IPAC2016 - List of Keywords (electromagnetic-fields)

Paper	Title	Other Keywords	Page
MOPMR060	C-Band Deflecting Cavity for Bunch Length Measurement of 2.5 MeV Electron Beam	cavity, vacuum, coupling, simulation	386
	J. Jiang, H.B. Chen, J. Shi, P. Wang, L. Zhang, S.X. Zheng TUB, Beijing, People's Republic of China
	The C-band deflecting cavity designed last year is finished. In this paper, the RF measurement of the cavity is introduced. After tuning, it works well at 5.712GHz with a coupling factor degree around 1.05. And we measured the electromagnetic field with bead-pull method. The flatness of the magnetic field is around 0.9, which is not ideal but meet the requirements of the bunch length measurement. And we propose a method of tuning to make sure both frequency and field flatness.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR060
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MOPMW007	On the Calibration Measurement of Stripline Beam Position Monitor for the ELI-NP Facility	simulation, linac, vacuum, impedance	411
	D. De Arcangelis, F. Cardelli, A. Mostacci, L. Palumbo University of Rome La Sapienza, Rome, Italy
	Stripline Beam Position Monitor (BPM) will be installed in the Compton Gamma Source in construction at the ELI Nuclear Physics facility in Romania. A test bench for the calibration of BPM has been built to characterize the device with stretched wire measurement in order to get the BPM response map. A full S-parameters characterisation is performed as well to measure the electrical offset with the "Lambertson method". This paper discusses the extensive simulations performed with full 3D electromagnetic CAD codes of the above measurements to investigate measurement accuracy, possible measurement artefacts and the beam position reconstruction.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW007
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TUPMY034	On Bunch Diagnostics with use of Surface Waves Generated on Planar Wire Grid	radiation, vacuum, electronics, diagnostics	1623
	V.V. Vorobev, S.N. Galyamin, A.V. Tyukhtin Saint-Petersburg State University, Saint-Petersburg, Russia
	Funding: Work is supported by the Grant of the President of Russian Federation (No. 6765.2015.2) and the Grants from Russian Foundation for Basic Research (No. 15-32-20985, 15-02-03913). Periodic structures can be used for non-destructive diagnostics of charged particle bunches. We consider structures which consist of thin conducting parallel wires. It is assumed that the structure period is much less than the typical wavelength under consideration. Therefore the influence of the structure on the electromagnetic field can be described with help of the averaged boundary conditions. We consider radiation of bunches which move along the grid but transversely to wires. Unlike previous works the bunch is assumed to have essential transversal dimensions along with definite longitudinal charge distribution. In particular we analyze the effect of reflection of the surface wave from the structure edge. For all considered situations, analytical and numerical results demonstrate that analysis of the surface waves allows estimating the size and the shape of the bunch. A.V. Tyukhtin et al., Phys. Rev. ST AB 17, 122802 (2014); A.V. Tyukhtin et al., Phys. Rev. E 91, 063202 (2015). ** M.I. Kontorovich et al., Electrodynamics of Grid Structures (Moscow, 1987).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY034
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WEPOR016	Pre-alignment of Accelerating Structures for Compact Acceleration and High Gradient using In-situ Radiofrequency Methods	alignment, dipole, linac, wakefield	2696
	N. Galindo Munoz, N. Catalán Lasheras, A. Grudiev CERN, Geneva, Switzerland V.E. Boria DCOM-iTEAM-UPV, Valencia, Spain A. Faus-Golfe IFIC, Valencia, Spain
	Funding: PACMAN is founded under the European Union's 7th Framework Program Marie Curie Actions, grant PITN-GA-2013-606839 To achieve a high accelerating gradient of 100 MV/m, the CLIC project under study at CERN uses a 23 cm long tapered normal-conducting travelling wave Accelerating Structure (AS) operating at 12 GHz. Minimisation of the long-range wakefields (WF) is assured by damping of the HOM through four radial waveguides in each cell without distorting the accelerating mode. As an extension of them, there are four bent waveguides called WF monitors (WFM) in the middle cell with two RF pick-ups. To obtain a small beam emittance in the collision point, micro-metric pre-alignment of the AS is required. We work to find the electrical centre of the AS through the use of the asymmetry in the RF scattering parameters created by an off-centre conductive wire, stretched along the axis. The accuracy required is of 7 μm with a resolution of 3.5 μm for the WFM signals including the acquisition electronics. Our simulations have shown that a resolution of 1 μm is possible using a calibrated VNA. Measurement results and improvements of the final accuracy will be presented and discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR016
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WEPOY034	Latest Improvements of OPAL	space-charge, dipole, simulation, linac	3058
	C.J. Metzger-Kraus, M. Abo-Bakr, B.C. Kuske HZB, Berlin, Germany A. Adelmann PSI, Villigen PSI, Switzerland
	OPAL (Object Oriented Parallel Accelerator Library) is an open source, C++ based tool for charged particle tracking in large accelerator structures and beam lines including 3D space charge, particle matter interaction and FFAG capabilities. The careful parallel design makes it possible to tackle large and complex problems, in a reasonable time frame. The current code status and latest program improvements and upgrades are introduced. One of the provided flavors, OPAL-T, was, so-far, used for relatively simple lattices and was not well suited for more complicated arrangements of elements. One of the major upgrades is the possibility to place elements in 3D space, giving the user a better control in absolute element positioning. The old input format with relative positioning is still supported. We show results of the BERLinPro lattice and compare it with results obtained with elegant.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY034
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THPOW010	Study on Characteristics of Asymmetric Centre Iris of Photocathode Microwave Electron Gun	gun, electron, emittance, cathode	3951
	Zh. X. Tang, X.M. Yang, W.Q. Zhang DICP, Dalian, People's Republic of China Y.J. Pei USTC/NSRL, Hefei, Anhui, People's Republic of China
	The characteristics of asymmetric iris between first cell and second cell of 1.6 cell photocathode gun are studied. For π-mode, the RF radial field of two sides of the iris is non anti-symmetric. Thus, the RF transverse force at the iris is not negligible. In this paper, we present the status of the optimization simulations, using the SUPERFISH and PARMELA particle-in-cell code. Numerical results of beam dynamics show that it can improve the emittance at the exit of the gun.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW010
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Paper

