| Paper | Title | Page |
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| WEPD015 | Inductive Shimming of Superconductive Undulators: Preparations for a Realistic Test | 3117 |
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The monochromaticity and intensity of synchrotron light emitted by undulators strongly depend on the undulator field quality. For the particular case of superconductive undulators it was shown recently that their field quality can be significantly improved by an array of coupled high temperature superconductor loops attached to the surface of the superconductive undulator. Local field errors induce currents in the coupled closed superconducting loops and, as a result, the hereby generated magnetic field minimizes the field errors. In previous papers the concept was described theoretically and a proof-of-principle experiment was reported. This paper reports results of the first quantitative measurement of the phase error reduction in a 12-period short model undulator equipped with a full-scale induction shimming system. |
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| WEPD016 | Reduction of Dynamic Field Errors in Superconductive Undulators | 3120 |
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In the superconductive undulator SCU14, installed at ANKA, time dependent drifts in the magnetic fields were observed*. Simulations with the software OPERA 3D showed, that the cause of these drifts might be leak and eddy currents in the iron body of the undulator caused by the time-varying currents and fields during current ramps, which slowly decay by ohmic losses. This assumption was crosschecked by measurements at different mockup bodies. This contribution discusses the results of the simulations and measurements and the consequential strategies for avoiding this effect. * S. Ehlers et. al. "Magnetic field transients in superconductive undulators", in Proceedings of the Particle Accelerator Conference, Vancouver, 2009, to be published. |
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| WEPD017 | Magnetic Measurements of the 1.5 m Coils of the ANKA Superconducting Undulator | 3123 |
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A 1.5 m long superconducting undulator with a period length of 15 mm is planned to be installed in ANKA middle 2010 to be the light source of the new beamline NANO for high resolution X-ray diffraction. The key specifications of the system are an undulator parameter K higher than 2 (for a magnetic gap of 5mm) and a phase error smaller than 3.5 degrees. In order to characterize the magnetic field properties of the superconducting coils local field measurements have been performed by moving a set of Hall probes on a sledge in a liquid helium bath: the results are reported. |
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| WEPD018 | Status of COLDDIAG: a Cold Vacuum Chamber for Diagnostics | 3126 |
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One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source DIAMOND is under discussion. Here we describe the technical design report of this device and the planned measurements with beam. |
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| WEPD019 | Development of Instrumentation for Magnetic Field Measurements of 2m Long Superconducting Undulator Coils | 3129 |
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Precise measurements of the magnetic properties of conventional, i.e., permanent magnet based insertion devices has undergone tremendous improvements over the past 10 to 15 years and initiated a new era in synchrotron light sources worldwide. A similar breakthrough is now necessary in the field of superconducting insertion devices. In this contribution we describe the planned instrumentation to perform magnetic measurements of the local field, the field integrals and the multipole components of superconducting undulator coils in a cold invacuum (cryogen free) environment. |
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| WEPD020 | Experimental Demonstration of Period Length Switching for Superconducting Insertion Devices | 3132 |
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One of the advantages of superconducting insertion devices (IDs) with respect to permanent magnet IDs is the possibility to enlarge the spectral range by changing the period length by reversing the direction of the current in a part of the windings. In this contribution we report the first experimental test of this principle demonstrated on a 70mm NbTi mock-up coil with period tripling, allowing to switch between a 15mm period length undulator and a 45mm wiggler. |
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| WEPD021 | Fabrication of the New Superconducting Undulator for the ANKA Synchrotron Light Source | 3135 |
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Superconducting insertion devices (IDs) are very attractive for synchrotron light sources since they allow increasing the flux and/or the photon energy with respect to permanent magnet IDs. Babcock Noell GmbH (BNG) completed the fabrication of a 1.5 m long unit for ANKA at KIT. The period length of the device is 15 mm for a total of 100.5 full periods plus an additional matching period at each end. The key specifications of the system are: a K value higher than 2 for a magnetic gap of 5 mm, the capability of withstanding a 4 W beam heat load and a phase error smaller than 3.5 degrees. The field performance of the magnets has been qualified with liquid helium in a vertical dewar. As a result of this test the local correction coils have been installed and the magnets inserted in the final cryostat. During the factory acceptance test, the conduction cooling operation has been qualified and at the moment the undulator is ready to be tested at KIT. This paper describes the main features of the system and the results of the factory acceptance tests. |