scholarly journals Anomalous Beam Transport through Gabor (Plasma) Lens Prototype

2021 ◽  
Vol 11 (10) ◽  
pp. 4357
Author(s):  
Toby Nonnenmacher ◽  
Titus-Stefan Dascalu ◽  
Robert Bingham ◽  
Chung Lim Cheung ◽  
Hin-Tung Lau ◽  
...  
Keyword(s):  
Cost Effective ◽  
Stable Operation ◽  
High Electron ◽  
Beam Transport ◽  
Focusing Effect ◽  
Energy Proton ◽  
Diocotron Instability ◽  
Strong Focusing ◽  
Axis Rotation ◽  
Mev Protons

An electron plasma lens is a cost-effective, compact, strong-focusing element that can ensure efficient capture of low-energy proton and ion beams from laser-driven sources. A Gabor lens prototype was built for high electron density operation at Imperial College London. The parameters of the stable operation regime of the lens and its performance during a beam test with 1.4 MeV protons are reported here. Narrow pencil beams were imaged on a scintillator screen 67 cm downstream of the lens. The lens converted the pencil beams into rings that show position-dependent shape and intensity modulation that are dependent on the settings of the lens. Characterisation of the focusing effect suggests that the plasma column exhibited an off-axis rotation similar to the m=1 diocotron instability. The association of the instability with the cause of the rings was investigated using particle tracking simulations.

SPALLATION YIELDS FROM HIGH ENERGY PROTON BOMBARDMENT OF HEAVY ELEMENTS

1957 ◽  
Vol 35 (1) ◽  
pp. 21-37 ◽  
Author(s):  
J. D. Jackson
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Heavy Elements ◽  
Collective Effects ◽  
Comparison With Experiment ◽  
Energy Proton ◽  
Stringent Test ◽  
Neutron Evaporation ◽  
Nuclear Processes ◽  
Mev Protons

The Monte Carlo calculations of McManus and Sharp (unpublished) for the prompt nuclear processes occurring upon bombardment of heavy elements by 400 Mev. protons are combined with a description of the subsequent neutron evaporation to determine spallation cross sections for comparison with experiment. The model employed is a schematic one which suppresses the detailed characteristics of individual nuclei, but gives the over-all behavior to be expected. Many-particle and collective effects such as alpha particle emission and fission are ignored. The computed cross sections are presented in a variety of different graphical forms which illustrate quantitatively the qualitative picture of high energy reactions first given by Serber (1947). The calculations are in general agreement with existing data when fission is not an important effect, but the agreement does not imply a very stringent test of the various features of the model.

Analytical Study of ZnO-based HEMT for Power Switching

2021 ◽  
Author(s):  
Pawan Kumar ◽  
Sumit Chaudhary ◽  
Md Arif Khan ◽  
Sanjay Kumar ◽  
Shaibal Mukherjee
Keyword(s):  
Ion Beam ◽  
Drain Current ◽  
Cost Effective ◽  
High Electron Mobility Transistor ◽  
Switching Frequency ◽  
Physical Parameters ◽  
High Electron ◽  
Ion Beam Sputtering ◽  
Power Switching ◽  
Group Iii

Abstract We investigate the power switching mechanism to evaluate the power loss ( P D ) and efficiency ( η ) in MgZnO/ZnO (MZO)-based power high electron mobility transistor (HEMT), and physical parameters responsible for P D in molecular beam epitaxy (MBE) and dual ion beam sputtering (DIBS) grown MZO HEMT and compare the performance with the group III-nitride HEMTs. This work extensively probes all physical parameters such as two-dimensional electron gas (2DEG) density, mobility, switching frequency, and device dimension to study their impact on power switching in MZO HEMT. Results suggest that the MBE and DIBS grown MZO HEMT with the gate width ( W G ) of ∼ 205 and ∼ 280 mm at drain current coefficient (k) of 11 and 15, respectively, will achieve 99.96 and 99.95% of η and 9.03 and 12.53 W of P D , respectively. Moreover, W G value for DIBS-grown MZO HEMT is observed to further reduce in the range of 112-168 mm by using a Y 2 O 3 spacer layer leading to the maximum η in the range of 99.98-99.97% and the minimum P D in the range of 5-7 W. This work is significant for the development of cost-effective HEMTs for power switching applications.

scholarly journals Low-temperature and ammonia-free epitaxy of GaN/AlGaN/GaN heterostructure

2021 ◽  
Author(s):  
David Maria Tobaldi ◽  
Valentina Triminì ◽  
Arianna Cretì ◽  
Mauro Lomascolo ◽  
Stefano Dicorato ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Chemical Vapour ◽  
High Growth ◽  
Wide Band ◽  
Cost Effective ◽  
Organic Chemical ◽  
High Electron ◽  
High Quality ◽  
Lower Growth ◽  
Green Approach

