This study is devoted to the development of amplifying paths for plasma diagnostics, a significant part of which use semiconductor detectors as sensors that form low-intensity current signals. One feature of these diagnostics is the oscillographic form of registering sensor signals. In tandem with detectors, broadband transimpedance amplifiers that are based on operational amplifiers are used to amplify and normalize sensor signals. The principles of constructing such amplifying paths are considered taking the factors affecting their final noise and frequency characteristics into account. Practical examples of the construction of amplifying paths of corpuscular and neutron plasma diagnostics, as well as the Thomson-scattering diagnostics, that are used at the plasma installations of the Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) are presented.

An Erratum to this paper has been published: https://doi.org/10.1134/S0020441222030204

Method of plasma potential and electrons mean energy measurement by single Langmuir probe in highly fluctuated plasma of magnetic open trap is described. Diagnostics based on this method allows for two types of measurements: plasma potential in the emission probe mode, as well as current-voltage characteristics of the probe, followed by calculating the plasma potential and the average electron energy. All diagnostic elements, including pulse shape recorders, are fully galvanically isolated. Power supply is provided by battery placed on board of the measuring system. Control and synchronization are realized by means of optical communication lines. This diagnostic design allows measurements relate to plasma electrodes, the potential of which fluctuates with a frequency of up to hundreds of kilohertz.

This paper describes a data acquisition system for Thomson scattering diagnostics on a gas-dynamic trap (GDT) (the Budker Institute of Nuclear Physics, Novosibirsk, Russia). It allows recording scattered laser radiation pulses of ~10-ns duration with 5-GSPS sampling rate and 14-bit amplitude resolution. The data acquisition system includes eight-channel high-speed recorders and photodetector modules. The photodetector modules are based on avalanche photodiodes and low-noise transimpedance amplifiers. The recording module design uses switched-capacitor array technology.

БЫСТРОДЕЙСТВУЮЩИЙ РЕГИСТРАТОР НА ОСНОВЕ ТЕХНОЛОГИЙ МАСШТАБНО-ВРЕМЕННОГО ПРЕОБРАЗОВАНИЯ ДЛЯ ДИАГНОСТИКИ ТОМСОНОВСКОГО РАССЕЯНИЯ НА УСТАНОВКЕ ГДЛЕ.А.Пурыга 1 , С.В.Иваненко 1, 2 , А.А.Лизунов 1 , А.Д.Хильченко 1 , А.Н.Квашнин 1 , П.В.Зубарев 1 , Д

The measuring system for Thomson scattering diagnostics of the GOL-3 and GDT facilities at the Budker Institute of Nuclear Physics is described. The system has a modular architecture and is based on eight-channel measuring subsystems, including photodetectors, two-channel recorders (ADC12500), synchronization modules, and the Ethernet/UART communication channel adapter. The photodetectors are based on avalanche photodiodes and are operable in the frequency range of 0–50 MHz. The ADC12500 recorders are used to measure scattering signals with a duration of ~20–30 ns at a sampling rate of to 500 MHz and an amplitude resolution of 12 bits and accumulate data in a buffer memory with a capacity as large as 2 MB.

A pulse-signal digitizer for laser, neutron, and gamma diagnostics of high-temperature plasma at the GOL-3 and GDL (Budker Institute of Nuclear Physics Siberian Branch, Russian Academy of Sciences) is described. The architecture of a two-channel 12-bit ADC12500PXIe digitizer with a sampling rate of 500MHz, a PXI Express interface, and a built-in reconfigurable digital signal processing unit is described. The results of ADC12500PXIe metrological tests are presented: its signal-to-noise ratio (SNR), jitter, effective number of bits, and differential and integral nonlinearities are shown. The high-temperature plasma diagnostic systems based on ADC12500PXIe are considered. The structure of the digital signal processing unit that was modified for a prototype of the ITER vertical neutron camera (Cadarache, France) is described.

The regularization and combination methods were applied to treat the small number of experimental results. The proposed algorithm permits to calculate the transverse phase space parameters, center dynamics, momentum spread of the beam as well as the structure dispertion characteristics. The reliability of the calculation results and carried out measurements is estimated.

The computer system for control of cw surface‐plasma source of negative ions is described. The system provides an automatic handling of source parameters by the specified scenario. It includes the automatic source start and long‐term operation with switching and control of the power supplies blocks, setting and reading of source parameters like hydrogen feed, cesium seed, electrodes’ temperature, checking of the protection and blockings elements like vacuum degradation, absence of cooling water, etc. The semi‐automatic mode of control is also available, where the order of steps and magnitude of parameters, included to scenario, is corrected in situ by the operator. Control system includes the main controller and a set of peripheral local controllers. Commands execution is carried out by the main controller. Each peripheral controller is driven by the stand‐alone program, stored in its ROM. Control system is handled from PC via Ethernet. The PC and controllers are connected by fiber optic lines, which prov...

Within this report we summarize the technical and experimental effort made on high power neutral beam injector system (NBI) and diagnostics neutral beam injector (DINA-5M which was installed at Gas Dynamic Trap device (GDT) last year. Basic components of NBI-systems and DINA are reviewed. Recent experimental results support the concept of the neutron source based on the gas dynamic trap.

The data recording system of a multichannel double-pass dispersion interferometer based on a CO2 laser is described. This system has been designed to record the linear density of plasmas in a real-time mode with a time discreteness of 4 μs and resolution 〈N e L〉 ∼ 0.34 × 1013 cm−2 (N e is the electron component of the plasma density, and L is the plasma size in the wave propagation direction) in the range of linear density variations of up to 1017 cm−2. The system is built from unified recording modules that use fast ADCs to record the shape of photodetector and modulator signals and FPGA-based digital units of dataflow processing to form results of measurements. The single-channel recording module of the dispersion interferometer has been tested under actual experimental conditions of the GDL gas-dynamic trap and the TEXTOR tokamak (Julich, Germany).

The simultaneously sampling data acquisition system contains 16 eight-channel modules, which record the shapes of single pulse signals, and the controller module of the system bus of the Eurocrate, which interacts with the basic computer of the diagnostic complex via an Ethernet-FX communication line supported by TCP/IP protocols. The recording modules are based on 12-bit analog-to-digital converters (ADC). The ADC samples are fixed in buffer storage units with a capacity of up to 1 Mword/channel. The current amplitudes of the input signals are measured simultaneously in all recording channels with a time jitter of ∼3 ns. The maximum sampling frequency is below 4 MHz.

The system is intended for recording data in the multichannel diagnostic sections of experimental plasma facilities. It contains eight four-channel modules that record the shapes of single pulse signals, a controller module of the system bus of the crate, a fiber-optic communication line, and an interface card for connection to the ISA bus of a personal computer. The recording modules are based on 12-bit analog-to-digital converters (ADCs) with a sampling frequency of up to 50 MHz, ensuring a conversion accuracy equal to the least significant bit in a band of the input signal of up to 20 MHz. The ADC samples are fixed in 32-Kword/channel buffer storage units with a page organization. The current values of the amplitude of the input signals in all of the recording channels are measured simultaneously with a time jitter of no more than 0.2 ns. The software selects an amplitude conversion scale and a zero offset voltage value for each recording channel, as well as the current value of the sampling frequency for all the channels.

Two modifications of multichannel recorders of single pulses employing AD9058 parallel 8-bit analog-to-digital converters are described. These devices cover a sampling rate range from 25 kHz to 200 MHz with a +/-0.5% accuracy up to 10-MHz frequency band of the input signal and comply with the CAMAC standard.