ANL, Argonne
HSRC, Higashi-Hiroshima
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A request from the light source user community for insertion devices that provide only monochromatic light has led to development of quasi-periodic undulators (QPUs). These devices generate shifted harmonics in the photon energy spectrum, thus allowing suppression of higher harmonics by optical monochromator systems. Until now such undulators have been technically realized with pure permanent magnets or with hybrid structures. A concept for a superconducting quasi-periodic undulator (SCQPU) is suggested and described in this paper.
ESRF, Grenoble
SOLEIL, Gif-sur-Yvette
Cryogenic Permanent Magnet Undulators (CPMU) are currently being developed in some Synchrotron Light Sources. Low Temperature NdFeB Permanent Magnets are used to achieve both a high remanence and a high coercive field. Low temperature magnetization hysteresis curves cannot be obtained by a simple transformation of ambient temperature curves; this requires a specific simulation tool. A Monte-Carlo based Permanent Magnet Simulator has been developed at the ESRF. In this simulator, the magnets can be described as a set of several magnetic grains. The model inputs are physical parameters such as anisotropy constants, easy-axis distribution and coercive field. The orientation of magnetic moments are calculated for each grain according to an analytical model and optimization methods are used for fast computations. Magnetization versus external field curves is calculated in a few seconds. This fits with low temperature NdFeB magnetization measurements. These curves have been efficiently used to obtain Radia material parameters for CPMU design.
LBNL, Berkeley, California
Funding: This work is supported by the Director, Office of Science, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.
In 2006, the 30mm period In-Vacuum Insertion Device (IVID) was operational for the femtosecond phenomena beamline at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory. Since then the IVID has been demonstrating unexpected behaviors especially at small gaps (minimum gap = 5.5mm). The main observations related to these issues are partial or total beam losses as well as sudden pressure increases while operating the IVID gap. This paper is reporting these observations and describes the investigations and the repair attempt performed on this insertion device.
LNLS, Campinas
UVX is a 1.37 GeV electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS). The ring is composed of a 6-fold symmetric double-bend achromat lattice with 4 sections reserved for insertion devices. The storage ring was commissioned in 1997 in a mode of operation with high (~12 m) vertical betatron functions in the insertion straights. However, the need for operation with reduced vertical aperture arose with the gradual installation of insertion devices over the years and is particularly important for operation with a 14 mm vertical aperture superconducting wiggler scheduled for installation in late 2009. To cope with this restricted aperture, a new mode with low (~0.8 m) vertical betatron function in all six long straights was deemed necessary and was implemented at the end of 2008. In this report we present the commissioning results of the low vertical beta mode and the advantages in operating in this mode with insertions.
ELETTRA, Basovizza
A full energy injector consisting of a 100 MeV linac and an up to 2.5 GeV booster is in operation since March 2008 replacing the previous 1 GeV linac injector to be used after refurbishing and upgrade for the new fourth generation light source (FEL) currently under construction at Sincrotrone Trieste. The measurements on the new injector, problems and solutions employed to increase its efficiency, reproducibility and reliability, aiming towards top-up operations in the near future, and its impact on the Elettra storage ring are presented and discussed.
ANL, Argonne
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava
Funding: * Work at Argonne supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357.
Hall probe is the best way to do tuning and measurements of insertion devices. Horizontal Hall probe magnetic field measurements in the presence of a strong vertical magnetic field were tested in 1997. The next step of this investigation was reported at the 2004 FEL Conference. Hall probe horizontal field measurements in the presence of a vertical magnetic field are complicated due to the influence of the Planar Hall probe effect on the resulting Hall voltage. 2-axis Sentron Hall probe was used for the Linear Coherent Light Source devices. By positioning the Hall probe accurately in the vertical direction, the probe could be used for fast measurements and tuning of FEL devices. To eliminate the high sensitivity to the positioning of the probe, a new type of Hall probe, consisting of two sensors combined so as to cancel the influence of the PHE, was developed at the Institute of Electrical Engineering, Slovak Academy of Sciences. The results of tests done at the APS showed that it is not sensitive to vertical position and is 60 times less sensitive than a Bell probe to the angle between the Hall sensor current and the in-plane component of the field direction.
