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The activation level of the JAEA-Tokai tandem accelerator facility was investigated experimentally in advance of the future decommissioning. JAEA-Tokai tandem accelerator facility has a higher terminal voltage of 18 MV and a larger total floor area, Compared to other electrostatic accelerators with terminal voltage of 1 MV to 6 MV. Therefore, determination for 'where,' 'what,' and 'how many' nuclides are produced in the facility is crucial. Thermal neutrons generated by beam losses associated with accelerator operations contribute significantly to the activation of equipment and facilities. The accumulated activities of60Co and152Eu; the most considerable radionuclides at the decommissioning, can be deduced by the thermal neutron fluence rate during the accelerator operation. In this study, thermal neutron fluence measurement on the surface of the pressure vessel and concrete building was conducted with conventional methods using dosimeters and metal foil detectors as well as a new method using a portable γ-ray detector. The thermal neutron fluence in the facility during the accelerator operation ranges from 101 to 104 n/cm2/s. The sum of deduced activities of60Co and152Eu in 50 years is much lower than the clearance level of 0.1 Bq/g in all areas except in the irradiation room. [ABSTRACT FROM AUTHOR]

The scanning nuclear microprobe of the Institute of Applied Physics of the National Academy of Sciences of Ukraine is an analytical channel based on the compact electrostatic accelerator "Sokol" of the Van de Graaff type with the maximum voltage at the high-voltage terminal of 2 MV and is designed for local non-destructive analysis of samples of various origins with high sensitivity (~1 ppm), as well as for the fabrication of three-dimensional small structures of high quality using proton beam writing. The resolution of the microprobe is about 3 μm with a beam current of I ~ 100 pA and 0.6 μm with I ~1 pA. The maximum scanning raster with a focused beam on the sample surface is 1 × 1 mm2. The microprobe implements the techniques of particle-induced X-ray emission, Rutherford backscattering, and secondary electron microscopy. The article also gives examples of the use of the nuclear microprobe in physical research.

The scanning nuclear microprobe of the Institute of Applied Physics of the National Academy of Sciences of Ukraine is an analytical channel based on the compact electrostatic accelerator “Sokol” of the Van de Graaff type with the maximum voltage at the high-voltage terminal of 2 MV and is designed for local non-destructive analysis of samples of various origins with high sensitivity (~1 ppm), as well as for the fabrication of three-dimensional small structures of high quality using proton beam writing. The resolution of the microprobe is about 3 μm with a beam current of I ~ 100 pA and 0.6 μm with I ~1 pA. The maximum scanning raster with a focused beam on the sample surface is 1 × 1 mm² . The microprobe implements the techniques of particle-induced X-ray emission, Rutherford backscattering, and secondary electron microscopy. The article also gives examples of the use of the nuclear microprobe in physical research. [ABSTRACT FROM AUTHOR]

As an effective methods of plasma heating, neutral beam injection (NBI) systems based on negative hydrogen ion sources will be utilized in future magnetic-confinement nuclear fusion experiments. Because of the collisions between the fast negative ions and the neutral background gas, the positive ions are inevitable created in the acceleration region in the negative NBI system. These positive ions are accelerated back into the ion source and become high energy backstreaming ions. In order to explore the characters of backstreaming ions, the track and power deposition of backstreaming H+ beam is estimated using the experimental and simulation methods at NNBI test facility. Results show that the flux of backstreaming positive ions is 1.93 % of that of negative ion extraction from ion source, and the magnet filed in the beam source has an effect on the backstreaming positive ions propagation.

Comprehensive Research Facility for Fusion Technology (CRAFT) is an integration of different demonstrating or testing facilities, which aim to develop the critical technology or composition system towards the fusion reactor. Due to the importance and challenge of the negative ion based neutral beam injection (NNBI), a NNBI test facility is included in the framework of CRAFT. The initial object of CRAFT NNBI test facility is to obtain a H0 beam power of 2 MW at the energy of 200–400 keV for the pulse duration of 100 s. Inside the negative ion accelerator of NNBI system, the interactions of the negative ions with the background gas and electrodes can generate abundant stray electrons. The stray electrons can be further accelerated and dumped on the electrodes or eject from the accelerator. The stray electrons, including the ejecting electrons, cause the unwanted particle and heat flux onto the electrodes and the inner components of beamline (especially the temperature sensitive cryopump). The suppression of the stray electrons from the CRAFT accelerator is carried out via a series of design and simulation works. The paper focuses the influence of different magnetic field configurations on the stray electrons and the character of the ejecting electrons.

