共查询到20条相似文献,搜索用时 31 毫秒
1.
Yu. E. Titarenko V. F. Batyaev V. M. Zhivun V. O. Kudryashov K. A. Lipatov A. V. Ignatyuk S. G. Mashnik 《Pramana》2007,68(2):289-295
The work is aimed at experimental determination of the independent and cumulative yields of radioactive residual nuclei produced
in intermediate-energy proton-irradiated thin targets made of highly isotopic enriched and natural lead (206,207,208,natPb) and 209Bi. 5972 radioactive product nuclide yields have been measured in 55 thin targets induced by 0.04, 0.07, 0.10, 0.15, 0.25,
0.6, 0.8, 1.2, 1.4, 1.6 and 2.6 GeV protons extracted from the ITEP U-10 proton synchrotron. The measured data have been compared
with data obtained at other laboratories as well as with theoretical simulations by seven codes. We found that the predictive
power of the tested codes is different but is satisfactory for most of the nuclides in the spallation region, though none
of the codes agree well with the data in the whole mass region of product nuclides and all should be improved further.
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2.
B. M. Abramov P. N. Alexeev Yu. A. Borodin S. A. Bulychjov K. K. Gudima I. A. Dukhovskoy A. P. Krutenkova V. V. Kulikov M. A. Martemianov M. A. Matsyuk S. G. Mashnik E. N. Turdakina A. I. Khanov 《Physics of Atomic Nuclei》2016,79(5):700-707
The yields of long-lived nuclear fragments at an angle of 3.5° that originate fromthe fragmentation of carbon ions with an energy of T0 = 0.6 GeV per nucleon on a berylliumtarget were measured in the FRAGMexperiment at the ITEP TWA heavy-ion accelerator. The momentum spectra of these fragments cover both the fragmentation-maximum region and the cumulative region. The respective differential cross sections change by about five orders of magnitude. The momentum distributions of fragments in the laboratory frame and their kinetic-energy distributions in the rest frame of the fragmenting nucleus are used to test the predictions of four models of ion–ion interactions: BC, INCL++, LAQGSM03.03, and QMD. 相似文献
3.
A. P. Krutenkova O. Hashimoto T. Watanabe H. Noumi P. K. Saha D. Abe A. B. Kaidalov V. V. Kulikov T. Nagae M. Nakamura T. Takahashi H. Tamura Y. Fujii 《Physics of Atomic Nuclei》2005,68(3):466-470
The inclusive cross section for pion double charge exchange on 16O at T 0 = 0.5 and 0.75 GeV was measured with the superconducting kaon spectrometer (SKS) at KEK in a joint ITEP/KEK experiment. The result shows a relatively weak energy dependence of the measured cross section, which is in contradiction with its rapid drop predicted within the conventional model of two sequential single charge exchanges. The data of this experiment agree with the results that were obtained previously from similar measurements at ITEP and which are indicative of a significant contribution from the mechanism of inelastic Glauber rescatterings for T 0 ? 0.6 GeV. 相似文献
4.
A. Andrighetto C. M. Antonucci S. Cevolani C. Petrovich M. Santana Leitner 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):591-601
The target system is one of the key issues for the facilities aimed at the production of neutron-rich radioactive ion beams.
In the framework of the SPES project (Study for the Production of Exotic Species), the possibility of using a target configuration
with a proton beam (40MeV, 0.2mA) directly impinging on multiple uranium carbide disks is investigated. The 238U fission fragments constitute the source for the exotic beams and for this purpose the disks are placed inside a graphite
box at 2000 °C. The target is split into several thin disks in order to allow the cooling of the system by thermal radiation. In this way
about ∼ 1013 fissions s
-1 are obtained with a relative simple system and with relative low costs. Further steps have been performed compared to previous
publications and now all the main parameters of the system have been analysed by means of calculation codes: the fission rates
and the fission fragment distribution; the power deposition and the thermal analysis; the thermo-mechanical behaviours of
the disks; the effusive and diffusive extraction release properties of the target. 相似文献
5.
