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At least 19 records

The Beam Dynamics and Beam Related Uncertainties in Fermilab Muon $g-2$ Experiment

The anomaly of the muon magnetic moment, $a_{\mu}\equiv (g-2)/2$, has played an important role in constraining physics beyond the Standard Model for many years. Currently, the Standard Model prediction for $a_{\mu}$ is accurate to 0.42 parts per million (ppm). The most recent muon $g-2$ experiment was done at Brookhaven National Laboratory (BNL) and determined $a_{\mu}$ to 0.54 ppm, with a central value that differs from the Standard Model prediction by 3.3-3.6 standard deviations and provides a strong hint of new physics. The Fermilab Muon $g-2$ Experiment has a goal to measure $a_{\mu}$ to unprecedented precision: 0.14 ppm, which could provide an unambiguous answer to the question whether there are new particles and forces that exist in nature. To achieve this goal, several items have been identified to lower the systematic uncertainties. In this work, we focus on the beam dynamics and beam associated uncertainties, which are important and must be better understood. We will discuss the electrostatic quadrupole system, particularly the hardware-related quad plate alignment and the quad extension and readout system. We will review the beam dynamics in the muon storage ring, present discussions on the beam related systematic errors, simulate the 3D electric fields of the electrostatic quadrupoles and examine the beam resonances. We will use a fast rotation analysis to study the muon radial momentum distribution, which provides the key input for evaluating the electric field correction to the measured $a_{\mu}$.

Wu, Wanwei↗

Dynamic Beam Solutions for Real-Time Simulation and Control Development of Flexible Rockets

In this study, flexible rockets are structurally represented by linear beams. Both direct and indirect solutions of beam dynamic equations are sought to facilitate real-time simulation and control development for flexible rockets. The direct solution is completed by numerically integrate the beam structural dynamic equation using an explicit Newmark-based scheme, which allows for stable and fast transient solutions to the dynamics of flexile rockets. Furthermore, in the real-time operation, the bending strain of the beam is measured by fiber optical sensors (FOS) at intermittent locations along the span, while both angular velocity and translational acceleration are measured at a single point by the inertial measurement unit (IMU). Another study in this paper is to find the analytical and numerical solutions of the beam dynamics based on the limited measurement data to facilitate the real-time control development. Numerical studies demonstrate the accuracy of these real-time solutions to the beam dynamics. Such analytical and numerical solutions, when integrated with data processing and control algorithms and mechanisms, have the potential to increase launch availability by processing flight data into the flexible launch vehicle's control system.

flexible body dyanmics fiber optic strain sensor p↗

Large dynamic range beam diagnostics and beam dynamics studies for high current electron LINACs

As described in the previous reports we have been working on an apodized optical system for transverse beam profile measurements by means of imaging. The key issues of LDR imaging is properly managing diffraction effects within the optical system, which is proposed to accomplish by means of amplitude apodization. Shortly before the time of the last progress report we have finished manufacturing of several apodizing elements. We have completed mechanical design of our first apodized imaging system and have built its prototype on an optical bench. Since testing diagnostic equipment with beam is costly and is not always possible due to limited beam availability, it has been our intention to make as much preliminary testing and characterization on a test bench in the laboratory.

43 PARTICLE ACCELERATORS↗

Electron-Beam Dynamics for an Advanced Flash-Radiography Accelerator

Beam dynamics issues were assessed for a new linear induction electron accelerator being designed for multipulse flash radiography of large explosively driven hydrodynamic experiments. Special attention was paid to equilibrium beam transport, possible emittance growth, and beam stability. Especially problematic would be high-frequency beam instabilities that could blur individual radiographic source spots, low-frequency beam motion that could cause pulse-to-pulse spot displacement, and emittance growth that could enlarge the source spots. Furthermore, beam physics issues were examined through theoretical analysis and computer simulations, including particle-in-cell codes. Beam instabilities investigated included beam breakup, image displacement, diocotron, parametric envelope, ion hose, and the resistive wall instability. The beam corkscrew motion and emittance growth from beam mismatch were also studied. It was concluded that a beam with radiographic quality equivalent to the present accelerators at Los Alamos National Laboratory will result if the same engineering standards and construction details are upheld.

