Permanent magnets including undulators and wigglers

After a few historic remarks on magnetic materials we introduce the basic definitions related to permanent magnets. The magnetic properties of the most common materials are reviewed and the production processes are described. Measurement techniques for the characterization of macroscopic and microscopic properties of permanent magnets are presented. Field simulation techniques for permanent magnet devices are discussed. Today, permanent magnets are used in many fields. This article concentrates on the applications of permanent magnets in accelerators starting from dipoles and quadrupoles on to wigglers and undulators.Comment: 45 pages, presented at the CERN Accelerator School CAS 2009: Specialised Course on Magnets, Bruges, 16-25 June 200

Propagation of Coherent Light Pulses with PHASE

The current status of the software package PHASE for the propagation of coherent light pulses along a synchrotron radiation beamline is presented. PHASE is based on an asymptotic expansion of the Fresnel Kirchhoff integral stationary phase approximation which is usually truncated at the 2nd order. The limits of this approximation as well as possible extensions to higher orders are discussed. The accuracy is benchmarked against a direct integration of the Fresnel Kirchhoff integral. Long range slope errors of optical elements can be included by means of 8th order polynomials in the optical element coordinates w and l. Only recently, a method for the description of short range slope errors has been implemented. The accuracy of this method is evaluated and examples for realistic slope errors are given. PHASE can be run either from a built in graphical user interface or from any script language. The latter method provides substantial flexibility. Optical elements including apertures can be combined. Complete wave packages can be propagated, as well. Fourier propagators are included in the package, thus, the user may choose between a variety of propagators. Several means to speed up the computation time were tested among them are the parallelization in a multi core environment and the parallelization on a cluste

Novel Magnet Production Technique Used for an Elliptically Polarizing Undulator

A common problem for elliptically polarizing undulators EPUs is that the magnetic forces give a mechanical deflection in the magnet holder construction when changing the undulator phase. Gluing horizontally and vertically magnetized blocks together can increase the mechanical stability of the magnet holders. The gluing process of pairs of magnetized magnet blocks is time consuming, expensive and difficult to carry out with high positional precision. A novel magnet production technique has been developed where un magnetized pairs of blocks are glued together before magnetization. The large number of parts, the time for assembly, and the cost of the EPU can be reduced with the novel magnet production technique. The novel magnet production method has been used for a 2.6 m long EPU of APPLE II type, which has been built in house at the MAX IV Laboratory. The frame for the EPU is made of cast iron in order to get a small mechanical deformation when changing phase in the inclined mode. The paper includes detailed descriptions of the novel magnet production technique, including measurements of the magnetization, and the new EP

Ermittlung von derzeitigen und absehbaren Vermarktungsproblemen entlang der Wertschöpfungskette differenziert nach Produktgruppen (Probleme hinsichtlich z.B. Mengen, Preise, Qualitäten, Logistik etc.) Teilbereich: Produktgruppe Rindfleisch

Die Studie zur Ermittlung von derzeitigen und absehbaren Vermarktungsproblemen im Markt für ökologisch erzeugtes Rindfleisch wurde mit der Forschungsmethode einer „mehrstufigen Befragung nach dem Delphi-Prinzip“ bearbeitet. Den Befragungen war eine umfassende Analyse der Veröffentlichungen über den Markt für ökologisch erzeugtes Rindfleisch vorausgegangen. Die Ergebnisse zeigen, dass die Branche sich in einem strukturellen Engpass befindet. Das individualistische Agieren zahlreicher kleiner Akteure stößt im größer werdenden Markt und angesichts zunehmender Komplexität an Grenzen. Es gibt Ansätze von verstärkter Kooperation, die auch mit Erfolg am Markt belohnt werden. Die Darstellung der Probleme im Ergebnisteil hat gezeigt, dass viele Probleme wie uneinheitliche Verbraucheransprache und fehlende Qualifikationen durch die Struktur des Ökomarktes allgemein entstanden sind. Andere Probleme wie Marktrisiken und Richtlinien liegen außerhalb des Einflussbereichs der Marktteilnehmer. Als ein zentrales Ergebnis, das sich wie ein roter Faden durch die Studie zieht, ist der Mangel an Kommunikation innerhalb der Branche und damit verbunden eine genereller Informationsmangel. Die vorgeschlagene Lösung, die als Schlüssel für einige angesprochene Schwierigkeiten gelten kann, ist der horizontale und vertikale Zusammenschluss von Partnern mit ähnlichen Interessen. Ein weiteres zentrales Problem könnte mit dem Begriff „Rechtsunsicherheit“ umrissen werden. Die Marktteilnehmer fühlen sich angesichts der Mängel der so genannten „EU-Öko-Verordnung“ (abweichende Produktions- und Kontrollstandards innerhalb benachbarter Märkte) stark verunsichert. Die Schwächen des bestehenden Kontrollsystems, das als zu schwerfällig, als zu ineffizient, als zu uneinheitlich innerhalb Europas aber auch innerhalb Deutschlands betrachtet wird, verstärken diese Unsicherheit