A. V. Davydov 《Physics of Particles and Nuclei》2012,43(2):187-203
Studying the gamma resonances of the long-lived nuclear isomers started at ITEP in the 1960s–1970s. The first experiments were conducted with silver isotopes. Its results did not contradict the existing theoretical ideas of large broadening of Mössbauer gamma lines via the interactions of nuclear magnetic moments. However, the data obtained in 11 experiments performed up until now with gamma sources made of silver metal doping by 109Cd showed that there is no large broadening of 109mAg Mössbauer gamma line with energy of 88.03 keV, that is the theoretically predicted gamma line broadening by ~105 times is absent. The instrument of quite a new type—“gravitational gamma spectrometer”, designed at ITEP, allowed one to determine the form of 109mAg gamma resonance, which proved to be ~108 times narrower than that of well known nuclide 57Fe. Some ideas are discussed as an attempt to explain this situation. 相似文献
6.
N. A. Demekhina G. S. Karapetyan S. M. Lukyanov Yu. E. Penionzhkevich N. K. Skobelev A. B. Yakushev 《Physics of Atomic Nuclei》2004,67(8):1417-1423
The absolute values of the cross sections for the production of target fragments in the interaction of copper with 7Li ions at an energy of 35 MeV per nucleon were measured. The measurements were performed by recording the yields of radioactive nuclear residues with the aid of a semiconductor detector from ultrapure germanium. The charge and isobaric distributions in the mass-number range 22–69 amu were used to deduce the mass yield of reaction products and to calculate the total interaction cross section. The results are presented that were derived from a comparison with data obtained for 12C + Cu reactions and with estimates based on theoretical models. 相似文献
7.
Nonperturbative theory is developed for the multiple ionization of fast heavy structure ions colliding with neutral complex atoms. The cross sections for multiple loss of electrons by structure uranium ions U10+ (loss of up to 82 electrons) and U28+ (loss of up to 64 electrons) colliding with argon atoms are calculated. The results are compared with available experimental data. 相似文献
8.
S. K. Sahoo 《Indian Journal of Physics》2009,83(6):787-797
Actinides have widely entered the environment as a result of nuclear accidents and atmospheric weapon testing. These radionuclides,
especially uranium, are outstanding radioactive pollutants, due to their high radiotoxicity and long half-lives. In addition
to this, since depleted uranium (DU) has been used in the Balkan conflict in 1999, there has been a concern about the possible
consequences of its use for the people and environment. Therefore, accurate, precise and simple determination methods are
necessary in order to evaluate the human dose and the concentration and effects of these nuclides in the environment. The
principal isotopes of uranium e.g.
235U and 238U are of primordial origin and 234U present in radioactive equilibrium with 238U. 236U occurs in nature at ultra trace concentrations with a 236U: 238U atom ratio of 10−14. Concentrations of uranium in soil samples were determined using inductively coupled plasma mass spectrometry (ICP-MS) and
isotope ratios of uranium were measured using a thermal ionisation mass spectrometer. Radioactive dis-equilibrium of 234/238U, depletion of 235/238U and significant evidence of 236U/238U were noticed in soil samples.
相似文献
9.
The aim of this work is to develop a short and cost-saving procedure for the determination of 241Am in sludge sample of the alkaline low-level radioactive waste (LL LRAW) collected from Nuclear Power Plant “Kozloduy”. The
determination of americium was a part of a complex analytical approach, where group actinide separation was achieved. An anion
exchange was used for separation of americium from uranium, plutonium and iron. For the separation of americium extraction
with diethylhexyl phosphoric acid (DEHPA) was studied. The final radioactive samples were prepared by micro co-precipitation
with NdF3, counted by alpha and gamma spectrometry. The procedure takes 2 hours. The recovery yield of the procedure amounts to (95
± 1.5)% and the detection limit is 53 mBq/kg 241Am (t=150 000 s). The analytical procedure was applied for actual liquid wastes and results were compared to standard procedure. 相似文献
10.
