Accelerator Tank Research Articles

Design and development of a small-scale cement-based 3D printing robot extrusion nozzle

Additive manufacturing (AM), also known as three-dimensional (3D) printing, offers great potential to create complex structures layer by layer from computer-aided design (CAD) models. Despite advancements in printable concrete technology, controlling printing quality remains a challenge associated with both the geometric and materials design of the printer nozzle, especially for small-scale printing that may be required by small and medium-sized enterprises (SMEs). Therefore, this study explored the design and development of a robot nozzle system, optimised for a small-scale 3D printing of cement-based structures. Key design considerations included weight, nozzle diameter/shape, material compatibility, flow control, mixing mechanism, temperature resistance, cost-effectiveness, adaptability, safety, and ease of maintenance. Iterative designs were developed, focusing on stress concentration mitigation and material flow optimisation. The challenge of incorporating mixing mechanisms during nozzle designs was discussed, leading to the adoption of an on-demand accelerator spraying system. This method involved a micro-peristaltic pump connected to an accelerator tank, spraying accelerator onto the surface of the deposited material, as the robot moved along its programmed path. Evidently, both the nozzle design and the spraying approach improved the buildability and print quality of the extrusion-based 3D-printed cement-based structures.

Effectiveness prediction of abrasive jetting stream of accelerator tank using normalized sparse autoencoder-adaptive neural fuzzy inference system

Abrasive jetting stream generated from accelerator tank is crucial to the precision machining of industrial products during the process of strengthen jet grinding. In this article, its effectiveness prediction using normalized sparse autoencoder-adaptive neural fuzzy inference system is carried out to provide an optimal result of jetting stream. A normalized sparse autoencoder-adaptive neural fuzzy inference system capable of calculating the concentration density of abrasive impact stress by normalized sparse autoencoder and identifying the effectiveness indexes of abrasive jetting by adaptive neural fuzzy inference system is proposed to predict the stream effectiveness index in grinding practices, indicating that when turbulence root-mean-square velocity ( VRMS) is 420 m/s, turbulence intensity ( Ti) is 570, turbulence kinetic energy ( Tc) is 540 kJ, turbulence entropy ( Te) is 620 J/K, and Reynolds shear stress ( Rs) is 430 kPa (Error tolerance = ± 5%, the same as follows), the optimized effectiveness quality of abrasive jetting stream could be ensured. The effectiveness prediction involve the following steps: measuring the jet impact data on the interior boundary surface of accelerator tank, calculating the concentration density of abrasive impact stress, establishing the descriptive analytical frame work of normalized sparse autoencoder-adaptive neural fuzzy inference system, adaptive prediction of abrasive jetting stream effectiveness through normalized sparse autoencoder-adaptive neural fuzzy inference system computation, and performance verification of actual effectiveness prediction in the efficiency quantification and quality assessment when it compared to that of alternative approaches, such as genetic, simulated annealing–genetic algorithm, Taguchi, artificial neural network–simulated annealing, and genetically optimized neural network system methods. Objective of this research is to adaptive predict the abrasive jetting stream effectiveness using a new-proposed prediction system, a stable and reliable abrasive jetting stream therefore can be achieved using jetting pressure ( Pw) at 320 MPa, mass of cast steel grits ( Mc) at 270 g, mass of bearing steel grits ( Mb) at 310 g, mass of brown-fused alumina grits ( Ma) at 360 g, and mass rate of abrasives ( Fa) at 0.46 kg/min. It is concluded that normalized sparse autoencoder-adaptive neural fuzzy inference system owns an outstanding predictive capability and possesses a much better working advancement in typical calibration indexes of accuracy and efficiency, meanwhile a high agreement between the fuzzy predicted and actual measured values of effectiveness indexes is ensured. This novel method could be promoted constructively to improve the quality uniformity for abrasive jetting stream and to facilitate the productive managements of abrasive jet machining consequently.

