University of Tokyo, Tokyo
KEK, Ibaraki
Recently, calculation of wake field and impedance has become more important. In many cases they are usually calculated numerically by using a mesh. It will be shown here that the mesh calculation based on the paraxial approximation can be much faster than ordinary methods when the bunch is very short. There are two advantages. One is to be able to choose the longitudinal mesh size independent of the bunch length. The other is that the problem can be solved as an initial-value problem in spite of frequency domain calculation.
TEMF, TU Darmstadt, Darmstadt
KU Leuven, Kortrijk
Numerical simulations are frequently used in the design, optimization and commissioning phase of accelerator components. Strict requirements on the accuracy as well as the complex structure of such devices lead to challenges regarding the numerical simulations in 3D. In order to capture all relevant details of the geometry and possibly strongly localized electromagnetic effects, large numerical models are often unavoidable. The use of parallelization strategies in combination with higher-order finite-element methods offers a possibility to account for the large numerical models while maintaining moderate simulation times as well as high accuracy. Using this approach, the magnetic properties of the SIS100 magnets designated to operate within the Facility of Antiproton and Ion Research (FAIR) at the GSI Helmholtzzentrum für Schwerionenforschung GmbH (GSI) in Darmstadt, are calculated. Results for eddy-current losses under time-varying operating conditions as well as field quality considerations are reported.
ANL, Argonne
BNL, Upton, Long Island, New York
ELEGANT is an open-source accelerator code that has been under development for approximately two decades. In that time, it has evolved from a graduate student project with a narrow purpose to a general code for the design and modeling of linacs and storage rings. ELEGANT continues to evolve, thanks in no small part to suggestions from users. ELEGANT has seen extensive application to modeling of linacs, particularly for applications related to free-electron lasers and energy recovery linacs. Recent developments have emphasized both linac and storage-ring-related enhancements, along with parallelization. In this paper, we briefly review the features of ELEGANT and its program suite. We then describe some of the recent progress made in the ongoing development of ELEGANT. We also discuss several noteworthy applications and directions for future work.
KEK, Ibaraki
Two methods were investigated to study microwave instability in LER of KEKB and SuperKEKB. One is macroparticle tracking code based on PIC. The other one solves the VFP equation directly. First we compare the two methods using a resonator impedance model of KEKB LER. Then we use the calculated impedance including CSR to study the beam instability of LER of KEKB and SuperKEKB. Convergence properties of these two methods due to numerical noise are discussed.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which accelerates ~3·1013 protons per pulse (ppp) from 70 to 800 MeV, corresponding to beam powers of ~0.2 MW. Studies are under way for major upgrades in the Megawatt regime. Underpinning this programme of operations and upgrades is a study of the high intensity effects that impose limitations on beam power. The behaviour of the beam in the 50 Hz rapid cycling synchrotron (RCS) is largely characterised by high space charge levels and the effects of fast ramping acceleration. High intensity effects are of particular importance as they drive beam loss, but are not fully understood with only limited analytical models available. This paper reviews several methods by which these effects are explored numerically on ISIS, and compares them where possible with experimental or analytical results. In particular we outline development of a new space charge code Set, which is designed to address key issues on ISIS and similar RCS machines.
KIT, Karlsruhe
FZK, Karlsruhe
ANKA is a synchrotron radiation source located in Karlsruhe, Germany. While the control system has always provided access to technical parameters, like power supply currents or RF frequency, direct access to physical parameters like tune or chromaticity has been missing. Thus the operator has to change and monitor the technical parameters manually and to calculate the physical parameters using separate tools. Therefore effort has been made to integrate the monitoring of physical parameters and simulation tools into the control system. At ANKA the MATLAB-based Accelerator Toolbox is used for simulation purposes, however the control system framework ("ACS") does not support MATLAB natively. For this reason, a software bridge has been created, which provides direct access to control system components from MATLAB. Thus operators can write their own MATLAB code simultaneously using simulation code and components from the control system. This system has already been used to automate measurements, thus allowing unattended long-term measurements, which have not been possible before. Future plans include creating a graphical user interface and various monitoring and stabilization loops.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK. Presently, it runs at beam powers of ~0.2 MW, with upgrades in place to supply increased powers for the new Second Target Station. Studies are also under way for major upgrades in the megawatt regime. Underpinning this programme of operations and upgrades is a study of the high intensity effects that impose the limitations on beam power. Spallation is driven by a 50 Hz rapid cycling synchrotron, characterized by high space charge and fast ramping acceleration. High intensity effects are of particular importance as they drive beam loss, but are poorly understood analytically. This paper reviews development of the space charge charge code Set.