Transverse coherence properties of X-ray beams in third-generation synchrotron radiation sources

This article describes a complete theory of spatial coherence for undulator radiation sources. Current estimations of coherence properties often assume that undulator sources are quasi-homogeneous, like thermal sources, and rely on the application of the van Cittert-Zernike theorem for calculating the degree of transverse coherence. Such assumption is not adequate when treating third generation light sources, because the vertical(geometrical) emittance of the electron beam is comparable or even much smaller than the radiation wavelength in a very wide spectral interval that spans over four orders of magnitude (from 0.1 Angstrom up to 10^3 Angstrom). Sometimes, the so-called Gaussian-Schell model, that is widely used in statistical optics in the description of partially-coherent sources, is applied as an alternative to the quasi-homogeneous model. However, as we will demonstrate, this model fails to properly describe coherent properties of X-ray beams from non-homogeneous undulator sources. As a result, a more rigorous analysis is required. We propose a technique, based on statistical optics and Fourier optics, to explicitly calculate the cross-spectral density of an undulator source in the most general case, at any position after the undulator. Our theory, that makes consistent use of dimensionless analysis, allows relatively easy treatment and physical understanding of many asymptotes of the parameter space, together with their region of applicability. Particular emphasis is given to the asymptotic situation when the horizontal emittance is much larger than the radiation wavelength, and the vertical emittance is arbitrary. This case is practically relevant for third generation synchrotron radiation sources.Comment: 71 pages, 20 figures - Version accepted for publication in Nuclear Inst. and Methods in Physics Research,

Development of Advanced Magnet Structures for Cryogenic In Vacuum Permanent Magnet Undulators

Short period undulators and in particular in vacuum cryogenic permanent magnet undulators are the upcoming technique for FEL radiators, because they permit a significant reduction of linac and undulator length. For achieving high photon energies with low electron energies short period lengths, e.g. below lOmm permanent magnet structures are superior, due to their high surface current density of 16 kA cm as compared to electromagnetic or even superconducting devices. The geom.etrical to1erances scale with the period length. This requires new fabrication techniques and structure designs, particularly for sub cm period lengths. Salutions for these demands will be presented and results from a first prototype using various new technologies such as compound poles will be discussed and compared with common approache

Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project

The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X ray beam line at the synchrotron light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY I

A Canted Double Undulator System with a Wide Energy Range for EMIL

At BESSY II a canted double undulator system for the Energy Materials In situ Laboratory EMIL is under construction. The energy regime is covered with two undulators, an APPLE II undulator for the soft and a cryogenic permanent magnet undulator CPMU 17 for the hard photons. The layout and the performance of the undulators are presented in detail. The minimum of the vertical betatron function is shifted to the center of the CPMU 17. The neighboring quadrupoles and an additional quadrupole between the undulators control the vertical betatron function. Prior to the undulator installation a testing chamber with four movable vertical scrapers has been implemented at the CPMU 17 location. Utilizing the scrapers the new asymmetric lattice optics will be tested and optimize

Beamline design and performance

The Energy Materials In-Situ Laboratory Berlin (EMIL) at BESSY-II is currently under construction. Two canted undulators for soft- and hard X-rays will be installed into the BESSY II storage ring in one straight section, complex beamlines with more than twenty optical elements will be set up and a new laboratory building attached to BESSY II will host three endstations and a large UHV-transfer system connecting various HV- and UHV-deposition systems. The undulators, UE48 and U17, provide a broad energy spectrum of 80 - 10000 eV, of which the harder radiation (>700 eV) is provided by a cryogenic in- vacuum device. Three monochromators (two plane grating monochromators (PGM) and one LN2-cooled double crystal monochromator (DCM)) disperse the radiation into separate pathways of 65 m length, while downstream of the monochromators split-mirror chambers distribute the photon beam to one (or simultaneously to two) of five upcoming endstations. Three of these endstations are designed for the full energy range with spatial overlap of the soft and hard foci, whereas one endstation (PEEM) uses only the soft and another one (PINK) only the hard branch, respectively

The Energy Materials in-Situ Laboratory Berlin (EMIL) at BESSY II

The Helmholtz Center Berlin (HZB) and the Max-Planck Society (MPG) strengthen their research in renewable energies with the implementation of the joint Energy Material in-Situ Lab Berlin (EMIL) at the third generation light source BESSY II. The new facility is dedicated to the in-situ and in-system x-ray analysis of materials and devices for photovoltaic applications, (photo-) catalytic processes, energie conversion and storage. To obtain a comprehensive understanding of the involved materials, spectroscopic methods with x-rays from the soft- up to the hard x-ray regime reveal an almost complete picture of their chemical and electronic properties. The contribution presents the layout of the x-ray beamlines and their performance in terms of photon flux, energy resolution and spot sizes