Electrical and thermal behavior of patterned superconducting disks

The effects of the resistivity and crystal orientation on the leakage current and radiation response characteristics have been studied. The detector with (111) oriented substrate shows higher leakage current than (100) orientation due to the higher interface trap density at the Si/SiO2 interface. And high resistive substrate shows larger leakage current than low resistive one because of its wider depletion width at the same bias voltage. However, in case of (100) oriented substrate, the leakage current of low resistive substrate is larger than high resistive substrate at high reverse bias. It seems that thermionic field emission (TFE) current for low resistive substrate increased at high reverse bias. To compare the charge generation and collection for the radiation, we irradiated an X-ray beam to each detector and read the output current. The detector with (111) oriented substrate shows 20% higher output current than (100) orientation and it is independent on the resistivity of the substrates. The most influential factor on the output current is the thickness of the wafer. From the results we can suggest a high resistive, (100) oriented and thick wafer for direct type radiation detector, and a low resistive and thin wafer for in-direct type detector. Finally, we assembled our detector with read-out integrated circuit for the application of gamma ray dosimeter and our detector is very sensitive to Cs137 natural gamma ray.

With the development of smart grid, the invasion of the transient magnetic field on secondary side low-voltage equipments and instruments in substations is increasingly prominent. Therefore, effective tools for transient electromagnetic field testing and assessment are imperatively needed. Existent transient magnetic field measurements in substations mainly rely on induction coil. The inductance, self-resistance, stray capacitance, radius, turns and materials of induction coil may directly affect the performance of the measurement, limiting its applications. This paper developed a novel transient magnetic field testing system, whose magnetic probe is developed based on magneto resistive effect. The probe uses three-axis magneto resistive sensor instead of induction coil, having the characteristics such as small size, high accuracy, and strong stability. It can achieve the point measurement of the magnetic field accurately, providing an effective mean for transient magnetic field testing.

The transient high frequency electric and magnetic fields are generated in Gas insulated substations(GIS) systems during switching operations by both radiation and conduction mechanisms. In this paper the radiated transient electric and magnetic fields are measured by using high frequency field sensors at important locations in the 245kV GIS were presented. The measurements are carried out at three important locations including at bus link, cable termination and C.T position respectively. The results of measured values are compared with the calculated values. The results shows that transient electric & magnetic field values are correlate with the measured values at bus link, near current transformer(CT)and at cable termination , the calculated values are slightly deviated from the measured values when moves along with XLPE cable. This may be due to a fast attenuation rate of electromagnetic fields with distance away from the DS3. These results are very useful in order to prepare some precautionary protection measure to avoid malfunctioning of secondary equipment and metering equipment in GIS systems.

Concrete guideways for proposed MAGLEV vehicles may be reinforced with electrically conducting and magnetizable steel rebars. Transient magnetic fields due to passing MAGLEV vehicles will then induce transient currents in the rebars leading to power dissipation and temperature rise as well as Lorentz and magnetization forces on the rebars. In order to evaluate if this heating and force on the rebars affects concrete life and performance, analysis is presented for an infinitely long conducting and magnetizable cylinder in imposed uniform axial or transverse magnetic fields. Exact and approximate solutions are presented for sinusoidal steady state and step transient magnetic fields inside and outside the cylinder, the induced current density, the vector potential for transverse magnetic fields, the time average dissipated power in the sinusoidal steady state, and the total energy dissipated for step transients. Forces are approximately calculated for imposed magnetic fields with a weak spatial gradient. The analysis is applied to representative rebar materials.

Molecular change due to biomagnetic stimulation and transient magnetic fields: mechanical interference constraints on possible effects by cell membrane pore creation via magnetic particles

The aim of this paper is to investigate the transient magnetic field radiating by electrostatic discharge (ESD) generators. Near field measurements have been conducted, a few centimeters far away from the discharge point (Pellegrini target). The Pellegrini target is mounted on the centre of a grounded metal plane, inside an anechoic chamber. The measurements were carried out to three different directions in relation to the discharge point. The experimental data show that each ESD generator produces a different transient magnetic field. Furthermore, additional differences referring to the produced magnetic field produced by each generator are noted, depending on the direction that the measurement is conducted. Finally, comparisons are stated concerning the magnetic field produced by each generator as well as useful conclusions for the decrease of the magnetic field