Ion Beam Facilities at the National Centre for Accelerator based Research using a 3 MV Pelletron Accelerator

A 3.0 MV (Pelletron 9 SDH 4, NEC, USA) low energy ion accelerator has been recently installed as the National Centre for Accelerator based Research (NCAR) at the Department of Pure & Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur, India. The facility is aimed to carried out interdisciplinary researches using ion beams with high current TORVIS (for H, He ions) and SNICS (for heavy ions) ion sources. The facility includes two dedicated beam lines, one for ion beam analysis (IBA) and other for ion implantation/ irradiation corresponding to switching magnet at +20 and -10 degree, respectively. Ions with 60kV energy are injected into the accelerator tank where after stripping positively charged ions are accelerated up to 29 MeV for Au. The installed ion beam analysis techniques include RBS, PIXE, ERDA and channelling.

H-mode accelerating structures with permanent-magnet quadrupole beam focusing

We have developed high-efficiency normal-conducting rf accelerating structures by combining $H$-mode resonator cavities and a transverse beam focusing by permanent-magnet quadrupoles (PMQ), for beam velocities in the range of a few percent of the speed of light. The shunt impedance of interdigital $H$-mode (IH-PMQ) structures is 10--20 times higher than that of a conventional drift-tube linac, while the transverse size is 4--5 times smaller. Results of the combined 3D modeling---electromagnetic computations, multiparticle beam-dynamics simulations with high currents, and thermal-stress analysis---for an IH-PMQ accelerator tank are presented. The accelerating-field profile in the tank is tuned to provide the best propagation of a 50-mA deuteron beam using coupled iterations of electromagnetic and beam-dynamics modeling. Measurements of a cold model of the IH-PMQ tank show a good agreement with the calculations. Examples of cross-bar $H$-mode structures with PMQ focusing for higher beam velocities are also presented. $H$-PMQ accelerating structures following a short radio-frequency quadrupole accelerator can be used both in the front end of ion linacs or in stand-alone applications.

Microgan electron cyclotron resonance ion source in a Van de Graaff accelerator terminal

The Van de Graaff accelerator at IRMM works since many years providing proton, deuteron, and helium beams for nuclear data measurements. The original ion source was of RF type with quartz bottle. This kind of source, as well known, needs regular maintenance for which the accelerator tank must be completely opened. The heavy usage at high currents of the IRMM accelerator necessitated an opening about once every month. In 2010, the full permanent magnet Microgan electron cyclotron resonance (ECR) ion source from PANTECHNIK was installed into a new terminal platform together with a solid state amplifier of 50 W, a dedicated dosing system for 4 gases (with respective gas bottles H(2), D(2), He, and Ar), and a set of dedicated power supplies and electronic devices for the remote tuning of the source. The new system shows a very stable behaviour of the produced beam allowing running the Van de Graaf without maintenance for several months. This contribution will describe the full installed system in details (working at high pressure in the terminal, spark effects, and optic of the extraction), as well as beam results in dc or pulsed mode.

Activation of the IFMIF prototype accelerator and beam dump by deuterons and protons

An assessment of the activation caused by deuteron and proton beam losses in the accelerating components and by the full beam current in the beam dump during the International Fusion Material Irradiation Facility (IFMIF) prototype accelerator testing period was performed. The losses along the acceleration line were calculated by the Monte Carlo codes PARTMTEQM and PARMILA. The activation analysis was performed by the European Activation System EASY-2007 recently upgraded to include charge particle-induced reactions. The deuteron and proton activation cross-sections from this library for the dominant reactions were validated against experimental data demonstrating an acceptable uncertainty. The transport of the decaying gamma-rays and the calculation of the radiation dose rate on the external surfaces of the accelerator tank and beam dump have been performed by the MCNP-5 code. The results show that activation induced by the deuteron and proton beam losses in the accelerating components are below the legal transport and hands-on limits. This is also proved to be the case for the proposed design of the beam dump employing the tungsten as ions stopper to accommodate 1.2 MW beam power.