Title

Other Keywords

Page

MOPMR060

C-Band Deflecting Cavity for Bunch Length Measurement of 2.5 MeV Electron Beam

cavity, vacuum, coupling, simulation

386

J. Jiang, H.B. Chen, J. Shi, P. Wang, L. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China

The C-band deflecting cavity designed last year is finished. In this paper, the RF measurement of the cavity is introduced. After tuning, it works well at 5.712GHz with a coupling factor degree around 1.05. And we measured the electromagnetic field with bead-pull method. The flatness of the magnetic field is around 0.9, which is not ideal but meet the requirements of the bunch length measurement. And we propose a method of tuning to make sure both frequency and field flatness.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR060

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW007

On the Calibration Measurement of Stripline Beam Position Monitor for the ELI-NP Facility

simulation, linac, vacuum, impedance

411

D. De Arcangelis, F. Cardelli, A. Mostacci, L. Palumbo
University of Rome La Sapienza, Rome, Italy

Stripline Beam Position Monitor (BPM) will be installed in the Compton Gamma Source in construction at the ELI Nuclear Physics facility in Romania. A test bench for the calibration of BPM has been built to characterize the device with stretched wire measurement in order to get the BPM response map. A full S-parameters characterisation is performed as well to measure the electrical offset with the "Lambertson method". This paper discusses the extensive simulations performed with full 3D electromagnetic CAD codes of the above measurements to investigate measurement accuracy, possible measurement artefacts and the beam position reconstruction.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW007

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TUPMY034

On Bunch Diagnostics with use of Surface Waves Generated on Planar Wire Grid

radiation, vacuum, electronics, diagnostics

1623

V.V. Vorobev, S.N. Galyamin, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

