The French High Magnetic Field Facility

The Laboratoire National des Champs Magnétiques Intenses (LNCMI) is a host laboratory for experiments in high magnetic fields. It was created on the 1st of January 2009 through the merger of the Laboratoire des Champs Magnetiques Intenses (Grenoble, specialized in DC fields) and the Laboratoire National des Champs Magnétiques Pulsés (Toulouse, specialized in pulsed fields). The facility is open to a large community of users from all over Europe and the rest of the world. In this paper we report our efforts to offer the highest magnetic fields, ranging from 35 T DC, through 80 T non-destructive, up to 170 T semi-destructive, in the best conditions for our in-house and visiting scientists. We describe the installations and coils improvements. As an example of our activity we present some recent scientific results.     

Design and Realization of the Control and Measurement System of the Wuhan Pulsed High Magnetic Field Facility

A user-friendly Control and Measurement System (CMS) is designed and realized at the Wuhan High Magnetic Field Center (WHMFC). Structure and functions of the CMS system are described in detail. Three kernel parts of CMS are discussed. The success of the comprehensive system test shows that the CMS is effective and reliable.     

Design and Realization of the Control and Measurement System of the Long Pulsed High Magnetic Field Facility Supplied by Battery

A Control and Measurement System (CMS) is designed to ensure the reliable operation in the long pulsed high magnetic field facility supplied by lead-acid batteries. The CMS is mainly composed of a Programmable Logic Controller (PLC), a fault monitor and protection circuit, a signal processing and data acquisition unit, a local triggering sequence generator and the main control program. The system architecture and kernel parts of the CMS are analyzed and described in detail. The results prove that the designed CMS could perform efficiently and reliably.     

Safety Analysis and Protection Measures of the Control System of the Pulsed High Magnetic Field Facility in WHMFC

A Pulsed High Magnetic Field Facility (PHMFF) has been established in Wuhan National High Magnetic Field Center (WHMFC) and various protection measures are applied in its control system. In order to improve the reliability and robustness of the control system, the safety analysis of the PHMFF is carried out based on Fault Tree Analysis (FTA) technique. The function and realization of 5 protection systems, which include sequence experiment operation system, safety assistant system, emergency stop system, fault detecting and processing system and accident isolating protection system, are given. The tests and operation indicate that these measures improve the safety of the facility and ensure the safety of people.     

The New Developed Components Tests for 1 MJ Capacitor Power Supply System in Wuhan High Magnetic Field Facility

A new 1 MJ, 25 kV, 40 kA pulsed capacitor power supply system for the Wuhan High Magnetic Field Facility (WHMFF) has been achieved. The desire for 70 or higher tesla magnetic field to support a lot of scientific researches based on it is just now beginning to be realized. The system consists of charger, capacitor bank, polarity changing switches, protective inductor, thyristor switch, crowbar, dump circuit and so on. In this paper, a series of tests for the new developed components such as high energy pulsed capacitor with 160 μF/25 kV/10 kA/10 ms/30% voltage reversal, thyristor switch (25 kV, 40 kA, 10 ms), polarity changing switch and ZnO linearly resistor disc for crowbar are introduced. The results show that all of new components are good or better than the old 1 MJ power supply system.     

The Renewed KU Leuven Pulsed Field Facility

The KU Leuven pulsed magnet facility was established in the sixties by the late Prof. A. Van Itterbeek (Van Itterbeek et al., Appl. Sci. Res., 18:105, 1967, Van Itterbeek et al., Les Champs Magnétiques Intenses, vol. 379, 1966). During the period 1972–1997 the laboratory was directed by Prof. F. Herlach (Witters and Herlach, J. Phys. D, Appl. Phys., 16:255, 1983, Li and Herlach, Meas. Sci. Technol., 6:1035, 1995, Herlach et al., Physica B, 201:542, 1994) who continuously developed the facility further along two lines: improved pulsed-field-coil design and enhanced capabilities for experimentation. From 1998 on, the facility is lead by Prof. V.V. Moshchalkov, in close collaboration with Prof. E.F. Herlach and Prof. J. Vanacken. Recently, the laboratory has been completely renewed; its present configuration is based on the former installation of the High Field Magnet Laboratory at the Radboud University Nijmegen (the Netherlands) (Rosseel et al., IEEE Trans. Appl. Supercond., 16:1664, 2006), which was originally developed in collaboration with the KU Leuven spin-off company METIS (http://www.metis.be/).     