43 PARTICLE ACCELERATORS↗

Low-energy high-brightness electron beam dynamics based on slice beam matrix method

Preserving the phase space quality has been of crucial importance to high-brightness electron beam transport. Any driving source of beam performance limitations in such a transport system must be carefully examined in order to preserve the beam phase space quality. It is found that in the low beam energy, high bunch charge regime, space charge effect on the charged particle beam evolution can be complicated. It may be insufficient to analyze the beam properties through the envelope or lower order moments for the mere bulk of the beam. In this work we will study the space-charge-dominated, low-energy, high-brightness electron beam dynamics based on the slice beam matrix method. The slice beam matrix method, extended from the existing bulk beam analysis, is applicable to an arbitrary longitudinal bunch distribution and can thus take the nonlinear RF curvature into account. The semi-analytical sliced beam space charge model is constructed and assumes an axisymmetric beam in the presence of perfect conducting cylindrical pipe with circular cross section. We present in this paper the theoretical formulation, starting from single-particle dynamics, space charge field calculation, followed by the moment description of a collection of particles, based on beam sigma matrix and longitudinal slice decomposition. We prove the equivalence between the beam matrix method and the envelope formalism in the presence of space charge effect, in both the transverse and longitudinal dimensions. Two examples are then demonstrated, one for a unit cell of superconducting radio-frequency (RF) cavity and the other for a 1.5-cell RF gun system. The semi-analytical results from beam matrix calculation are discussed and compared with particle tracking simulation using ASTRA. In conclusion, we expect that the analysis based on the slice beam matrix method shall serve as an efficient and advanced tool to further investigate the low-energy high-brightness electron beam dynamics.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Beam Dynamics Simulations of Transient Beam Loading Effects in the 10GeV EIC Electron Storage Ring

We report on beam dynamics studies of transient beam loading effects in the 10 GeV EIC electron storage ring [1]. The studies are carried out with time-dependent Vlasov-Fokker-Planck simulations performed with the parallel, particle tracking code SPACE [2], which allows to follow self-consistently the dynamics of h bunches, where h in the number of RF buckets, in arbitrary multi-bunch configurations. The specific goal of the numerical simulations is to determine stable RF cavity settings under heavy beam loading. We also study the option to operate with a passive, third-harmonic cavity (3HC) system for bunch lengthening, addressing both stability and the performance limitation due to a gap in the uniform filling pattern for ion clearing.

43 PARTICLE ACCELERATORS↗

Beam dynamics simulations of post low energy beam transport section in RAON heavy ion accelerator

RAON (Rare isotope Accelerator Of Newness) heavy ion accelerator of the rare isotope science project in Daejeon, Korea, has been designed to accelerate multiple-charge-state beams to be used for various science programs. In the RAON accelerator, the rare isotope beams which are generated by an isotope separation on-line system with a wide range of nuclei and charges will be transported through the post Low Energy Beam Transport (LEBT) section to the Radio Frequency Quadrupole (RFQ). In order to transport many kinds of rare isotope beams stably to the RFQ, the post LEBT should be devised to satisfy the requirement of the RFQ at the end of post LEBT, simultaneously with the twiss parameters small. We will present the recent lattice design of the post LEBT in the RAON accelerator and the results of the beam dynamics simulations from it. In addition, the error analysis and correction in the post LEBT will be also described.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Beam Dynamics for ARIA

Beam dynamics issues are assessed for a new linear induction electron accelerator being designed for flash radiography of large explosively driven hydrodynamic experiments. Special attention is paid to equilibrium beam transport, possible emittance growth, and beam stability. It is concluded that a radiographic quality beam will be produced possible if engineering standards and construction details are equivalent to those on the present radiography accelerators at Los Alamos.

43 PARTICLE ACCELERATORS↗

ICFA Beam Dynamics Newsletter

Electron beam ion sources technology made significant progress since 1968 when this method of producing highly charged ions in a potential trap within electron beam was proposed by E. Donets. Better understanding of physical processes in EBIS, technological advances and better simulation tools determined significant progress in key EBIS parameters: electron beam current and current density, ion trap capacity, attainable charge states. Greatly increased the scope of EBIS and EBIT applications. An attempt is made to compile some of EBIS engineering problems and solutions and to demonstrate a present stage of understanding the processes and approaches to build a better EBIS.

43 PARTICLE ACCELERATORS↗

The thermal-wave model: A Schroedinger-like equation for charged particle beam dynamics

We review some results on longitudinal beam dynamics obtained in the framework of the Thermal Wave Model (TWM). In this model, which has recently shown the capability to describe both longitudinal and transverse dynamics of charged particle beams, the beam dynamics is ruled by Schroedinger-like equations for the beam wave functions, whose squared modulus is proportional to the beam density profile. Remarkably, the role of the Planck constant is played by a diffractive constant epsilon, the emittance, which has a thermal nature.

Fedele, Renato↗

CoSyR: A novel beam dynamics code for the modeling of synchrotron radiation effects

