[en] The annual report on 1998 of the Horia Hulubei National Institute for Physics and Nuclear Engineering, presents the Institute's activity in the fields of Theoretical Physics (Nuclear and Atomic Physics, Mathematical Physics, Field Theory, and Particle Physics, and Physics of Information), Experimental Physics (Nuclear Structure, Nuclear Reactions, Atomic Physics, Particle Physics, Cosmic Rays and Nuclear Astrophysics, Inertial Physics, Neutron Physics, and Nuclear Transmutations and Nuclear Instruments and Methods), Biophysics, Applied Physics, Radiation Processing, Tracers and Radiometry, Technological Development, Waste Management and Site Restoration, Standardization. Also, data concerning the Publications, Conferences, Patents, PhD Theses, Scientific Exchanges, Visitors, Invited Seminars, Visits and Seminars abroad are given in appendices. The Report gives also the Directorate, the Heads of Departments and the Research Staff

[en] This annual report of the Horia Hulubei National Institute for Physics and Nuclear Engineering on 1997 covers the following eight main directions: 1 - Theoretical Physics (42 p.); 2 - Experimental Physics (76 p.); 3 - Biophysics (8 p.); 4 - Applied Physics (40 p.); 5 - Radiation Processing, Tracers and Radiometry (16 p.); 6 - Technological Development (12 p.); 7 - Waste Management and Site Restoration (16 p.); 8 - Standardization (6 p.). The Theoretical Physics division contains four research fields: 1 - Nuclear and Atomic Physics; 2 - Condensed Matter: 3 - Mathematical Physics, Field Theory and Elementary Particles: 4 - Physics of Information. The Experimental Physics division is divided in the following seven directions: 1 - Nuclear Structure; 2 - Nuclear Reactions; 3 - Atomic Physics; 4 - Particle Physics; 5 - Cosmic Rays and Nuclear Astrophysics; 6 - Inertial Fusion, Physics of Neutrons and Nuclear Transmutations; 7 - Nuclear Instruments and Methods. The Waste Management and Site Restoration section is dealing with: 1 - Nuclear Reactors; 2 - Radioactive Waste Treatment Facility. The document contains also appendices reporting: Publications (journals, books and preprints); Contributions at international conferences; Patents; PhD Theses; Training courses; Scientific exchanges (foreign visitors, invited seminars, visits abroad, seminars abroad); Research Staff

[en] The annual report of the Horia Hulubei National Institute for Physics and Nuclear Engineering, IFIN-HH, on 1999 presents progress reports in the fields of Theoretical Physics (Nuclear and Atomic Physics (14 papers); Mathematical Physics, Field Theory and Elementary Particles (5 ); Physics of Information (6)), Nuclear Physics (Nuclear Structure (11), Nuclear Reactions (10), Atomic Physics (3), Cosmic Rays and Nuclear Astrophysics (3), Physics of Neutrons (2); Nuclear Instruments and Methods (11)), Particle Physics (7), Health and Environmental Physics (10), Applied Physics (21), Tracers, Radiopharmaceuticals and Radiometry (16), Technological Development (2), Waste management and Site Restoration (2) and Standardization (4). Appendices are added listing the publications in journals, monographs and as preprints, contributions to international conferences, PhD theses, and scientific exchanges (foreign visitors, invited seminars, visits abroad, seminars abroad). Finally the Institute scientific board and research staff are listed

[en] The annual report of the Horia Hulubei National Institute for Physics and Nuclear Engineering, IFIN-HH, on 2000 presents progress reports in the fields of Theoretical Physics (Nuclear and Atomic Physics (1 paper), Mathematical Physics, Field Theory and Elementary Particles (4 papers), Physics of Information (11 papers)), Nuclear Physics (Nuclear Structure (12 papers), Nuclear Reactions (11 papers), Applied Nuclear Physics (6 papers)), Atomic Physics (1 paper), Cosmic Rays and Nuclear Astrophysics (3 papers), Inertial Fusion, Physics of Neutrons and Nuclear Transmutations (3 papers), Nuclear Instruments and Methods (12 papers), Particle Physics (11 papers), Health and Environmental Physics (8 papers), Applied Physics (13 papers), Tracers, Radiopharmaceuticals and Radiometry (8 papers), Waste management and Site Restoration (1 paper) and Standardization (2 papers). Appendices are added listing the publications in journals, monographs and as preprints, contributions to international conferences, PhD theses, and scientific exchanges (foreign visitors, invited seminars, visits abroad, seminars abroad). Finally the Institute scientific board and research staff are listed

[en] The annual report of the Horia Hulubei National Institute for Physics and Nuclear Engineering - IFIN-HH on 2003-2004 presents progress reports in the fields of Theoretical Physics, Nuclear and Particle Physics, Health and Environmental Physics, Waste Management and Miscellaneous Applications. Appendices are added listing the publications in journals, books and preprints, PhD theses, participations in international conferences and scientific exchanges (foreign visitors, visits abroad, seminars abroad). Finally, the Institute research staff and author index are listed