Funding: Work is supported by the Grant of the President of Russian Federation (No. 6765.2015.2) and the Grants from Russian Foundation for Basic Research (No. 15-32-20985, 15-02-03913).
Periodic structures can be used for non-destructive diagnostics of charged particle bunches*. We consider structures which consist of thin conducting parallel wires. It is assumed that the structure period is much less than the typical wavelength under consideration. Therefore the influence of the structure on the electromagnetic field can be described with help of the averaged boundary conditions**. We consider radiation of bunches which move along the grid but transversely to wires. Unlike previous works the bunch is assumed to have essential transversal dimensions along with definite longitudinal charge distribution. In particular we analyze the effect of reflection of the surface wave from the structure edge. For all considered situations, analytical and numerical results demonstrate that analysis of the surface waves allows estimating the size and the shape of the bunch.
* A.V. Tyukhtin et al., Phys. Rev. ST AB 17, 122802 (2014); A.V. Tyukhtin et al., Phys. Rev. E 91, 063202 (2015).
** M.I. Kontorovich et al., Electrodynamics of Grid Structures (Moscow, 1987).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY034

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WEPOR016

Pre-alignment of Accelerating Structures for Compact Acceleration and High Gradient using In-situ Radiofrequency Methods

alignment, dipole, linac, wakefield

2696

N. Galindo Munoz, N. Catalán Lasheras, A. Grudiev
CERN, Geneva, Switzerland
V.E. Boria
DCOM-iTEAM-UPV, Valencia, Spain
A. Faus-Golfe
IFIC, Valencia, Spain

Funding: PACMAN is founded under the European Union's 7th Framework Program Marie Curie Actions, grant PITN-GA-2013-606839
To achieve a high accelerating gradient of 100 MV/m, the CLIC project under study at CERN uses a 23 cm long tapered normal-conducting travelling wave Accelerating Structure (AS) operating at 12 GHz. Minimisation of the long-range wakefields (WF) is assured by damping of the HOM through four radial waveguides in each cell without distorting the accelerating mode. As an extension of them, there are four bent waveguides called WF monitors (WFM) in the middle cell with two RF pick-ups. To obtain a small beam emittance in the collision point, micro-metric pre-alignment of the AS is required. We work to find the electrical centre of the AS through the use of the asymmetry in the RF scattering parameters created by an off-centre conductive wire, stretched along the axis. The accuracy required is of 7 μm with a resolution of 3.5 μm for the WFM signals including the acquisition electronics. Our simulations have shown that a resolution of 1 μm is possible using a calibrated VNA. Measurement results and improvements of the final accuracy will be presented and discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR016

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WEPOY034

Latest Improvements of OPAL

space-charge, dipole, simulation, linac

3058

C.J. Metzger-Kraus, M. Abo-Bakr, B.C. Kuske
HZB, Berlin, Germany
A. Adelmann
PSI, Villigen PSI, Switzerland

OPAL (Object Oriented Parallel Accelerator Library) is an open source, C++ based tool for charged particle tracking in large accelerator structures and beam lines including 3D space charge, particle matter interaction and FFAG capabilities. The careful parallel design makes it possible to tackle large and complex problems, in a reasonable time frame. The current code status and latest program improvements and upgrades are introduced. One of the provided flavors, OPAL-T, was, so-far, used for relatively simple lattices and was not well suited for more complicated arrangements of elements. One of the major upgrades is the possibility to place elements in 3D space, giving the user a better control in absolute element positioning. The old input format with relative positioning is still supported. We show results of the BERLinPro lattice and compare it with results obtained with elegant.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW010

Study on Characteristics of Asymmetric Centre Iris of Photocathode Microwave Electron Gun

gun, electron, emittance, cathode

3951

Zh. X. Tang, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

The characteristics of asymmetric iris between first cell and second cell of 1.6 cell photocathode gun are studied. For π-mode, the RF radial field of two sides of the iris is non anti-symmetric. Thus, the RF transverse force at the iris is not negligible. In this paper, we present the status of the optimization simulations, using the SUPERFISH and PARMELA particle-in-cell code. Numerical results of beam dynamics show that it can improve the emittance at the exit of the gun.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)