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

Construction status and prospects of the Hyper-Kamiokande project

The Hyper-Kamiokande project is a 258-kton Water Cherenkov together with a 1.3-MW high-intensity neutrino beam from the Japan Proton Accelerator Research Complex (J-PARC). The inner detector with 186-kton fiducial volume is viewed by 20-inch photomultiplier tubes (PMTs) and multi-PMT modules, and thereby provides state-of-the-art of Cherenkov ring reconstruction with thresholds in the range of few MeVs. The project is expected to lead to precision neutrino oscillation studies, especially neutrino CP violation, nucleon decay searches, and low energy neutrino astronomy. In 2020, the project was officially approved and construction of the far detector was started at Kamioka. In 2021, the excavation of the access tunnel and initial mass production of the newly developed 20-inch PMTs was also started. In this paper, we present a basic overview of the project and the latest updates on the construction status of the project, which is expected to commence operation in 2027

Prospects for neutrino astrophysics with Hyper-Kamiokande

Hyper-Kamiokande is a multi-purpose next generation neutrino experiment. The detector is a two-layered cylindrical shape ultra-pure water tank, with its height of 64 m and diameter of 71 m. The inner detector will be surrounded by tens of thousands of twenty-inch photosensors and multi-PMT modules to detect water Cherenkov radiation due to the charged particles and provide our fiducial volume of 188 kt. This detection technique is established by Kamiokande and Super-Kamiokande. As the successor of these experiments, Hyper-K will be located deep underground, 600 m below Mt. Tochibora at Kamioka in Japan to reduce cosmic-ray backgrounds. Besides our physics program with accelerator neutrino, atmospheric neutrino and proton decay, neutrino astrophysics is an important research topic for Hyper-K. With its fruitful physics research programs, Hyper-K will play a critical role in the next neutrino physics frontier. It will also provide important information via astrophysical neutrino measurements, i.e., solar neutrino, supernova burst neutrinos and supernova relic neutrino. Here, we will discuss the physics potential of Hyper-K neutrino astrophysics

On feasibility of optimizing the neutronic parameters of a laser system pumped by a pulsed reactor

The paper examines the calculated feasibility of improving the energy characteristics of power pulses in a system consisting of a reactor and a subcritical block. A BARS-type fast neutron reactor is used as a self-quenching pulsed reactor. The subcritical block is a cylindrical structure comprising laser-active elements, moderator components and two reflectors (internal and external). The internal reflector material is zirconium hydride, and the external reflector material is beryllium. The pumping area containing the laser-active elements consists of zirconium hydride moderator, aluminum and uranium–molybdenum fuel (95% enriched uranium). The system operates in a pulsed mode. Fast neutrons are generated in the nuclear reactor at the pulse moment, many of which are leakage neutrons entering the subcritical block, slowing down there and inducing fissions of uranium nuclei in the laser-active elements. After the pulse terminates, the reactor changes to a deeply subcritical state, and the laser pulse generation stops. The neutron kinetics in the system under consideration is modeled based on a modified integral model. The pulse maximum power and energy in the system's subcritical block, as well as its weight and energy-to-weight ratio are selected as functionals for the optimization. The fissile material and moderator weight and the thickness of the subcritical block's internal and external reflectors are adopted as variables. The calculations have shown that it is possible to improve the energy characteristics of a reactor-laser system by increasing the amount of the fissile material in the block, not using the moderator in the block and fixing the thickness of the internal zirconium hydride reflector at a level of 3.1cm. It has been shown that a change in the external beryllium reflector thickness leads to a highly multidirectional behavior of the functionals (energy and maximum power, as well as the block weight and energy-to-weight ratio)