L.P. Zakatov
Kurchatov Institute
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Featured researches published by L.P. Zakatov.
IEEE Transactions on Plasma Science | 1998
Georgi I. Dolgachev; L.P. Zakatov; A.G. Ushakov
Repetitive plasma opening switch (POS) research for X-ray and electron beam generators for commercial applications is reviewed. This research was started on the RS-20 generator in 1991 with submicrosecond conduction times, 100 kA currents, and MV voltages. In the experiments wall-plug to electron beam production efficiency was increased from 10-50%. Maximum voltage obtained at POS was 3 MV starting from 0.8 MV at the Marx generator. POS operation was improved using an applied external magnetic field for the opening phase. Diode current and total generator efficiency were increased by combining the POS and diode system in one technology unit. For the opening phase of the high-impedance, repetitive POS, a set of conditions based on early POS experiments in the Kurchatov Institute were proposed. Repetitive POS generators have obtained peak X-ray dose rates of 1 MGy/s and electron dose rates of 10 GGy/s. This may be important for applications as pulsed irradiation may cause more efficient sterilization at lower doses. An X-ray generator based on repetitive POS technology at 5 MV and 200 kW in the electron beam is proposed.
ieee international pulsed power conference | 1997
N.U. Barinov; G.S. Belenki; G.I. Dolgachev; L.P. Zakatov; D.D. Maslennikov; M.S. Nitishinski; A.G. Ushakov
The report describes possibilities to make existing repetitive plasma opening switch (RPOS) technology competitive with existing accelerator X-ray radiating systems. The use of an external magnetic field for magnetic insulation of the RPOS system allows to increase the achievable voltage in RPOS and diode and the total efficiency of the system from the wall plug to X-ray irradiation. The experiments on an RS-20 pulsed power generator with the use of an external magnetic field allows one to raise the RPOS voltage from 2-2.2 to 2.8-3 MV. Another option is to combine the RPOS and diode in one unit to avoid energy losses when switching current to the diode with a wall plug to e-beam efficiency of 50-70%. On this basis, a concept of a 5 MV RPOS X-ray generator is proposed, capable of producing 200-300 kW in an e-beam.
ieee international pulsed power conference | 1995
N.U. Barinov; G.S. Belenki; G.I. Dolgachev; Yu.I. Kovalev; D.D. Maslennikov; M.S. Nitishinski; A.G. Ushakov; L.P. Zakatov
The report represents the results of experimental research into the plasma opening switch (POS) in an applied longitudinal magnetic field. Applying magnetic field on an area of the POS reduced the electron component of the current through the POS on a stage of sharp increase of the resistance. The POS which has been chosen for the experiments is one of the versions which the authors used in the repetitive pulsed power X-ray generator RS-20. The parameters of the the electron accelerator are as follows: electron energy 2.5 MeV; electron beam current 10-20 kA; pulse width 100 ns; and average power 10-20 kW. The scheme of the electron diode which is represented allowed X-ray flow focusing.
international conference on plasma science | 1996
G.I. Dolgachev; Yu. G. Kalinin; A. S. Kingsep; M.S. Nitishinski; L.P. Zakatov; A.G. Ushakov
Summary form only given. We consider the effect of anomalous resistance in the plasma opening switch which plays an important role in the conduction phase before sharp switching. This effect should be taken into account together with EMH and erosion mechanisms. A low frequency turbulence was studied experimentally by observing Stark broadening of hydrogen lines with enhanced spatial resolution implementing a Fabry-Perot interferometer. This plasma diagnostic was similar to that we used in previous experiments. H/sub /spl alpha// line contour (6563 A) observed was compared with modeling of ion-acoustic oscillations with adding of ion micro-fields (Holzmark) together with Doppler broadening and allowed us to estimate the turbulent field and its localizing during the conduction phase. As a result a turbulent electric field in the POS gap was estimated to be 10-30 kV/cm near the anode increasing up to 50 kV/cm near the cathode. These estimations were made at 1-3 eV electron temperature and corresponded to near 1 Ohm POS resistance during the conduction phase.
