209 research outputs found
Investigation of the reaction Ni-64+U-238 being an option of synthesizing element 120
No full textThis study is concerned with the search for entrance channels suitable to synthesize elements with Z > 118. Mass-energy distributions as well as capture cross-sections of fission-like fragments have been measured for the reactions (64)Ni+ (238)U -> (302)U ->(302)120 and (48)Ca + (238)U -> (286)112 at energies near the Coulomb barrier. Compound nucleus fission cross-sections were estimated from the analysis of mass and total kinetic energy distributions. The cross-section drops three orders of magnitude for the formation of the compound nucleus with Z = 120 obtained in the reaction (64)Ni + (238)U compared to the formation of the compound nucleus with Z = 112 obtained in the reaction (48)Ca + (238)U at an excitation energy of the compound nucleus of about 45 MeV. From our analysis it turns out that the reaction (64)Ni + (238)U is not suitable for the synthesis of element Z = 120
Signatures of large extra dimensions
No full textString theory suggests modifications of our spacetime such as extra dimensions and the existence of a mininal length scale. In models with addidional dimensions, the Planck scale can be lowered to values accessible by future colliders. Effective theories which extend beyond the standart-model by including extra dimensions and a minimal length allow computation of observables and can be used to make testable predictions. Expected effects that arise within these models are the production of gravitons and black holes. Furthermore, the Planck-length is a lower bound to the possible resolution of spacetime which might be reached soon
Physics of Atomic Nuclei V. 66, I. 06
No full textPhysics of Atomic Nuclei -- June 2003
Volume 66, Issue 6, pp. 1009-1210
Exotic Nuclei: From Superheavies to Hyper- and Antimatter
W. Greiner
pp. 1009-1014 Full Text: PDF (294 kB)
Calculated Masses of Heaviest Nuclei
I. Muntian, Z. Patyk, and A. Sobiczewski
pp. 1015-1019 Full Text: PDF (173 kB)
The Study of Superheavy Elements at SHIP: Results and Plans
S. Hofmann
pp. 1020-1025 Full Text: PDF (147 kB)
An Idea for Predicting the Evaporation Residue Cross Section in Superheavy Mass Region
M. Ohta and Y. Aritomo
pp. 1026-1032 Full Text: PDF (248 kB)
Fusion–Fission Dynamics and Perspectives of Future Experiments
V. I. Zagrebaev, M. G. Itkis, and Yu. Ts. Oganessian
pp. 1033-1041 Full Text: PDF (1008 kB)
The Upgrade of the Kinematic Separator VASSILISSA—Experimental Results and Plans
A. V. Yeremin, A. V. Belozerov, M. L. Chelnokov, V. I. Chepigin, V. A. Gorshkov, A. P. Kabachenko, O. N. Malyshev, Yu. Ts. Oganessian, A. G. Popeko, R. N. Sagaidak, A. I. Svirikhin, S. Hofmann, G. Berek, I. Brida, and S. Saro
pp. 1042-1052 Full Text: PDF (302 kB)
Effect of Nuclear Shell Structure on Fusion Reaction
H. Ikezoe, K. Satou, S. Mitsuoka, K. Nishio, and S. C. Jeong
pp. 1053-1056 Full Text: PDF (173 kB)
Theory of Fusion for Superheavy Elements
Y. Abe, C. W. Shen, G. I. Kosenko, and D. Boilley
pp. 1057-1064 Full Text: PDF (243 kB)
The Mechanism of Compound Nucleus Formation in Complete Fusion of Two Massive Nuclei
V. V. Volkov
pp. 1065-1070 Full Text: PDF (262 kB)
Synthesis of Heavy and Superheavy Elements by Reactions of Massive Nuclei
G. Fazio, G. Giardina, A. Lamberto, R. Ruggeri, F. Bonsignore, R. Palamara, A. I. Muminov, A. K. Nasirov, B. Benoit, F. Hanappe, T. Materna, and L. Stuttgé
