N.A. Mezentsev

The experimental station for X-ray microscopy and microtomography at the VEPP-3 storage ring

Abstract The experimental station for X-ray scanning transmission microscopy and microtomography using synchrotron radiation from the VEPP-3 is described. The station allows usual and difference microroentgenographs and microtomographs to be taken in the quanta energy range 5–35 keV. At present the achievable spatial resolution is estimated to be 2–3 μm.

A MULTIPOLE SUPERCONDUCTING WIGGLER FOR CANADIAN LIGHT SOURCE

A contract for multipole superconducting wiggler design and fabrication between The University of Saskatchewan and Budker Institute of Nuclear Physics was signed in October 2003. A wiggler with the photons energy range 4 to 40 keV, the maximum field 1.9 T, and the period length as small as possible was required for the micro-XAFS beamline. In 2004 the 2 T 63-pole superconducting wiggler with the average period length 34 mm was fabricated in BINP. To eliminate the undulator-type spectrum, the periodicity of the wiggler was broken. A new approach to the cryostat design enabled long-time (up to 6 months) machine operation without liquid helium refilling (LHe consumption <0.03 l/h). After successful tests the wiggler was installed on the Canadian Light Source (CLS) storage ring with the energy 2.9 GeV in January 2005. The main parameters of the magnet and the cryogenic systems, as well as magnet measurements data, cryogenic system test data, and experimental results during machine operation on the CLS storage ring are presented.

Test Results of the CLIC Damping Wiggler Prototype

The Compact Linear Collider (CLIC) will require ultralow emittance electron and positron beams. Such emittance will be achieved by radiative damping in the CLIC damping rings that will be realized by a use of high-field short-period superconducting damping wigglers. In the course of the CLIC technical feasibility studies, a full-scale damping wiggler prototype was fabricated in BINP. Main parameters of the wiggler are 51 mm of period, 3 T of magnetic field, 1.8 m of magnetic length, 18 mm of the pole gap, and indirect cooling by LHe. Four cryocoolers were used in the wiggler design, which allow its ordinary operation without LHe consumption. Above the magnetic requirements, the main design challenges for this prototype are scalability, particularly of the cooling concept, modularity, and the capability of sustaining a high radiative heat load. The wiggler powering tests and performance of the cryogenic system are described in this paper.

X-ray focusing monochromator for an X-ray scanning microscopy and microtomography station

Abstract The first results concerning an X-ray focusing monochromator in the energy range 5–35 keV for an X-ray scanning microscopy and microtomography station at the VEPP-3 storage ring are presented. Sagittal focusing with the use of Si(111) crystal in the Von Hamos scheme is investigated and discussed.

Construction and Tests of the 49-pole 3.5 Tesla Superconducting Wiggler for ELETTRA Storage Ring

The necessity of extending the useful spectrum of synchrotron radiation at higher energies (> 10 keV) for X‐Ray Diffraction applications was the reason for developing and constructing a novel superconducting insertion device the Elettra storage ring. The superconducting wiggler with 45 full poles and a field strength of 3.5 T, 16.5 mm magnetic gap and a period of 64 mm has been developed and produced by the Budker Institute of Nuclear Physics SB RAS. This article describes some technical properties and characteristics of the wiggler as well as the results of the wiggler tests.

Simultaneous two energies anomalous scattering for the study of the dynamics of structural transformation

Abstract In this work the wiggler of VEPP-3 is used for the generation of two beams of synchrotron radiation. After the focusing monochromator, both beams have an energy near the Ni K-edge; they differ by 20 eV. At the sample position the two beams are separated by 2.3 mm. The simultaneous registration of two X-ray diffraction patterns at different energies was made by two position sensitive detectors OD-2. A comparison of the two diffraction patterns, registered at different energies, clearly shows the anomalous scattering effect for the test sample NiO. This method was used for the investigation of the behavior of the Ni atom during the solid state chemical reaction NiO + MoO 3 → NiMoO 4 at T = 600–800°C. This method gives an anomalous scattering signal when the Ni atoms appear in the molybdenum oxide phase. The kinetics of formation of β-NiMoO 4 was obtained. At different temperatures the Ni atoms occupied different positions in the β-NiMoO 4 structure, at 650°C they were at the sites of the crystal lattice, at 690°C they were in the interstitial positions.

Short-period superconducting undulator coils with neutral poles: test results

The success in creating new bright magnetic structures of synchrotron radiation (SR) sources allows generation of subnanometric-emittance electron beams. This has motivated many SR centers to upgrade the old structures to increase the brightness of the SR sources. Smaller emittance imposes higher requirements on the generators of undulator radiation. With the advent of new materials, the production of undulators on permanent magnets has progressed greatly. Superconducting undulators are less common, but as sources of undulator radiation they are much more promising than undulators with permanent magnets. This paper presents test results of a prototype superconducting undulator magnet using active and neutral poles with a period of 15.6 mm and an operational field of ∼1.2xa0T. A pole gap of 8xa0mm provides a vertical aperture of 6xa0mm for an electron beam. In contrast to the traditional type of undulator with vertical racetrack coils, in this type of undulator the coils are of the horizontal racetrack type. The magnet design consists of the aluminum-alloy frame, into which individual poles are inserted. The design can significantly improve the manufacturing accuracy and, ultimately, reduce the phase errors. The coils are made of NbTi/Cu superconducting wires, which will be indirectly cooled by cryocoolers in own cryostat to the temperature of liquid helium.

The Research of the Superconducting Undulator Prototype with Neutral Poles and Features of the Magnetic Field Distribution in it

Abstract The article describes superconducting undulator prototype with neutral poles designed and fabricated in Budker Institute of Nuclear Physics. In the upper half of the undulator even-numbered poles have a core with a winding and odd - core without winding. In the lower half vice versa. This design allows to provide more accurate period and reduces the probability of mechanical movements caused by the action of ponderomotive forces leading to quench of superconductivity. The article also describes the features of the magnetic field distribution in such windings configuration.

Magnetic System of the High-Field Superconducting Multipole Wiggler for LSU CAMD

Center for Advanced Microstructures and Devices of Louisiana State University (LSU CAMD) is a research center for optimization of synchrotron radiation (SR) for production of soft X-rays. New research projects have necessitated expansion of the SR spectral range to harder X-rays. This task was solved via installation of a superconducting insertion device. This paper presents a description of the superconducting wiggler with a field of 7.5 T made by Budker INP and installed on the storage ring of LSU CAMD. The wiggler consists of 11 main bending magnets with magnetic field with alternating sign and an amplitude of 7.5 T and four side poles (two on each end of the magnet array), which are to make the first and second field integrals in the longitudinal direction equal to zero at any field level of the main poles. The main attention at the designing and production of the magnetic system of the wiggler was paid to the magnetic field quality at all field levels. Presented are results of field magnetic measurements using Hall probes. The dynamic behavior of the first and second field integrals during field ramping up and down, as measured by the method of stretched wire with current, is discussed. The wiggler was installed and successfully commissioned on the CAMD LSU storage ring in 2013.

Superconducting Insertion Devices for Light Sources at Budker INP

The first superconducting insertion devices were designed, fabricated and installed on electron storage rings more than 25 years ago, and used for generation of synchrotron radiation in Budker INP. Since then, a wide experience of manufacturing and use of such superconducting (SC) insertion devices as SC wave length shifters, multipole wigglers, and superbend is accumulated. A review of various types of Superconducting Insertion Devices for Light Sources is given in the report. Their basic characteristics as SR sources are discussed.