M. M. Stepanenko

Cauchois–Johansson x-ray spectrograph for 1.5–400 keV energy range

A Cauchois–Johansson optical scheme is proposed, based on a specially designed cylindrical quartz crystal. The corresponding x-ray spectrograph is manufactured, which provides high spectral resolution in transmission and reflection regimes and covers the wide energy range of 1.5–400 keV. The device is calibrated with an x-ray tube and is suggested to be used in high-temperature plasma diagnostics.

Vacuum photodiode detectors for soft x-ray ITER plasma tomography

A special type of vacuum photodiode detector (VPD) for x-ray tomography of (ITER) plasma is described. Laboratory experiments demonstrate that VPD has high sensitivity to thermal x-rays and low sensitivity to hard gamma rays and neutrons. It was shown that in ITER environment the signal due to thermal x-rays will surpass the background signal by more than a factor of 100.

X-ray spectropolarimeter

We have constructed a novel single-crystal x-ray spectropolarimeter that separates spatially the two perpendicularly polarized components of an x-ray beam. We have tested this device by using an x-ray tube, and confirmed its performance to be satisfactory as expected from its design.

A low-voltage ionization chamber for the ITER

An ionization chamber with an operating supply voltage of 10 V has been designed for use at the ITER. The sensitivity of the chamber filled with air at atmospheric pressure is 100–200 times higher than the sensitivity of the chamber pumped down to a pressure of 10−3–10−4 Torr. It is shown that application of the supply voltage modulation technique allows the pickup noise to be substantially reduced; as a result, the amplifier can be located at a large (70–100 m) distance from the chamber. Results of the experiments aimed at testing this technique on the T-10 facility are described.

The radiation-tolerant x-ray monitor

A vacuum photoelectric detector (monitor) (VPD) designed for plasma tomography, megnetohydrodynamics monitoring, and imaging with the help of thermal x-ray radiation on the ITER facility is described. Laboratory experiments demonstrate that VPD has high sensitivity to thermal x rays and low sensitivity to hard gamma rays and neutrons. The results of tests of a prototype of this monitor on a (60)Co source of gamma rays, on nuclear reactor and its calibration using radiation from an x-ray tube, and tests of its serviceability on the T-10 facility are presented.

Radiation-tolerant X- and γ-ray detectors

Radiation-tolerant X-ray detectors capable of operating in vacuum, a low-voltage ionization chamber, and a γ detector, as well as a noise compensation system allowing location of all electronic devices at a distance of at least 70 m from the detectors, are described. Owing to the simplicity of their design, these detectors can be adapted for any specific conditions. These detectors are intended for operation in high- intensity γ-ray and neutron fields; in particular, they can be used on the ITER tokamak reactor.

Testing LaMgAl11O19 crystal for x-ray spectroscopy

We investigated the properties of the rare earth crystal LaMgAl11O19 and its application to soft x-ray spectroscopy. Its relative reflectivity and half-width rocking curve were measured to up to the reflection order of 28. In addition, a comparative measurement of the iron L-shell soft x-ray line emission was made on the EBIT-I Livermore electron beam ion trap by fielding the LaMgAl11O19 crystal side by side with a rubidium hydrogen phthalate crystal in a flat crystal spectrometer. From these measurements, reflectivity and spectral resolving power were determined.

偏光プラズマ分光 6.X 線偏光分光における装置技術:結晶分光器, 偏光子, 天体観測のための検出器

This report discusses the various problems which are encountered when a crystal spectrometer is used for the purpose of observing polarized x-ray lines. A polarimeter is proposed based on the novel idea of using two series of equivalent atomic planes in a single crystal. The present status of the astronomical x-ray detection techniques are described with emphasis on two dimensional detectors which are polarization sensitive.