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An accelerator complex for hadron therapy is under design at the Joint Institute for Nuclear Research (Dubna, Russia). The complex consists of two superconducting cyclotrons. The facility is intended for generating accelerated beams of protons, carbon, and H 2 + ions. The main cyclotron named K1600 is a separated sector machine, which accelerates carbon ions to the output energy of 400 MeV/u. As an injector, a compact cyclotron K280 is provided for production of proton, carbon, and H 2 + ion beams with the output energy of 70 MeV/u. The ions are injected into the machine from an ECR ion source. Two extraction methods can be used in the cyclotron. One is based on using an electrostatic deflector and is intended for extracting carbon and H 2 + ions. The other uses a stripping foil for production of protons from H 2 + ions. The K280 can also be used as a stand-by facility for medical purposes like treating eye melanoma or for producing radioisotopes. The basic parameters of the cyclotron-injector and detailed investigation of its systems along with the beam dynamics are described. [ABSTRACT FROM AUTHOR]

An accelerator complex for hadron therapy based on a chain of cyclotrons is under development at JINR (Dubna, Russia), and the corresponding conceptual design is under preparation. The complex mainly consists of two superconducting cyclotrons. The first accelerator is a compact cyclotron used as an injector to the main accelerator, which is a six-fold separated sector machine. The facility is intended for generation of protons and carbon beams. The H 2 + and 12 C 6 + ions from the corresponding ECR ion sources are accelerated in the injector-cyclotron up to the output energy of 70 MeV/u. Then, the H 2 + ions are extracted from the injector by a stripping foil, and the resulting proton beam with the energy of 70 MeV is used for medical purposes. After acceleration in the main cyclotron, the carbon beam can be either used directly for therapy or introduced to the main cyclotron for obtaining the final energy of 400 MeV/u. The basic requirements to the project are the following: compliance to medical requirements, compact size, feasible design, and high reliability of all systems of the complex. The advantages of the dual cyclotron design can help reaching these goals. The initial calculations show that this design is technically feasible with acceptable beam dynamics. The accelerator complex with a relatively compact size can be a good solution for medical applications. The basic parameters of the facility and detailed investigation of the magnetic system and beam dynamics are described. [ABSTRACT FROM AUTHOR]

The authors consider and evaluate the physical parameters and regularities of the process of consolidation of Fe-Cu, Cu-Nb, Ag-Ni, Fe-Pb nanoparticles when creating composite materials by means of shock wave compaction. As a result of theoretical consideration of explosive compaction process, researchers established and discussed the physical process conditions, established a number of threshold pressure values corresponding to different target indicators of the state of the compact. The time of shock wave impact on powders for powder consolidation was estimated. [ABSTRACT FROM AUTHOR]

The influence of introduction of particles of detonation-synthesized nanodiamonds into composites and aluminum-base light alloys on their physical and mechanical properties is analyzed. The data on microstructure and physical and mechanical properties of composites and cast aluminum alloys reinforced with diamond nanoparticles are presented. The introduction of nanoparticles is shown to result in a significant improvement of the material properties. [ABSTRACT FROM AUTHOR]

The results obtained from investigations into the microstructure and physical-mechanical and electrical properties of cast aluminum-based alloys reinforced with nanodiamonds are presented. Addition of the diamond nanoparticles is shown to change the structural parameters and improve the mechanical properties of the materials. [ABSTRACT FROM AUTHOR]

This paper presents a comparative analysis of morphology, chemical and phase compositions, and particle size distribution of nanopowders produced by electric explosion of wire (EEW) and plasma-chemical methods. The possibility of introduction of Al2O3 particles into Al alloy by means of a special master alloy and with ultrasonic processing is shown. The improvement of tensile properties of an Al-based composite material reinforced with 0.1 wt% of EEW Al2O3 is demonstrated. [ABSTRACT FROM AUTHOR]

A 12.5 MeV, 25 μA, proton compact superconducting cyclotron for medical isotope production has been designed and is currently in fabrication. The machine is initially aimed at producing 13 N ammonia for Positron Emission Tomography (PET) cardiology applications. With an ultra-compact size and cost-effective price point, this system will offer clinicians unprecedented access to the preferred radiopharmaceutical isotope for cardiac PET imaging. A systems approach that carefully balanced the subsystem requirements coupled to precise beam dynamics calculations was followed. The system is designed to irradiate a liquid target internal to the cyclotron and to minimize the need for radiation shielding. The main parameters of the cyclotron, its design, and principal steps of the development work are presented here. [ABSTRACT FROM AUTHOR]

Results of an x-ray phase analysis and investigations into the structure and mechanical properties of aluminum-base alloys produced by shock-wave compaction are presented. The method under study makes it possible to obtain samples with density approaching the theoretical value and improved mechanical characteristics. [ABSTRACT FROM AUTHOR]

Results obtained from an x-ray phase analysis and mechanical tests on compression of hot-pressed Al-Al C composites with 5 or 10 wt.% C added to the initial powder mixture are presented. It is shown that the higher is the amount of aluminum carbide formed under hot pressing, the higher are the yield stress and the effective elastic modulus of the composite. [ABSTRACT FROM AUTHOR]

The process of introduction of submicron agglomerates and nanostructured particles into a poorly wetting liquid exposed to ultrasound is theoretically considered. The main dependences relating the exposure time to the physical and chemical properties of particles and liquid as well as to the characteristics of acoustic radiation are obtained. [ABSTRACT FROM AUTHOR]