international conference on high power particle beams | 1998
N.U. Barinov; G.I. Dolgachev; D. D. Maslennikov; M.S. Nitishinsky; A.G. Ushakov; L.P. Zakatov; O.A. Zinoviev
The results of sterilization tests made at the RS-20 generator of Bremsstrahlung for sterilizing purpose are reported. The measurements were done under different conditions in the area of 10-30 kGy dose levels at 1 MGy/s peak dose rate range for various microorganisms. The immediately irradiated volume was 0.036 of cubic meter with average dose rate at 1 kGy/hour provided in the center of the volume. The Bremsstrahlung was created by 2.0 MeV 10 kA 100 ns pulsed e-beam directed toward the target at 2 Hz. The tests were compared with those made simultaneously at continuous radionucleic radiation source using Co-60 isotope providing same dose values. It was found that full sterilization effect at RS-20 using 1 MGy/s peak dose rate takes 2-5 times lesser dose against radionucleic source and increases total efficiency of the system. Total dose decrease down to 5-12 kGy allows to reduce radiation loads on the equipment and broadens the area of sterilizing application.
international symposium on discharges and electrical insulation in vacuum | 1994
N.U. Barinov; G.S. Belenki; G.I. Dolgachev; Yu.I. Kovalev; L.P. Zakatov; A.G. Ushakov
The paper considers pulsed power repetitive systems using plasma opening switches. The solutions of a row of technical problems connected with both repetitive operation of accelerator having high peak power and x-ray radiation converter are proposed. These machines are to be prospective for advanced radiation technologies.
ieee international conference on pulsed power | 1991
G.I. Dolgachev; L.P. Zakatov; A.G. Ushakov
Main results of the Plasma Current Interrupting Switch (PCIS) or Plasma Opening Switch (POS) are adduced. A comparison with other nanosecond and microsecond POS experiments is represented. Scheme and model of switch operation are proposed.
international conference on high power particle beams | 1998
N.U. Barinov; G.I. Dolgachev; D. D. Maslennikov; M.S. Nitishinsky; A.G. Ushakov; L.P. Zakatov
Experiments on efficiency increase of the X-ray sterilizer RS-20 are reported. Increase in X-ray output for a given wall plug power may be obtained due to growth of both electron energy and electron diode current. In the first experiment to increase the electron beam energy (up to 3 MeV) a coaxial POS in applied external magnetic field was utilized. An electron diode with anode-converter was parallel to POS. 25% of total current was transmitted to the diode. A dose per pulse was 0.024 Gy at 1 m from the converter. The second experiment used POS with planar anode in the open circuit regime so the anode was utilized for electron beam conversion into bremsstrahlung.
international symposium on discharges and electrical insulation in vacuum | 1996
N.U. Barinov; G.S. Belenki; G.I. Dolgachev; L.P. Zakatov; Yu.I. Kovalev; D.D. Maslennikov; M.S. Nitishinski; A.G. Ushakov
The report considers the research undertaken to implement repetitive pulsed power technique based on the plasma opening switch (POS) for industrial technology requiring high dose rate irradiation. It considers the results of the research undertaken at 100 kW level to optimize existing POS-using accelerator RS-20 created in Russia and to extend this technique for the parameters required for technology. The new schemes for the further development of this technology for higher power levels are proposed from the analysis.
international conference on plasma science | 1996
G.I. Dolgachev; V.S. Nitishinski; L.P. Zakatov; A.G. Ushakov
Summary form only given, as follows. The report discusses technical opportunities and basic conditions to implement plasma opening switch technology for industrial purposes. Having a certain experience in near 100 kW range in 1991-95 (RS-20 and subsequent machines) we plan to extend this technology for new uses but we can not do it simply on a base of RS-20. When we analyze requirements of the certain technology we can use POS-based accelerator only when high peak dose rate together with short pulse width are required. This is important firstly for radiation-biology technologies (sterilizing) and for those used to destroyed hazardous organic materials and substances. Experiments on sterilizing have shown an increase of sterilizing effect at RS-20 comparing with /sup 60/Co source sterilizing. Dose decreasing due to high peak dose rate allowed not only accelerator power decrease but could be important for medical sterilizing due to low radiation dose strength of materials used in medicine. Limits on POS operation such as vacuum recovery process limiting repetition rate and maximum voltage could be obtained in the POS gap are also discussed. Analyzing an efficiency of the accelerator based on POS technology new schemes are proposed combining POS and diode in one unit to avoid current losses and to improve efficiency of the machine.