pp. 1071-1085 Full Text: PDF (342 kB)
Competition of Fusion and Quasifission in the Reactions Leading to Production of Superheavy Elements
M. Veselsky
pp. 1086-1094 Full Text: PDF (229 kB)
Cold Valleys of Superheavy Elements with Deformed Targets and Projectiles
S. Misicu and W. Greiner
pp. 1095-1104 Full Text: PDF (886 kB)
Analysis of Fusion–Fission Process with Neutron Evaporation in Superheavy Mass Region
Y. Aritomo and M. Ohta
pp. 1105-1113 Full Text: PDF (402 kB)
Reaction Dynamics at the Barrier for Heavy Compound Systems
D. Ackermann
pp. 1114-1117 Full Text: PDF (151 kB)
Fusion–Fission of Heavy and Superheavy Nuclei
M. G. Itkis, S. Beghini, A. A. Bogatchev, L. Corradi, O. Dorvaux, A. Gadea, G. Giardina, A. A. Goverdovski, F. Hanappe, I. M. Itkis, M. Jandel, J. Kliman, G. N. Kniajeva, N. A. Kondratiev, I. V. Korzyukov, E. M. Kozulin, L. Krupa, L. Latina, T. Materna, G. Montagnoli, K. J. Moody, Yu. Ts. Oganessian, I. V. Pokrovsky, V. A. Ponomarenko, E. V. Prokhorova, N. Rowley, A. Ya. Rusanov, F. Scarlassara, A. M. Stefanini, L. Stuttgé, S. Szilner, M. Trotta, A. M. Vinodkumar, and V. M. Voskressensky
pp. 1118-1124 Full Text: PDF (1520 kB)
Accuracy of the Chemical Data Evaluated from One-Atom-at-a-Time Experiments
I. Zvára
pp. 1125-1130 Full Text: PDF (174 kB)
Heavy Element Nuclear Chemistry at JAERI
Y. Nagame, M. Asai, H. Haba, K. Tsukada, I. Nishinaka, S. Goto, A. Toyoshima, K. Akiyama, M. Sakama, Y. L. Zhao, S. Ichikawa, and H. Nakahara
pp. 1131-1136 Full Text: PDF (202 kB)
New Outlook on the Possible Existence of Superheavy Elements in Nature
A. Marinov, S. Gelberg, D. Kolb, R. Brandt, and A. Pape
pp. 1137-1145 Full Text: PDF (246 kB)
Perspective for the Determination of Chemical Properties of Element 112
R. Eichler et al. (for a PSI–University Bern–GSI–TU Munich–FLNR–University Mainz–IMP Collaboration)
pp. 1146-1151 Full Text: PDF (236 kB)
Accuracy and Efficiency of Modern Methods for Electronic Structure Calculation on Heavy- and Superheavy-Element Compounds
A. V. Titov, N. S. Mosyagin, T. A. Isaev, and A. N. Petrov
pp. 1152-1162 Full Text: PDF (223 kB)
Probing Fission Time Scales with Neutrons and GDR Gamma Rays
R. P. Schmitt, T. Botting, G. G. Chubarian, K. L. Wolf, B. J. Hurst, H. Jabs, M. Hamelin, A. Bacak, Yu. Ts. Oganessian, M. G. Itkis, E. M. Kozulin, N. A. Kondratiev, V. S. Salamatin, I. V. Pokrovsky, F. Hanappe, E. de Goès Brennand, A. Huck, L. Stuttgé, E. Liatard, J. Beene, R. Varner, M. Halbert, and N. Gan
pp. 1163-1167 Full Text: PDF (238 kB)
Tracking Dissipation in Capture Reactions
T. Materna, C. Schmitt, Y. Aritomo, J. Bartel, B. Benoit, A. A. Bogatchev, E. de Goès Brennand, O. Dorvaux, G. Giardina, F. Hanappe, M. G. Itkis, I. M. Itkis, J. Kliman, G. N. Kniajeva, N. A. Kondratiev, E. M. Kozulin, L. Krupa, Yu. Ts. Oganessian, I. V. Pokrovsky, E. V. Prokhorova, N. Rowley, K. Siwek-Wilczynska, and L. Stuttgé
pp. 1168-1172 Full Text: PDF (195 kB)
The Complex Trajectory Method and Dissipation in Fission
F. F. Karpeshin
pp. 1173-1177 Full Text: PDF (137 kB)
Fission Paths in Fm Region Calculated with the Gogny Forces
M. Warda, J. L. Egido, L. M. Robledo, and K. Pomorski
pp. 1178-1181 Full Text: PDF (148 kB)
Fission Dynamics with the 4pi Detector 8piLP
E. Vardaci, A. Brondi, G. La Rana, R. Moro, A. Ordine, A. Boiano, M. A. DiMeo, A. Scherillo, D. Fabris, M. Lunardon, G. Nebbia, G. Viesti, M. Cinausero, E. Fioretto, G. Prete, N. Gelli, and F. Lucarelli
