Pulsed Facility Research Articles

Studies on the Effect of Pulsed Magnetic Field on the Productivity of Algae Grown in Dye Industry Effluent

Magnetic fields are capable of eliciting in vivo and in vitro effects in many biological systems. Increasing attention is being directed towards bio-electromagnetic stimulation using the low frequency pulsed magnetic fields (PMF). Currently, microalgae have been considered to be the most promising candidates for biomass production. PMF may affect organisms in both negative and positive manner which includes acceleration of growth and metabolism. The present study deals with the studies on the effect of pulsed magnetic field (PMF) on the productivity selected micro algae Desmococcus sp. grown in the dye industry effluent. Desmococcus sp. was grown in photo bioreactors (1L) with a pulsed magnetic field facility. The magnetic field is set in a circular form from which the solenoid coil system set to a highly homogenous sinusoidal magnetic field intensity of 3mg for a period of 4hrs duration per day for 12 days. Aeration and light (intensity 2000-3000lux) have been provided for 12hr per day. Division rate, growth studies and physicochemical parameters have been analyzed that gave positive results by reducing the BOD, COD and the nitrates level in the effluent. By the end of the 12th day the effluent colour changed and a two fold increase in the algal biomass productivity in the dye effluent treated with PMF exposure is observed.

Dynamic characteristics of azimuthally correlated structures of axial instability of wire-array Z pinches

Particular attention was placed on observations of dynamic properties of the azimuthally correlated structures of axial instability of wire-array Z pinches, which were conducted at 10-MA (for short circuit load) pulsed power generator-the Primary Test Stand facility. Not well fabricated loads, which were expected to preset bubble or spike in plasma, were used to degrade the implosion symmetry in order to magnify the phenomenon of instability. The side-view sequence of evolution of correlation given by laser shadowgraphy clearly demonstrates the dynamic processes of azimuthal correlation of the bubble and spike. A possible mechanism presented here suggests that it is the substantial current redistribution especially in regions surrounding the bubble/spike resulting from change of inductance due to the presence of the bubble/spike that plays an essential part in establishment of azimuthal correlation of wire array and liner Z pinches.

Analysis of energy resolution in the KURRI-LINAC pulsed neutron facility

In this study, we carried out Monte Carlo simulations to obtain the energy resolution of the neutron flux for TOF measurements in the KURRI-LINAC pulsed neutron facility. The simulation was performed on the moderated neutron flux from the pac-man type moderator at the energy range from 0.1 eV to 10 keV. As the result, we obtained the energy resolutions (ΔE/E) of about 0.7% to 1.3% between 0.1 eV to 10 keV. The energy resolution obtained from Monte Carlo simulation agreed with the resolution using the simplified evaluation formula. In addition, we compared the energy resolution among KURRI-LINAC and other TOF facilities, the energy dependency of the energy resolution with the pac-man type moderator in KURRI-LINAC was similar to the J-PARC ANNRI for the single-bunch mode.

Strong magnetic fields generated with a metal wire irradiated by high power laser pulses and its effect on bow shock

Laboratory astrophysics is a rapid developing field studying astrophysical or astronomical processes on a high-power pulsed facility in laboratory. It has been proved that with the similarity criteria, the parameters in astrophysical processes can be transformed into those under laboratory conditions. With appropriate experimental designs the astrophysical processes can be simulated in laboratory in a detailed and controlled way. Magnetic fields play an important role in many astrophysical processes. Recently, the generation of strong magnetic fields and their effects on relevant astrophysics have attracted much interest. According to our previous work, a strong magnetic field can be induced by a huge current formed by the background cold electron flow around the laser spot when high power laser pulses irradiate a metal wire. In this paper we use this scheme to produce a strong magnetic field and observe its effect on a bow shock on the Shenguang II (SG II) laser facility. The strength of the magnetic field is measured by B-dot detectors. With the measured results, the magnetic field distribution is calculated by using a three-dimension code. Another bunch of lasers irradiates a CH planar target to generate a high-speed plasma. A bow shock is formed in the interaction of the high-speed plasma with the metal wire under the strong magnetic condition. The effects of the strong magnetic field on the bow shock are observed by shadowgraphy and interferometry. It is shown that the Mach number of the plasma flow is reduced by the magnetic field, leading to an increase of opening angle of the bow shock and a decrease of the density ratio between downstream and upstream. In addition, according to the similarity criteria, the experimental parameters of plasma are scaled to those in space. The transformed results show that the magnetized plasma around the wire, produced by X-ray emitted from the laser-irradiated planar target in the experiment, is suitable for simulating solar wind in astrophysics. In this paper, we provide another method to produce strong magnetic field, apply it to a bow shock laboratory astrophysical study, and also generate the magnetized plasma which can be used to simulate solar wind in the future experiments.

