ICAP2012 - List of Keywords (insertion)

Paper	Title	Other Keywords	Page
TUSCC3	Undulator Radiation Inside a Dielectric Waveguide	radiation, vacuum, undulator, synchrotron	96
	A. Kotanjyan, A.A. Saharian YSU, Yerevan, Armenia
	We investigate the radiation from a charge moving along a helix around a dielectric cylinder immersed in a homogeneous medium. We are mainly concerned with the radiation propagating inside the cylinder. The radiation intensity for the modes propagating inside the cylinder is evaluated by the work done by the radiation field on the charge and by evaluating the energy flux through the cross-section of the cylinder. The insertion of a dielectric waveguide provides an additional mechanism for tuning the characteristics of the undulator radiation by choosing the parameters of the waveguide. The radiated energy inside the cylinder is redistributed among the cylinder modes, the corresponding spectrum differs significantly from the homogeneous medium or free-space results. This change is of special interest in the low-frequency range where the distribution of the radiation energy among small number of modes leads to the enhancement of the spectral density for the radiation intensity. The radiation emitted on the waveguide modes propagates inside the cylinder and the waveguide serves as a natural collector for the radiation.
	Slides TUSCC3 [0.809 MB]

TUADC3	Implementing New Beam Line Elements into a Moment Method Beam Dynamics Code	rfq, quadrupole, simulation, radio-frequency	104
	T. Roggen, H. De Gersem, B. Masschaele KU Leuven, Kortrijk, Belgium W. Ackermann, S. Franke, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This research is funded by grant "KUL 3E100118" "Electromagnetic Field Simulation for Future Particle Accelerators". Developing beam dynamics simulation tools using the moment method has advantages in terms of precision and efficiency when interests lie in average or rms dimensions of the beam, projected emittances or total energy. The moment method implemented in the V-Code solves the Vlasov equation by time integration, from an initial particle distribution represented by a discrete set of characteristic moments, accounting for all acting internal and external forces along the particle's path. The moment method delivers highly accurate beam dynamics results within a very small CPU time. This article proposes, illustrates and validates a new beam line element for a radiofrequency quadrupole (RFQ) for insertion in the V-Code. The focus will be on the RFQ cell structure, the electric field distribution and the insertion of the field distribution in the moment code.
	Slides TUADC3 [4.387 MB]

WEP11	Stochastic Response Surface Method for Studying Microphoning and Lorenz Detuning of Accelerator Cavities	cavity, radiation, simulation, SRF	158
	J. Deryckere, H. De Gersem, B. Masschaele, T. Roggen KU Leuven, Kortrijk, Belgium
	Funding: This research is funded by grant KUL_3E100118 and grant KUL_3E080005. The dependence of the eigenfrequencies of a superconductive cavity on its geometry are represented by a stochastic response surface model. The model is constructed on the basis of both information on the eigenfrequencies as on their sensitivities with respect to the geometry. The eigenmodes are calculated using the 2D or 3D finite element method or finite integration technique. The stochastic representation does not only model uncertainties on the geometrical parameters but also inaccuracies of the eigenmode solvers, e.g. due to remeshing. Variations or optimisations of the geometry are carried out on the surrogate model. The model allows an efficient evaluation of microphoning and Lorentz detuning of accelerator cavities.
	Poster WEP11 [0.665 MB]

THP06	An OpenMP Parallelisation of Real-time Processing of CERN LHC Beam Position Monitor Data	controls, target, HOM, non-linear-dynamics	230
	H. Renshall, L. Deniau CERN, Geneva, Switzerland
	SUSSIX is a FORTRAN program for the post processing of turn-by-turn Beam Position Monitor (BPM) data, which computes the frequency, amplitude, and phase of tunes and resonant lines to a high degree of precision. For analysis of LHC BPM data a specific version run through a C steering code has been implemented in the CERN Control Centre to run on a server under the Linux operating system but became a real time computational bottleneck preventing truly on-line study of the BPM data. Timing studies showed that the independent processing of each BPMs data was a candidate for parallelization and the OpenMP package with its simple insertion of compiler directives was tried. It proved to be easy to learn and use, problem free and efficient in this case reaching a factor of ten reduction in real-time over twelve cores on a dedicated server. This paper reviews the problem, shows the critical code fragments with their OpenMP directives and the results obtained.

