Conveners
Thu-Mo-Po4.03 - Novel Diagnostics and Other Techniques
- Emmanuele Ravaioli (CERN)
- Takanobu Kiss (Kyushu University)
The operation of next generation accelerator facilities like the Facility for Antiproton and Ion Research (FAIR) around the world requires novel approaches for instrumentation to survive the expected radiation doses in, for example, secondary beam production regions. As particle beams at high energies are guided with strong magnetic fields one key piece of instrumentation is a precise,...
A rotating coil measurement system was developed for the DC magnets of the CSNS accelerator. This system solves the compatibility problems of different center heights, masses, effective lengths, and magnetic field strengths among CSNS bulk magnets. After testing, the repeatability error of the integral field measurement is less than ±0.02%, the repeatability error of harmonics are less than...
Many superconducting devices operate in persistent mode. Heat losses from current leads are one of the major design challenges, especially when limited low-volume cryogen is available during normal operations. To reduce the heat losses, the current leads are either retracted after charging, or have permanent leads carrying smaller current when in a charging mode but have small heat load when...
The automation of magnetic measurements prevents human operator errors from impacting measurements and ensures the repeatability of the measurements and the traceability of the results to specific measurement scenarios. The presented approach achieves automation via parametrized scripting; this offers the user additional flexibility by providing the ability to define families of measurements...
This paper presents a numerical method to calculate spatial harmonic coefficients of magnetic fields generated by screening currents in a high temperature superconductor (HTS) magnet. First, current density with screening currents considered in the individual turns of an HTS magnet is calculated using the 2D axisymmetric edge-element formulation and the domain homogenization technique. With...
Accurate and reliable magnetic field measurement is of great significance at various stages in the lifetime of accelerator magnets. The method of search coils is the most widely used on the magnetic measurements. Traditional search coils are machined and/or hand-wound, which have the poor repetition and weakness in the precision of the coil geometry and position. To overcome these issues, the...
In an HVDC high-temperature superconducting (HTS) cable composed of polypropylene laminated paper (PPLP), a butt-gap which is unavoidable in the fabrication process may lead to form voids. When dc voltage higher than partial discharge inception voltage (PDIV) is applied, partial discharge occurs in the void. If void discharge sustains, the electrical ageing of PPLP accelerates, and eventually...
Abstract: Temperature measurement is very important for the state monitoring and safe operation of High Temperature Superconducting (HTS) cables. Distributed optical fiber can be used to measure the temperature along power cable because of the advantages of anti-electromagnetic interference, high voltage resistance and convenient fixing, etc. In this paper, the feasibility of distributed...
The no-insulation (NI) winding technique improves the thermal stability of REBCO pancake coils. A radial bypass current protects an NI pancake coil from burning-out when it turns a normal state. That is, the characteristic resistance (turn-to-turn contact resistance) of NI REBCO pancake coil characterizes the electrical behavior inside the coil as a function of “self-protecting.” To estimate...
Compared with other magnetic materials, nanocrystalline alloy has specific advantages. It can be made into strips that much thinner than silicon steel sheets and its conductivity is lower, which effectively reduces the high frequency loss. The permeability of nanocrystalline alloy is higher than that of ferrite, so the capacity and power density of the equipment made from nanocrystalline...
A hypothetical ground fault in the superconducting (sc) magnet system of Wendelstein 7-X would shift the midpoint of the grounding system and therefore increase the voltage to ground during a fast discharge of the sc magnet system. As this voltage could endanger the high voltage integrity of the sc magnet system, an In-Service-Test system has been developed to monitor the insulation of the sc...
