ANL, Argonne
MSU, East Lansing, Michigan
Many processes in Physics can be described by Partial Differential equations (PDE’s). For various practical problems, very precise and verified solutions of PDE are required; but with conventional finite element or finite difference codes this is difficult to achieve because of the need for an exceedingly fine mesh which leads to often prohibitive CPU time. We present an alternative approach based on high-order quadrature and a high-order finite element method. Both of the ingredients become possible through the use of Differential Algebra techniques. Further the method can be extended to provide rigorous error verification by using the Taylor model techniques. Application of these techniques and the precision that can be achieved will be presented for the case of 3D Laplace’s equation. Using only around 100 finite elements of order 7, verified accuracies in the range of 10-7 can be obtained.
Diamond, Oxfordshire
JAI, Oxford
The Diamond light source started operation for users in January 2007. With the successful commissioning of the nominal optics, delivering a 2.75 nm emittance beam at 3 GeV, we now routinely provide the users with a 250 mA beam with a lifetime of >20 h, exceeding the minimum specified current-lifetime product of 3000 mAh. Driven by the necessity to guarantee a correct implementation of the nonlinear optics, a significant experimental and theoretical effort is ongoing to understand and improve the nonlinear beam dynamics in the storage ring. The necessity to control the nonlinear beam dynamics is even more urgent with the installation of a large number of small gap (5 mm) in-vacuum insertion device and the need to control the injection efficiency with Top-Up operation. We report here the present status of the analysis of the nonlinear beam dynamics and the main experimental results.
BNL, Upton, Long Island, New York
In the quest for brigthness, the horizontal emittance remains one of the main performance parameters for modern synchrotron light sources. A control theory approach that takes the nonlinear dynamics aspects into account, by a few simple (linear) optics guidelines, at an early stage generates robust designs. Modern analytic- and computational techniques enables the optics designer to avoid the fallacy of the traditional approach guided by the Theoretical Minimum Emittance (TME) cell: the "chromaticity wall". In particular, by an interleaved computational approach with the nonlinear dynamics analyst/model. We also outline how to implement the correction algorithms for a realistic model so that they can be re-used as part of an on-line model/control server for commissioning- and operations of the real system.
Northern Illinois University, DeKalb, Illinois
When faced with the challenge of the design optimization of a charged particle beam system involving beam-material interactions, a framework is needed that seamlessly integrate the following tasks: 1) high order accurate and efficient beam optics, 2) a suite of codes that model the atomic and nuclear interactions between the beam and matter, and 3) the option to run many different optimization strategies at the code language level with a variety of user-defined objectives. To this end, we developed a framework in COSY Infinity with these characteristics and which can be run in two modes: map mode and a hybrid map-Monte Carlo mode. The code, its applications to the FRIB, and plans involving large-scale computing will be presented.
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.