The incoherent Thomson scattering diagnostic with multiple lines of sight is installed at the gas dynamic trap (GDT) for measurements of radial profiles of the plasma electron temperature and density. The diagnostic is built on the Nd:YAG laser operating at 1064 nm. The laser input beamline is provided with an automatic system for alignment status monitoring and correction. The collecting lens uses ∼90° scattering geometry having 11 lines of sight in total. Presently, six of them (covering the full plasma radius from the axis to the limiter) are equipped with high etendue (f/2.4) interference filter spectrometers. The design of the spectrometer's data acquisition system based on the "time stretch" principle allowed for the 12 bits vertical resolution with a sampling rate of 5 GSample/s and a maximum sustainable measurement repetition frequency of 40 kHz. The repetition frequency is the crucial parameter for the study of plasma dynamics with a new pulse burst laser to be started in early 2023. Results of the diagnostic operation in several GDT campaigns show that radial profiles are routinely delivered with the typical observation error of 2%-3% for Te ⩾ 20 eV in a single pulse. After Raman scattering calibration, the diagnostic is capable to measure the electron density profile with the resolution ne (min)≃4⋅1018m-3 and error bars of 5%.

The incoherent Thomson scattering diagnostic with multiple line of sight is installed at the gas dynamic trap (GDT) for measurements of radial profiles of the plasma electron temperature and density. The diagnostic is based on a Nd:YAG laser with the wavelength of $1064 nm$. Its collecting lens uses $90^\circ$ scattering geometry having eleven lines of sight in total. At the current stage, six of them are equipped with interference filter spectrometers. Results of the initial operation within a month-long experimental campaign at GDT show that radial profiles are delivered with the accuracy of few percent for $T_e \geqslant 20 eV$ and $n_e \geqslant 10^{19} m^{-3}$. The next planned boost of the diagnostic performance is upgrade with the pulse burst laser to study a fast dynamics of plasma parameters in every GDT shot.

The article presents the design and first test results of the neutron spectrometer with count rate up to 7 × 10 6 events per second with remote detector based on artificial diamond, intended for use on burning plasma experiments. The spectrometer consists of the broadband low-noise amplifier and the data acquisition and processing unit. The design of the amplifier with characteristic impedance matching of the cable line by the dynamic resistance of the transistor base-emitter junction is considered. The data acquisition and processing unit is realized using a real-time event-processing algorithm based on harmonic data analysis. This algorithm includes effective techniques for detecting and excluding overlaps and suppression of fluctuations in the baseline level corresponding to zero signal.

The optical diagnostic observing D-alpha line emission along multiple chords in the boundary region close to the plasma absorber, is recently installed at the gas dynamic trap. The implemented pattern of viewing lines is suitable for a tomographic reconstruction of local emissivity profiles, although steps towards increasing the channel count and extending of angular plasma coverage must be taken. The optical registration system of a modular design uses avalanche photodiodes with wideband amplifiers for a large signal dynamic range and the effective time resolution of 1 mks. The iterative backward projection technique based on the maximum likelihood principle, demonstrates an acceptable computation accuracy. Images of plasma evolution in the cross section were obtained. Tools for the correlation analysis were also developed and first results of study of the plasma turbulence are presented.

New experiments with higher electron temperatures in the gas dynamic trap (GDT) magnetic mirror require a substantial upgrade of the Thomson scattering diagnostic. The paper presents the recently developed polychromator based on interference filters, which has the data acquisition and processing system onboard. The six spectral channels have wavelength pass bands distributed from 900 nm to 1057 nm to enable measurements of the electron temperature in the range from 20 eV to approximately 2 keV. The optimized design of the detection module with the avalanche photodiode and the signal amplifier yields the transmission factor of 4 x 10(6) V/W in the bandwidth of 1 to 50 MHz in the high-speed detection channel. For a 1064 nm laser pulse of 10 ns duration, the amplifier noise equivalent is only 30 photons. Every detection module is also equipped with the low-speed (0 to 1 kHz) detection channel for separate measurements of background plasma radiation. This option also enables an easy calibration of the spectral response function using a continuous-wave light source like tungsten lamp. The high-speed acquisition channel utilizes the "time stretch" principle. It uses the 5.5 GSample/s analog memory arranged in the switched capacitor array to hold the signal trace of 200 ns duration, which is then processed by a relatively slow 14-bit digitizer. The acquisition and readout sequence can be cycled at the frequency of up to 40 kHz providing the necessary time resolution in experiments with multiple laser beam pulses. The polychromator onboard data processing electronics is controlled by the System on Chip solution with the procedures of data processing implemented in the Field Programmable Gate Array. Lab test results along with first plasma measurements are presented in the paper.

