J. Chavanne

The ID23-2 structural biology microfocus beamline at the ESRF

Beamline ID23-2, the first dedicated and highly automated high-throughput monochromatic macromolecular crystallography microfocus beamline, is described.

A three-dimensional magnetostatics computer code for insertion devices.

RADIA is a three-dimensional magnetostatics computer code optimized for the design of undulators and wigglers. It solves boundary magnetostatics problems with magnetized and current-carrying volumes using the boundary integral approach. The magnetized volumes can be arbitrary polyhedrons with non-linear (iron) or linear anisotropic (permanent magnet) characteristics. The current-carrying elements can be straight or curved blocks with rectangular cross sections. Boundary conditions are simulated by the technique of mirroring. Analytical formulae used for the computation of the field produced by a magnetized volume of a polyhedron shape are detailed. The RADIA code is written in object-oriented C++ and interfaced to Mathematica [Mathematica is a registered trademark of Wolfram Research, Inc.]. The code outperforms currently available finite-element packages with respect to the CPU time of the solver and accuracy of the field integral estimations. An application of the code to the case of a wedge-pole undulator is presented.

Development of a new state-of-the-art beamline optimized for monochromatic single-crystal and powder X-ray diffraction under extreme conditions at the ESRF.

A new state-of-the art synchrotron beamline fully optimized for monochromatic X-ray diffraction at high pressure and high (or low) temperature is presented. In comparison with the old high-pressure beamline ID30, this new beamline exhibits outstanding performance in terms of photon flux and focusing capabilities. The main components of this new instrument will be described in detail and compared with the performance of beamline ID30. In particular, the choices in terms of X-ray source, X-ray optics, sample environment and detectors are discussed. The first results of the beamline commissioning are presented.

The ID23-1 structural biology beamline at the ESRF.

The demand for access to macromolecular crystallography synchrotron beam time continues to increase. To meet this demand the ESRF has constructed a dual station beamline using a canted undulator system as the X-ray source. The first phase of the beamline to be constructed is ID23-1, a tunable MAD-capable station with a mini-focus X-ray beam. The beamline makes use of well characterized optical elements: a channel-cut monochromator with a high-precision toroidal mirror to focus the X-ray beam. The beamline has been conceived with the aim of providing high levels of automation to create an industrial-like environment for protein crystallography. A new software suite has been developed to permit reliable easy operation for the beamline users and beamline staff. High levels of diagnostics are built in to allow rapid trouble-shooting. These developments are now being exported to the ESRF macromolecular crystallography beamline complex and have been made in a modular fashion to facilitate transportability to other synchrotrons.

Computing 3D magnetic fields from insertion devices

A 3D magnetostatics computer code optimized for Undulators and Wigglers is described. The code uses a boundary integral method and makes extensive use of analytical expressions for the field and field integrals along a straight line. The code outperforms currently available finite element packages in the area of simple data input, CPU time of the solver and accuracy reached for the estimation of field integrals. It is written in C++ and takes advantage of object-oriented programming. The code is interfaced to Mathematica. Pre- and post-processing of the field data is done in the Mathematica Language. It has been extensively benchmarked with respect to a commercial finite element code. All ESRF Insertion Devices built during the last 4 years have been designed using this code or an older version.

A Low-Emittance Lattice for the ESRF

In the framework of its upgrade, the ESRF is designing a new lattice to replace the present double-bend achromat structure. This new lattice fulfills the following constraints and requirements: It fits in the present tunnel and keeps the insertion device source points at the same location; Its target horizontal emittance is around 150 pm; It keeps the electron energy at 6 GeV in order to preserve the spectral properties of the present beamlines; It minimizes the radiation losses and the magnet electrical consumption in order to decrease operating costs; The present injector complex is re-used with minor changes.

End field structures for linear/helical insertion devices

The field integral tolerances required on third generation synchrotron sources are of the order of 10-20 Gcm in the whole gap range of an insertion device. This can be achieved without electromagnet correction by a proper magnetic design of the field termination. The paper describes several such end field terminations to be used for planar undulators. A new termination valid for an APPLE II undulator is presented which produces a field integral variation smaller than 20 Gcm for any useful setting of the magnetic gap and phase. It compares quite favorably with other known type of terminations.

A new powerful flexible linear/helical undulator for soft X-rays

Abstract The purpose of the undulator Helios is to generate intense and bright circularly or linearly polarized synchrotron radiation. The horizontal and vertical fields constituting the helicoidal field are generated separately by two jaws of magnet blocks. Helios will be built for installation on the European Synchrotron Radiation Facility (ESRF), a 6 GeV synchrotron source which has been built to cover the hard X-ray range of the spectrum. The radiation from Helios will be tunable from 0.5 to 5 keV (25 to 2.5 A) with a high polarization rate (> 90%) and flexible polarization (linear-helical) achieved by using the fundamental and higher harmonics.

SPring‐8 in‐vacuum undulator beam test at the ESRF

Before the commissioning of SPring-8, the in-vacuum hybrid undulator developed at SPring-8 had been brought to the ESRF for the first beam test in the summer of 1996. The purpose of this test was to investigate the influence of the in-vacuum undulator on the beam and check its vacuum system. However, heating by the resistive wall impedance turned out to be a critical issue for the in-vacuum undulators.

Insertion devices at the ESRF

Fifteen undulators and wigglers are now installed on the ESRF. They have been designed and measured in‐house. The magnetic field has been corrected using iron shims which remove all multipoles and fully corrects the radiation spectrum. The measured spectra confirm the expected low emittance of the beam resulting in an unprecedented high brilliance above 10 keV of photon energy. The observed interaction with the electron beam is negligible.