Wide band gap semiconductors are very attractive because of their broad applications as electronics and optoelectronics materials − GaN-based materials being by far the most promising. For the production of such nitride-based optical and power devices, metal-organic chemical vapour deposition (MOCVD) is routinely used. However, this has disadvantages, such as the large consumption of ammonia gas, and the need for high growth temperature. To go beyond such a limit, in this study we successfully developed a remote plasma assisted MOCVD (RPA-MOCVD) approach for the epitaxial growth of high-quality GaN/AlGaN heterostructures on 4H-SiC substrates. Our RPA-MOCVD has the advantages of lower growth temperature (750 °C) compared to conventional MOCVD route, and the use of a remote N2/H2 plasma instead of ammonia for nitrides growth, generating in situ the NHx (x = 0−3) species needed for the growth. As assessed by structural, morphological, optical and electrical characterisation, the proposed strategy provides an overall cost-effective and green approach for high-quality GaN/AlGaN heteroepitaxy, suitable for high electron mobility transistors (HEMT) technology.

Measurements of Displacement Cross Section of Tungsten under 389-MeV Proton Irradiation and Thermal Damage Recovery

2021 ◽  
Vol 1024 ◽  
pp. 95-101
Author(s):  
Yosuke Iwamoto ◽  
Makoto Yoshida ◽  
Hiroki Matsuda ◽  
Shin Ichiro Meigo ◽  
Daiki Satoh ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Thermal Conduction ◽  
Thermal Damage ◽  
Proton Irradiation ◽  
High Energy ◽  
Wire Sample ◽  
Energy Proton ◽  
Measured Displacement ◽  
Mev Protons

For validating the number of displacements per atom (dpa) for tungsten under high-energy proton irradiation, we measured displacement cross sections related to defect-induced electrical resistivity changes in a tungsten wire sample under irradiation with 389-MeV protons under 10 K. The Gifford–McMahon cryocooler was used to cool the sample using a conductive coolant via thermal conduction plates of oxygen-free high-conductivity copper and electrical insulation sheets of aluminum nitride ceramic. In this experiment, the displacement cross section was 1612 ± 371 b for tungsten at 389 MeV. A comparison of the experimental displacement cross sections of tungsten with the calculated results obtained using Norgett–Robinson–Torrens (NRT) dpa and athermal recombination-corrected (arc) dpa cross sections indicates that arc-dpa was in better agreement with the experimental data than NRT-dpa; this is similar to the displacement cross sections of copper. From the measurements of damage recovery of the accumulated defects in tungsten through isochronal annealing, which is related to the defect concentration of the sample, approximately 20% of the damage was recovered at 60 K. This trend was similar to those observed in other experimental results for reactor neutrons.

scholarly journals Design and development of a MgB2-based sector dipole and beam transport channel for a strong-focusing cyclotron

2014 ◽  
Author(s):  
K. Melconian ◽  
K. Damborsky ◽  
N. Glasser ◽  
E. Holik ◽  
J. Kellams ◽  
...  
Keyword(s):  
Beam Transport ◽  
Design And Development ◽  
Transport Channel ◽  
Strong Focusing

scholarly journals Fouling-resistant biofilter of an anaerobic electrochemical membrane reactor

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Qilin Yu ◽  
Yaobin Zhang
Keyword(s):  
Membrane Fouling ◽  
Membrane Reactor ◽  
Dynamic Equilibrium ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Stable Operation ◽  
High Electron ◽  
Electrochemical Membrane Reactor ◽  
Anode Oxidation ◽  
Initial Stage

Abstract Membrane fouling is a considerable challenge for the stable operation of anaerobic membrane-based bioreactors. Membrane used as a cathode is a common measure to retard fouling growth in anaerobic electrochemical membrane bioreactors (AnEMBR), which; however, cannot avoid the fouling growth. Here we report a strategy using the membrane as an anode to resist membrane fouling in an AnEMBR. Although aggravating in the initial stage, the fouling on the anode membrane is gradually alleviated by the anode oxidation with enriching exoelectrogens to finally achieve a dynamic equilibrium between fouling growth and decomposition to maintain the operation stable. A mesh-like biofilter layer composed of cells with less extracellular polymeric substance (EPS) is formed on the membrane surface to lower the trans-membrane pressure and promote the interception of the anode membrane. The membrane has high electron storage and transfer capacities to accelerate the oxidation of the intercepted fouling materials, especially, the redundant EPSs of the biofilter layer.