A Dual-Capacitors Type Energy Recovery Power System for Repetitive Pulsed High Magnetic Fields

As a flexible and convenient tool, a repetitive pulsed high magnetic field (RPHMF) would be employed for scientific research and industrial applications. A novel RPHMF system design adopting a dual-capacitors type energy recovery power system is introduced in this paper. The energy stored in the magnet can be fed back to the capacitor by a choke coil and a resonant capacitor while the energy dissipated in the discharge will be replenished to the capacitor through a high frequency resonant capacitor charging power system (CCPS). The main advantages of the design are as followed: first, the energy feedback make the system more efficient; second, during the whole process there is no reverse voltage on the metalized film capacitors, improving the energy storage capacitors’ service lifetime and reliability remarkably; finally, convenience can be brought to the high frequency CCPS’s application. In this paper, theoretic analysis of RPHMF system is described and an experimental device with a bitter magnet as the load is built to test the design for its verification. A 1.2 Hz, 8 T repetitive pulsed high magnetic field is generated. Experimental results show that there is no reverse voltage on the energy storage capacitors in the whole process. The factors influencing the efficiency and frequency of the system are analyzed in detail.     

The High Field Project at Dresden/Rossendorf: A Pulsed 100 T/10 ms Laboratory at an Infrared Free-Electron-Laser Facility

This article describes the project to build a pulsed magnetic field user laboratory at the Forschungszentrum Rossendorf near Dresden. Using a 50 MJ/24 kV capacitor bank, pulsed fields and rise times of 100 T/10 ms, 70 T/100 ms, and 60 T/1 s should be achieved. The laboratory will be built next to a free-electron-laser-facility for the middle and far infrared (5 to 150 µm, 2 ps, cw). We describe the work which has been performed until now to start the construction of the laboratory in 2003: coil concepts and computer simulations, materials development for the high field coils, and design of the capacitor bank modules. In addition, a pilot laboratory has been set up where fields up to 62 T/15 ms have been obtained with a 1 MJ/10 kV capacitor module. It is used to gain experience in the operation of such a facility and to test various parts of it. In this test laboratory special devices have been developed for measurements of magnetization and magnetoresistance, and have been successfully used to investigate various materials including semiconductors and Heavy Fermion compounds. In particular, metamagnetic transitions in intermetallic compounds and the irreversibility field of a high-T _c superconductor have been determined. Shubnikov–de Haas oscillations have been observed in the semimetallic compound CeBiPt. Resistance relaxation has been observed to start less than 1second after the field pulse. It could be shown for the first time that nuclear magnetic resonance (NMR) is detectable in pulsed fields.     

脉冲强磁体导体材料研究

在脉冲强磁体设计中,磁应力是我们面临的最大挑战,当磁场强度达到100T时,磁体绕组中的磁应力高达4GPa,这是目前任何实用导体材料都无法承受的,因此,脉冲强磁体的发展在很大程度上取决于磁应力的解决情况.文章从提高导体材料机械强度的角度出发,介绍了目前各种导体材料的加工过程和技术参数,包括铜、铜宏复合导体材料、铜微复合导体材料、多层绞线复合导体材料等.     

Magnet-Technology Development at the Dresden High Magnetic Field Laboratory

The Dresden High Magnetic Field Laboratory (HLD) is a user facility which provides scientists with the possibility to perform a broad range of experiments in pulsed magnetic fields. Recent progress in the magnet-technology development at the HLD has led to significant advances in achieving non-destructive pulsed magnetic fields close to the megagauss mark. Using 9.5 MJ dual-coil magnets with 16 mm bore, in 2011 a world-record field of 91.4 T has been achieved. Later 94.2 T have been reached. We report on the magnet design and performance of these magnets as well as on the design for the next generation of dual-coil magnets characterized by interchangeable inner sub-coils and improved control of the axial preload.     

Design and Performance of the First Dual-Coil Magnet at the Wuhan National High Magnetic Field Center

The first 80 T dual-coil magnet was manufactured and tested at the Wuhan National High Magnetic Field Center (WHMFC). The inner coil consists of 8 layers of 2.8 mm × 4.3 mm CuNb microcomposite wire developed in China; the bore diameter is 14 mm and the outer diameter 135 mm. The outer coil was wound directly on the inner coil with 12 layers of 3 mm × 6 mm soft copper. Each conductor layer of both coils was reinforced by Zylon/epoxy composite. The inner and outer coil were driven by a 1.6 MJ/5.12 mF capacitor bank and by eight 1 MJ/3.2 mF modules, respectively. At the voltage of 14.3 kV for the inner coil and 22 kV for the outer coil, the inner and outer coils produced peak fields of 48.5 T and 34.5 T respectively, which gave a total field of 83 T. This was the first combined operation of the new capacitor banks installed at the WHMFC. We present details of the design, manufacture and test of the dual-coil magnet and discuss crucial material properties. Based on this experience, a second dual-coil magnet will be designed; the enhanced design will be discussed. With the total energy of 12.6 MJ, peak field up to 90 T is expected.     