Paper

Title

Other Keywords

Page

TUSCC3

Undulator Radiation Inside a Dielectric Waveguide

radiation, vacuum, undulator, synchrotron

96

A. Kotanjyan, A.A. Saharian
YSU, Yerevan, Armenia

We investigate the radiation from a charge moving along a helix around a dielectric cylinder immersed in a homogeneous medium. We are mainly concerned with the radiation propagating inside the cylinder. The radiation intensity for the modes propagating inside the cylinder is evaluated by the work done by the radiation field on the charge and by evaluating the energy flux through the cross-section of the cylinder. The insertion of a dielectric waveguide provides an additional mechanism for tuning the characteristics of the undulator radiation by choosing the parameters of the waveguide. The radiated energy inside the cylinder is redistributed among the cylinder modes, the corresponding spectrum differs significantly from the homogeneous medium or free-space results. This change is of special interest in the low-frequency range where the distribution of the radiation energy among small number of modes leads to the enhancement of the spectral density for the radiation intensity. The radiation emitted on the waveguide modes propagates inside the cylinder and the waveguide serves as a natural collector for the radiation.

Slides TUSCC3 [0.809 MB]

TUADC3

Implementing New Beam Line Elements into a Moment Method Beam Dynamics Code

rfq, quadrupole, simulation, radio-frequency

104

T. Roggen, H. De Gersem, B. Masschaele
KU Leuven, Kortrijk, Belgium
W. Ackermann, S. Franke, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This research is funded by grant "KUL 3E100118" "Electromagnetic Field Simulation for Future Particle Accelerators".
Developing beam dynamics simulation tools using the moment method has advantages in terms of precision and efficiency when interests lie in average or rms dimensions of the beam, projected emittances or total energy. The moment method implemented in the V-Code solves the Vlasov equation by time integration, from an initial particle distribution represented by a discrete set of characteristic moments, accounting for all acting internal and external forces along the particle's path. The moment method delivers highly accurate beam dynamics results within a very small CPU time. This article proposes, illustrates and validates a new beam line element for a radiofrequency quadrupole (RFQ) for insertion in the V-Code. The focus will be on the RFQ cell structure, the electric field distribution and the insertion of the field distribution in the moment code.

Slides TUADC3 [4.387 MB]

WEP11

Stochastic Response Surface Method for Studying Microphoning and Lorenz Detuning of Accelerator Cavities

cavity, radiation, simulation, SRF

158

J. Deryckere, H. De Gersem, B. Masschaele, T. Roggen
KU Leuven, Kortrijk, Belgium

Funding: This research is funded by grant KUL_3E100118 and grant KUL_3E080005.
The dependence of the eigenfrequencies of a superconductive cavity on its geometry are represented by a stochastic response surface model. The model is constructed on the basis of both information on the eigenfrequencies as on their sensitivities with respect to the geometry. The eigenmodes are calculated using the 2D or 3D finite element method or finite integration technique. The stochastic representation does not only model uncertainties on the geometrical parameters but also inaccuracies of the eigenmode solvers, e.g. due to remeshing. Variations or optimisations of the geometry are carried out on the surrogate model. The model allows an efficient evaluation of microphoning and Lorentz detuning of accelerator cavities.

Poster WEP11 [0.665 MB]

THP06

An OpenMP Parallelisation of Real-time Processing of CERN LHC Beam Position Monitor Data

controls, target, HOM, non-linear-dynamics

230

H. Renshall, L. Deniau
CERN, Geneva, Switzerland

SUSSIX is a FORTRAN program for the post processing of turn-by-turn Beam Position Monitor (BPM) data, which computes the frequency, amplitude, and phase of tunes and resonant lines to a high degree of precision. For analysis of LHC BPM data a specific version run through a C steering code has been implemented in the CERN Control Centre to run on a server under the Linux operating system but became a real time computational bottleneck preventing truly on-line study of the BPM data. Timing studies showed that the independent processing of each BPMs data was a candidate for parallelization and the OpenMP package with its simple insertion of compiler directives was tried. It proved to be easy to learn and use, problem free and efficient in this case reaching a factor of ten reduction in real-time over twelve cores on a dedicated server. This paper reviews the problem, shows the critical code fragments with their OpenMP directives and the results obtained.