Variable-period permanent magnet undulators

To change the wavelength of undulator radiation, variation of the undulator magnetic field amplitude is frequently applied. Another option is changing the undulator period. A corresponding scheme is described. Both the period and number of periods can be changed. For a set of undulator sections (as in the x-ray free-electron lasers ), the mechanical motion of the periods allows doing without phase shifters between the undulator sections. Magnetic field calculations for some undulator parameters of interest were performed. Numerous advantages of the new undulators (fixed gap, strong dependence of the undulator radiation wavelength on the period, relatively low field amplitude variation, and variable number of periods) look very attractive. The prospects for this new type of undulators are discussed

Modeling and designing of variable-period and variable-pole-number undulator

The concept of permanent-magnet variable-period undulator (VPU) was proposed several years ago and has found few implementations so far. The VPUs have some advantages as compared with conventional undulators, e.g., a wider range of radiation wavelength tuning and the option to increase the number of poles for shorter periods. Both these advantages will be realized in the VPU under development now at Budker INP. In this paper, we present the results of 2D and 3D magnetic field simulations and discuss some design features of this VPU

Beamline standard component designs for the Advanced Photon Source

The Advanced Photon Source (APS) has initiated a design standardization and modularization activity for the APS synchrotron radiation beamline components. These standard components are included in components library, sub-components library and experimental station library. This paper briefly describes these standard components using both technical specifications and side view drawings

First prototype undulator for the LCLS project - mechanical design and prototype lessons.

The design of a new hybrid-type undulator with a fixed gap of 6 mm, a period of 30 mm, and a length of 3.4 m is presented. The undulator line, consisting of 33 such units, is a critical part of the LCLS project, which is one step toward the design of a fourth-generation synchrotron radiation source. Magnetic tolerance of all 33 undulators, as well as the corresponding mechanical uniformity, is a major challenge. A ridged C-shape design with a titanium housing of 12 inch diameter was chosen to provide easy access to the gap area for magnetic measuring and tuning. Lessons learned while working with this prototype are critical for successful project execution. Assembly and tests results, as well as possible design changes, are presented

A new gap separation mechanism for APS insertion devices.

A new gap separation mechanism for use with the standard Advanced Photon Source (APS) 3.3-cm-period undulator magnetic structures has been designed and built and the first system has been installed in the APS storage ring. The system allows a minimum magnetic gap of 10 mm for use with the APS 8-mm insertion device vacuum chambers. The mechanism is a bolted steel frame structure with a simple 4-motor mechanical drive train. The control system uses servomotors with incremental rotary encoders and virtual absolute linear encoders

Design of high heat load white-beam slits for wiggler/undulator beamlines at the Advanced Photon Source

A set of horizontal and vertical white-beam slits has been designed for the Advanced Photon Source wiggler/undulator beamlines at Argonne National Laboratory. While this slit set can handle the high heat flux from on e APS undulator source, it has large enough aperture to be compatible with a wiggler source also. A grazing-incidence, knife-edge configuration has been used in the design to eliminate downstream X-ray scattering. Enhanced heat transfer technology has been used in the water-cooling system. A unique stepping parallelogram driving structure provides precise vertical slit motion with large optical aperture. The full design detail is presented in this paper

An electromagnetic helical undulator for polarized x-rays

Linearly and circularly polarized x-rays have been very successfully applied to the study of the properties of materials. Many applications can benefit from the availability of energy-turnable, high-brilliance x-ray beams with adjustable polarization properties. A helical undulator that can generate beams of variable (linear to circular) polarization has been designed and built by the Budker Institute of Nuclear Physics and the Advanced Photon Source. The first harmonic of this 12.8-cm-period device will cover the energy range from 0.4 keV to 3.5 keV. An important feature of this fully electromagnetic device is that it will allow one to generate 100% horizontally (K{sub x}=O)or vertically (K{sub y}=O) plane-polarized radiation, which will enable many experiments otherwise not technically feasible. With symmetric deflection parameters (K{sub x}=K{sub y}), the on-axis radiation will be circularly polarized, with a user-selectable handedness. The polarization can be changed at rates up to 10 Hz