The ACCEL Model for Accelerating the Detoxification Kinetics of Hydrocarbons Requiring Initial Monooxygenation Reactions

The two-tank accelerator/aerator modification of activated sludge significantly increases the biodegradation of hydrocarbons requiring initial monooxygenation reactions, such as phenol and 2,4-dichlorophenol (DCP). The small accelerator tank has a controlled low dissolved oxygen (DO) concentration that can enrich the biomass in NADH + H+. It also has a very high specific growth rate (mu acc) that up-regulates the biomass's content of the monooxygenase enzyme. Here, we develop and test the ACCEL model, which quantifies all key phenomena taking place when the accelerator/aerator system is used to enhance biodegradation of hydrocarbons requiring initial monooxygenations. Monooxygenation kinetics follow a multiplicative relationship in which the organic substrates (phenol or DCP) and DO have separate Monod terms, while the biomass's content of NADH + H+ has a first-order term. The monooxygenase enzyme has different affinities (K values) for phenol and DCP. The biomass's NADH + H+ content is based on a proportioning of NAD(H) according to the relative rates of NADH + H+ sources and sinks. Biomass synthesis occurs simultaneously through utilization of acetate, phenol, and DCP, but each has its own true yield. The ACCEL model accurately simulates all trends for one-tank and two-tank experiments in which acetate, phenol, and DCP are biodegraded together. In particular, DCP removal is affected most by DOacc and the retention-time ratio, Theta acc/Theta total. Adding an accelerator tank dramatically increases DCP removal, and the best DCP removal occurs for 0.2 < DOacc < 0.5 mg/l and 0.08 < Theta acc/Theta total < 0.2. The rates of phenol and DCP utilization follow the multiplicative relationship with a maximum specific rate coefficient proportional to mu acc. Finally, mu acc increases rapidly for Theta acc/Theta total < 0.25, acetate removal in the accelerator fuels the high mu acc, and the biomass's NADH + H+ content increases very dramatically for DO acc < 0.25 mg/l.

Radiation measurements in the new tandem accelerator FEL

The Israeli tandem electrostatic accelerator FEL (EA-FEL), which is based on an electrostatic Van der Graaff accelerator was relocated to Ariel 3 years ago, and has now returned to operation under a new configuration. In the present FEL, the millimeter-wave radiation generated in the resonator is separated from the electron beam by means of a perforated Talbot effect reflector. A quasi-optic delivery system transmits the out-coupled power through a window in the pressurized gas accelerator tank into the measurement room (in the previous configuration, radiation was transmitted through the accelerator tubes with 40 dB attenuation). This makes it possible to transmit useful power out of the accelerator and into the user laboratories. After re-configuring the FEL electron gun and the e-beam transport optics and installing a two stage depressed collector, the e-beam current was raised to 2 A. This recently enabled us to measure both spontaneous and stimulated emissions of radiation in the newly configured FEL for the first time. The radiation at the W-band was measured and characterized. The results match the predictions of our earlier theoretical modeling and calculations.

Radiation measurements in the new tandem accelerator FEL

The Israeli tandem electrostatic accelerator FEL (EA-FEL), which is based on an electrostatic Van der Graaff accelerator was relocated to Ariel 3 years ago, and has now returned to operation under a new configuration. In the present FEL, the millimeter-wave radiation generated in the resonator is separated from the electron beam by means of a perforated Talbot effect reflector. A quasi-optic delivery system transmits the out-coupled power through a window in the pressurized gas accelerator tank into the measurement room (in the previous configuration, radiation was transmitted through the accelerator tubes with 40 dB attenuation). This makes it possible to transmit useful power out of the accelerator and into the user laboratories. After re-configuring the FEL electron gun and the e-beam transport optics and installing a two stage depressed collector, the e-beam current was raised to 2 A. This recently enabled us to measure both spontaneous and stimulated emissions of radiation in the newly configured FEL for the first time. The radiation at the W-band was measured and characterized. The results match the predictions of our earlier theoretical modeling and calculations.