Changes in structure, phase composition and crystal structure parameters are studied for materials of the ZrO-MgO system after cyclic thermal shock effects. Features are revealed for formation of ceramic structure and phase condition with implementation of internal stresses connected with a sharp change in temperature. Optimum compositions are established for refractory materials based on ZrO answering high specifications for thermal shock resistance and refractoriness. [ABSTRACT FROM AUTHOR]

The results obtained from investigations into the special features inherent in the mechanical characteristics (Hugoniot elastic limit and spall strength) observed under shock-wave loading of Al-AlO composite samples produced by an explosive powder compaction technique are presented. Embedding 10 wt.% of aluminum oxide in the aluminum matrix has been found to increase the Hugoniot elastic limit as opposed to the commercialgrade AD1(Al 1013) aluminum alloy. [ABSTRACT FROM AUTHOR]

Flash radiotherapy is a technology that could modify the way radiotherapy is delivered in the future. Radiotherapy's main goal is delivering dose to the tumor while sparing the surrounding healthy tissues. The Flash scheme utilizes much higher dose rates in much shorter irradiation times compared to conventional radiotherapy. In this context, the high energy proton machine (220–230 MeV) to irradiate deeply sited tumor should provide output beam intensity of tens and hundred microA in pulse regime. The best candidate in this sense would be an isochronous cyclotron. But unfortunately, all existing facilities of the cyclotron type have substantially lower beam current in the indicated energy range. To meet ultra-high intensity requirement, an external injection to the cyclotron could be tried. But again, none of operational cyclotrons with energy ∼ 230 MeV has an external ion source installed. So, the design of the accelerator foreseen is quite a challenge due to many difficult technical problems to be solved on its way. In this paper the results of detailed computer modeling of a compact cyclotron intended for Flash radiotherapy are given. The superconducting technology for the cyclotron magnet design is selected to substantially reduce the weight and size of the facility. The outline of the main cyclotron systems with parameters obtained by scrutinized beam dynamics simulations in spatial field distributions and taking into account the beam space charge effects is given. [ABSTRACT FROM AUTHOR]

The principles of formation of structure and properties of materials produced by self-propagating hightemperature synthesis (SHS) from the Al-Ti-B/B4C powder systems are identified. It is shown that the SHSmaterials produced from the Al-Ti-B powder systems consist of a TiAl intermetallic matrix with inclusions of titanium diboride particles. It is found out that an introduction of 1 wt.% of TiB2 particles into the melt of the AD35 aluminum alloy allows reducing the grain size from 620 to 220 μm and gives rise to an increase in the ultimate tensile strength of as-cast specimens from 100 to 145 MPa and in the plasticity from 7 to 9%. [ABSTRACT FROM AUTHOR]

To increase the beam intensity of cyclotrons used for producing radionuclides, beam loss during extraction must be reduced. Extraction efficiency is limited by the beam parameters in front of the deflector, especially angular distribution. Computer simulation of the second harmonic mode for 18 MeV protons, which is frequently used, has been carried out to understand beam behavior in a cyclotron. The extraction efficiency is determined by the width of the angular distribution of particles in the phase space plot at the deflector. An effective method to reduce the width is to shorten the bunch at injection. The simulation shows that the bunch phase length at injection must be ⩽30° to realize a 30 μA extraction beam current and satisfy the deflector heat limit of 200 W. [ABSTRACT FROM AUTHOR]

The article focuses on the self propagating and high temperature synthesis of Aluminium (Al) and Titanium (Ti) borides. Topics discussed include properties of Al and Ti such as high melting temperature and thermal stability, exothermic reactions of Ti and Al interaction with boron and study on the problems associated with the synthesis of Al and Ti borides by combustion.

The driver linac for the facility for rare isotope beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research. The linac will be capable of accelerating a uranium beam to an energy of up to 200 Mev/u and delivering it to a fragmentation target with a maximum power of 400 kW. Stable ion beams will be produced by a high performance electron cyclotron resonance ion source operating at 28 GHz. The ion source will be located on a high voltage platform to reach an initial beam energy of 12 keV/u. After extraction, the ion beam will be transported vertically down to the linac tunnel in a low energy beam transport (LEBT) system and injected into a radio frequency quadrupole (RFQ) operating at a frequency of 80.5 MHz. To meet the beam power requirements, simultaneous acceleration of two-charge states will be used for heavier ions (≥Xe). This paper presents the layout of the FRIB LEBT and the beam dynamics in the LEBT. In particular, simulation and design of the beam line section before charge state selection will be detailed. The need to use an achromatic design for the charge state selection system and the advantage of an ion beam collimation system to limit the emittance of the beam injected into the RFQ will be discussed in this paper. [ABSTRACT FROM AUTHOR]

A U.S./Russian collaboration of accelerator scientists was directed to the development of high averaged-current (∼1 mA) and high-quality (emittance ∼15 πmm mrad; energy spread ∼0.1%) 1.75 MeV proton beams to produce active interrogation beams that could be applied to counterterrorism. Several accelerator technologies were investigated. These included an electrostatic tandem accelerator of novel design, a compact cyclotron, and a storage ring with energy compensation and electron cooling. Production targets capable of withstanding the beam power levels were designed, fabricated, and tested. The cyclotron/storage-ring system was theoretically studied and computationally designed, and the electrostatic vacuum tandem accelerator at BINP was demonstrated for its potential in active interrogation of explosives and special nuclear materials. [ABSTRACT FROM AUTHOR]