In this paper, we describe the upgrade of a small electrostatic dust accelerator located at the University of Stuttgart. The newly developed dust source, focusing lens, differential detector and linac stage were successfully installed and tested in the beam line. The input voltage range of the dust source was extended from 0–20 kV to 0–30 kV. A newly developed dust detector with two differential charge sensitive amplifiers is employed to monitor particles with speeds from several m/s to several km/s and with surface charges above 0.028 fC. The post-stage linac provides an additional acceleration ability with a total voltage of up to 120 kV. The entire system of this dust accelerator works without protection gas and without a complex high voltage terminal. The volumes to be pumped down are small and can be quickly evacuated. The new system was used to accelerate micron- and submicron-sized metal particles or coated mineral materials. Improvements in the acceleration system allow for a wider variety of dust materials and new applications. [ABSTRACT FROM AUTHOR]

The Applied Nuclear Physics Group at Lund University is constructing a prototype CANS (Compact Accelerator-driven Neutron Source). The CANS is based around a 3 MV, single-ended, Pelletron accelerator, which is used to impinge a 2.8 MeV deuterium beam into a beryllium target. The anticipated neutron production will be on the order of 1010 n/s in 4π sr. A further upgrade to the ion source of the Pelletron is expected to increase neutron production to 1011 n/s. Neutron energies will be up to 9 MeV with peak emission at ∼5 MeV. Shielding and moderation will be provided by a large water tank surrounding the target, with three exit ports to allow neutrons of different energies to be directed to experiments. The design is supported by simulation results which predict fast-neutron fluxes of 9×104 to 5×106 n/cm2/s, and thermal-neutron fluxes of 1×104 to 5×104 n/cm2/s to be readily obtainable with a 10 µA deuteron beam. [ABSTRACT FROM AUTHOR]

In this paper, we describe the upgrade of a small electrostatic dust accelerator located at the University of Stuttgart. The newly developed dust source, focusing lens, differential detector and linac stage were successfully installed and tested in the beam line. The input voltage range of the dust source was extended from 0–20 kV to 0–30 kV. A newly developed dust detector with two differential charge sensitive amplifiers is employed to monitor particles with speeds from several m/s to several km/s and with surface charges above 0.028 fC. The post-stage linac provides an additional acceleration ability with a total voltage of up to 120 kV. The entire system of this dust accelerator works without protection gas and without a complex high voltage terminal. The volumes to be pumped down are small and can be quickly evacuated. The new system was used to accelerate micron- and submicron-sized metal particles or coated mineral materials. Improvements in the acceleration system allow for a wider variety of dust materials and new applications.

Aerosol samples (PM10 and PM2.5) were collected during the 2018-2019 dry-cold season, inside an electrostatic particle accelerator laboratory at Instituto de Física, Universidad Nacional Autónoma de México, and on the rooftop. The goal was to measure gravimetric mass and elemental concentrations, to identify emitting sources, and to assess risks to human health due to inhalation, ingestion and dermal deposition, through Hazard Quotients. Concentrations of Mg, Al, Si, P, S, Cl, K, Ca, V, Mn, Fe, Ni, Cu, and Zn were measured with X-ray Fluorescence. Mass concentrations were lower indoors than outdoors. Elemental/gravimetric mass concentrations ratios showed that S, Ni, Cu, and Zn were more abundant in both indoors particle sizes, plus P in PM2.5. Possible sources, found through Cluster Analysis, were geogenic, SF6 subproducts, vacuum pump oil, and air conditioning, supported by Scanning Emission Microscopy and Electron Probe Microanalysis. Health risks due to enriched elements are not significant.

