Status of Work on the VÉPP-5 Injection Complex

The VÉPP-5 injection complex under construction at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences is a powerful source of intense electron and positron bunches at 510 MeV, which covers all needs of the electron–positron colliding beam setups currently operating and under construction at the Institute of Nuclear Physics. The complex includes a 285 MeV linear electron accelerator, a 510 MeV linear positron accelerator, and an accumulator–cooler with beam injection and ejection channels. Intense work on the design, assembly, and tuning of the linear electron accelerator has been conducted in the last 2 yr. As a result, by August 2002 the linear electron accelerator was put into operation with all standard subsystems. By this time, the isochronous achromatic turning of the electron beam, a system for converting electrons into positrons, and the first accelerating structure of the linear positron accelerator were assembled and put into operation. All this made it possible to accelerate the positron beam up to 75 MeV. Preliminary results of tests of the linear accelerators are presented.     

Potential of the uranium atom and calculation of the ionization energy

The potential of the uranium atom and ions are calculated on the statistical model, allowing for exchange interaction and electron correlation. It is demonstrated that due allowance for electron correlation is essential in calculating the integral atomic characteristics. The ionization energies I₁, I₂, I₃ are calculated from the curves obtained for the atomic and ionic potentials. Theoretical results are compared with experiment.Translated from Atomnaya Énergiya, Vol. 22, No. 2, pp. 83–85, February, 1967.     

Some characteristics of radiolysis under the influence of a pulsed beam of fast electrons

The purpose of this paper is to study the main characteristics of radiolysis associated with the use of electron pulse accelerators. On the basis of a typical mechanism of the chemical reactions of free radicals formed under the influence of a pulsed fast electron beam, the mean stationary concentration of free radicals [R]_st is calculated as a function of the duty factor q of the electron current pulses. The calculation is carried out for various powers, corresponding to various rates of formation of the free radicals, various current pulse widths, and various free radical loss constants for reactions of the first and second orders. Graphs of [R]_st as a function of q are presented.Translated from Atomnaya Énergiya, Vol. 17, No. 5, pp. 393–400, November, 1964     

One and two electron transitions in energetic ion and helium collisions

The single ionization (SI) and double ionization (DI), single and double ionization accompanying one electron loss (SS) of the projectile and the single and double electron capture of the projectile from target atom are investigated for 2.0–8.0 MeV Na^q+–He and C1^q+–He collisions. The cross-section ratio of the double ionization (DI) to that of the SI, the ratio of SS+DI to SS+SI, and ratio of double capture (DC) cross-section to that of single capture (SC), are measured by means of time-of-flight technique. The velocity and charge state dependences of the measured cross-section ratios are studied and discussed. The obtained capture cross-section ratios are compared with the theoretical calculations using the classical over-barrier model.     

Rectification Decontamination of Tritium-Containing Waters

The results of experimental investigations of the main rectification processes for removing tritium from reactor, process, and waste waters are presented. The separation coefficients are presented for rectification of water (1.028), ammonia (1.05), the azeotrope H₂O–HTO–HNO₃ (1.098), and D₂O–DTO–DNO₃ (1.039). Practical schemes for detritization setups are examined.     

Apparatus for studying the motion of particles in accelerators

The construction and operating principles of an analog apparatus facilitating the simulation of a large number of problems linked with the operation of accelerators are described. The apparatus consists of an electron tube with electrodes of special form and suitable attachments. An electron cloud formed in the tube simulates a beam of particles moving in the accelerator.Translated from Atomnaya Énergiya, Vol. 17, No. 2, pp. 88–93, August, 1964     

System for Nondestructive Inspection of Large Objects in Machine Engineering

A nondestructive inspection system based on two new linear accelerators UÉLV-15-2D-100 with nominal energy 15 MeV and bremsstrahlung dose rate up to 120 Gy/min 1 m from the target has been developed and built. This system will be used for transillumination of thick objects using the radiographic and introscopic methods. Combining two systems – radiographic and introscopic – into a single system has made it possible to obtain results much more quickly. Fourth-generation accelerators have yielded unique results at 1-1T ASTM resolution in a wide range of object thicknesses.     