A detailed analysis of the mechanisms controlling the acceleration of 2,4-DCP monooxygenation in the two-tank suspended growth process.

The mechanisms underlying the observed acceleration of monooxygenation reactions in two-tank accelerator/aerator suspended growth system are evaluated in detail. The accelerator tank is characterized by a very high electron flow through reduced nicotinamide adenine dinucleotide (NADH + H+), particularly when the retention-time ratio is small. Only a small fraction of the electron flow was diverted to oxygenation reactions, and the major sinks of NADH + H+ were respiration and biomass synthesis. The main producer of NADH + H+ is oxidation of acetate, a rapidly degraded electron-donor substrate. The half-maximum-rate concentration for oxygen used in respiration was 0.03 mg/L, while the half-maximum-rate concentration for oxygen used as a cosubstrate in monooxygenation was 0.18 mg/L. Thus, monooxygenations were more sensitive to oxygen limitation than was respiration. The NADH + H+ concentration had a direct effect on the monooxygenation kinetics. The rate coefficients for both monooxygenation reactions were directly proportional to the specific growth rate in the accelerator, which supports that the accelerator tank caused an up-regulation of the monooxygenase content. Because the rate coefficients in the aerator tank were much larger than in the one-tank system, even though the specific growth rates were nearly the same, monooxygenases may have carried over from the accelerator tank to the aerator tank. Its higher concentration of 2,4-dichlorophenol (2,4-DCP) and the higher specific growth rate were the main reasons why the accelerator had faster kinetics for 2,4-DCP utilization than did the aerator tank. The apparently higher levels of monooxygenase in both tanks of the two-tank system also appears be a primary reason why its performance was substantially superior to that of the one-tank system in terms of 2,4-DCP removal.

Lasing and radiation-mode dynamics in a Van de Graaff accelerator–free-electron laser with an internal cavity

The lasing of a Van de Graaff electrostatic accelerator–free-electron laser (EA–FEL) with an internal cavity is reported. An EA–FEL employing an internal cavity is a FEL configuration that has a potential to operate at high average power, high frequency, and possibly in a continuous wave (cw) mode. The initial lasing provided a pulsed radiation power of 1 kW at 100.5 GHz frequency. The FEL operated with a 1.4 A, 1.4 MeV electron beam in a recirculation (depressed collector) configuration. It utilizes a high quality (Q≈30 000) Talbot effect resonator and a Halbach-type wiggler placed internally in the center of the accelerator tank. Nonlinear features of the oscillation power buildup and decay near saturation and mode hopping were observed and are interpreted.

The Vivitron process control

The operation of the Vivitron electrostatic accelerator, which was designed in 1981 and has been under construction at the CRN since 1985, needs a dedicated process control system. The study and design of this control system started in 1987. Little knowledge is available in this field for electrostatic accelerators. The timing problems are generally small but the Vivitron specific structure, with seven porticos (large field-shaping shields) in the tank and sophisticated beam handling in the terminal, requires control equipment operating inside the tank under extremely severe conditions. Several steps are necessary to achieve the full control system. Some tests in the existing MP accelerator, used as a pilot machine, supplied practical information about the environment inside the accelerator tank. They also provided better knowledge of the beam behavior, especially inside the accelerator tube.

A concept for earthquake protection of the Bucharest tandem accelerator

A concept for an earthquake protection of a tandem accelerator has been developed starting from a better understanding of the earthquake effects upon an FN column structure as a result of dynamic interaction between the ground, building and accelerator. The characteristics of earthquakes in Bucharest as well as the preliminary full-scale vibration tests are described. The main requirements for an efficient earthquake protection system are derived. These requirements are best met by a protection system that performs the vibration isolation of the accelerator tank by supporting it on spring and damper units. By means of specially designed devices (“mechanical fuses”), these units are blocked under normal operation conditions to ensure the alignment of the accelerator and are released in case of an earthquake whose acceleration exceeds a certain limit. Such a vibration isolation system might be useful for other scientific or industrial equipment too.

