the terahertz to\u0000the extreme ultraviolet (EUV), including high-power EUV generation for\u0000semiconductor lithography. This contribution will discuss the status of the OSC\u0000experimental program and its potential to achieve the first demonstration of\u0000SSMB during the upcoming experimental run.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antonin Sulc, Thorsten Hellert, Raimund Kammering, Hayden Houscher, Jason St. John
As particle accelerators grow in complexity, traditional control methods face increasing challenges in achieving optimal performance. This paper envisions a paradigm shift: a decentralized multi-agent framework for accelerator control, powered by Large Language Models (LLMs) and distributed among autonomous agents. We present a proposition of a self-improving decentralized system where intelligent agents handle high-level tasks and communication and each agent is specialized control individual accelerator components. This approach raises some questions: What are the future applications of AI in particle accelerators? How can we implement an autonomous complex system such as a particle accelerator where agents gradually improve through experience and human feedback? What are the implications of integrating a human-in-the-loop component for labeling operational data and providing expert guidance? We show two examples, where we demonstrate viability of such architecture.
{"title":"Towards Agentic AI on Particle Accelerators","authors":"Antonin Sulc, Thorsten Hellert, Raimund Kammering, Hayden Houscher, Jason St. John","doi":"arxiv-2409.06336","DOIUrl":"https://doi.org/arxiv-2409.06336","url":null,"abstract":"As particle accelerators grow in complexity, traditional control methods face\u0000increasing challenges in achieving optimal performance. This paper envisions a\u0000paradigm shift: a decentralized multi-agent framework for accelerator control,\u0000powered by Large Language Models (LLMs) and distributed among autonomous\u0000agents. We present a proposition of a self-improving decentralized system where\u0000intelligent agents handle high-level tasks and communication and each agent is\u0000specialized control individual accelerator components. This approach raises some questions: What are the future applications of AI\u0000in particle accelerators? How can we implement an autonomous complex system\u0000such as a particle accelerator where agents gradually improve through\u0000experience and human feedback? What are the implications of integrating a\u0000human-in-the-loop component for labeling operational data and providing expert\u0000guidance? We show two examples, where we demonstrate viability of such\u0000architecture.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Russo, G. Franchetti, M. Giovannozzi, E. H. Maclean
Harmonic analysis has provided powerful tools to accurately determine the tune from turn-by-turn data originating from numerical simulations or beam measurements in circular accelerators and storage rings. Methods that have been developed since the 1990s are suitable for stationary signals, i.e., time series whose properties do not vary with time and are represented by stationary signals. However, it is common experience that accelerator physics is a rich source of time series in which the signal amplitude varies over time. Furthermore, the properties of the amplitude variation of the signal often contain essential information about the phenomena under consideration. In this paper, a novel approach is presented, suitable for determining the tune of a non-stationary signal, which is based on the use of the Hilbert transform. The accuracy of the proposed methods is assessed in detail, and an application to the analysis of beam data collected at the CERN Large Hadron Collider is presented and discussed in detail.
{"title":"Harmonic analysis of non-stationary signals with application to LHC beam measurements","authors":"G. Russo, G. Franchetti, M. Giovannozzi, E. H. Maclean","doi":"arxiv-2409.05406","DOIUrl":"https://doi.org/arxiv-2409.05406","url":null,"abstract":"Harmonic analysis has provided powerful tools to accurately determine the\u0000tune from turn-by-turn data originating from numerical simulations or beam\u0000measurements in circular accelerators and storage rings. Methods that have been\u0000developed since the 1990s are suitable for stationary signals, i.e., time\u0000series whose properties do not vary with time and are represented by stationary\u0000signals. However, it is common experience that accelerator physics is a rich\u0000source of time series in which the signal amplitude varies over time.\u0000Furthermore, the properties of the amplitude variation of the signal often\u0000contain essential information about the phenomena under consideration. In this\u0000paper, a novel approach is presented, suitable for determining the tune of a\u0000non-stationary signal, which is based on the use of the Hilbert transform. The\u0000accuracy of the proposed methods is assessed in detail, and an application to\u0000the analysis of beam data collected at the CERN Large Hadron Collider is\u0000presented and discussed in detail.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maximilian Herbert, Tobias Eggert, Joachim Enders, Markus Engart, Yuliya Fritzsche, Maximilian Meier, Julian Schulze, Vincent Wende
GaAs-based photocathodes are the only viable source capable of providing spin-polarized electrons for accelerator applications. This type of photocathode requires a thin surface layer, in order to achieve negative electron affinity (NEA) for efficient photo-emission. However, this layer is vulnerable to environmental and operational effects, leading to a decay of the quantum efficiency $eta$ characterized by a decay constant or lifetime $tau$. In order to increase $tau$, additional agents can be introduced during the activation procedure to improve the chemical robustness of the surface layer. This paper presents the results of recent research on Li as enhancement agent for photocathode activation using Cs and O$_2$, forming Cs-O$_2$-Li as enhanced NEA layer. Measurements yielded an increase in lifetime by a factor of up to 19 $pm$ 2 and an increase in extracted charge by a factor of up to 16.5 $pm$ 2.4, without significant reduction of $eta$. This performance is equal to or better than that reported for other enhanced NEA layers so far.