Modeling of high power pulse generator based on the non-linear elements of pulsed facilities

The article considered the software implementation mathematical model of the voltage pulse generator with a hard switch. The interactive object-oriented software interface provides the choice of generator parameters and the type of its load, as well as pulses parameters analysis on the load at the generator switching.

전자빔가속기를 이용한 펄스감마선 출력특성 분석용 빔프로파일링 장치개발

Recently, most countries in the world have pursued a denuclearization. So it has been of interest to increase to Nuclear weapon in such as North Korea`s continued nuclear test. Pulsed gamma rays produced in the nuclear explosion and the space environment can give the big damage to the electronic device in a very short period of time. To confirm the extent of damage of these electronic devices, pulsed gamma irradiation facility that can occur in nuclear weapon or space environment are required. In this paper, we implemented the pulsed gamma-ray detection module and analyzed output of the irradiation test. We have experimented using an electron beam accelerator research facilities in Pohang Accelerator similar conditions to equip and Nuclear weapon. As a result, we confirmed that the pulsed gamma rays emitted by the gamma radiation and electron beam conversion device. The results of this paper will contribute to improve the reliability and accuracy of studies for utilizing pulsed gamma rays.

Influences of Freestream Turbulence on Flame Dynamics in a Supersonic Combustor

Turbulent flame dynamics in an ethylene-fueled model scramjet is experimentally investigated in Mach 4.5 freestream flows with a total temperature of 2600 K using a pulsed arc-heated hypersonic wind-tunnel facility at the University of Notre Dame. Gaseous ethylene fuel is injected into the combustor through a supersonic nozzle, and is autoignited by high-enthalpy flows that are compressed and decelerated by a train of shock waves through the scramjet isolator/combustor. The turbulence level of the freestream is manipulated to investigate the influence of freestream turbulence on the flame dynamics in the supersonic combustor. General flame behavior is observed in time-averaged ethylene-flame-chemiluminescence images, whereas the detailed turbulent flame structures are resolved by imaging instantaneous ground-state hydroxyl radical (OH) distributions using the planar-laser-induced-fluorescence technique, wherein a planar laser sheet is projected into the scramjet in the counterstreamwise direction to illuminate the entire internal flow region, including the isolator and supersonic combustor of the model scramjet. Enhanced freestream turbulence can improve fuel–air mixing efficiency and, therefore, determine the flame dynamics, such as the turbulent burning velocity and flame geometry. A direct impact of the freestream turbulence is clearly seen, that being a significant combustion enhancement in the supersonic flow.

Host-based data acquisition system to control pulsed facilities of the accelerator

The report discusses development of the host-based system to carry out timed measurements and data acquisition for the control of pulsed facilities of the accelerator. We consider modes of timing and allocation of operations of channels and the system node. The time of any working cycle of the pulsed facilities, rate of a data flow and an amount of serviced channels are coordinated with operation characteristics of the system node. Estimations of the readout rate of the data and the waiting time demonstrate the system efficiency. The technique has been developed to provide checking of groups of pulse parameters and control the facilities of the linear accelerator of electrons LUE-200 of the neutron source IREN.

Investigation of microstructure within metal welds by energy resolved neutron imaging

The recent development of bright pulsed neutron sources and high resolution neutron counting detectors enables simultaneous acquisition of a neutron transmission spectrum for each pixel of the image. These spectra can be used to reconstruct microstructure parameters within welds, such as strain, texture and phase composition through Bragg edge analysis, and in some cases elemental composition through resonance absorption analysis. In this paper we demonstrate the potential of energy-resolved neutron imaging to study the microstructures of two steel welds, where the spatial distribution of residual strain within the welds, as well as some information on the texture, are obtained with sub-mm spatial resolution. A friction stir weld of two steel plates and a conventional weld of two steel pipes were studied at pulsed neutron facilities, where a Δλ/λ resolution as low as 0.2% can be attained over a wide range of neutron wavelengths ranging from 0.5 Å to 8 Å.