scholarly journals An all-solid-state heterojunction oxide transistor for the rapid detection of biomolecules and SARS-CoV-2 spike S1 protein

2021 ◽  
Author(s):  
Yen-Hung Lin ◽  
Yang Han ◽  
Abhinav Sharma ◽  
Wejdan S. AlGhamdi ◽  
Chien-Hao Liu ◽  
...  
Keyword(s):  
Solid State ◽  
Real Time ◽  
High Sensitivity ◽  
Cost Effective ◽  
High Electron ◽  
Real Time Detection ◽  
Bioanalytical Applications ◽  
Detection Of Biomolecules ◽  
Dimensional Electron Gas ◽  
Sensitivity Specificity

AbstractSolid-state transistor sensors that can detect biomolecules in real time are highly attractive for emerging bioanalytical applications. However, combining cost-effective manufacturing with high sensitivity, specificity and fast sensing response, remains challenging. Here we develop low-temperature solution-processed In2O3/ZnO heterojunction transistors featuring a geometrically engineered tri-channel architecture for rapid real-time detection of different biomolecules. The sensor combines a high electron mobility channel, attributed to the quasi-two-dimensional electron gas (q2DEG) at the buried In2O3/ZnO heterointerface, in close proximity to a sensing surface featuring tethered analyte receptors. The unusual tri-channel design enables strong coupling between the buried q2DEG and the minute electronic perturbations occurring during receptor-analyte interactions allowing for robust, real-time detection of biomolecules down to attomolar (aM) concentrations. By functionalizing the tri-channel surface with SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) antibody receptors, we demonstrate real-time detection of the SARS-CoV-2 spike S1 protein down to attomolar concentrations in under two minutes.

Experiments on cosmic radiation by means of artificial satellites

1959 ◽  
Vol 253 (1275) ◽  
pp. 482-487 ◽  
Keyword(s):  
Cosmic Radiation ◽  
Primary Particle ◽  
Rest Mass ◽  
High Energy ◽  
Artificial Satellites ◽  
The Past ◽  
Energy Proton ◽  
Strong Focusing ◽  
The Subject ◽  
Under Construction

In this brief review, I propose to give an account of the main facts about the cosmic radiation as they are at present known to us, and of the outstanding problems which await solution. The intention is to provide a suitable background against which to discuss the advantages to be gained by experiments with artificial satellites. I shall address myself particularly to those who are not specialists in the subject. During the past ten years, two aspects of the study of cosmic radiation have received particular attention: 1. The cosmic radiation provides us with a source of particles of much greater energy than any which we shall be able to generate in the next one or two decades. The great acclerators under construction will give us beams of protons with energies up to 25 GeV. It is possible that machines of similar design, employing the strong-focusing principle, will be constructed for energies up to 50 GeV. Such a machine has been designed, for example, by Russian scientists. But the construction of even larger machines would encounter great technical difficulties. Further, when a high-energy proton collides with one at rest, the energy made available in the C -system of the interaction, E a , increases only slowly with the speed of the primary particle, E p ; E a ~ E 1/2 p ; and it is this quantity E a which determines the amount of energy which can appear in the form of the rest-mass of new particles created in the collision. In this situation, it is not clear that the advantages to be gained would justify the great expense of even larger machines based on present methods.

scholarly journals The quantum plasma lens concept: A preliminary investigation

2013 ◽  
Vol 79 (4) ◽  
pp. 421-427 ◽  
Author(s):  
FATEMA TANJIA ◽  
RENATO FEDELE ◽  
SERGIO DE NICOLA ◽  
DUSAN JOVANOVIĆ ◽  
ABDUL MANNAN
Keyword(s):  
Preliminary Investigation ◽  
Particle Beam ◽  
Magnetized Plasma ◽  
Quantum Plasma ◽  
Charged Particle Beam ◽  
Focusing Effect ◽  
Wake Field ◽  
Quantum Approach ◽  
Relativistic Charged Particle ◽  
Strong Focusing

AbstractRecently, a theoretical investigation of the collective and nonlocal quantum effects has been carried out within the framework of a quantum approach to the relativistic charged particle beam travelling in a cold, collisionless, strongly magnetized plasma. This has been done taking into account both the plasma wake field excitation and the quantum paraxial approximation. On the basis of this theory, here we carry out a preliminary study of the transverse effects experienced by a cold relativistic beam through a thin plasma slab (plasma lens). In the strongly nonlocal regime, in which the beam experiences a very strong focusing effect, the scheme of plasma lens is reviewed in terms of the wave description provided by the above quantum theory.

Sign in / Sign up

Export Citation Format

Share Document