We derive a Hamiltonian control theory which can be applied to a 4D symplectic map that models a ring particle accelerator composed of elements with sextupole nonlinearity. The controlled system is designed to exhibit a more regular orbital behavior than the uncontrolled one. Using the Smaller Alignement Index (SALI) chaos indicator, we are able to show that the controlled system has a dynamical aperture up to 1.7 times larger than the original mode
This report summarizes the findings of the AF1 Topical Subgroup to Snowmass 2021, which investigates beam physics and accelerator education within the accelerator frontiers (AF). The report focuses primarily on opportunities for basic accelerator and beam physics, formulated into four grand challenges. In addition, the report also studies the current status of accelerator education, outreach and diversity issues. Physics limits of ultimate beams for future colliders are also briefly discussed.
This paper gives an introduction of longitudinal beam dynamics for circular accelerators. After briefly discussing some types of circular accelerators, it focuses on particle motion in synchrotrons. It summarizes the equations of motion, discusses phase-space matching during beam transfer, and introduces the Hamiltonian of longitudinal motion.
This is the Snowmass Whitepaper on Beam Test Facilities for R&D in Accelerator Science and Technologies and it is submitted to two topical groups in the Accelerator Frontier: AF1 and AF6.
Beam halo is one of the crucial issues limiting the machine performance and causing radioactivation in high-intensity accelerators. A clear picture of beam-halo formation is of great importance for successful suppression of the undesired beam loss. We present numerical and experimental studies of transverse and longitudinal halos in the KEK Accelerator Test Facility. The fair accordance between predictions and observations in various conditions indicates that the Touschek scattering is the dominant mechanism forming the horizontal and momentum halos.
This report is a summary of two preparatory workshops, documenting the community vision for the national accelerator and beam physics research program. It identifies the Grand Challenges of accelerator and beam physics (ABP) field and documents research opportunities to address these Grand Challenges. This report will be used to develop a strategic research roadmap for the field of accelerator science.
We report on the development of multi-beam RF linear ion accelerators that are formed from stacks of low cost wafers and describe the status of beam power scale-up using an array of 120 beams. The total argon ion current extracted from the 120-beamlet extraction column was 0.5 mA. The measured energy gain in each RF gap reached as high as 7.25 keV. We present a path of using this technology to achieve ion currents >1 mA and ion energies >100 keV for applications in materials processing.
Accelerator and beam physics (ABP) is the science of the motion, generation, acceleration, manipulation, prediction, observation and use of charged particle beams. It focuses on fundamental long-term accelerator and beam physics research and development. Accelerator and beam physics research has resulted in important advances in accelerator science, yet support for this research is declining. NSF has terminated its program in accelerator Science and funding by DOE through GARD and Accelerator Stewardship has been steady or declining. The declining support for accelerator research will slow adv…
Feasibility of OTR Imaging For Laser-Driven Plasma Accelerator Electron-Beam Diagnostics
我们报告的初步考虑使用线偏振光学跃迁辐射（OTR）的激光等离子体加速器（LPAs），如在德克萨斯大学奥斯汀分校的电子束的特征。这两个LPA在100 MeV和2-GeV下工作，目前估计归一化发射度为~ 1 mm mrad，束流发散度小于1/γ，束流尺寸在微米级确定。分析建模结果表明，使用这些OTR技术的LPA应用的可行性。
The PIP2IT accelerator was assembled in multiple stages in 2014 - 2021 to test concepts and components of the future PIP-II linac that is being constructed at Fermilab. In its final configuration, PIP2IT accelerated a 0.55 ms x 20 Hz x 2 mA H- beam to 16 MeV. To determine location of the beam loss in the accelerators low-energy part, where radiation monitors are ineffective, a method using oscillating trajectories was implemented. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync, produces a line at the cor…
For modern high-intensity linear accelerators, the well-known envelope instability and recently reported fourth-order particle resonance impose a fundamental operational limit (i.e., zero-current phase advance should be less than 90 deg). Motivated by the stability of spinning flying objects, we propose a novel approach of using spinning beams to surpass this limit. We discovered that spinning beams have an intrinsic characteristic that can suppress the impact of the fourth-order resonance on emittance growth and the associated envelope instability.