This paper describes the status of the developments made by ATLAS HVCMOS and HVMAPS collaborations. We have proposed two HVCMOS sensor concepts for ATLAS pixels—the capacitive coupled pixel detector (CCPD) and the monolithic detector. The sensors have been implemented in three semiconductor processes AMS H18, AMS H35 and LFoundry LFA15. Efficiency of 99.7% after neutron irradiation to 1015 neq/cm2W has been measured with the small area CCPD prototype in AMS H18 technology. About 84% of the particles are detected with a time resolution better than 25 ns. The sensor was implemented on a low resistivity substrate. The large area demonstrator sensor in AMS H35 process has been designed, produced and successfully tested. The sensor has been produced on different high resistivity substrates ranging from 80 Ωcm to more than 1 kΩ. Monolithic- and hybrid readout are both possible. In August 2016, six different monolithic pixel matrices for ATLAS with a total area of 1 cm2 have been submitted in LFoundry LFA15 process. The matrices implement column drain and triggered readout as well as waveform sampling capability on pixel level. Design details will be presented.

Multi-scale modeling of direct copper plating on resistive non-copper substrates

In this paper, a theory based on dual‐feedback circuit methodology is adopted to explain the anomalous dips of scattering parameter S22 in deep sub‐micrometer MOSFETs. It is found that the output impedance intrinsically behaves as a series RC circuit (for low substrate resistance) or a “shifted” series RC circuit (for very high substrate resistance) at low frequencies, and a parallel RC circuit at high frequencies. This inherent triple characteristic of the output impedance can cause two types of anomalous dips of S22 in a Smith chart. In this way, the two experimental results [1, 2], that is, the anomalous dips caused by high substrate resistance and high trans‐conductance (or wide gate‐width), can be explained simultaneously for the first time. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 193–200, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10718

Optical and electrical characterization of microwave power system chemical vapour deposited (MPS-CVD) graphene on Ni electroplated Cu foil at varying temperatures

The general diffusion equation for the magnetic field penetration into cables is used to find the solutions for the induced currents in the strands of finite cables in the low frequency limit. The homogeneous magnetic field is applied on the whole cable length l. These results are compared with the properties of infinite cables in the same homogeneous applied magnetic field. The current distribution in the strands close to the central part of the cable is strongly influenced by the total length of the cable, l. On the other hand, the current distribution in a large part of the cable is nearly the same as that close to the ends, determined by the boundary condition of zero current at the ends. The maximum amplitude of the induced currents in finite cables is two times higher than that in the infinite one. This enhancement of the induced current, decreasing the critical current of the cable, can be important for the stability of some magnets. The magnetic field due to the induced currents is also changing strongly along the cable axis, nearly periodically with the period of the cabling pitch. Therefore, the measurements of the local magnetic induction or local magnetic moment can lead to misinterpretation of the magnetic flux distribution and the electromagnetic properties of the cables. To avoid this, one should always perform some measurements of these quantities also at different positions along the axial direction of the cable.

Azimuthally fluctuating magnetic field and its impacts on observables in heavy-ion collisions

On the origin of transient magnetic fields

Magnetic field measurements and numerical simulation of the current distribution in the emitter region of solar cells

The diffusion of transient magnetic fields through the walls of a hollow conductive shell is an important phenomenon of interest throughout a variety of pulsed power applications. Basic solutions do exist for cylindrical geometries in the limiting case that the skin depth is much larger than the wall thickness; however, in many pulsed applications, the transient skin depth is often similar to the conductor thickness. As the underlying thin-wall assumption begins to breakdown, the production of complex eddy current distributions in the conductor walls results in deviation from these simplified analytical solutions of the diffused field. Precise calculation of these current distributions is essential for many applications including inductive shielding and magnetic field diagnostics near conductors. Electromagnetic simulations using the finite-element method provide a more accurate picture of the diffusion process in this regime. A high magnetic field testbed facilitates measurement of the diffused fields in order to verify simulation accuracy. The effect of material conductivity, wall thickness, and conductor geometry on the diffusion process is examined.