Improving beam simulations as well as machine and target protection in the SINQ beam line at PSI-HIPA

2020 ◽  
Vol 22 (2-3) ◽  
pp. 325-335
Author(s):  
Davide Reggiani ◽  
Bertrand Blau ◽  
Rudolf Dölling ◽  
Pierre Andre Duperrex ◽  
Daniela Kiselev ◽  
...  
Keyword(s):  
High Intensity ◽  
Beam Steering ◽  
Beam Current ◽  
General Purpose ◽  
Beam Line ◽  
Beam Current Density ◽  
Proton Accelerator ◽  
Beam Power ◽  
Particle Accelerators ◽  
Beam Delivery

With a nominal beam power of nearly 1.4 MW, the PSI High Intensity Proton Accelerator (HIPA) is currently at the forefront of the high intensity frontier of particle accelerators. Key issues of this facility are minimization of beam losses as well as safe operation of the SINQ spallation source. Particular attention is being recently paid towards an improved understanding of the properties of the SINQ beam line by both enhancing the beam transport simulations and developing new diagnostic elements which can also, in some cases, preserve the target integrity by preventing too large beam current density, inaccurate beam steering or improper beam delivery. Moreover, part of the SINQ beam diagnostic concept is being rethought in order to include important missing devices like BPMs. On the simulation side, newly developed composite calculations involving general purpose particle transport programs like MCNPX and BDSIM will deliver insights about beam losses and transmission through collimators. All recent and planned developments of the SINQ beam line will be discussed in this contribution.

scholarly journals Fore-vacuum plasma-cathode electron sources

2008 ◽  
Vol 26 (4) ◽  
pp. 619-635 ◽  
Author(s):  
V.A. Burdovitsin ◽  
E.M. Oks
Keyword(s):  
Electron Beam ◽  
High Pressures ◽  
Electrical Breakdown ◽  
Current Density Distribution ◽  
Beam Current ◽  
Beam Current Density ◽  
Beam Power ◽  
Plasma Cathode ◽  
Local Maxima ◽  
Electron Sources

AbstractThis paper presents a review of physical principles, design, and performances of plasma-cathode direct current (dc) electron beam guns operated in so called fore-vacuum pressure (1–15 Pa). That operation pressure range was not reached before for any kind of electron sources. A number of unique parameters of the e-beam were obtained, such as electron energy (up to 25 kV), dc beam current (up 0.5 A), and total beam power (up to 7 kW). For electron beam generation at these relatively high pressures, the following special features are important: high probability of electrical breakdown within the accelerating gap, a strong influence of back-streaming ions on both the emission electrode and the emitting plasma, generation of secondary plasma in the beam propagation region, and intense beam-plasma interactions that lead in turn to broadening of the beam energy spectrum and beam defocusing. Yet other unique peculiarities can occur for the case of ribbon electron beams, having to do with local maxima in the lateral beam current density distribution. The construction details of several plasma-cathode electron sources and some specific applications are also presented.

Current Status and Performance of the J-PARC Accelerators

2009 ◽  
Author(s):  
Hiroyuki Sako
Keyword(s):  
Radio Frequency ◽  
Particle Physics ◽  
Beam Current ◽  
Current Status ◽  
Proton Accelerator ◽  
Beam Power ◽  
Injection Technique ◽  
Beam Loss ◽  
Beam Commissioning ◽  
And Performance

J-PARC (Japan Proton Accelerator Research Complex) is a multi-purpose research facility for materials and life sciences, nuclear and particle physics, and nuclear engineering with extremely high power proton beams of 1 MW. The accelerator complex consists of a 400-MeV linac, a 3-GeV Rapid Cycling Synchrotron (RCS), and a 50-GeV Main Ring synchrotron (MR). Its goals are to provide MW-class beams at 3 GeV and at several 10 GeV, while it is a challenge to localize and suppress beam loss to the level to allow hands-on maintenance of accelerator components. The RCS scheme is adopted to realize them, which is advantageous over conventional Accumulation Ring (AR) regarding less beam loss problems due to lower beam current and easier construction and operation of a linac. RCS, however, required various challenging technologies such as ceramic ducts to reduce eddy current effects, high field Radio Frequency (RF) system, and paint injection technique (an injection scheme to reduce phase space density of the beam) to reduce space charge effects. The linac has also unique technologies to minimize beam loss, such as compact electromagnet Drift Tube Quadrupoles (DTQ’s) to control beam envelopes precisely, and a fast beam suspending system in Machine Protection System (MPS) with Radio Frequency Quadrupole linac (RFQ). The beam commissioning of the linac started in Nov. 2006, and its design energy of 181 MeV in the first construction phase was achieved in Jan. 2007. RCS beam commissioning started in Sep. 2007 and the beam was accelerated to the designed energy of 3 GeV in Oct. 2007. MR beam commissioning started in May 2008, and the beam acceleration to 30 GeV was established in Dec. 2008. The first neutron and muon beams were produced in May and Sep. 2008, respectively, at Materials and Life science experimental Facility (MLF). The linac commissioning has resulted in very stable beam with short down time. RCS commissioning quickly achieved beam acceleration and extraction, and paint injections are being studied intensively. RCS recorded the highest beam power of 0.21 MW in Sep. 2008 with beam loss well localized at the collimators. The linac beam energy will be upgraded to 400 MeV with Annular Coupled Structure linac (ACS) in order to increase the beam power to 1 MW. In the second construction phase, upgrade of the linac with 600-MeV Super-Conducting Linac (SCL) for Accelerator-Driven nuclear waste transmutation System (ADS) and upgrade of MR energy from 30 to 50 GeV are planned.