Laser-induced separation of isotopes

Conclusion In the last 10–15 years of intensive research on basically new approaches to isotope separation by isotope-selective excitation of atoms and molecules of the required isotope composition and by subsequent photophysical or photochemical conversion of the excited particles, there have been found new specific techniques which provide all the parameters required for the elementary separation event: separation coefficients, energy consumption, yield of the process, etc. The broad spectrum of these new techniques in principle even now makes it possible to reliably plan a laser technique for the isotope separation of almost any element of the periodic system. A successfully concluded stage of search investigations has led to a stage of developing complete laser separation processes, establishing similarity laws, and building pilot plants for isotopes to which the new techniques are indicated for economic reasons or other reasons. Interest is focused now upon the additional requirements, namely the cost of the initial raw materials, the consumption of energy for preparing the material to be irradiated in the required state (chemical compounds of specific type, state of aggregation of the material), the efficiency and safety of the chemical treatment of the enriched material, the capital expenditures for building the lasers needed, the reliability of their operation, etc. The laser-induced isotope separation techniques described make use of three different types of lasers with a high pulse repetition frequency; these lasers can be termed the laser basis for the corresponding separation techniques: dye lasers of the visible range, UV excimer lasers, and IR CO₂ lasers in combination with various frequency conversion techniques. To the extent to which these laser types can be converted into highly reliable systems with an average power in excess of 1 kW, the time of the industrial use of the laser-induced isotope separation techniques described is approached.Translated from Atomnaya Énergiya, Vol. 62, No. 4, pp. 252–262, April, 1987.     

Distribution of specific ionization along a track as a function of the initial energy of U235 fission fragments

By means of a telescope consisting of 11 pulse ionization chambers and a two-dimensional pulse height analyzer, measurements were made of the distribution of specific ionization energy loss along a track as a function of the initial energy of fission fragments. Studies were made of U²³⁵ fission fragments produced by thermal neutrons in the initial energy ranges 78–115.5 MeV (light fragments) and 34–88 MeV (heavy fragments). The data obtained made it possible to discover the dependence of specific ionization on fission fragment velocity. Those relationsMps indicated some differences in the nature of ionization energy losses for light and heavy fragments.Translated from Atomnaya Énergiya, Vol. 19, No. 3, pp. 244–250, September, 1965     

Development of Free-Electron x-Ray Lasers on the TESLA Test Accelerator (DESY, Germany)

The program for developing free-electron x-ray lasers at TESLA started in 1994. The plan is to use the TESLA test accelerator to develop an x-ray laser with minimum wavelength 0.1–6 nm. The first phase of the project was successfully completed in 2001. At saturation, the laser produces ultrashort 30–100 fsec, gigawatt, radiation pulses. The wavelength can be tuned smoothly over the range 80–120 nm.     

Microstructural stability of modified 9Cr–1Mo steel during long term exposures at elevated temperatures

This paper describes the stability of microstructure in normalized and tempered modified 9Cr–1Mo steel exposed to service temperatures in the range of 773–873 K for different time durations. A detailed microstructural and microchemical analysis of the secondary phases was carried out using optical and electron microscopy techniques. The microstructural observations, supported by hardness measurements showed that the lath morphology of the tempered martensite was retained even after 10 000 h of aging. The coarsening of M₂₃C₆ carbide was observed until 5000 h, when the Laves phase started appearing. The microstructural features observed are discussed in conjunction with the embrittlement observed in this steel on high temperature aging exceeding 5000 h.     

Experimental determination of the radiation quality factor near high-energy accelerators

Experimental data characterizing the effective quality factor QF of multicomponent pulse radiation in various parts of a 10-GeV synchrophasotron are presented. The measurements were made by the recombination method. The value of QF varied from 3 to 11. The results of the measurements are compared with values determined for other high-energy accelerators. Values of QF obtained in experiments on particle beams in a 680-MeV synchrocyclotron are also given.Translated from Atomnaya Énergiya, Vol. 20, No. 5, pp. 392–396, May, 1966.     

High power pulsed lasers

Pulsed high power lasers can deliver sufficient energy on inertial fusion time scales (0.1–10 ns) to heat and compress DT fuel to fusion reaction conditions. Several laser systems have been examined for application to the fusion problem. Examples are Ndglass, CO₂, KrF, and I₂, etc. A great deal of developmental effort has been applied to the Ndglass laser and the CO₂ gas laser systems. These systems now deliver >10⁴ kJ and >20×10¹² W to inertial fusion targets. The Nova Ndglass laser is being constructed to provide >200 kJ and >200×10¹² W of 1 m radiation for fusion experimentation in the mid-1980s. For inertial fusion target gain, >100 times the laser input, it is expected that the laser must deliver 3–5 MJ of energy on the 10–20 ns time scale. This paper reviews the developments in laser technology and outlines approaches to construction of a 3–5 MJ driver.     

Superpowerful Linear Proton Accelerators for Neutron Generators and Electoronuclear Setups (review of projects)

Suggestions for superpowerful linear accelerators for electronuclear setups and high-intensity neutron generators are reviewed. The most important technical solutions, the characteristic features, and the state of the projects for linear accelerators with average accelerated beam power from 1 to 100 MW are examined: APT, SNS, JAERI/KEK, TRISPAL, TRASCO, ESS, KOMAC, Energy Amplifier, IFMIF, joint proposal by the Institute of Theoretical and Experimental Physcis, the Moscow Radio Electronics Institute, the Institute for High-Energy Physics, and other nuclear centers. 8 figures, 3 tables, 74 references.     