V. A. Belov E. V. Brakchman O. Ya. Zeldovich A. K. Karelin V. V. Kirichenko A. S. Kobyakin O. M. Kozodaeva A. V. Kuchenkov T. N. Tsvetkova 《Physics of Atomic Nuclei》2009,72(9):1421-1425
In the DEVIS tracking experiment that is being performed at the Institute of Theoretical and Experimental Physics (ITEP, Moscow,
Russia) and which is devoted to searches for 136Xe double-beta decay, the 222Rn concentration is measured in xenon samples with different content of the isotope 136Xe. The number of probable double-electron events from 214Bi decay mimicking the double-beta decay of 136Xe is estimated. 相似文献
11.
Yu. E. Titarenko V. F. Batyaev A. Yu. Titarenko M. A. Butko K. V. Pavlov S. N. Florya R. S. Tikhonov V. M. Zhivun A. V. Ignatyuk S. G. Mashnik S. Leray A. Boudard J. Cugnon D. Mancusi Y. Yariv K. Nishihara N. Matsuda H. Kumawat G. Mank W. Gudowski 《Physics of Atomic Nuclei》2011,74(4):573-579
The cross sections for the production of 148Gd in natW and 181Ta targets irradiated by 0.4-, 0.6-, 0.8-, 1.2-, 1.6-, and 2.6-GeV protons at the ITEP accelerator complex have been measured by direct α spectrometry without chemical separation. The experimental data have been compared with the data obtained at other laboratories and with the theoretical simulations of the yields on the basis of the BERTINI, ISABEL, CEM03.02, INCL4.2, INCL4.5, CASCADE07, and PHITS codes. 相似文献
12.
V. A. Belov E. V. Brakhman O. Ya. Zeldovich A. K. Karelin V. V. Kirichenko A. S. Kobyakin O. M. Kozodaeva A. V. Kuchenkov T. N. Tsvetkova 《Physics of Atomic Nuclei》2013,76(4):397-403
Measurement of the 214Po half-life with the DEVIS track setup at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) by means of a procedure based on determining lifetimes of individual nuclei is described. The value obtained for the 214Po half-life is 163.8 ± 3.0 µs. The possibility of reaching the accuracy of the measurements that is required for testing the statement that the decay of some nuclei has a nonexponential character and the source intensity necessary for this are discussed. 相似文献
13.
Laser ion source (LIS) is the only type of source capable of generating 10–30 mA beams of highly charged ions for the ITEP–TeraWatt (TWAC) accelerator/accumulator facility [B.Yu. Sharkov et al., Nucl. Instrum. Methods Phys. Res. A 415 20 (1998).]. The assembling stage of the new LIS based on 100 J/1 Hz master oscillator–power amplifier CO2-laser system [Yu. Satov, et al., J. Russ. Laser Res. 25(3) 205 (2004).] is in progress at ITEP now. In the first phase, the ion beam parameters (charge state distribution, current, pulse length and emittance) will be specified for different elements and target irradiation conditions. According to the planning, the new LIS and the new high-current injector [D. Kashinsky, et al., Proceedings of the Heavy Ion Fusion Conference, Moskow (2002).] will be used to deliver the beams of highly charged ions for the ITEP–TWAC accelerator/accumulator facility. 相似文献
14.
Krzysztof Kozak Jadwiga Mazur Janja Vaupotič Dominik Grządziel Ivan Kobal Khaled M.H. Omran 《Isotopes in environmental and health studies》2013,49(2):274-282
Natural radioactivity is one of the essential components of the environment. Unlike the Sudety mountains area in Poland, the Tatra Mountains were not the subject of wide survey as regards the levels of natural radioactivity. Especially, the concentrations of radon (natural radioactive gas) have not been investigated there in terms of their possible negative health impact. Within the frame of bilateral cooperation between the Institute of Nuclear Physics in Kraków, Poland, and the Jo?ef Stefan Institute in Ljubljana, Slovenia, the measurements of natural radioactive elements in old uranium mines in the Tatra National Park were performed in June 2010. The investigated sites were located in Dolina Bia?ego (The Valley of the White). One of the mines is situated near the tourist path. The paper presents the results of complex measurements of natural radioactivity in both uranium drifts. The concentration of radon gas inside the mining drifts exceeded 28,000 Bq m?3. Also, very high gamma dose rates were observed (up to 5600 nSv h?1). The maximum concentrations of natural radioactive elements (potassium 40K, radium 226Ra, thorium 232Th) in rock samples amounted to 535, 2137, and 18 Bq kg?1, respectively. The effective dose rates due to radon and thoron inhalation have been assessed as 0.013 mSv h?1 (for the lowest concentration) and 0.121 mSv h?1 (for the highest concentration). 相似文献
15.