pp. 1182-1189 Full Text: PDF (307 kB)
Isotopic Invariance of Fission Fragment Charge Distributions for Actinide Nuclei at Excitation Energies above 10 MeV
D. M. Gorodisskiy, S. I. Mulgin, A. Ya. Rusanov, and S. V. Zhdanov
pp. 1190-1197 Full Text: PDF (315 kB)
The Effect of the Entrance Channel on the Fission of 216Ra
I. V. Pokrovsky, A. Yu. Chizhov, M. G. Itkis, I. M. Itkis, G. N. Kniajeva, E. M. Kozulin, N. A. Kondratiev, R. N. Sagaidak, V. M. Voskressensky, L. Corradi, A. M. Stefanini, M. Trotta, A. M. Vinodkumar, S. Beghini, G. Montagnoli, F. Scarlassara, A. Ya. Rusanov, F. Hanappe, O. Dorvaux, N. Rowley, and L. Stuttgé
pp. 1198-1202 Full Text: PDF (225 kB)
Reduction Coefficient in Surface-Plus-Window Dissipation: Analysis of Experimental Data From Fusion–Fission Reactions within a Stochastic Approach
P. N. Nadtochy, A. V. Karpov, D. V. Vanin, and G. D. Adeev
pp. 1203-1210 Full Text: PDF (212 kB)Archived web conten
Asymmetric and symmetric fission of excited nuclei of Hg 180,190 and Pb 184,192,202 formed in the reactions with Ar 36 and Ca 40,48 ions
No full textBackground: Observation of asymmetric fission of Hg180 has led to intensive theoretical and experimental studies of fission of neutron-deficient nuclei in the lead region. Purpose: The study of asymmetric and symmetric fission modes of Hg180,190 and Pb184,192,202 nuclei. Methods: Mass-energy distributions of fission fragments of Hg180,190 and Pb184 formed in the Ar36+Sm144,154 and Ca40+Sm144 reactions, respectively, at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET and compared with previously measured Pb192,202 isotopes produced in the Ca48+Sm144,154 reactions. The mass distributions for Hg180,190 and Pb184,192,202 together with old data for Ir187, Au195, Hg198, Tl201, Bi205,207, Po210, and At213 [J. Nucl. Phys. 53, 1225 (1991)] have been decomposed into symmetric and asymmetric fission modes. The total kinetic-energy distributions for different fission fragment mass regions have been analyzed for Hg180,190 and Pb184. Results: The stabilization role of proton numbers at Z≈36, 38, Z≈45, 46, and Z=28/50 in asymmetric fission of excited preactinide nuclei has been observed. The high (≈145-MeV) and the low (≈128-MeV) energy components have been found in the total kinetic-energy distributions of Hg180,190 fission fragments corresponding to the fragments with proton numbers near Z≈46 and Z≈36, respectively. In the case of fission of Pb184 only the low-energy component (≈135MeV) for the fragments with masses corresponding to the proton numbers Z≈36 and 46 has been found. Conclusions: The studied properties of asymmetric fission of Hg180,190 and Pb184,192,202 nuclei point out the existence of well deformed proton shell at Z≈36 and less deformed proton shell at Z≈46
The fusion-fission process in the reaction 34S+186W near the interaction barrier
No full textThe reaction S-34 + W-186 at E-lab=160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The coupling of the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fission process and gives information regarding production of neutron-rich heavy nuclei. The FF-gamma coincidence method is of better use then the gamma - gamma coincidence method when dealing with low statistic measurements and also offers the opportunity to precisely correct the Dopler shift for in-flight emitted gamma rays.
Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. Coincident measurements allow for discrimination between the gamma rays by accepting a specific range within the mass distribution of the reaction products. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented
Shell effects in Fusion-Fission of heavy and superheavy nuclei
No full textThe process of fusion-fission of heavy and superheavy nuclei (SHE) with Z=82−122 formed in the reactions with 48Ca and 58Fe ions at energies near and below the Coulomb barrier has been studied. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR) and at the XTU Tandem accelerator of the National Laboratory of Legnaro (LNL) using the time-of-flight spectrometer of fission fragments CORSET and the neutron multi-detector DEMON. As a result of the experiments, mass and energy distributions (MED) of fission fragments, fission, quasi-fission and evaporation residues cross sections, multiplicities of neutrons and γ quanta and their dependence on the mechanism of formation and decay of compound systems have been studied
INVESTIGATION OF NEUTRON-RICH OSMIUM ISOTOPES IN THE REACTION (XE)-X-136+(PB)-P-208 AT THE ENERGIES CLOSE TO COULOMB BARRIER
No full textOn the Tightness of Forward-Secure Signature Reductions
No full textIn this paper, we revisit the security of factoring-based signature schemes built via the Fiat-Shamir transform and show that they can admit tighter reductions to certain decisional complexity assumptions such as the quadratic-residuosity, the high-residuosity, and the ϕϕ-hiding assumptions. We do so by proving that the underlying identification schemes used in these schemes are a particular case of the lossy identification notion recently introduced by Abdalla et al. at Eurocrypt 2012. Next, we show how to extend these results to the forward-security setting based on ideas from the Itkis-Reyzin forward-secure signature scheme. Unlike the original Itkis-Reyzin scheme, our construction can be instantiated under different decisional complexity assumptions and has a much tighter security reduction. Moreover, we also show that the tighter security reductions provided by our proof methodology can result in concrete efficiency gains in practice, both in the standard and forward-security setting, as long as the use of stronger security assumptions is deemed acceptable. Finally, we investigate the design of forward-secure signature schemes whose security reductions are fully tight
On the Tightness of Forward-Secure Signature Reductions
No full textIn this paper, we revisit the security of factoring-based signature schemes built via the Fiat-Shamir transform and show that they can admit tighter reductions to certain decisional complexity assumptions such as the quadratic-residuosity, the high-residuosity, and the ϕϕ-hiding assumptions. We do so by proving that the underlying identification schemes used in these schemes are a particular case of the lossy identification notion recently introduced by Abdalla et al. at Eurocrypt 2012. Next, we show how to extend these results to the forward-security setting based on ideas from the Itkis-Reyzin forward-secure signature scheme. Unlike the original Itkis-Reyzin scheme, our construction can be instantiated under different decisional complexity assumptions and has a much tighter security reduction. Moreover, we also show that the tighter security reductions provided by our proof methodology can result in concrete efficiency gains in practice, both in the standard and forward-security setting, as long as the use of stronger security assumptions is deemed acceptable. Finally, we investigate the design of forward-secure signature schemes whose security reductions are fully tight
Changes of MPO Activity and Brain Water Accumulation in Traumatic Brain Injury Experiments
No full text- …