{"title":"Cs-O$_2$-Li as enhanced NEA surface layer with increased lifetime for GaAs photocathodes","authors":"Maximilian Herbert, Tobias Eggert, Joachim Enders, Markus Engart, Yuliya Fritzsche, Maximilian Meier, Julian Schulze, Vincent Wende","doi":"arxiv-2409.04319","DOIUrl":"https://doi.org/arxiv-2409.04319","url":null,"abstract":"GaAs-based photocathodes are the only viable source capable of providing\u0000spin-polarized electrons for accelerator applications. This type of\u0000photocathode requires a thin surface layer, in order to achieve negative\u0000electron affinity (NEA) for efficient photo-emission. However, this layer is\u0000vulnerable to environmental and operational effects, leading to a decay of the\u0000quantum efficiency $eta$ characterized by a decay constant or lifetime $tau$.\u0000In order to increase $tau$, additional agents can be introduced during the\u0000activation procedure to improve the chemical robustness of the surface layer.\u0000This paper presents the results of recent research on Li as enhancement agent\u0000for photocathode activation using Cs and O$_2$, forming Cs-O$_2$-Li as enhanced\u0000NEA layer. Measurements yielded an increase in lifetime by a factor of up to 19\u0000$pm$ 2 and an increase in extracted charge by a factor of up to 16.5 $pm$\u00002.4, without significant reduction of $eta$. This performance is equal to or\u0000better than that reported for other enhanced NEA layers so far.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Henderson, J. P. Edelen, J. Einstein-Curtis, C. C. Hall, J. A. Diaz Cruz, A. L. Edelen
Industrial particle accelerators typically operate in dirtier environments than research accelerators, leading to increased noise in RF and electronic systems. Furthermore, given that industrial accelerators are mass produced, less attention is given to optimizing the performance of individual systems. As a result, industrial accelerators tend to underperform their own hardware capabilities. Improving signal processing for these machines will improve cost and time margins for deployment, helping to meet the growing demand for accelerators for medical sterilization, food irradiation, cancer treatment, and imaging. Our work focuses on using machine learning techniques to reduce noise in RF signals used for pulse-to-pulse feedback in industrial accelerators. Here we review our algorithms and observed results for simulated RF systems, and discuss next steps with the ultimate goal of deployment on industrial systems.
{"title":"Machine Learning for Reducing Noise in RF Control Signals at Industrial Accelerators","authors":"M. Henderson, J. P. Edelen, J. Einstein-Curtis, C. C. Hall, J. A. Diaz Cruz, A. L. Edelen","doi":"arxiv-2409.03931","DOIUrl":"https://doi.org/arxiv-2409.03931","url":null,"abstract":"Industrial particle accelerators typically operate in dirtier environments\u0000than research accelerators, leading to increased noise in RF and electronic\u0000systems. Furthermore, given that industrial accelerators are mass produced,\u0000less attention is given to optimizing the performance of individual systems. As\u0000a result, industrial accelerators tend to underperform their own hardware\u0000capabilities. Improving signal processing for these machines will improve cost\u0000and time margins for deployment, helping to meet the growing demand for\u0000accelerators for medical sterilization, food irradiation, cancer treatment, and\u0000imaging. Our work focuses on using machine learning techniques to reduce noise\u0000in RF signals used for pulse-to-pulse feedback in industrial accelerators. Here\u0000we review our algorithms and observed results for simulated RF systems, and\u0000discuss next steps with the ultimate goal of deployment on industrial systems.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"542 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Benjamin Sims, John W. Lewellen, Xu Ting, Sergey V. Baryshev
In this work, a combination of cathode retraction and two-slit emittance measurement technique is proposed as an advanced means to individually modify emittance growth components, specifically, rf injector fringe fields, to isolate and directly measure the thermal emittance, the fundamental beam emittance metric for an electron beam. A case study of the LCLS-II-HE Low Emittance Injector (LEI), a state-of-the-art superconducting radiofrequency (SRF) gun, designed for LCLS-II HE upgrade is used to showcase the power of the two-slit technique. Particularly, it is demonstrated that generating a high resolution phase-space distribution map, dominated by the intrinsic emittance of the electron bunch, is possible. This result goes beyond the normal single-parameter distribution characterizations (e.g. RMS emittance and Twiss parameters) provided by the solenoid scan. One key feature making this technique work (and in the end practically useful) is the ability to retract the cathode, because it provides the ability to compensate for radiofrequency (rf) de-focusing. It is demonstrated how the cathode retraction can serve as an additional optimisation tool for tailoring the routine performance of the photoinjector. We posit that a variable position cathode may be a useful method for optimizing photoinjector performance across multiple parameters regimes.