T. Kühl S. Borneis St. Becker A. Dax T. Engel R. Grieser G. Huber I. Klaft O. Klepper A. Kohl D. Marx K. Meier R. Neumann F. Schmitt P. Seelig L. Völker 《Hyperfine Interactions》1996,99(1):145-153
Recently, intense beams of highly charged ions have become available at heavy ion cooler rings. The obstacle for producing these highly interesting candidates is the large binding energy of K-shell electrons in heavy systems in excess of 100 keV. One way to remove these electrons is to strip them off by passing the ion through material. In the cooler ring, the ions are cooled to a well defined velocity. At the SIS/ESR complex it is possible to produce, store, and cool highly charged ions up to bare uranium with intensities exceeding 108 atoms in the ring. This opens the door for precision laser spectroscopy of hydrogenlike-heavy ions, e.g.209Bi82+, and allows to examine the interaction of the single electron with the large fields of the heavy nucleus, exceeding any artificially produced electric and magnetic fields by orders of magnitude. In the electron cooler the interaction of electrons and highly charged ions otherwise only present in the hottest plasmas can be studied. 相似文献
16.
A. Ya. Rusanov M. G. Itkis N. A. Kondratiev I. V. Pokrovsky V. S. Salamatin G. G. Chubarian 《Physics of Atomic Nuclei》2007,70(10):1669-1678
Correlations between folding angular distributions of fission fragments and the gamma-ray multiplicity are studied for 18O + 208Pb interactions at energies of the beam of 18O ions in the range E lab = 78–198.5 MeV. The probabilities are determined for complete-and incomplete-fusion processes inevitably followed by the fission of nuclei formed in these processes. It is found that the probability of incomplete fusion followed by fission increases with increasing energy of bombarding ions. It is shown that, for the incomplete-fusion process, folding angular distributions of fission fragments have a two-component structure. The width of folding angular distributions (FWHM) for complete fusion grows linearly with increasing energy of 18O ions. The multiplicity of gamma rays from fission fragments as a function of the linear-momentum transfer behaves differently for different energies of projectile ions. This circumstance is explained here by the distinction between the average angular momenta of participant nuclei in the fusion and fission channels, which is due to the difference in the probabilities of fission in the cases where different numbers of nucleons are captured by the target nucleus. 相似文献
17.
I. G. Alekseev P. E. Budkovsky V. P. Kanavets L. I. Koroleva B. V. Morozov V. M. Nesterov V. V. Ryltsov D. N. Svirida A. D. Sulimov V. V. Zhurkin Yu. A. Beloglazov A. I. Kovalev S. P. Kruglov D. V. Novinsky V. A. Shchedrov V. V. Sumachev V. Yu. Trautman N. A. Bazhanov E. I. Bunyatova 《Physics of Atomic Nuclei》2002,65(2):220-228
New experimental data on the spin-rotation parameters A and R measured for elastic π ± p scattering in the resonance region and on the asymmetry in pC scattering at primary momenta in the range 1.35–2.02 GeV/c, as well as in quasielastic proton scattering on nuclei in the same momentum range, are summarized. All these data were recently obtained by using the proton synchrotron installed at the Institute of Theoretical and Experimental Physics (ITEP, Moscow). The spectrum and features of seven isospin-3/2 baryon resonances that form a peak in the total cross section at a c.m. energy of 1.9 GeV are analyzed on the basis of new data on the parameters A and R, and the results of this analysis are presented. The experiments surveyed in this article were performed by a collaboration of researchers from ITEP and the Petersburg Nuclear Physics Institute (PNPI, Gatchina), the ITEP-PNPI collaboration. 相似文献
18.
