An accelerator laboratory is presently under construction in Sofia at the Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences. The laboratory will use a TR24 type of ...cyclotron, which provides a possibility to accelerate a proton beam with an energy of 15 to 24 MeV and current of up to 0.4 mA. An accelerator with such parameters allows to produce a large variety of radioisotopes for development of radiopharmaceuticals. The most common radioisotopes that could be produced with such a cyclotron are PET isotopes like: 11C, 13N, 15O, 18F, 124I, 64Cu, 68Ge 68Ga, and SPECT isotopes like: 123I, 111In, 67Ga, 57Co, 99mTc. Our aim is to use the cyclotron facility for research in the fields of radiopharmacy, radiochemistry, radiobiology, nuclear physics, solid state physics, applied research, new materials and for education in all these fields including nuclear energy. The building of the laboratory will be constructed nearby the Institute for Nuclear Research and Nuclear Energy and the cyclotron together with all the equipment needed will be installed there.
The development and the optimisation of negative hydrogen/deuterium ion sources goes hand in hand with modelling. In this paper a brief introduction on the physics and types of different sources, and ...on the Kinetic and Fluid theories for plasma description is made. Examples of some recent models are considered whereas the main emphasis is on the model behind the concept and design of a matrix source of negative hydrogen ions. At the Institute for Nuclear Research and Nuclear Energy of the Bulgarian Academy of Sciences a new cyclotron center is under construction which opens new opportunities for research. One of them is the development of plasma sources for additional proton beam acceleration. We have applied the modelling technique implemented in the aforementioned model of the matrix source to a microwave plasma source exemplifying a plasma filled array of cavities made of a dielectric material with high permittivity. Preliminary results for the distribution of the plasma parameters and the φ component of the electric field in the plasma are obtained.
The Institute for Nuclear Research and Nuclear Energy is preparing to operate a high-power cyclotron for production of radioisotopes for nuclear medicine, research in radiochemistry, radiobiology, ...nuclear physics, solid state physics. The cyclotron is a TR24 produced by ASCI, Canada, capable to deliver proton beams in the energy range of 15 to 24 MeV with current as high as 400 µA. Multiple extraction lines can be fed. The primary goal of the project is the production of PET and SPECT isotopes as 18F, 67,68Ga, 99mTc, etc. This contribution reports the status of the project. Design considerations for the cyclotron vault will be discussed for some of the target radioisotopes.
The Institute for Nuclear Research and Nuclear Energy at the Bulgarian Academy of Sciences is building an accelerator laboratory to operate a TR-24 cyclotron. Thus, a preliminary radiation shielding ...analysis of the accelerator bunker is required. For this purpose Monte-Carlo simulations have been performed and dosimetric (Dose equivalent) quantities have been estimated in two model geometries - simplified spherical geometry and full-scale bunker, respectively during operation and after the end of the cyclotron life. Our current efforts are directed to the production of 18F thus in all the conducted simulations a water target enriched with 18O is considered. NiGa3 as a target for production of 68Ge has also been simulated and a comparison of the radiation shielding characteristics of the bunker for the two targets has been made.
Nuclear structure studies in mirror nuclei Tonev, D.; de Angelis, G.; Deloncle, I. ...
Journal of physics. Conference series,
03/2023, Letnik:
2453, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Abstract
The nuclear structure of the A=31 and A=47 mirror couples produced by two fusion evaporation reactions has been elaborated, utilizing the Doppler-shift attenuation method. Excited states in
...31
P and
31
S were populated using the 1p and 1n exit channels, respectively, of the reaction
20
Ne +
12
C, while in
47
Cr and
47
V couple excited states were populated based on
28
Si +
28
Si reaction, as products of 2αn and 2αp exit channels. The A=31 mirror couple was studied utilizing Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro with GASP multidetector array and for A=47 one - with the EUROBALL array using XTU Tandem also in Legnaro. In both cases the lifetime measurements in mirror couples at the same experiment open possibilities for investigations of isospin symmetry. Determined B(E1) strengths in the mirror nuclei
31
P and
31
S allow to extract the isoscalar component, which can reach up to 24% of the isovector one. The B(E1) values can be modeled by the Equation of motion method. In the case of A=47 mirror couple, the quadrupole moments can be described by shell-model calculations.