scholarly journals Design study for medium energy high intensity proton accelerator

2020 ◽  
Vol 23 (9) ◽  
Author(s):  
Abhishek Pathak ◽  
Shweta Roy ◽  
SVLS Rao ◽  
Srinivas Krishnagopal
Keyword(s):  
High Intensity ◽  
Proton Accelerator ◽  
Medium Energy ◽  
Design Study

Alloy surface composition resulting from fabrication, as determined by s.i.m.s. (secondary ion mass spectrometry)

1980 ◽  
Vol 295 (1413) ◽  
pp. 134-135
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Surface Composition ◽  
Ion Beam ◽  
Sample Surface ◽  
Beam Current ◽  
Ion Source ◽  
Beam Current Density ◽  
Dynamic Mode ◽  
Static Mode ◽  
Subsequent Performance

In s.i.m.s. the sample surface is ion bombarded and the emitted secondary ions are mass analysed. When used in the static mode with very low primary ion beam current densities (10 -11 A/mm 2 ), the technique analyses the outermost atomic layers with the following advantages (Benninghoven 1973, I975): the structural—chemical nature of the surface may be deduced from the masses of the ejected ionized clusters of atoms; detection of hydrogen and its compounds is possible; sensitivity is extremely high (10 -6 monolayer) for a number of elements. Composition profiles are obtained by increasing the primary beam current density (dynamic mode) or by combining the technique in the static mode with ion beam machining with a separate, more powerful ion source. The application of static s.i.m.s. in metallurgy has been explored by analysing a variety of alloy surfaces after fabrication procedures in relation to surface quality and subsequent performance. In a copper—silver eutectic alloy braze it was found that the composition of the solid surface depended markedly on its pretreatment. Generally there was a surface enrichment of copper relative to silver in melting processes while sawing and polishing enriched the surface in silver

scholarly journals Динамическое управление мощностью мегаваттного электронного пучка субмиллисекудной длительности в источнике с плазменным катодом

2021 ◽  
Vol 47 (10) ◽  
pp. 38
Author(s):  
М.С. Воробьёв ◽  
П.В. Москвин ◽  
В.И. Шин ◽  
Н.Н. Коваль ◽  
К.Т. Ашурова ◽  
...  
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Maximum Rate ◽  
Control Method ◽  
Beam Current ◽  
Rate Of Change ◽  
Beam Power ◽  
Metallic Materials ◽  
Plasma Cathode ◽  
Variable Power

The paper describes a method for a controlled change in the power of an electron beam during a pulse of submillisecond duration, using a source "SOLO" with a plasma cathode. The beam power is controlled by changing the amplitude of the beam current with a corresponding change in the concentration of the emission plasma. This control method allows generating submillisecond beams of variable power (up to 10 MW at a maximum rate of change of no more than 0.5 MW/µs), which can be used for processing various metallic materials in order to change the functional properties of their surface with the ability to control the rate of input of beam energy into the surface of these materials.

Quantitative Composition and Thickness Mapping With High Spatial Resolution By XEDS In a 300kv FEG-AEM

1998 ◽  
Vol 4 (S2) ◽  
pp. 136-137
Author(s):  
M. Watanabe ◽  
D. B. Williams
Keyword(s):  
Spatial Resolution ◽  
Collection Efficiency ◽  
Bulk Sample ◽  
Beam Current ◽  
Vacuum System ◽  
Beam Current Density ◽  
Quantitative Composition ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
Major Disadvantage

Since the first demonstration by Cosslett and Duncumb, X-ray mapping by an electron probe microanalyzer (EPMA) has become a most popular approach in microanalysis because elemental distributions of constituents in a bulk sample can be displayed visually. The major disadvantage of EPMA mapping is poor spatial resolution (∼ 1 μm). The spatial resolution of X-ray microanalysis can be improved to a few nanometers using electron transparent thin-specimens in the analytical electron microscope (AEM). However, X-ray count rates from thin specimens are strictly limited because of the improved spatial resolution (i.e. smaller interaction volume) and the poor collection efficiency of X-ray. To obtain reasonable counts for accurate quantification in the AEM, extraordinarily long mapping times are required. Therefore, quantitative X-ray mapping is rarely attempted in the AEM. However, these limitations can be overcome by use of intermediate-volt age instruments combined with field-emission guns to increase the beam current-density, careful stage design to maximize the X-ray collection efficiency and the peak-to-background ratio, and ultrahigh vacuum system to reduce contamination.

scholarly journals NUMERICAL ANALYSIS OF LASING DYNAMICS IN VOLUME FREE ELECTRON LASER

2008 ◽  
Vol 13 (2) ◽  
pp. 263-273
Author(s):  
Svetlana Sytova
Keyword(s):  
Electron Beam ◽  
Free Electron ◽  
Free Electron Laser ◽  
Initial Conditions ◽  
Beam Current ◽  
Beam Current Density ◽  
Electron Beam Current ◽  
Nonlinear Phenomena ◽  
Experimental Development ◽  
Lasing Dynamics

Nonlinear phenomena originating in volume free electron laser (VFEL) are investigated by methods of mathematical modelling using computer code VOLC. It was demonstrated the possibility of excitation of quasiperiodic oscillations not far from threshold values of electron beam current density and VFEL resonator length. It was investigated sensibility of numerical solution to initial conditions for different VFEL regimes of operation. Parametric maps with respect to electron beam current and detuning from synchronism condition present complicated root to chaos with windows of periodicity in VFEL. Investigation of chaotic lasing dynamics in VFEL is important in the light of experimental development of VFEL in Research Institute for Nuclear Problems.

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