New circuits of high-voltage pulse generators with inductive-capacitive energy storage

The paper describes new electric circuits of multi-cascade generators based on stepped lines. The distinction of the presented circuits consists in initial storage of energy in electric and magnetic fields simultaneously. The circuit of each generator, relations of impedances, values of initial current and charge voltages are selected in such a manner that the whole of initially stored energy is concentrated at the generator output as a result of transient wave processes. In ideal case the energy is transferred with 100% efficiency to the resistive load where a rectangular voltage pulse is formed, whose duration is equals to the double electrical length of the individual cascade. At the same time there is realized a several time increase of output voltage as compared to the charge voltage of the generator. The use of the circuits proposed makes it possible to ensure a several time increase (as compared to the selection of the number of cascades) of the generator energy storage, pulse current and output electric power

Results of LIA-10M accelerator investigations

There are presented basic results of experiments on the LIA-10M accelerator since its putting into operation (1994) till today. There were investigated various modes of accelerator operation and its output characteristics depending on the parameters of injected electron beam, number of connected accelerator modules, time program of inductors switch-in etc. There was obtained a large scope of experimental data that are of interest for LIA-10M accelerator practical use and for the development of new facilities of this type. The investigations that have been performed recently make it possible to considerably (half as much again) increase the output dose parameters of the accelerator as compared to the level achieved before: maximal dose (Si) and dose rate on the output flange constitute 400 Gy and 2.5.1010 Gy/s, while at a 1 meter distance from the target they are equal to 7.5 Gy and 5.108 Gy/s, respectively

Design of STRAUS-R accelerator

The paper presents a design of the direct-operation high-current electron accelerator STRAUS-R that is a modification of STRAUS-2 now in force. The accelerator is aimed at generating single bremsstrahlung pulses in the mode of electron beam focusing on the target. According to the calculations it should provide for getting the dose (Si) of 0.2÷0.25 Gy at a 1 meter distance from the target, the electron beam current being equal to 50÷60 kA, boundary energy of electrons – to 2.7÷3.0 MeV, bremsstrahlung pulse duration – to ≤ 50 ns and beam diameter on the target – to ≤ 5 mm. The description and results of numerical simulation of physics processes taking place in the accelerator are given

Numerical simulation of the processes of small-diameter high-current electron beam shaping and injection

With the aid of BEAM25 program there was carried out the numerical simulation of the non-stationary process of shaping a small-diameter (≤ 20 mm) high-current hollow electron beam in a diode with magnetic insulation, as well as of the process of beam injection into the accelerating LIA track. The diode configuration for the purpose of eliminating the leakage of electron flux to the anode surface was updated. Presented are the results of calculation of the injected beam characteristics (amplitude-time parameters of a current pulse, space-angle distributions of electrons etc.) depending on diode geometric parameters

Investigation of STRAUS-2 pulsed electron accelerator characteristics

Last years a successful development of highvoltage pulse forming techniques based on stepped transmission lines led to creation of a set of powerful and compact electrophysics facilities including a highcurrent pulsed electron accelerator STRAUS-2 [1, 2]. The first sample of this accelerator was started up into exploitation in 1989. At present, three facilities of the same type exist in VNIIEF, one of them is used as an injector for a linear induction accelerator LIA-10M [2-5]. Two others are autonomous and applied for research in radiation physics

Optimization of electron beam parameters of LIA-10M accelerator

A numerical simulation of the LIA-10M accelerator was carried out. It is shown that at the existing configuration of the diode unit and maximal for LIA-10M injection parameters (3 MeV, 50 kA) significant (up to 40%) beam losses in the accelerating channel are possible. As a result of calculations the injector cathode geometry was optimized what permitted to avoid beam electron leakage onto the walls of accelerating channel and to improve significantly output parameters of the LIA-10M accelerator.Проведено численное моделирование ускорителя ЛИУ-10М. Показано, что при существующей конфигурации диодного узла и максимальных для ЛИУ-10М параметрах инжекции (3 МэВ, 50 кА) возможны значительные (до 40%) потери пучка в ускорительном тракте. В результате расчетов оптимизирована геометрия катода инжектора, что позволило избежать утечки электронов пучка на стенки ускорительного тракта и существенно улучшить выходные параметры ускорителя.Проведено чисельне моделювання прискорювача ЛІП-10М. Показано, що при існуючій конфігурації діодного вузла і максимальних для ЛІП-10М параметрах інжекції (3 МеВ, 50 кА) можливі значyі (до 40%) втрати пучка в прискорюючому тракті. У результаті розрахунків оптимізована геометрія катода інжектора, що дозволило уникнути витоку електронів пучка на стінки прискорюючого тракту і суттєво поліпшити вихідні параметри прискорювача