Excited states in the mirror nuclei 31P and 31S were populated in the 1p and 1n exit channels of the reaction 20Ne + 12C, at a beam energy of 33 MeV. The 20Ne beam was delivered for the first time by ...the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. Angular correlations of coincident γ-rays and Doppler-shift attenuation lifetime measurements were performed using the multi-detector array GASP in conjunction with the EUCLIDES charged particle detector. In the observed B(E1) strengths, the isoscalar component, amounting to 24% of the isovector one, provides strong evidence for breaking of the isospin symmetry in the A=31 mass region. Self-consistent beyond mean field calculations using Equation of Motion method based on a chiral potential and including two- and three-body forces reproduce well the experimental B(E1) strengths, reinforcing our conclusion. Coherent mixing from higher-lying states involving the Giant Isovector Monopole Resonance accounts well for the effect observed. The breaking of the isospin symmetry originates from the violation of the charge symmetry of the two- and three-body parts of the potential, only related to the Coulomb interaction.
In this study, we used PVD deposition of TiN/TiO2 coatings on polished and electron-beam-treated Ti6Al4V alloy to explore the changes in the surface roughness and mechanical properties of the coated ...systems. After the electron-beam treatment (EBT), the average surface hardness and roughness (Ra) increased from 323±5.62 HV0.2 and 0.14±0.004 μm up to 387.5±9.33 HV0.2 and 1.58±0.05 μm, respectively. After coating with 3.7-μm thick TiN/TiO2, the average Sa roughness and nanohardness of the film on the polished substrate reached 0.87±0.1 μm and 13.05±2.07 GPa while that on the EBT was equal to 1.57±0.2 μm and 9.02±2.15 GPa, respectively. However, the comparison of the coefficient of friction (COF) evolution of the substrates and the coated specimens indicated a COF decrease by about 0.18±0.03 for the coated EBT alloy as compared with the polished and EBT substrates, whose average COF were 0.45±0.04 and 0.38±0.06, respectively. A high average COF (0.68±0.16) was registered for the coated as-received alloy because of the gradual and complete wearing off of the film during the test. These results indicate that the combination of initial EBT of the Ti6Al4V alloy with PVD deposition of a TiN/TiO2 coating could substantially improve the roughness and tribological properties of the coated systems.
This report describes a series of experiments aimed on investigating characteristics of spontaneous fission of nuclei in the exotic region of short-lived neutron-deficient isotopes with Z ≥ 100. ...Unique data on the decay properties of neutron-deficient isotopes 244,246Fm, 250No, 252No, 254Rf and 256Rf produced in the complete fusion reactions with accelerated heavy ions 40Ar + 206,208Pb → 246,248Fm*, 48Ca + 204,206Pb → 252,254No*, 50Ti + 206,208Pb →256,258Rf* were obtained in experiments at the VASSILISSA (SHELS) separator combined with a neutron detector.
We present the cyclotron project of the Institute for Nuclear Research and Nuclear Energy which aims to centralize national the production of radioisotopes and radiopharmaceuticals and to provide ...opportunities for interdisciplinary research and education in the fields of Physics, Chemistry, Biology and Nuclear Energy. The human resources needed for the successful operation of the production program of the centre are also described in this article. An account of the ongoing research related to the radiation protection and radiation shielding of the cyclotron is made.
A new version of the differential decay curve method is proposed for the analysis of Doppler-shift attenuation lifetime measurements. The lifetime is derived directly from the line shapes of the ...depopulating and feeding transitions on the basis of the Blaugrund approximation without including any assumptions or fitting of the time dependence of the population of the corresponding levels. For specific simulated cases, the method shows promise for its applicability. In the future, we intend to generalize the method for the case of an arbitrary multi-detector setup.
PDF
