Investigation of edge radiation intensification effect generated by periodic alignment of three-pole wigglers

2022 ◽  
Author(s):  
Shigeru Koda ◽  
Yuichi Takabayashi ◽  
Tatsuo Kaneyasu ◽  
Yoshitaka Iwasaki
Keyword(s):  
Numerical Study ◽  
Concentric Circle ◽  
Harmonic Structure ◽  
Characteristic Structure ◽  
K Value ◽  
Undulator Radiation ◽  
Peak Intensity ◽  
Edge Radiation ◽  
Radiation Properties ◽  
Large Gradient

Abstract The intensification effect of edge radiation due to the periodic alignment of three-pole wigglers was analytically and numerically investigated. The radiation properties were studied using a simple model that had an alternating alignment of straight sections and large gradient orbit sections due to the use of three-pole wigglers. The angular distribution of the radiation was concentrated on a concentric circle. The peak intensity of the radiation was roughly on the same order as that of the peak radiation of a planar undulator. The spectrum of the radiation had a characteristic structure that was rather similar to the higher harmonic structure of undulator radiation. A numerical study showed that a planar undulator with a specific K value satisfies approximately the radiation intensification condition due to the periodic alignment of the three-pole wigglers. The intensified edge radiation is included in the undulator radiation.

scholarly journals Ground settlement prediction of embankment treated with prefabricated vertical drains in soft soil

2018 ◽  
Vol 195 ◽  
pp. 03014
Author(s):  
Siswoko Adi Saputro ◽  
Agus Setyo Muntohar ◽  
Hung Jiun Liao
Keyword(s):  
Numerical Study ◽  
Soft Soil ◽  
Soil Permeability ◽  
K Value ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Prefabricated Vertical Drain ◽  
Actual Settlement ◽  
Final Settlement ◽  
Best Fit

Excessive settlement due to consolidation can cause damage to the structure’s rest on soft soil. The settlement takes place in relatively longer. The preloading and prefabricated vertical drain (PVD) is often applied to accelerate the primary settlement. The issue in this research is the estimation of the settlement. The Asaoka method and the finite element method using PLAXIS-2D are used to estimate the final settlement of a PVD treated embankment. For the former, a complete record of the settlement was required; for the latter, some ground parameters are needed for the PLAXIS-2D analysis, such as the permeability of the soil. Because the installation process of PVD tends to influence the permeability of the in-situ soil around the PVD, the soil permeability after the installation of PVD needs to be adjusted. The numerical results were compared with actual settlement data to find out the best-fit input parameters (i.e. soil permeability) of the actual data. It was found that the best-fit soil permeability (k) used in the numerical study was about one-half of the k value determined from the laboratory test. The Root Mean Square Deviation shows that the settlement predicted by the numerical analysis has approximately 30% of the actual settlement.

Analytic and numerical study of two-frequency undulator radiation

1993 ◽  
Vol 47 (3) ◽  
pp. 2061-2066 ◽  
Author(s):  
F. Ciocci ◽  
G. Dattoli ◽  
L. Giannessi ◽  
A. Torre ◽  
G. Voykov
Keyword(s):  
Numerical Study ◽  
Undulator Radiation

OBSERVATION OF COHERENT EDGE RADIATION EMITTED BY A 100 FEMTOSECOND COMPRESSED ELECTRON BEAM

2007 ◽  
Vol 22 (23) ◽  
pp. 4101-4114 ◽  
Author(s):  
G. ANDONIAN ◽  
M. DUNNING ◽  
E. HEMSING ◽  
J. B. ROSENZWEIG ◽  
A. COOK ◽  
...  
Keyword(s):  
Transition Radiation ◽  
Electron Beams ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Test Facility ◽  
Beam Physics ◽  
Coherent Synchrotron Radiation ◽  
Edge Radiation ◽  
Radiation Properties ◽  
Physics Experiments

A chicane compressor developed by UCLA for the production of ultra-short, 60 MeV electron beams at the Brookhaven National Laboratory Accelerator Test Facility has been commissioned, and initial beam physics experiments have been performed. These measurements have established the compression of electron beams to the 100 femtosecond (1 kA peak current) regime, via coherent transition radiation (CTR) based measurements. Investigations of coherent edge radiation (CER) include signatures that differentiate it from coherent synchrotron radiation (CSR), such as polarization and far-field angular distribution. Additionally, the radiation wavelength spectrum is determined from autocorrelation measurements. Radiation properties are compared to detailed start-to-end simulations derived from PARMELA and QUINDI (a Lienard-Wiechert code developed at UCLA). Plans for future experiments which further explore the observed wavelength spectra are presented.

Practical aspects of undulator radiation properties

1996 ◽  
Author(s):  
Peter P. Ilinski ◽  
Roger J. Dejus ◽  
Efim S. Gluskin ◽  
Timothy I. Morrison
Keyword(s):  
Undulator Radiation ◽  
Radiation Properties

scholarly journals Effects of energy spread on brightness and coherence of undulator sources

2018 ◽  
Vol 25 (5) ◽  
pp. 1335-1345 ◽  
Author(s):  
Gianluca Geloni ◽  
Svitozar Serkez ◽  
Ruslan Khubbutdinov ◽  
Vitali Kocharyan ◽  
Evgeni Saldin
Keyword(s):  
Wigner Distribution ◽  
Energy Spread ◽  
Gaussian Beams ◽  
Spectral Brightness ◽  
Undulator Radiation ◽  
At Resonance ◽  
Radiation Properties ◽  
Coherent Sources ◽  
On Line ◽  
Laser Sources

The (spectral) brightness for partially transverse coherent sources such as synchrotron radiation and free-electron laser sources can be defined as the maximum of the Wigner distribution. Then, the brightness includes information on both coherence and wavefront characteristics of the radiation field. For undulator sources, it is customary to approximate the single-electron electric field at resonance with a Gaussian beam, leading to great simplifications. Attempts to account for the modified spatial and angular profile of the undulator radiation in the presence of detuning due to energy spread, currently build on the simplified brightness expression derived under the assumption of Gaussian beams. The influence of energy spread on undulator radiation properties is becoming important in view of diffraction-limited rings with ultralow emittance coming on-line. Here the effects of energy spread on the brightness of undulator radiation at resonance are discussed, as well as relevant relations with coherence properties.

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