A 800-kV and 32-kJ pulse generator

The characteristics of oil-insulated 8-stage Marx generator aimed at charging water-insulated line of STRAUS-R electron beam accelerator are presented. Two IEPM-100-0.4 capacitors are installed in each stage. Switches in the first three stage are 100-kV gas-filled trigatrons while in other stages – two-electrode trigatrons. Operation delay time is 108±5 ns at electric strength reserve of each switch being equal to ~ 80%. The circuit inductance is ~1.4 µH.Приведены характеристики маслоизолированного восьмикаскадного генератора (ГИН) Аркадьева-Маркса для зарядки до 700 кВ за < 1 мкс водоизолированной линии ускорителя пучка электронов СТРАУС-Р. В каждом каскаде установлено по два конденсатора ИЭПМ-100-0.4. Коммутаторы в первых трех каскадах – газонаполненные тригатроны на 100 кВ, в остальных – двухэлектродные. Время задержки срабатывания 108+-5 нс при запасе электропрочности каждого разрядника ̴ 80%. Индуктивность контура ГИН ̴ 1,4 мнГн.Наведено характеристики маслоізольованого восьмикаскадного генератора (ГІН) Аркадьєва-Маркса для зарядки до 700 кВ за 1 мкс водоізольованої лінії прискорювача пучка електронів СТРАУС-Р. У кожному каскаді встановлено по два конденсатора ІЕПМ-100-0.4. Комутатори в перших трьох каскадах – газонаповнені тригатрони на 100 кВ, в інших – двохелектродні. Час затримки спрацьовування 108+-5 нс при запасі електроміцності кожного розрядника ̴ 80%. Індуктивність контуру ГІН ̴ 1,4 мкГн

High-current pulse electron accelerators based on stepped forming lines

There presented is a brief review of I-3000, STRAUS, STRAUS-2 and LIA-10M accelerators produced in VNIIEF over the period from 1981 to 1994. All the installations function in the mode of single pulses. Their distinction consists in using the systems of forming high-voltage pulses on the basis of stepped forming lines. Such installations formed of line sections of a similar electrical length with a stepped character of impedance variance provide a high efficiency and as a result of wave processes increase for a several time the output voltage as compared to the charge voltage of lines. The limiting energy of accelerated electrons for the created accelerators lies within the range from 2.3 to 25 MeV, beam current amplitude – from 20 to 50 kA, current pulse width at half-height – from 16 to 40 ns. The basic characteristics of each accelerator are presented

Study of operating modes of STRAUS-R accelerator

The description of a pulsed electron accelerator STRAUS-R (3.5 MeV, 60 kA, 60 ns) and results of its experimental research for two operation modes are given. In the mode of electron beam focusing the accelerator provides the focal spot of 3-4 mm diameter on a target and maximum exposure dose of 27 R at 1-m distance from the output window. In the irradiating mode the maximum dose achieves 36 R at 1-m distance from the target with inhomogeneity ≤ 30% within the area 0.36 m² (irradiation spot diameter is 0.6 m).Приведены описание и результаты исследований импульсного электронного ускорителя СТРАУС-Р (3,5 МэВ, 60 кА, 60 нс) в двух режимах его работы. В режиме фокусировки электронного пучка ускоритель обеспечивает получение на мишени фокусного пятна диаметром 3…4 мм при максимальной дозе тормозного излучения 27 Р на расстоянии 1 м от выходного фланца. В облучательном режиме максимальная доза тормозного излучения на расстоянии 1 м от мишени по оси ускорителя достигает 36 Р с неоднородностью ≤ 30% на площади 0,36 м² (диаметр пятна облучения 0,6 м).Наведено опис і результати досліджень імпульсного електронного прискорювача СТРАУС-Р (3,5 МеВ, 60 кА, 60 нс) у двох режимах його роботи. У режимі фокусування електронного пучка прискорювач забезпечує одержання на мішені фокусної плями діаметром 3...4 мм при максимальній дозі гальмівного випромінювання 27 Р на відстані 1 м від вихідного фланця. При опроміненні максимальна доза гальмового випромінювання на відстані 1 м від мішені по осі прискорювача досягає 36 Р с неоднорідністю ≤ 30% на площі 0,36 м² (діаметр плями опромінення 0,6 м)