Water boiling on the corium melt surface under VVER severe accident conditions

Experimental results are presented on the interaction of corium melt with water supplied on its surface. The tests were conducted in the ‘Rasplav-2’ experimental facility. Corium melt was generated by induction melting in the cold crucible. The following data were obtained: heat transfer at boiling water-melt surface interaction, gas and aerosol release, post-interaction solidified corium structure. The corium melt charge had the following composition, mass%: 60% UO_2+x–16% ZrO₂–15% Fe₂O₃–6% Cr₂O₃–3% Ni₂O₃. The melt surface temperature ranged within 1920–1970 K.     

Kinetic energy and angular distribution of the fragments from neutron and photon fission of U238

Angular and energy distribution measurements obtained by means of a gridded, double pulse ionization chamber are reported for fragments from the fission of U²³⁸ by 14 MeV neutrons and by photons with E_max=85 MeV. A study was made of the behavior of the most probable total kinetic energy for fixed mass ratios, m_H/m_L, of the fragments in five ranges of the angle between the direction of fragment emission and the direction of the neutron or photon beam.Translated from Atomnaya Énergiya, Vol. 15, No. 3, pp. 191–194, September, 1963     

Determination of the composition and instability constants of complex Pu+3oxalate ions

The solubility of Pu₂(C₂O₄)₃ · 9H₂O in aqueous solutions of K₂C₂O₄ of various concentrations (0.01–2.4 moles /liter) has been determined at constant ionic strength of the solution at 20. It was found that Pu⁺³ complexes are formed in these solutions. It was found from the results of Pu₂(C₂O₄)₃ · 9H₂O solubility determinations that in the region of K₂C₂O₄ concentrations studied the following complex ions are formed [Pu(C₂O₄)₂]^–, [Pu (C₂O₄)₃]^–3 and [Pu (C₂O₄)₄]^–5, the total instability constants of which are 4.9 · 10^–10; 4.10 · 10^–10 and 11.9 · 10^–11 respectively. The solubility of Pu₂(C₂O₄)₃ · 9H₂O in aqueous (NH₄)₂C₂O₄ solutions has also been determined in the range of ammonium oxalate concentrations from 0.07 to 0.7 mole/liter at 70 °. It is shown that the composition of the complex ions under these conditions corresponds to [Pu(C₂O₄)₂]^–, [Pu(C₂O₄)₃]^–3 and [Pu(C₂O₄)₄]^–5. The calculated total instability constants of these complex ions are 11.6 · 10^–9; 5.6 · 10^–9 and 2.5 · 10^–9 respectively. The heats of formation of complex Pu⁺³ oxalate ions have been calculated for the reaction Pu⁺³ + nC₂O₄ ^–2 [Pu(C₂O₄)_n]^3–2n ¯Q for the [Pu(C₂O₄)₂]^– ion is 1300 cal., for [Pu(C₂O₄)₃]^–3, 1200 cal., and for [Pu(C₂O₄)₄]^–5, 1300 cal.     

Measurements of neutron shielding properties of heavy concretes using a Cf-252 source

This investigation reports the experimental results of neutron transport and shielding properties of heavy concretes made from locally available ilmenite and magnetite sand. The experiment has been carried out with a ²⁵²Cf source and a BF₃ detector as a long counter. The thickness dependent removal cross section has been investigated and found to vary from 0.0936 cm⁻¹ at 5 cm to 0.0346 cm⁻¹ at 100 cm and 0.0990 cm⁻¹ at 5 cm to 0.0366 cm⁻¹ at 100 cm for ilmenite and magnetite concretes respectively. The results illustrate the effectiveness of ilmenite and magnetite heavy concretes so far as their sheilding properties are concerned. These materials may be used as a neutron shield in reactors, accelerators and neutron sources.     

Measurements of K-shell ionization cross-sections of S,Ca and Zn by 7–30 keV electron impact

The absolute K-shell ionization cross-sections of S, Ca and Zn by 7–30 keV electron impact have been measured. The targets were prepared by evaporating the compounds ZnS and CaF₂ to the thick pure carbon substrates. The effects of multiple scattering of electrons penetrating the target films, electrons reflected from the thick pure carbon substrates and Bremsstrahlung photons produced when incident electrons impacted on the targets are corrected by using Monte Carlo method. The uncertainties of our measured K-shell ionization cross-sections are, respectively, ～13% for S, ～15% for Ca and ～12% for Zn. The experimental results were compared with some theoretical results and available experimental data from the literature. The experimental data for S K-shell ionization cross-sections by 7–30 keV electron impact are given here for the first time.