在这项工作中，提出了一种阴极回缩和双缝幅射测量技术的组合，作为单独修改幅射增长成分（特别是射频注入器边缘场）的先进手段，以分离和直接测量热幅射，这是电子束的基本束幅射指标。LCLS-II-HE 低幔度注入器（LEI）是最先进的超导射频（SRF）枪，专为 LCLS-II HE 升级而设计，通过对它的案例研究，展示了双缝技术的威力。特别是，它证明了生成由电子束本征发射率主导的高分辨率相空间分布图是可能的。这一结果超越了螺线管扫描所提供的常规单参数分布特性（例如均方根辐照度和捻度参数）。使这项技术发挥作用（并最终发挥实际作用）的一个关键特征是能够缩回阴极，因为它提供了补偿射频（rf）失焦的能力。我们展示了阴极缩回如何作为一种额外的优化工具，用于定制光电注射器的常规性能。我们认为，可变位置阴极可能是在多种参数条件下优化光注入器性能的有用方法。
{"title":"Thermal Emittance Isolation by Cathode Retraction","authors":"Benjamin Sims, John W. Lewellen, Xu Ting, Sergey V. Baryshev","doi":"arxiv-2409.03499","DOIUrl":"https://doi.org/arxiv-2409.03499","url":null,"abstract":"In this work, a combination of cathode retraction and two-slit emittance\u0000measurement technique is proposed as an advanced means to individually modify\u0000emittance growth components, specifically, rf injector fringe fields, to\u0000isolate and directly measure the thermal emittance, the fundamental beam\u0000emittance metric for an electron beam. A case study of the LCLS-II-HE Low\u0000Emittance Injector (LEI), a state-of-the-art superconducting radiofrequency\u0000(SRF) gun, designed for LCLS-II HE upgrade is used to showcase the power of the\u0000two-slit technique. Particularly, it is demonstrated that generating a high\u0000resolution phase-space distribution map, dominated by the intrinsic emittance\u0000of the electron bunch, is possible. This result goes beyond the normal\u0000single-parameter distribution characterizations (e.g. RMS emittance and Twiss\u0000parameters) provided by the solenoid scan. One key feature making this\u0000technique work (and in the end practically useful) is the ability to retract\u0000the cathode, because it provides the ability to compensate for radiofrequency\u0000(rf) de-focusing. It is demonstrated how the cathode retraction can serve as an\u0000additional optimisation tool for tailoring the routine performance of the\u0000photoinjector. We posit that a variable position cathode may be a useful method\u0000for optimizing photoinjector performance across multiple parameters regimes.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruihu Zhu, Chris Rogers, Jiancheng Yang, He Zhao, Cheng Guo, Jiangdong Li
The muon collider has the potential to be a powerful tool for the exploration of frontiers in particle physics. In order to reach high luminosity, the 6D emittance of the muon beam needs to be reduced by several orders of magnitude. The cooling process for a muon collider involves two parts; initial six-dimensional cooling and final transverse cooling. This paper focuses on the former and proposes a conceptual design of the rectilinear cooling channel with additional dipole magnets. In this paper, we first introduce a general method for designing the rectilinear cooling channel. Subsequently, we apply this method to develop two rectilinear cooling channels before and after a bunch merging system. Furthermore, we investigate the impact on cooling performance by employing $pi$-mode RF cavities and considering the effect of errors in the magnetic and RF fields.
{"title":"Performance and tolerance study of the rectilinear cooling channel for a muon collider","authors":"Ruihu Zhu, Chris Rogers, Jiancheng Yang, He Zhao, Cheng Guo, Jiangdong Li","doi":"arxiv-2409.02613","DOIUrl":"https://doi.org/arxiv-2409.02613","url":null,"abstract":"The muon collider has the potential to be a powerful tool for the exploration\u0000of frontiers in particle physics. In order to reach high luminosity, the 6D\u0000emittance of the muon beam needs to be reduced by several orders of magnitude.\u0000The cooling process for a muon collider involves two parts; initial\u0000six-dimensional cooling and final transverse cooling. This paper focuses on the\u0000former and proposes a conceptual design of the rectilinear cooling channel with\u0000additional dipole magnets. In this paper, we first introduce a general method\u0000for designing the rectilinear cooling channel. Subsequently, we apply this\u0000method to develop two rectilinear cooling channels before and after a bunch\u0000merging system. Furthermore, we investigate the impact on cooling performance\u0000by employing $pi$-mode RF cavities and considering the effect of errors in the\u0000magnetic and RF fields.","PeriodicalId":501318,"journal":{"name":"arXiv - PHYS - Accelerator Physics","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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