脉冲磁场传感器的时域标定

针对脉冲磁场测量的要求，对传感器的时域标定问题进行了研究，组建基于高压脉冲源，ＴＥＭ传输室，数字存贮示波器及计算机的时域标定系统，提出了基于输出误差模型的时域定数据处理方法，利用该模型可方便地获得的传感器的灵敏度，转折频率等参数，成功地利用所建立的误差修正模型对传感器造成的测量失真进行了恢复。     

磁参量计量标准装置的设计和建立

本文主要论述了目前我国磁参量计量标准装置及技术标准的发展现状,磁量具和磁测仪器的检定条件以及二等磁参量计量标准装置的组成和技术指标。     

The Design of Stabilized Power Supplies for Incandescent Light Sources

Incandescent lamps are used as wide-band sources of light in many optical/electronic instruments, and the present paper describes some approaches to the design of stabilized power units for these lamps. Both dc and pulse-width modulated ac supplies are described, and a series of design equations for the latter are established. Where the lamp voltage is to be monitored rather than the light output itself, some unique advantages are claimed for the use of a lamp-photoresistor assembly (or calistor) within the feedback loop. Several example designs are given, from which a variety of power supplies may be developed.     

脉冲射频/40kV高压直接耦合等离子体离子注入电源系统研制

研制的用于等离子体浸没离子注入(PIII)的电源系统采用高压隔离与高频滤波技术,将40 kV高压脉冲电源与13.56 MHz射频电源直接耦合,由单一输出电缆连接到实验靶台上,通过射频与高压脉冲的时序控制,实现了40 kV的高压脉冲与脉冲射频交替输出。工作过程中,通过射频产生等离子体,而后施加高压脉冲获得离子注入,进而实现PIII与沉积。该电源系统的性能指标为:高压脉冲电压幅值10~40 kV,脉冲频率10~1000 Hz,射频脉冲宽度0.01~10 ms,射频与高压间隔0.1~10 ms,高压脉冲功率6 kW,射频脉冲功率1 kW。实验研究表明能够有效的实现PIII。本文将介绍该种新电源的设计思想、电路以及在内凹零部件(如管筒内壁)等离子体离子注入等方面的应用。     

Special Coils Development at the National High Magnetic Field Laboratory in Toulouse

The Laboratoire National des Champs Magnétiques Intenses (LNCMI) develops different types of coils suited to specific experiments. We present some recent developments on magnet design. Several coils are dedicated to experiments in large scale facilities in France and Switzerland. A 30 T split-pair coil for X-rays diffraction and one 40 T coil for plasma physics at the LULI, two 30 T coils with axial access (one with an conical bore) for X-ray diffraction and absorption experiments. A 40 T wide angle conical access solenoid with a high duty-cycle for neutron scattering at the ILL is being constructed. For use at the installation in Toulouse we have developed, apart from our standard 60 and 70 T coils, several special coils: a coil with a long optical path with 30 T transverse magnetic field and a 90 T long pulse dual coil system.     

Design of a Large Oxygen Magnetic Levitation Facility

The present magnetic levitation facility offers an alternative to space means for studying fluids and especially liquid oxygen that exhibits important safety requirements. The station has great use flexibility. Thus it enables us to study hydrodynamic instabilities (acceleration and deceleration phase) and also to focus on thermal exchanges (nuclear and film boiling) and transition phase of fluids under reduced gravity such as Lunar, Martian or micro-gravity. The volume of liquid oxygen levitated is about two litres with a resulting acceleration less than 0.1 m/s². Besides the aspect ratio of the working cell can be changed.     

高精度智能磁场测量仪的设计

设计了一种由微处理器控制的具有通信接口的高精度智能磁场测量仪,通过双只配对的集成霍尔传感器来获取磁感应强度的信号,采用压频变换器完成数据的采集,并对仪器进行了校准和实验．实验结果表明,所设计的磁场测量仪在整个量程范围内的测量精度达到了0.1mT．该仪器不但可进行磁场的精密测量,还可用于对无线通讯基站电磁辐射的网络化远程监测．     

Automatic EMI Measurement and Filter Design System for Telecom Power Supplies

Tests for compliance with conducted emission limits are usually carried out during the electrical product design process. Electromagnetic interference (EMI) filters are widely used for filtering excessive conducted emissions on a power cord. In this paper, a personal computer (PC)-based automatic EMI measurement and filter design system for telecom power supplies is proposed. The common-mode (CM) and differential-mode (DM) emissions in the live or the neutral line can be measured and recorded separately. The trial-and-error guesswork in selecting the filter components can be minimized by the proposed automatic filter design system. In other words, the EMI suppression effort is greatly reduced by the fast PC computing speed and the man-machine interface. The developed system can be an effective noise diagnosis and filter design tool for EMI engineers.     

The National High Magnetic Field Laboratory at Los Alamos National Laboratory

Los Alamos National Laboratory (LANL) is the home institution of the Pulsed Field Facility of the National High Magnetic Field Laboratory (NHMFL). The NHMFL laboratories are the only facilities in the US (among a few world-wide) to host qualified users while running strong in-house science programs related to high magnetic field research. At Los Alamos, the NHMFL advances the frontiers of condensed matter physics at extreme conditions of high magnetic field, low temperature and pressure, utilizing start-of-the-art pulsed magnets and unique experimental capabilities. This paper will describe the current and future plans of pulsed magnet technology and science at the NHMFL Pulsed Field Facility at LANL.