[en] The annual report of the Horia Hulubei National Institute for Physics and Nuclear Engineering - IFIN-HH on 2001-2002 presents progress reports in the fields of Theoretical Physics (Nuclear, Atomic and Molecular Physics, Mathematical Physics, Field Theory and Elementary Particles, Computational Physics (Physics of Information) and Solid State Physics), Nuclear Physics (Nuclear Structure, Nuclear Reaction, Atomic Physics, Cosmic Rays and Nuclear Astrophysics, Inertial Fusion, Physics of Neutrons and Nuclear Transmutation, Nuclear Instruments and Methods), Particle Physics, Health and Environmental Physics, Applied Physics, Tracers, Radiopharmaceuticals and Radiometry, Waste Management and Site Restoration and Standardization. Appendices are added listing the publications in journals, books and preprints, participations in international conferences and scientific exchanges (foreign visitors, visits abroad, seminars abroad). Finally, the Institute directorate and research staff are listed

[en] Full text: In the framework of the Lindblad theory for open quantum systems, a master equation for the quantum harmonic oscillator interacting with a dissipative environment, in particular with a thermal bath, is derived for the case when the interaction is based on deformed algebra. The equations of motion for observables strongly depend on the deformation function. The expectation values of the number operator and squared number operator are calculated in the limit of a small deformation parameter for the case of zero temperature of the thermal bath. The steady state solution of the equation for the density matrix in the number representation is obtained and its independence of the deformation is shown. (author)

[en] Full text: Thin Layer Activation (TLA) and Ultra Thin Layer Activation (UTLA) methods are frequently used to follow real time wear, corrosion and/or erosion of different surfaces, engine parts, mechanical constructions, structural material, surface loss of sculptures, etc. The principle of these nondestructive techniques involves activation/incorporation of a suitable radionuclide over a certain thickness of the sample part followed by continuous measurement of the radioactivity of the radionuclide during the wear, corrosion and/or erosion process. The material removed from the surface by wear, corrosion or erosion process should be separated from the remaining bulk activity completely in order to be able to measure the change of the activity. A calibration curve between the thickness of the layer removed and the residual activity is generated before the investigation. The paper describes the general features of these methods and applications on biomaterials, and presents also the conclusions of the exchanged experience with partners from JRC IHCP Ispra Italy and CNRS-CERI Orleans France. (author)

[en] Full text: The research activities performed by the Department of Radioactive Waste Management is focused on the LLAW treatment products obtained by chemical precipitation and on the conditioning of these products by cementation. The individual mechanisms involved in the chemical precipitation process are directly dependent on the precipitate properties and structure, which are connected with the initial system composition and the precipitation procedure, i.e. reagent concentration, rate and orders of chemical addition, mixing rate and time and ageing conditions. In the case of conditioning by cementation, the chemical nature and proportion of the sludges or concentrates affect both the hydrolysis of the initial cement components and the reactions of metastable hydration constituents, as well as the mechanical strength and chemical resistance of the hardened cemented matrix. Generally, the study of the precipitation products and their behaviour during cementation and the long-term disposal is extremely difficult because of the system complexity (phase composition and structure) and the lack of non-destructive analytical methods. The experience accumulated by the countries who developed nuclear programs in military and socioeconomic fields and which produced important volumes of radioactive wastes, lead us to study some of mineral additives to be used in the conditioning and disposal technology. It is well known that mineral additives are diminishing the leaching rate of the radionuclides in the disposal environment. The studies have the purpose to obtain the most propitious mixture of cement-bentonite and cement-volcanic tuff which have the mechanical properties similar to the cement paste used for the conditioning of radioactive waste. Taking into consideration the characteristics of these mineral binders, namely a very good plasticity and capacity of adsorption, which lead to the decrease of porosity, in the future, the mixture is planned to be used at the Radioactive Waste Treatment Plant - NIPNE-HH - Bucharest, Magurele for the conditioning of the radioactive waste. (author)

[en] Full text: The basis of PET consists in administration of a radioactive isotope attached to a tracer that permits to reveal its molecular pathways in a human body. A 3-D Whole-Body-Scan is desired in order to minimize the radiation exposure of the patient and to increase the axial field of view (FOV). A major candidate for gamma pair detection in 3-D Complete- Body-Scan are the RPCs (Resistive Plate Counters). They consist in a longitudinal microstrip grid 1.5 mm thick, spaced at 1 mm; the grid is placed between a large electric resistive glass anode (ρ =10¹² Ω cm) and an aluminium cathode; the gap, around 300 μm is filled with a special gas and is polarized at around 6 kV. Several detecting structures based on Resistive Plate Counters (RPCs) are evaluated for the use in a positron emission 3-D Whole-Body-Scan tomograph. The coincidence matrix is built for the specific detecting structure by means of random gamma pair ray generation, and then the filtered backprojection algorithm is used to reconstruct the original picture. The accuracy of image reconstruction is examined for the four different detecting structures. (author)