The results of observation and simulation of the superhyperfine (ligand hyperfine) structure (SHFS) of the electron paramagnetic resonance (EPR) spectra of rare-earth and uranium impurity ions in dielectric crystals have been systematized. The resolved SHFS of the EPR spectra of doped cubic crystals (with the fluorite and perovskite structures) has been observed for orientations of a constant magnetic field along the crystallographic axes. Most attention has been paid to tetragonal double fluorides LiRF4 (R = Y, Lu, Tm), in which the SHFS of the EPR spectra has also been found for intermediate orientations of the magnetic field. For the LiYF4: Nd3+ single crystal, the splitting of optical spectral lines due to the interaction of Nd3+ ions with nuclear magnetic moments of the nearest neighbor fluorine ions has been observed for the first time. The Van Vleck paramagnet LiTmF4: U3+ is characterized by the SHFS with clearly distinguishable components due to the interaction of uranium ions both with nuclei of the fluorine ions and with enhanced magnetic moments of the thulium nuclei. The SHFS envelopes of the EPR spectra of Yb3+, Ce3+, Nd3+, and U3+ ions in LiYF4 and LiLuF4 crystals are well reproduced by numerical calculations based on the microscopic model using only three fitting parameters: the width of transitions between the electron-nuclear sublevels of the complex containing the paramagnetic ion and nuclei of the ligands and two constants of covalent bonding of the f electrons with 2s and 2p electrons of the nearest neighbor fluorine ions. 相似文献
19.
N. N. Agapov A. V. Butenko V. I. Volkov A. V. Eliseev G. G. Khodzhibagiyan V. N. Karpinskii A. D. Kovalenko O. S. Kozlov I. N. Meshkov V. A. Mikhailov V. A. Monchinskii R. V. Pivin A. O. Sidorin A. V. Smirnov G. V. Trubnikov 《Physics of Particles and Nuclei Letters》2010,7(7):437-441
NICA is a new accelerator complex being constructed at the Joint Institute for Nuclear Research; the main task of this complex is to perform collider experiments for ion beams up to uranium with energies of up to 3.5 × 3.5 GeV/nucleon. This complex includes an electron string ion source, a 6 MeV/nucleon linear accelerator, a booster, the Nuclotron, and a collider with an average luminosity of 1027 cm2 s?1. The main tasks of the booster are to accumulate up to 4 × 109 197Au32+ ions, to accelerate to 600 MeV/nucleon (sufficient enough energy for completely stripping nuclei), to reduce the requirements of vacuum conditions for the Nuclotron, and to form the necessary beam emittance using an electron cooling system. The specific features of the NICA booster and the requirements for the basic systems of the synchrotron and their parameters are presented in this paper. 相似文献
20.
F. Ames P. Schmidt O. Forstner G. Bollen O. Engels D. Habs G. Huber 《Hyperfine Interactions》2001,132(1-4):465-468
The beam quality of radioactive ion beams produced by present target ion source technology is often not sufficient for direct
post-acceleration. Furthermore, pulsed beams insure a more efficient use of an accelerator. In the case of REX-ISOLDE, the
post accelerator at the CERN ISOLDE facility, a gas-filled Penning trap (REXTRAP) has been chosen for accumulation of the
radioactive ions and conversion into cooled bunches. Radial centering of the ions is achieved by applying an rf field with
a frequency equal to the cyclotron frequency of the desired ion species. The efficiency achieved in the first tests with different
isotopes covering nearly the entire mass range was already >20%. Going to total numbers of >105 stored ions in the trap a shift of the centering frequency could be observed, which is most likely due to space charge effects.
Despite this, it was possible to accumulate up to 107 ions and deliver them as cooled bunches.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献