The self-consistent nonlinear dynamics of a relativistic charged particle beam interacting with its complete self-fields is a fundamental problem underpinning many of the accelerator design issues in high brightness beam applications, as well as the development of advanced accelerators. Particularly, synchrotron radiation induced effects in a magnetic dispersive beamline element can lead to collective beam instabilities and emittance growth. A novel beam dynamics code is developed based on a Lagrangian method for the calculation of the particles’ radiation near-fields using wavefront/wavelet meshes via the Green’s function of the Maxwell equations. These fields are then interpolated onto a moving mesh for dynamic update of the beam. This method allows radiation co-propagation and self-consistent interaction with the beam in 2D/3D simulations at greatly reduced numerical errors. Multiple levels of parallelisms are inherent in this method and implemented in our code CoSyR to enable at-scale simulations of nonlinear beam dynamics on modern computing platforms using MPI, multi-threading, and GPUs. Here, the current 2D implementation of CoSyR has been used to evaluate the transverse and longitudinal coherent radiation effects on the beam and to investigate beam optics designs proposed for mitigation of beam brightness degradation in a magnetic bunch compressor. In this paper, the design of CoSyR, as well as the benchmark with other coherent synchrotron radiation models, are described and discussed. Extension of the core algorithms to 3D is possible and planned.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Editorial announcements and information — ICFA Beam Dynamics Newsletter No. 82

This is a general information article of the ICFA Beam Dynamics Newsletter No. 81. It contains two forewords from the Editor-in-Chief and the issue editor, a workshop and conference report section, a recent Ph.D. thesis section, a forthcoming beam dynamics events section, and a section of announcements from the beam dynamics panel.

43 PARTICLE ACCELERATORS↗

Beam-dynamics codes used at DARHT

Several beam simulation codes are used to help gain a better understanding of beam dynamics in the DARHT LIAs. The most notable of these fall into the following categories: for beam production – Tricomp Trak orbit tracking code, LSP Particle in cell (PIC) code, for beam transport and acceleration – XTR static envelope and centroid code, LAMDA time-resolved envelope and centroid code, LSP-Slice PIC code, for coasting-beam transport to target – LAMDA time-resolved envelope code, LSP-Slice PIC code. These codes are also being used to inform the design of Scorpius.

43 PARTICLE ACCELERATORS↗

Multi-objective optimization with an integrated electromagnetics and beam dynamics workflow

In particle accelerators, RF cavities are used to accelerate charged particle beams to designed high energy for physical applications. In a typical accelerator design, the optimization of RF cavities and the optimization of beam dynamics are carried out in separate studies. For a more general and unrestricted accelerator design, a coupled optimization of the RF cavities and the beam parameters is required. For this coupled optimization problem, we have developed an integrated electromagnetics and beam dynamics workflow management system. Within this system, the geometries for a set of cavity components are first adjusted; the field modes are then computed with an electromagnetics program, and imported into a beam dynamics program for beam dynamics simulation. This workflow is encapsulated into a parallel multi-objective optimizer to achieve the integrated accelerator design optimization. A multi fidelity strategy is developed to improve the speed of the optimizer. Furthermore, this integrated global optimization capability is illustrated using a photoinjector design example and yields an improved design.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Editorial announcements and information — ICFA Beam Dynamics Newsletter No. 85

This is a general information article of the ICFA Beam Dynamics Newsletter No. 85. It contains foreword from the Editor-in-Chief and the issue editor, a workshop and conference report section, a recent Ph.D. thesis section, a forthcoming beam dynamics events section, and a section of announcements from the beam dynamics panel.

43 PARTICLE ACCELERATORS↗

Advances in Beam Dynamics at Nuclear Physics Accelerator Facilities

Beam dynamics of particle accelerators is a rich subfield that enables accelerators to be used in pursuit of fundamental topics in particle physics in increasingly complex ways. The field is constantly evolving as new and advanced accelerators push the limits of energy, luminosity, and accelerated species. This talk will cover some recent beam dynamics developments for future operation of DOE nuclear physics user facilities, including upgrade options for Jefferson Lab's 12 GeV CEBAF. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.

Sy, Amy↗

Generalized 3D beam dynamics model for industrial traveling wave linacs design and simulations

Beam dynamics simulations in traveling wave (TW) accelerating structures with significant beam loading is a challenging problem. Some codes are capable of calculating the TW electromagnetic fields, and some can track particles through such fields, but most cannot treat both self-consistently. A few commercial codes can model the physics correctly at the expense of many processor-hour computations to obtain converged self-consistent solutions. However, simple, accurate equations of motion for intensive beam dynamics in TW accelerating structure analysis have been previously obtained by Masunov and subsequently implemented in the Hellweg code, which was developed at the Moscow Engineering-Physics Institute. Hellweg is based on equations that allow fast simulations of beam dynamics while taking into account such effects as beam loading, space charge, and external magnetic fields. In this paper, we describe in detail some recent improvements to the Hellweg physics kernel. We have generalized the Masunov results into a 3D set of equations of motion, which include all spatial components of the radiofrequency (RF) and external magnetic fields. We have also improved the Lapostolle space charge model to the general 3D ellipsoid form for any dimensions’ ratio, consideration for the particles outside the beam core, and the fields from the neighboring bunches that can exist in the real machine. These modifications allow approaching the Hellweg accuracy to the self-consistent commercial codes while keeping the simulation time short, which is essential during the linac design and optimization stage. The implementation of these new capabilities in Hellweg is carefully benchmarked against other codes and analytical calculations. The code is freely available with an open source license.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