Aerosol samples (PM10 and PM2.5) were collected during the 2018-2019 dry-cold season, inside an electrostatic particle accelerator laboratory at Instituto de Física, Universidad Nacional Autónoma de México, and on the rooftop. The goal was to measure gravimetric mass and elemental concentrations, to identify emitting sources, and to assess risks to human health due to inhalation, ingestion and dermal deposition, through Hazard Quotients. Concentrations of Mg, Al, Si, P, S, Cl, K, Ca, V, Mn, Fe, Ni, Cu, and Zn were measured with X-ray Fluorescence. Mass concentrations were lower indoors than outdoors. Elemental/gravimetric mass concentrations ratios showed that S, Ni, Cu, and Zn were more abundant in both indoors particle sizes, plus P in PM2.5. Possible sources, found through Cluster Analysis, were geogenic, SF6 subproducts, vacuum pump oil, and air conditioning, supported by Scanning Emission Microscopy and Electron Probe Microanalysis. Health risks due to enriched elements are not significant. [ABSTRACT FROM AUTHOR]

The accurate knowledge of the beam energy is of first importance in most applications using ion beams delivered by electrostatic accelerators. Regular beam energy calibration is thus required. The standard procedure is to use neutron thresholds and well known gamma-ray resonances. However, only a few calibration points are available between 2 MeV and 4 MeV despite the need of such beam energies, for instance, for nuclear reaction analyses. In this work, the suitability of 27Al(p,γ)28Si and 45Sc(p,n)45Ti resonances has been studied in this specific energy range by comparison with well-established calibration energies. The methodology used for the experiments and data treatment is fully detailed. The usefulness of these resonances is shown through several calibration campaigns that led to a complete energy calibration of two accelerator based facilities from 500 keV up to 4 MeV. [ABSTRACT FROM AUTHOR]

The article presents the results of operation of ion source with Penning discharge developed in the IAP of NAS of Ukraine to produce doubly charged helium ions He2+ beam and to increase the energy of accelerated ions up to 3.2 MeV. This energy is necessary for ERDA channel when measuring hydrogen concentration in the structural materials used in nuclear engineering. The ion source parameters are the following: discharge voltage is 6 kV, discharge current is 0.8 - 1.2 mA, the current of singly charged helium ions He+ 24 μA, the current of doubly charged helium ions He2+ 0.5 μA.

Up to now, different designs have been introduced for measurement beam profile accelerators. Secondary electron emission monitors (SEM) are one of these devices which have been used for this purpose. In this work, a SEM has been constructed to measure beam profile of ES-200 accelerator, a proton electrostatic accelerator which is installed at SBU. Profile grid for both planes designed with 16 wires which are insulated relative to each other. The particles with maximum energy of 200 keV and maximum current of 400 μA are stopped in copper wires. Each of the wires has an individual current-to-voltage amplifier. With a multiplexer, the analogue values are transported to an ADC. The ADCs are read out by a microcontroller and finally profile of beam shows by a user interface program

Optimizations on 200 kV electrostatic accelerator have been done in order to increasing ion current on target, improving vacuum condition and reduction in x-rays emission, increasing stability of high voltage power supply and reaching much greater achievable voltage value. The accelerator tube has most important effect on beam tracing in the electrostatic accelerators. So precautions most be considered in designing and constructing of this part. In order to finding permissible tolerances in construction and assembling of 200 kV electrostatic accelerator column, first the effects of angle deviation of a part from accelerator axis on beam track in the accelerator tube was simulated with Simion 7.0 computer program. We found that in order to prevent beam lost, the tolerances of balancing and co-centering of each part should be smaller than 0.1 mm. Each part of accelerator tube constructed by tolerances lower than 0.05 mm. Ultrasonic cleaning method used in pre-assembling process of parts. Because of its excellences, in the new tube we used borosilicate glass instead of high density alumina as insulators between the metallic electrodes. After three days of working vacuum pumps the system reached to 8.0×10-7 and after months to 5.0×10-7 ultimate pressure values. Measurements showed that by these considerations the maximum of reachable ion current on target was 1.1 mA which increased 50% compared to old machine, while x-ray emission intensity was increased by 25%. Optimizations of high voltage power supply are now under studies and tests

