New 15 MeV electron accelerator for non-destructive testing

A 15 MeV accelerator with the dose rate from 80 to 120 Gy/min at 1m from the target has been designed and manufactured in NPK LUTS, the D.V.Efremov Institute, NIIEFA. The accelerator is intended for nondestructive testing (radiography, introscopy, tomography) of large scale products. Under tests an X-ray beam with the boundary energy of 15-16 MeV and dose rate of 100 Gy/min has been produced. When operating with longer pulse lengths of the accelerated electron current, the beam power was up to 140 Gy/min; with lower currents the 18 MeV energy was attained at a dose rate of 40-50 Gy/min. Biperiodic accelerating structure with axial coupling cells is applied in the accelerator. The accelerating structure buncher provides RF-focusing of the electron beam, therefore there is no need for focusing the solenoid. The focus spot diameter is no more than 2mm. To provide the electron beam stability, the accelerator is equipped with a system for automatic frequency tuning (AFT). The AFT system ensures both coarse tuning of the driver frequency against the temperature of the accelerating structure and fine tuning - against the minimum reflected power. The anode voltage of the klystron amplifier is stabilized by using a de-Q-ing system. A charging choke and pulse forming network (PFN) are located inside the irradiator unit to increase the distance between the modulator and irradiator up to 100m and to reduce losses when high-voltage high-current pulses are transmitted. The low-voltage klystron (anode voltage up to 55 kV) applied in the accelerator allows reducing the machine weight and dimensions (1100 kg and 2040x880x920mm). The accelerator is equipped with a PC-based automatic control system. In the accelerator intended for the radiographic inspection there is an external collimator with movable diaphragm jaws for testing small fragments of an inspected product

Unified 1.9…4.0 MeV linear accelerators with interchangeable accelerating structures for customs inspection

A series of compact linear electron accelerators for 1.9, 2.5 and 4.0 MeV equipped with a local radiation shielding has been designed and constructed in the NPK LUTS, the D.V. Efremov Institute (NIIEFA). The accelerators are intended for mobile facilities used for customs inspection of large-scale containers. Results of optimizing calculations of irradiator parameters and electron dynamics, verified under accelerators’ testing, are presented in the report. The main design approaches allowing the construction of unified accelerators with interchangeable accelerating structures for energies in the range of 1.9…4.0 MeV are also given.У НПК ЛУЦ НІІЕФА розроблені і виготовлені кілька моделей компактних лінійних прискорювачів електронів на енергії 1.9, 2.5, і 4.0 МеВ, що призначені для митного огляду великогабаритних контейнерів. Особливістю розробки є уніфікація вузлів прискорювача, що дозволила при використанні взаємозамінних структур, що прискорюють, у тому самому конструктивному виконанні одержувати прискорені електрони з енергією у діапазоні 1.9…4.0 МеВ. Приведено результати оптимізації параметрів опромінення, що підтверджені при іспиті прискорювачів.В НПК ЛУЦ НИИЭФА разработаны и изготовлены несколько моделей компактных линейных ускорителей электронов на энергии 1.9, 2.5, и 4.0 МэВ, которые предназначены для таможенного досмотра крупногабаритных контейнеров. Особенностью разработки является унификация узлов ускорителя, что позволило при использовании взаимозаменяемых ускоряющих структур в одном и том же конструктивном исполнении получать ускоренные электроны с энергий в диапазоне 1.9…4.0 МэВ. Приведены результаты оптимизации параметров облучения, которые подтверждены при испытании ускорителя

Organoboron ionic liquids as extractants for distillation process of binary ethanol + water mixtures

© 2020 by the authors. Aminoethers of boric acid, which are organoboron ionic liquids, were synthesized by using boric acid, triethanolamine, and triethylene glycol/diethylene glycol. Due to the formation of intermolecular complexes of borates, the structure of aminoethers of boric acid contains ion pairs separated in space, giving these compounds the properties inherent to ionic liquids. It is established that the thermal stability of aminoethers under normal atmospheric conditions increases with an increase in the size of the glycol. According to measurements of fast scanning calorimetry, density, dynamic viscosity, and electrical conductivity, water is involved in the structural organization of aminoethers of boric acid. The impact of the most thermostable organoboron ionic liquids on the phase equilibrium conditions of the vapor-liquid azeotropic ethanol-water mixture is studied. It is shown that the presence of these substances leads to increase in the relative volatility of ethanol. In general, the magnitude of this effect is at the level shown by imidazole ionic liquids, which provide high selectivity in the separation of aqueous alcohol solutions. A large separation factor, high resistance to thermal oxidative degradation processes, accompanied by low cost start reagents, make aminoethers of boric acid on the basis of triethylene glycol a potentially effective extractant for the extractive distillation of water-alcohol mixtures