36 research outputs found
Theoretical and experimental considerations of the critical current density of DI-BiSCCO superconducting tapes as a function of magnetic field, field orientation, temperature and strain
No full textThe critical current density (Jc) of DI-BiSCCO superconducting tapes was measured as a function of magnetic field (B), field orientation (θ), temperature (T) and strain (e) in a 15 T split-pair horizontal superconducting magnet using probes designed and built in-house. Strain was applied to samples using a modified bending beam apparatus with a copper beryllium springboard-shaped sample holder, which is capable of applying uniaxial strains of -1.4% < e < 1.0%. The temperature of the sample was controlled with the use of an inverted insulating cup with a temperature stability of +/-80 mK to +/-200 mK. The vapour-cooled brass critical-current leads (incorporating high-temperature superconducting tapes) were optimised to minimise helium consumption. Optimisation includes consideration of the maximum safe temperature of the current leads and the effects of duty cycle and static helium boil-off. The optimised helium consumption of the leads is a factor of two lower than standard current leads optimised for magnets. Jc(B,T,θ,e) data of the DI-BiSCCO tapes were characterised based on the superconducting-normal-superconducting Josephson junction model where Jc is determined by flux flow along the grain boundaries (or the normal junctions). It was found that grain boundaries in the DI-BiSCCO tapes are thick (several tens of nanometre) and exhibit semiconducting behaviour. The degree of misalignment has been included into the anisotropy analysis of Jc and the correlation between the effective anisotropy and texturing of the sample obtained. Analysis of three different samples (Nb3Sn, YBCO and BiSCCO) is presented where the average local properties of the grain boundaries were extracted from magnetisation and the transport Jc data
Critical current measurements of DI-BSCCO tapes as a function of angle in high magnetic fields
No full textAngular, Temperature, and Strain Dependencies of the Critical Current of DI-BSCCO Tapes in High Magnetic Fields
No full textHigh critical current density (Jc) DI-BSCCO Bi-2223 superconducting tape has been developed by Sumitomo Electric Industries (SEI) using the Controlled Over-Pressure (CT-OP) technique to improve the texturing and densification. Further enhancement of the mechanical properties has been obtained using lamination. We have investigated the effect of magnetic field and field orientation on Jc for a series of test DI-BSCCO tapes at 77 K and 4.2 K under tensile and compressive strains. These critical current data are strongly influenced by the anisotropy of Bi-2223, the texturing of the tape and its architecture. The magnetic field and angular dependence of Jc at 77 K can be described using a simple anisotropic exponential magnetic field model which includes the effects of the two-dimensionality and grain misalignment in these composites. The variation in the normalized Jc with respect to the strain is linear over the reversible range of strain where the gradient of the strain dependence is independent of temperature and field. The reversibility of Jc is extended further into the compressive regime after Jc degradation by compression
MIST - The MESA-Injector Source Two
No full textThe new accelerator MESA (Mainz Energy Recovering Superconducting Accelerator) will provide an average CW electron beam current of up to 10 mA. Operating at 1.3 GHz, this corresponds to a bunch charge of 7.7 pC. The new DC photoemission source MIST is optimized for these requirements. A challenge is heating of the photocathode at high laser power. By a suitable mechanical construction and the use of specific materials, the heat can be dissipated during operation. Options for further improvements are discussed
Crosstalk Simulation of Magnets for Siam Photon Source II Storage Ring
No full textDuring the detailed design of magnets for the storage ring of Siam Photon Source II (SPS-II), the influence of magnetic crosstalk between adjacent magnets in the compact Double Triple Bend Achromat (DTBA) lattice was investigated. Using Opera-3D magnetostatic simulation, six magnet pairs were analyzed to investigate the changes in magnetic field distribution along the electron trajectory and integrated magnetic field within each magnet aperture. The study employed polynomial and Fourier analyses to calculate multipole field components. Results indicate that magnetic crosstalk affects the field distribution in the region between magnets, particularly for the defocusing quadrupole and dipole magnets (QD2-D01) and the focusing quadrupole and octupole magnets (QF42-OF1) pairs, which have the pole-to-pole distances of 153.37 mm and 116.45 mm, respectively. Although these separations exceed the estimated fringe field regions, deviations of up to 1% in the main field components were observed. Notably, even an unpowered neighboring magnet contributes to magnetic field distortion due to the modified magnetic flux distribution. Crosstalk effects on the higher-order multipole fields are mostly within the acceptable limit, except for the extra quadrupole field from QD2 found in the dipole D01 magnet. This study highlights the effects of magnetic interference in tightly packed lattice and underscores the need to include a complete multipole field data with crosstalk consideration in the SPS-II lattice model in order to ensure an accurate beam dynamics simulation and predict the operating current adjustments for machine commissioning
Design of a Prototype Gas Jet Profile Monitor for Installation Into the Large Hadron Collider at CERN
No full textThe Beam-Gas Curtain or BGC is the baseline instrument for monitoring the concentricity of the LHC proton beam with a hollow electron beam for the hollow e-lens (HEL) beam halo suppression device which is part of the High-Luminosity LHC upgrade. The proof-of-principles experiments of this gas-jet monitor have now been developed into a prototype instrument which has been built for integration into the LHC ring and is now under phased installation for operation in the upcoming LHC run. This paper describes the challenges overcome to produce a gas-jet fluorescence monitor for the ultra-high vacuum accelerator environment. It also presents preliminary results from the installation of the instrument at CERN
Online Optimization of the Transfer Line from UNILAC towards SIS18 at GSI Using a Genetic Autotune Algorithm
No full textStatus of Diamond and LGAD Based Beam-Detectors for the mCBM and CBM Experiments at GSI and FAIR
No full textThe Compressed Baryonic Matter (CBM) experiment* is currently under construction at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The aim of the experiment is the exploration of the Quantum Chromodynamics (QCD) phase diagram of matter at high net-baryon densities and for moderate temperatures. In this contribution a beam monitoring (BMON) system will be presented which will include a high-speed time-zero (T0) detector. The detector system must meet the requirements of the CBM time-of-flight (ToF) measurement system for proton and heavy-ion beams and should also allow for beam monitoring. The detector technology is planned to be based on chemical vapor deposition (CVD) diamond basis but also new Low Gain Avalanche Detector (LGAD) developments are evaluated. In this contribution the beam detector concept will be presented and the results of first prototype tests in the mini-CBM setup will be shown
Commissioning of a Gas Jet Beam Profile Monitor for EBTS and LHC
No full textA gas jet beam profile monitor was designed for measuring the electron beam at the electron beam test stand (EBTS) for the Hollow electron lens (HEL) and the proton beam in the large hadron collider (LHC). It is partially installed in the LHC during the second long shutdown. The current monitor is tailored to the accelerator environment including vacuum, geometry, and magnetic field for both the EBTS and the LHC. It features a compact design, a higher gas jet density, and a wider curtain size for a better integration time and a larger detecting range. In this contribution, the commissioning of this monitor at the Cockcroft Institute will be discussed