Nowadays, middle energy electrostatic accelerators in industries are widely used due to their high efficiency and low cost compared with other types of accelerators. In this paper, the importance and applications of electrostatic accelerators with 800 keV energy are studied. Design and simulation of capacitive coupling of a dynamitron accelerator is proposed. Furthermore, accelerating tube are designed and simulated by means of CST Suit Studio

Experimental study results are presented for a beam profile and emittance of an electrostatic accelerator “Sokol” before and after being equipped with magnet X-ray suppression system.

Abstract Semiconductor devices used in space applications suffer degradation due to the space radiation environment, which affects their electric parameters, eventually reducing the in-orbit lifetime. This relatively slow behavior is due to cumulative total dose effects. On the other hand, radiation can destroy information or even damage electronic parts of the device in a sudden way. These processes are known as Single Event Effects (SEE). Heavy ion beams from electrostatic tandem or other accelerators can be used to test and characterize the response of the electronics to SEE. Two conditions are necessary for this purpose: to use very low fluxes of only a few hundred to hundreds of thousand particles/(cm2·s), and to browse over a wide Linear Energy Transfer (LET) interval by changing the energy and/or the type of the impinging particles. In this work we describe the facility developed at the Argentine tandem accelerator (Tandar) to study SEE, and especially the fabrication and use of a perforated Ta foil to reduce the beam current to the required values. The determination of the resulting beam uniformity over the area of irradiation is also reported. The system has been tested by a SEE experiment on a webcam sensor. [ABSTRACT FROM AUTHOR]

Tandem electrostatic accelerators often require the flexibility to operate at a variety of terminal voltages to accommodate various user requirements. However, the ion beam transmission will only be optimal for a limited range of terminal voltages. This paper describes the operational performance of a novel focusing system that expands the range of terminal voltages for optimal transmission. This is accomplished by controlling the gradient of the entrance of the low-energy tube, providing an additional focusing element. In this specific case it is achieved by applying up to 150 kV to the fifth electrode of the first unit of the accelerator tube. Numerical simulations and beam transmission tests have been performed to confirm the effectiveness of the lens. An analytical expression has been derived describing its focal properties. These tests demonstrate that the entrance lens control eliminates the need to short out sections of the tube for operation at low terminal voltage. [ABSTRACT FROM AUTHOR]

The paper discusses peculiarities of the resonance proton scattering use for the beam parameters control of the electrostatic accelerators. The expediency of the use has been confirmed by experiment. Peculiarities are caused because elastic resonance scattering through the stage of compound nucleus is always accompanied by potential and Coulomb scattering. These three components interfere and for that reason the resonance form de-pends on a scattering angle and total angular moment of a compound nucleus level. However, possessing neces-sary information in the given field of nuclear spectroscopy enables the selection of resonance with the character-istics suitable for the calibration purpose. Considerable increase of the scattering cross section in the resonance region saves the time and simplifies the experiment technical maintenance. The experiments were performed at the 10 MeV tandem accelerator of the Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, after its modernization. Silicon and oxygen were used as the targets. Silicon targets were of two types of thickness: 1) the target of complete absorption, 2) the target with the thickness in which the loss of protons ener-gy exceeded the width of the selected resonance. The elastic and non elastic scattering from silicon were used in region of the 3,100 MeV proton energy resonance. Oxygen target, as component of the surface oxidizing layer on beryllium had the thickness which in terms of the loss of proton energy was less than the width of the selected elastic narrow resonance at 3,470 MeV proton energy. As result of the measurement the corrections concerning the energy scale of the accelerator and protons energy spread in the beam were proposed.