RadiaBeam, Marina del Rey
BNL, Upton, Long Island, New York
Funding: DOE
A High Temperature Superconducting Dysprosium Pole Undulator (HTS-DPU) is proposed to achieve an ultra-high peak field in a very short period undulator structure. This design utilizes the unique ferromagnetic properties of dysprosium (Dy) at liquid nitrogen temperature. The fabrication of textured Dy fabricated via economic and highly reproducible process is studied experimentally with the goal to achieve sufficient magnetic anisotropy and desired field saturation level at a practical cost. In addition, utilizing the latest capabilities of the 2G HTS wire is investigated. The practical implementation of HTS-DPU would enable the development of short period insertion devices with superior performance.
SOLEIL, Gif-sur-Yvette
BNL, Upton, Long Island, New York
SOLEIL storage ring presents a very high fraction of the total circumference dedicated to accommodate insertion devices. Over the presently planned 25 insertion devices presenting a large variety of systems, 15 have been already installed and commissioned by the end of 2008. The UV-VUV region is covered with electromagnetic devices (one HU640 and 3 HU256), offering tuneable polarisations. An electromagnet/permanent magnet undulator using copper sheets as coils for fast switching of the helicity is under construction. 13 APPLE-II types undulators, with period ranging from 80 down to 36 mm, provide photons in the 0.1-10 keV region, some of them featuring tapering or quasi-periodicity. 5 U20 in-vacuum undulators cover the 3-30 keV range whereas an in-vacuum wiggler, with magnetic forces compensation via adequate springs is designed to cover the 10-50 keV spectral domain. R&D on cryogenic in-vacuum undulator has also been launched. A magnetic chicane using permanent magnet dipoles has also been designed in order to accommodate two canted undulators on the same straight section. The processes for optimizing the insertion devices and their achieved performances will be described.
KIT, Karlsruhe
FZK, Karlsruhe
University Erlangen-Nuernberg, Erlangen
Recently a new concept for automatically reducing magnetic field errors in superconductive undulators was proposed. According to this proposal the field errors are compensated by an array of coupled high temperature superconductor loops attached to the surface of the superconductive undulator. The field errors induce currents in the coupled type II-superconducting loops and, as a result, the magnetic field generated by these currents minimizes the field errors. In this paper the results of a first successful experimental test of this concept are described.
BNL, Upton, Long Island, New York
The NSLS-II Light Source being built at Brookhaven National Laboratory is expected to provide submicron stability of the electron orbit in the storage ring in order to utilize fully the very small emittances and electron beam sizes. This requires high stability supports for BPM pick-up electrodes, located near insertion device source. Description of the efforts for development of supports including carbon tubes and invar rods is presented.
LBNL, Berkeley, California
Funding: Supported by DOE BES contract DE-AC03-76SF00098.
Recently there has been a proposal to use pulsed high order multipole elements for injection. One of the advantages of this proposed injection scheme would be that it would be less disruptive to the stored beam and thus advantageous for Top-off operation. In addition to Top-off, such novel injectors might open the door to operating storage rings in more desirable lattice settings. In this paper we will explore some of the possibilities for taking advantage of high order multipole pulsed kick injection.
SLAC, Menlo Park, California
We describe a set of tools that interface to the Tracy particle tracking library. The state of the machine including misalignments, multipole errors and corrector settings is captured in a 'flat' file, or 'machine' file. There are three types of tools designed around this flat file: 1) flat file creation tools. 2) flat file manipulation tools. 3) tracking tools. We describe the status of these tools, and give some examples of how they have been used in the design process for NSLS-II.