An external gas supply system for a Van De Graaff positive ion accelerator

A simple system, which allows an ion source gas bottle (located in the terminal of the accelerator) to be pressurized through copper and polypropylene tubing from an external gas cylinder, is described. Since it is not necessary to remove the insulating gas from the accelerator tank, a complete change in accelerated ions can be made in 30 min or less. Electrical breakdowns in the polypropylene tubing (with subsequent rupture) is prevented by backfilling with insulating gas.

Persulfate Bleach and Motion-Picture Film Processes

This paper summarizes two years of successful experience with sodium persulfate bleach in reversal and negative/positive motion-picture processes. First, the important parameters governing persulfate bleach performance are reviewed. Then, the major advantages in using persulfate bleach are discussed. Finally, our experience at Kodak with persulfate bleach has led to several changes in process specifications, which are discussed in detail. These changes include a new sound developer formula that makes repairing misapplication errors of sound developer easier, a persulfate bleach accelerator additive that increases the accelerator tank solution life, and a simplification in the bleach tank formula.

Some improvements of the Pelletron accelerator in lund

Several improvements that have been implemented in the Pelletron system are described. The main components are protective automatically closing valves at each end of the accelerator tank, pick-up wheels and corona point supports of a new design, and valves in the stripper housing. These modifications result in improved operation reliability and a minimum of service interruptions.

Mechanical Technologies for PIGMI

PIGMI (Pion Generator for Medical Irradiations) is a compact linear proton accelerator designed for a hospital environment. The prototype of the low energy section of PIGMI has been designed and is being fabricated at the Los Alamos Scientific Laboratory. It is an accelerator design which makes use of several advanced or innovative technologies. The PIGMI Prototype consists of a 250 keV injector, a double harmonic buncher, a tape-wound 13 kG solenoid magnet, and four accelerator tanks with a total of 63 drift tubes of which 18 contain strong focusing quadrupoles of permanent magnets. The accelerator tanks are mild steel, copper-plated using a bright acid leveling technique. Drift tubes are stainless steel, fabricated using electron beam welding, shaped in a lathe and then copper plated. Drift tubes loaded with permanent magnets are sealed using laser welding. The samarium cobalt magnets are shaped by cutting and grinding techniques developed at Los Alamos.

Mechanical Description of PIGMI

PIGMI (Pion Generator for Medical Irradiation) is a compact linear proton accelerator whose prototype is being designed and built at the Los Alamos Scientific Laboratory. PIGMI consists of a 250-keV injector, a double harmonic buncher, a tape-wound 13-kG solenoid magnet, and four accelerator tanks with a total of 63 drift tubes of which 18 will contain strong focusing quadrupoles of permanent magnets. Small component sizes (for example, one drift tube is only 0.690-cm long) necessitates innovative design approaches. Fabrication and assembly are in progress, and some of the mechanical aspects of some of the accelerator components are described in this paper.

Resonantly Coupled Standing Wave Accelerator Structures for Electron and Proton Linac Applications

Standing wave accelerator tanks which utilize non-excited resonant elements for field stabilization have become standard in proton linac designs during the last few years. A general description of resonant coupling, with special emphasis on the energy propagation characteristics of resonantly coupled systems is given. Extension of resonant coupling to the coupling of short 0 or ? mode like sections is briefly discussed. The transient response of two resonantly coupled linac tanks, a post coupled drift tube linac and a side coupled linac tank are compared to conventional 0 or ? mode tank responses. Finally, a brief description of applications of resonantly coupled linac tanks to electron and proton linacs under construction in the U.S. is given.

Tuning error sensitivity of stabilized linear accelerator tanks with full cell terminations

A slightly lossy biperiodic multicoupled resonator model is used to analyze the sensitivity of the fields to tuning errors in a standing wave linac tank. Perturbations of the 1 2 π- mode are used to represent the field behavior of stabilized or near-stabilized linac structures. The effects of couplings to cells beyond the nearest neighbor and the effects of an error in the average coupling resonator frequency are shown. Tables of error effects are given.