The vertical neutron camera (VNC) diagnostic system's role is the study of the plasma physics and plasma pulse control at the ITER tokamak. The VNC provides neutron flux measurements and the neutron and alpha source profile across the plasma. The VNC is composed of two neutron cameras: an upper one and a lower one. The upper VNC is located in upper port plug 18 and contains 6 fan-shaped collimators to observe the inner part of the plasma. The lower VNC is located in lower port plug 14 behind the diverter cassette and contains 5 fan-shaped collimators with the line of sight (LoS) focused on the outer part of the plasma. Each collimator has a detector unit composed of two diamond detectors and two fission chambers. The electrical signal is transmitted from the neutron detectors to the data acquisition system by a triaxial cable with mineral isolation. The signal from the neutron detectors is preliminarily amplified by current pre-amplifiers, digitized with a sampling rate of 250 MHz and transmitted from the port cell zone to the diagnostic building under normal environmental conditions by digital optical lines. In the diagnostic building, signal is preliminarily processed and transmitted to the ITER central control system. The data acquisition system was designed according to the following ITER guidelines: the Radiation Hardness Policy (RHA), the Electrical Design Handbook (EDH), the Plant Control Design Handbook (PCDH), and the Annex B for VNC Procurement Arrangement (specifies the special requirements for measurement procedures and results).

After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 x 10(19) m(-3), central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.

One of the most important research directions on the Gas Dynamic Trap (GDT) magnetic mirror [1] is a complex study of the divertor physics. The foundation stone of this research program is a study of physical processes in a volume of divertor with expanding magnetic field lines. The exploration of the region near the plasma absorber is also considered. Because of neutralization of the plasma flux on the absorber surface, the adjacent plasma layer is characterized by a high density of atomic and molecular particles. Such a compound considerably affects the whole system particle balance, thus having an effect on the electrostatic potential spatial distribution. Measurement of intensity distributions of light emitted by atoms of plasma offer a direct instrument to observe the dynamics of this plasma component. In this paper, a new visible light tomography diagnostic system is proposed. The two-dimensional tomographic system is designed, constructed and installed on GDT. An avalanche photodiode (APD) based de...

A new station for optical observation of electron beam parameters at the electron storage ring SIBERIA-2 is dedicated for measurement of the transverse and longitudinal size of electron bunches with the use of the synchrotron radiation (SR) visible spectrum in single-bunch and multibunch modes and for study of time-dependent behavior of individual electron bunches with changing accelerator parameters. The article briefly describes the main components of the diagnostics and the experimental results.

A spectrometer based on a linear array photomultiplier tube (PMT) has been developed and calibrated. A 0.635 m focal length Czerny-Turner monochromator combined with a coupling optics provides an image of a narrow 0.5 nm spectral range with a resolution of 0.015 nm/channel on a 32-anode PMT. The system aims at spectroscopy of D(α) or H(α) lines emitted by a diagnostic atomic beam in a plasma (primarily a motional Stark effect diagnostics). To record a low photon flux of ∼10(6) s(-1) per channel with the time resolution of 100 μs, a pulse counting approach has been used. Wideband amplifiers scale single-electron pulses and transmit them to a digital data processing core hardwired in a programmable logic matrix. Calibrations have shown that the aberration-limited instrument function fits to a single detector channel of 1 mm width. Pilot results of passive measurements of D(α) light emission from the plasma confined in a magnetic trap are presented.

We present a prototype of the data acquisition system for Thomson scattering diagnostic of ITER divertor. The system allows the recording of the plasma scattered laser radiation beams. They have 1064 nm wavelength, 3 ns duration and 100 Hz - 1 kHz repetition rate. The system consists of 48 simultaneous sampling ADC modules with 10 bit total resolution and 2 GHz sampling rate. The digital units of the ADC modules use FPGA (Field-Programmable Gate Array) for data processing and storage.

An advanced neutral particle analyzer for the diagnostics of hot plasma has been designed and fabricated in the Budker Institute of Nuclear Physics. The analyzer measures the ion energy distributions of both bulk plasma ions as well of fast ions created by neutral beam injection. The main feature of the analyzer is the ability to simultaneously measure hydrogen and deuterium atoms. The design of the analyzer, calculation of registration efficiency, and possible applications for plasma diagnostics on GOL-3 and GDT facilities are presented.