Temperature-dependent stoichiometric alteration in ZnO:Mn nanostructured thin films for enhanced ferromagnetic response

The study investigates the effect of in-situ substrate temperature and argon-oxygen ambient gas pressure of pulsed laser deposition facility on material composition, optical quality and magnetic response of ZnO:Mn thin films. Structural and optical analyses revealed the existence of an optimal in-situ substrate temperature (450°C) at which thin films showed relatively better texture and optical quality with minimum concentration of structural defects. The detailed analysis of Zn 2p3/2 and O 1s core level XPS spectra revealed that the structural disorder was considerably reduced in thin films after being annealed (in-situ) at substrate temperature of 450 °C. Magnetic measurements revealed the stronger p-d hybridization between oxygen 2p and Mn 3d orbitals in ZnO:Mn thin films being annealed in-situ at 450°C under Ar:O2 admixture of 2.5mbar subsequently leading to improved ferromagnetic response.

Neutron time-of-flight spectroscopy measurement using a waveform digitizer**Supported by Strategic Priority Research Program of the Chinese Academy of Science(TMSR) (XDA02010100), National Natural Science Foundation of China(NSFC)(11475245,No.11305239), Shanghai Key Laboratory of Particle Physics and Cosmology (11DZ2260700)

The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the Thorium Molten Salt Reactor (TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal used for TOF calculation, with information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and γ-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The DAQ system developed is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy.

Transient High Heat Load Performance of Atmospheric Plasma Sprayed Tungsten Coating

Tungsten coatings on oxygen-free copper substrates were fabricated by atmospheric plasma spraying (APS) technique. The properties of the microstructure, porosity, microhardness and oxidation of the coatings were characterized and measured. In order to evaluate the thermal properties of the APS-W coating, a high current pulsed electron beam facility was introduced to carry out the transient high heat load tests. Three power densities of 0.2, 0.5 and 1.0 GW/m2 and total pulse duration of 5 ms were performed on the coating surfaces. The surface temperature and behavior of the APS-W coatings under the transient high heat load were investigated. Obvious melting and re-solidification were found on the treated APS-W coatings, and cracks were also observed on coating surface.

Analysis and design of a control system for the 100T pulsed high magnetic field facility at WHMFC

A pulsed high magnetic field of 90.6 T has been achieved by discharging the energy in a capacitor bank to a nondestructive magnet at Wuhan National High Magnetic Field Center (WHMFC), and recently, the project for a 100-T magnetic field has been under development. The pulsed magnet with a 100-T magnetic field will be composed of three coils, which are driven by three types of power sources. Based on the existing control subsystems of these power sources, the design of the control system that can control different types of power supplies to discharge would be taken into consideration for the implementation of the 100-T magnetic field. This paper first analyzes the control process for the 100-T system, which can divided into three stages, and the time requirement for each stage. Based on the analysis, the structure and main functions of the control system are discussed, and then the main control program and the global control block are designed. To protect the safety of the system, some protection measures are finally discussed. This paper provides design bases for the realization of the control system.

Probing beneath the surface without a scratch — Bulk non-destructive elemental analysis using negative muons

The development of elemental analysis at the ISIS pulsed neutron and muon facility, STFC Rutherford Appleton Laboratory, UK, is described. Presented are recent results from the calibration of the new setup and this shows the technique can be a powerful tool in determining the composition of materials in bulk, not just at the surface. Moreover, this technique is non-destructive and should be sensitive to all elements (perhaps with the exception of H and He).

Preliminary results on time-resolved ion beam induced luminescence applied to the provenance study of lapis lazuli

This work will present preliminary results concerning the use of time-resolved ion beam induced luminescence applied to provenance studies of lapis lazuli. Measurements were performed at the pulsed beam facility at LABEC laboratory in Florence. Lapis lazuli is a semi-precious gemstone, used as ornament since the early civilizations that can be found in few places on Earth. The importance of this work lies in understanding the origin of various samples of lapis lazuli, from which it may be possible to gain insight into trade routes from ancient times. The samples studied in this work originated from Chile, Afghanistan, Tajikistan, Myanmar, and Siberia. The stones were irradiated with 3MeV protons and the resulting luminescence was detected by a photomultiplier tube, whose output was acquired using a sampling digitizer VME module (CAEN/V1720). Wavelength discrimination was performed at 430nm utilizing a range of beam currents. The results showed that, by changing the beam current intensity, one can study different features of lapis lazuli, and this may aid in distinguishing lapis lazuli from different provenances.