Comment on "Physics considerations for laser-plasma linear colliders" and on "Beamstrahlung considerations in laser-plasma-accelerator-based linear colliders"
C. B. Schroeder，E.埃萨雷角Benedetti和W. P. Leemans {Phys.Rev.STAccel. Beams 13，101301（2010）和15，051301（2012）}已经提出了基于等离子体尾场加速器原理的TeV级对撞机的一组参数。特别是，它建议，大于10^34 cm-2s-1的亮度是可以实现的电子-正电子对撞机。在这篇评论中，我们在第一原理的基础上对这组参数进行了争论。加速束与等离子体的相互作用对束的性质和可达到的亮度值施加了基本的限制。
Circular particle accelerators at the energy frontier are based on superconducting magnets that are extremely sensitive to beam losses as these might induce quenches, i.e.\ transitions to the normal-conducting state. Furthermore, the energy stored in the circulating beam is so large that hardware integrity is put in serious danger, and machine protection becomes essential for reaching the nominal accelerator performance. In this challenging context, the beam halo becomes a potential source of performance limitations and its dynamics needs to be understood in detail to assess whether it could b…
Beam-driven collinear wakefield accelerators (CWAs) that operate by using slow-wave structures or plasmas hold great promise toward reducing the size of contemporary accelerators. Sustainable acceleration of charged particles to high energies in the CWA relies on using field-generating relativistic electron bunches with a highly asymmetric peak current profile and a large energy chirp. A new approach to obtaining such bunches has been proposed and illustrated with the accelerator design supported by particle tracking simulations. It has been shown that the required particle distribution in the…
Purpose: To describe a concept of a compact electron accelerator for external radiation therapy with variable energy in the range of 6 - 20 MeV, based on linotron principle. Methods: Beam dynamics simulation using the CST and MAD-X code. Various optimization methods of multi-parameter problem. Results: Our accelerator differs from the Reflexotron in a number of essential details: a much more compact and more efficient C-band accelerating structure, optimized for the high capture efficiency, narrow energy and phase spectra, and low transverse emittance; magnetic mirror with fixed field based on…
加速器设备的保护与加速器技术一样古老，多年来一直与高功率设备有关。例如，防止供电设备过热（磁铁、功率转换器、高电流电缆），防止超导磁铁失超后损坏，以及速调管。尽管早在1967年就有一篇论文讨论了SLAC直线加速器（斯坦福直线加速器中心）的束流损伤，但对设备束流事故的保护是最近才出现的。它与高功率质子加速器束流功率的提高、电子-正电子加速器同步辐射光的发射以及束流能量的增加有关。设计机器保护系统需要对加速器物理和操作有很好的理解，以预测可能导致损坏的可能故障。机器保护包括射束和设备监控、安全停止射束操作的系统（例如，倾倒射束或在低能量时停止射束）以及在这些系统之间提供胶水的联锁系统。最新的加速器LHC将以每束约3 x 10 $^{14}$质子运行，对应于每束360 MJ的能量存储。在不受控制的射束损失的情况下，这种能量会对加速器设备造成巨大损害，并且损坏加速器重要部件的单一事故可能会中断多年的运行。本讲座将概述加速器设备的保护要求，并介绍各种保护系统。这些例子主要来自LHC和ESS。
We present a method to compressed the 2D transverse phase space projections from a hadron accelerator and use that information to predict the beam transmission. This method assumes that it is possible to obtain at least three projections of the 4D transverse phase space and that an accurate simulation model is available for the beamline. Using a simulated model we show that, a procedure using a convolutional autoencoder can be trained to reduce phase-space information which can later be used to predict the beam transmission. Finally, we argue that although using projections from a realistic no…
Notes on the design of experiments and beam diagnostics with synchrotron light detected by a gated photomultiplier for the Fermilab superconducting electron linac and for the Integrable Optics Test Accelerator (IOTA)
This article presents a method that uses turn-by-turn beam position data and k-modulation data to measure the calibration factors of beam position monitors in high energy accelerators. In this method, new algorithms have been developed to reduce the effect of coupling and other sources of uncertainty, allowing accurate estimates of the calibration factors. Simulations with known sources of errors indicate that calibration factors can be recovered with an accuracy of 0.7% rms for arc beam position monitors and an accuracy of 0.4% rms for interaction region beam position monitors. The calibratio…