The tokamak TEXTOR at the Research Centre in Julich is in operation since more than 25 years. The various control systems at the start, in 1982, were based on analogue techniques, a standard at the time, and were later partly replaced by specially developed digital systems. These systems proved their robustness over the years. As a replacement for the old system, off-the-shelf products were used to ensure continuity, reliability and to reduce the development cost. To provide advanced control scenarios, the new system allows the implementation of more sophisticated algorithms for magnetic and kinetic control. The LabVIEW Real-Time (RT) modules and real-time hardware from National Instruments satisfy these requirements to a large extent. The new system has already been successfully commissioned at TEXTOR and is used to calculate in real-time the plasma density profile (10 ms), the Shafranov shift (10 ms), the plasma vertical and horizontal position (20 mu s) and to control the plasma shape (1 ms). TEXTOR has circular plasmas and has an iron core. Its central part is operated in saturation. During the saturation phase, stray fields change the plasma shape from nearly circular to slightly triangular. By using a shape-control coil set, we can control and adjust the plasma form. The new real-time system is presented as well as the implemented control applications. (C) 2009 Elsevier B.V. All rights reserved.

A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction (7)Li (p, n)(7) Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction (13)C(p, gamma)(14)N, absorption in nitrogen. (C) 2008 American Institute Of Physics.

One year experience of dc H(-) source operation at 2 MeV tandem accelerator is described. The source delivers H(-) ion beams with controlled current in the range of 1-8 mA and energy up to 25 keV. Normalized 1 rms emittance for 8 mA beam is less than 0.2 pi mm mrad. Negative ions are produced on the cesiated anode of the Penning discharge, driven by plasma injection from the hollow cathode inserts.

The design and main characteristics of 14-channel dispersion interferometer for plasma profile measurement and control in TEXTOR tokamak are presented. The diagnostic is engineered on the basis of modular concept, the 10.6 microm CO(2) laser source and all optical and mechanical elements of each module are arranged in a compact housing. A set of mirrors and retroreflectors inside the TEXTOR vacuum vessel provides full coverage of the torus cross section with 12 vertical and two diagonal lines of sight, no rigid frame for vibration isolation is required. Results of testing of the single-channel prototype diagnostic and the pilot module of the multichannel dispersion interferometer are presented.

The status of a unique 2.0MeV, 10mA proton tandem accelerator with vacuum insulation is presented. The accelerator is intended to be used in facilities generating resonant gamma rays for explosives detection and epithermal neutrons for boron neutron-capture therapy of brain tumors. A magnetically coupled DC voltage multiplier derived from an industrial ELV-type electron accelerator is used as a high voltage source for the accelerator. A dc high current negative ion source has been developed for injection into the tandem. In the tandem accelerator there is set of nested potential electrodes with openings which form a channel for accelerating the negative hydrogen ion beam and subsequently accelerating the proton beam after stripping in the gas target. The electrodes are connected to a high voltage feedthrough insulator to which required potentials are applied from the high voltage power supply by means of a resistor voltage divider. In the paper the first experimental results obtained with the vacuum insulated tandem accelerator are also given.

Status of direct current hydrogen negative-ion source development for tandem accelerator is described. The electrodes enforcing its water cooling and introducing of the electrons’ interception permitted to increase the source discharge power and to obtain regularly the H−-ion beam with energy >25kV and current up to 15mA.

The results of the tandem commissioning as initial high voltage tests and beam injection experiments on BINP proton tandem-accelerator are given. The ac- celerator is intended to be used in facilities generat- ing resonant gamma rays for explosives detection and epithermal neutrons for boron neutron-capture ther- apy of brain tumors. A magnetically coupled DC voltage multiplier derived from an industrial ELV- type electron accelerator is used as a high voltage source for the accelerator. A dc high-current nega- tive ion source has been developed for injection into the tandem. In the tandem accelerator there is set of nested potential electrodes with openings which form a channel for accelerating the negative hydrogen ion beam and subsequently accelerating the proton beam after stripping in the gas target. The electrodes are connected to a high voltage feedthrough insulator to which required potentials are applied from the high voltage power supply by means of a resistor voltage divider.

Status of cw hydrogen negative ion source development for tandem accelerator of boron capture neutron therapy is described. The experimental source study and upgrade was continued. The electrodes enforcing, its water cooling and introducing of the electrons interception permitted to increase the source discharge power up to 0.7 kW and to obtain regularly the H- ion beam with energy 25 kV and current up to 8 mA. The experimental optimization and modelling of the beam formation is in progress. The flange version of the source is designed for cw beam study at the new test bed under construction.