Single Pulse Calibration of Magnetic Field Sensors Using Mobile 43 kJ Facility

Abstract In this work we present a mobile 43 kJ pulsed magnetic field facility for single pulse calibration of magnetic field sensors. The magnetic field generator is capable of generating magnetic fields up to 40 T with pulse durations in the range of 0.3-2 ms. The high power crowbar circuit is used for the reverse voltage protection and pulse shaping purposes. The structure, the development challenges and the implemented solutions to improve the facility for the calibration of the magnetic field sensors are overviewed. The experimental data of the application of the proposed generator for the calibration of manganite magnetic field sensors are presented.

Development and testing of cost-effective, 6 cm×6 cm MCP-based photodetectors for fast timing applications

Micro-channel plate (MCP)-based photodetectors are capable of picosecond level time resolution and sub-mm level position resolution, which makes them a perfect candidate for the next generation large area photodetectors. The large-area picosecond photodetector (LAPPD) collaboration is developing new techniques for making large-area photodetectors based on new MCP fabrication and functionalization methods. A small single tube processing system (SmSTPS) was constructed at Argonne National Laboratory (ANL) for developing scalable, cost-effective, glass-body, 6cm×6cm, picosecond photodetectors based on MCPs functionalized by Atomic Layer Deposition (ALD). Recently, a number of fully processed and hermitically sealed prototypes made of MCPs with 20μm pores have been fabricated. This is a significant milestone for the LAPPD project. These prototypes were characterized with a pulsed laser test facility. Without optimization, the prototypes have shown excellent results: the time resolution is ~57ps for single photoelectron mode and ~15ps for multi-photoelectron mode; the best position resolution is ≤0.8mm for large pulses. In this paper, the tube processing system, the detector assembly, experimental setup, data analysis and the key performance will be presented.

Development of a 50-T pulsed magnetic field facility by using an 1.5-MJ capacitor bank

Because DC magnets consume a huge amount of electricity (resistive DC magnet) or liquid helium (superconducting magnet), a capacitor-bank-driven pulsed magnet is known to be a cost-effective way of generating high magnetic fields. This type of pulsed magnet is normally operated at liquid nitrogen temperature and consumes little electric power to generate over 50 tesla (T) during a short transient time of less than 50 millisecond (ms). With modern fast data acquisition systems, almost all kinds of physical quantities, such as photoluminescence, magnetization or resistance can be measured during a short magnetic field pulse. We report a recently home-built capacitor-bankdriven pulsed magnetic field facility, in which a capacitor bank of 1.5-MJ maximum stored energy is utilized to generate pulsed magnetic fields up to 50 T with transient pulse time of 22 ms.

О выборе параметров технологической импульсной плазменной установки

О выборе параметров технологической импульсной плазменной установки

Comparative research on “high currents” induced by single event latch-up and transient-induced latch-up**Project supported by the National Natural Science Foundation of China (Grant No. 41304148).

By using the pulsed laser single event effect facility and electro-static discharge (ESD) test system, the characteristics of the “high current”, relation with external stimulus and relevance to impacted modes of single event latch-up (SEL) and transient-induced latch-up (TLU) are studied, respectively, for a 12-bit complementary metal–oxide semiconductor (CMOS) analog-to-digital converter. Furthermore, the sameness and difference in physical mechanism between “high current” induced by SEL and that by TLU are disclosed in this paper. The results show that the minority carrier diffusion in the PNPN structure of the CMOS device which initiates the active parasitic NPN and PNP transistors is the common reason for the “high current” induced by SEL and for that by TLU. However, for SEL, the minority carrier diffusion is induced by the ionizing radiation, and an underdamped sinusoidal voltage on the supply node (the ground node) is the cause of the minority carrier diffusion for TLU.