A radiochromic film, Gafchromic HD-V2, is applied to a possible method of measuring a two-dimensional (2D) spatial profile of MeV cluster ion beams. The coloration responses of the HD-V2 film to MeV carbon and gold cluster ion beams are experimentally investigated since some cluster effect may appear. The degree of the film coloration is quantified as a change in optical density (OD) by reading the films with an image scanner for high-resolution measurement of the 2D beam profile. The OD response of HD-V2 is characterized as a function of the ion and atom fluence for comparison. The dependences of the OD response on the cluster size, kinetic energy, and ion species are discussed. It is found that the sensitivity of the OD change is reduced when the cluster size is large. The beam profile of MeV cluster ion beams delivered from the tandem accelerator in TIARA is characterized from the measurement result using HD-V2 films. The present results show that the use of the Gafchromic HD-V2 film is suitable for the detail beam profile measurement of MeV cluster ions, especially C 60 ions, whose available intensity is rather low in comparison with that of monatomic ion beams. [ABSTRACT FROM AUTHOR]

The ITER project requires at least two Neutral Beam Injectors (NBIs), each accelerating to 1 MV a 40A beam of negative deuterium ions, to deliver to the plasma a power of about 33 MW for one hour as additional heating. The fulfilment of such demanding performances required the realization of the full size prototype of the negative ion source (SPIDER − Source for Production of Ion of Deuterium Extracted from RF plasma), as well as the full size prototype of the whole 1 MV ITER injector (MITICA − Megavolt ITER Injector & Concept Advancement) at PRIMA, the test facility for the ITER neutral beams now under construction at the Consorzio RFX in Padua, Italy. The SPIDER plasma source- housed in a stainless steel vessel maintained in high vacuum − is polarized at 112 kV (12 kV extraction voltage and 100 kV accelerating voltage), so that the vacuum vessel must be equipped with three large alumina feedthroughs, ring shaped insulators (820 mm in diameter) necessary to supply the electric, hydraulics gas and diagnostic services to the plasma source. These insulators (bushings) belong to the most critical items in the SPIDER assembly and they required a particular effort in designing, manufacturing and testing. This paper gives an overview of the insulator design, development, manufacturing activities and presents the results of the high voltage acceptance tests. [ABSTRACT FROM AUTHOR]

The article presents the results of operation of ion source with Penning discharge developed in the IAP of NAS of Ukraine to produce doubly charged helium ions He2+ beam and to increase the energy of accelerated ions up to 3.2 MeV. This energy is necessary for ERDA channel when measuring hydrogen concentration in the structural materials used in nuclear engineering. The ion source parameters are the following: discharge voltage is 6 kV, discharge current is 0.8 - 1.2 mA, the current of singly charged helium ions He+ 24 pA, the current of doubly charged helium ions He2+ 0.5 uA. [ABSTRACT FROM AUTHOR]

The paper presents optimization data obtained for an immersion probe-forming system of the ion microprobe to be used in 3 MeV H+ ion accelerator generating 0,4 μm beam spot for normalized acceptance of 7 μm2 · mrad2 · MeV. To achieve higher microprobe resolution it is intended to place an electrostatic lens between the collimators and the accelerating tube.

An electrostatic accelerator tube capable of accelerating proton, deuteron, alpha beam and heavier ions up to an energy of 150keV has been designed and constructed. This tube can be operated with a Cockroft-Walton type high voltage generator. The construction of the tube is important from two different standpoints. First, because it will initiate the use of low energy accelerators for both scientific and industrial development in country and also this step will lead the country toward approaching the accelerator design technology, an issue which has been severely overlooked for the past few decades. The present accelerator tube consists of 11 different electrodes forming 3 cylindrical lenses, i.e., extractor lens, focusing lens and cooling lens. An accelerator column which includes 7 collimating lenses follows the cooling lens. The tube can accelerate 2H+ up to an energy of 150keV. The accelerator column was successfully tested for the high vacuum and the voltage up to 150kV. A radio frequency type ion source was used to check the performance of the tube. Measurements demonstrated that a beam current close to 850µA can be readily obtained in the present system.

