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Berdin S.A.,National Scientific Center Kharkov Physical and Technological Institute | Gadetski N.P.,National Scientific Center Kharkov Physical and Technological Institute | Korenev V.G.,National Scientific Center Kharkov Physical and Technological Institute | Lebedenko A.N.,National Scientific Center Kharkov Physical and Technological Institute | And 7 more authors.
Telecommunications and Radio Engineering (English translation of Elektrosvyaz and Radiotekhnika) | Year: 2014

In this work the authors continue their investigation of a millimeter wave weakly relativistic pulse magnetron [1,2], aimed at the optimization of electric parameters of the device and pointing out the disturbing factors in its efficient performance. The research is illustrated by experimental results featuring the excitation conditions of an 8-mm relativistic magnetron consisting of 48 resonators (RM8). The experiment sought to define oscillations frequency and modes and to obtain numerical values of the relations between the generation intensity and the magnitudes of the external static E- and H-fields. It was revealed that, over a wide value range of the external fields, the π-mode is the principal oscillation mode of the frequency range under study (37...41 GHz). The paper also reports the results of optimizing the operation modes of generation (pulse high-voltage U0 and external magnetic field induction B0) and their dependence on the geometric parameters of magnetron interaction space, namely on cathode dimension and the cathode-to-anode distance dca. © 2014 by Begell House, Inc. Source


Lobzov L.D.,National Scientific Center Kharkov Physical and Technological Institute | Shulika N.G.,National Scientific Center Kharkov Physical and Technological Institute | Kovalenko V.F.,National Scientific Center Kharkov Physical and Technological Institute | Belan V.N.,National Scientific Center Kharkov Physical and Technological Institute | And 3 more authors.
Telecommunications and Radio Engineering (English translation of Elektrosvyaz and Radiotekhnika) | Year: 2015

Multipactor discharges, accompanied by electron reproduction of secondary electron emission (SEE) and reaching electron close of electrodes in linear ion accelerator (LIA) are undesirable phenomena that must be eliminated. In the scientific literature there is no information on disruption of the accelerator characteristics, distorted by discharges in its different areas. In such cases, discharge areas outside the acceleration channel can be visually identified and eliminated. In this study, a modern accelerator excitation circuit is used, consisting of two identical HF-sources with independent positive feedbacks. They operation together on the same resonant load (primary or perturbed frequency) which allows to provide both sustainable HF excitation voltages and suppression of multipactor processes and discharges. Examination of the internal structure LIA showed that there are intense glow discharges in other areas of the accelerator. At the entrance it is a gap of 1.353 cm with sections of parallel end surfaces of the first drift tubes. In the periphery it is a spurious slot of ∼ 0.1...0.2 mm (measured with the vacuum jacket open), formed by the surface structure and the end of the copper plate (patch that closes the unnecessary through hole); the tin solder between them was partially sublimated. From the analysis of pulse distortion of the reference voltages and total currents of SEE, it became clear that the basic rules relevant to the research subject are observed. Visual observation of the radiant emittance of the discharge area and the analysis of time dynamics of these distortions of voltage pulse shapes and electronic currents allowed to characterize unambiguously both discharges as multipactor ones, which greatly facilitates their research and selection of methods for their elimination. The investigation allowed us to better understand the conditions of development and control of multipactor processes and discharges in high-Q (Q0>>1) resonator structures, which is essential to provide time-constant characteristics of a linear ion accelerator. © 2015 by Begell House, Inc. Source


Belyaev A.A.,National Scientific Center Kharkov Physical and Technological Institute | Lukhanin A.A.,National Scientific Center Kharkov Physical and Technological Institute | Popov V.F.,National Scientific Center Kharkov Physical and Technological Institute | Rudychev Ye.V.,National Scientific Center Kharkov Physical and Technological Institute | And 3 more authors.
Telecommunications and Radio Engineering (English translation of Elektrosvyaz and Radiotekhnika) | Year: 2015

There was developed and build stand for the study of static and dynamic thermal parameters of Li-ion batteries cooled by air flow with up to 80 m/sec rate and in the temperature range from - 20OC to +50OC. Air flow is produced by air station with maximum possible pressure drop up to 7000 Pa and applied air can flow in both directions. There is presented the design of the stand and experimental chamber. We studied battery cooling efficiency with the round half sphere surfaces depending on the air flow rate and temperature. The data from sensors placed on the imitator surface was transferred to computer through the 80 channel DAQ (Data Acquisition) PC card, 4 analog switchboards were collected by Lab View DAQ package. We obtained temperature map for such surfaces for the incoming temperature range 10-40OC and air flow up to 2.4 L/sec. The experimental results were compared to the computer simulation using Solid Works Flow Simulation software. © 2015 by Begell House, Inc. Source

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