The neutron inelastic scattering cross section of In 115 has been measured by the activation technique at neutron energies of 2.95, 3.94, and 5.24 MeV with the neutron capture cross sections of Au 197 as an internal standard. The effects of multiple scattering and flux attenuation were corrected using the Monte Carlo code GEANT4. Based on the experimental values, the In 115 neutron inelastic scattering cross sections data were theoretically calculated between the 1 and 15 MeV with the TALYS software code, the theoretical results of this study are in reasonable agreement with the available experimental results. [ABSTRACT FROM AUTHOR]

The feasibility of the transverse intensity distribution measurement of low-energy (keV/u range) heavy-ion beams using radiochromic films is experimentally explored. We employ a Gafchromic radiochromic film, HD-V2, whose active layer is not laminated by a surface-protection layer. The coloration response of films irradiated with several ion beams is characterized in terms of optical density (OD) by reading the films with a general-purpose scanner. To explore the energy dependence of the film response widely, the kinetic energy of the beams is varied from 1.5 keV/u to 27 MeV/u. We have found that the coloration of HD-V2 films is induced by irradiation with low-energy ion beams of the order of 10 keV/u. The range of the beams is considerably shorter than the thickness of the film's active layer. The dependence of OD response on ion species is also discussed. We demonstrate that the Gafchromic film used here is useful for measuring the intensity distribution of such low-energy ion beams. [ABSTRACT FROM AUTHOR]

The ion beam facility at the Takasaki Advanced Radiation Research Institute, the National Institutes for Quantum and Radiological Science and Technology, consists of a cyclotron and three electrostatic accelerators, and they are dedicated to studies of materials science and bio-technology. The paper reviews this unique accelerator complex in detail from the viewpoint of its configuration, accelerator specification, typical accelerator, or irradiation technologies and ion beam applications. The institute has also irradiation facilities for electron beams and 60Co gamma-rays and has been leading research and development of radiation chemistry for industrial applications in Japan with the facilities since its establishment. The configuration and utilization of those facilities are outlined as well.

This paper describes the R&D work performed in support of the design of the alumina insulators for the MITICA Neutral Beam Injector. The ceramic insulators are critical elements, both from the structural and electrical point of view, of the 1 MV electrostatic accelerator of the MITICA injector, as they are required to sustain both the mechanical loads due to the cantilevered weight of the ion source and the high electric field between the accelerator grids. This paper presents the results of numerical simulations and experimental tests on prototypes that have been carried out to validate the insulator design under realistic operating conditions. [ABSTRACT FROM AUTHOR]

In this work, design and construction process of a Faraday Cup (FC) for measuring the beam current in a 200 keV, 80 W electrostatic proton accelerator (ES-200) at Shahid Beheshti University has been presented. After choosing the appropriate material, optimum thickness and dimensions of the FC have been calculated using SRIM, MCNPX and CST Studio package, respectively. Geometrical parameters are optimized to reduce the scape of secondary electrons from the cup. The designed FC has been constructed and installed on the ES-200 accelerator. According to the experimental results, maximum proton current of 400 μA ± 10% has been measured. In addition, the required cooling system has been designed and simulated using ANSYS. Based on the computational results with the water volumetric flow rate of 4 × 10 −5 m 3 s −1 , the maximum temperature in the FC would not exceed 320 K. [ABSTRACT FROM AUTHOR]

A micro-PIXE analysis system based on the ion beam analysis system by Oxford Microbeams Ltd. has been developed at the NIRS-electrostatic accelerator facility. The introduction of the CdTe X-ray detector dramatically improved the detection efficiencies for heavy elements that are important in the life sciences and environmental science. This system has been used for various projects and has provided several meaningful results, thus establishing the micro-PIXE system as an effective tool for the determination of elemental distribution with a high spatial resolution. In this paper, outline of the features of the micro-PIXE system at NIRS along with its recent application in research are introduced. [ABSTRACT FROM AUTHOR]

Experimental study results are presented for a beam profile and emittance of an electrostatic accelerator "Sokol" before and after being equipped with magnet X-ray suppression system. [ABSTRACT FROM AUTHOR]

Highlights: [•] Discussion of properties of electrostatic accelerators. [•] Listing and description of the main techniques used for materials analysis and modification. [•] Summary of specific applications and the related technique. [•] New trends in fission reactor research and biomedical research related to electrostatic accelerators. [ABSTRACT FROM AUTHOR]