Duplex multiwire proportional x-ray detector for multichord time-resolved soft x-ray and electron temperature measurements on T-10 tokamak

Abstract

Compact 64-channel multiwire proportional chamber is successfully used on T-10 and TCV tokamaks as a continuous-current soft x-ray detectors. The duplex multiwire proportional x-ray detector is a new generation of these detectors. It has been designed for simultaneous multichord measurement of plasma soft x-ray emissivity in a two spectral ranges and determination of the electron temperature by the two-absorber method. The detector consists of two identical multiwire proportional chambers filled by 90%Kr+10%CH(4) gas mixture at atmospheric pressure. The first multiwire chamber has 64 channels. The second multiwire chamber (installed behind the first one) has 32 channels. Both chambers view the plasma through the one helium-filled slot-hole camera. Thus, the first multiwire chamber serves as an absorber filter for the second one. Such construction of the detector allows us in addition to soft x-ray measurements to provide measurement of the plasma core electron temperature with spatial resolution of about 2 cm and a time resolution of less than 50 mus. The construction of the detector and experimental results illustrating the potential of the diagnostic are presented.

Experimental demonstration of an up-down asymmetry effect on intrinsic rotation in the TCV tokamak

“…and temperature measurements over the whole collection window as a function of the radial coordinate ρ ψ , together with the error bars and a cubic spline fit with tension. The sawtooth inversion radius estimated from soft x-ray measurements with a multiwire chamber operated in the proportional regime [58] is also indicated in the figure by a dashed line. The spatial resolution of the soft x-ray measurement is ρ ψ < 0.05 at the midplane of the vacuum chamber.…”

Restoration of the Plasma Stability During Density Limit Disruption in T-10 Tokamak Using Ecrh and Ohmic Power Suply Systems

“…Детекторы AXUV обеспечивают мониторинг излучения, возникающего во время срыва из-за радиационного рассеяния и возбуждения фоновой плазмы и примесей надтепловыми электронами [28]. Внутренняя структура МГД-возмущений определялась с помощью томографических измерений интенсивности мягкого рентгеновского излучения с помощью 2D-наборов поверхностно-барьерных кремниевых диодов [29] и газовых многопроволочных детекторов [30]. Для регистрации жёсткого рентгеновского и гамма-излучения (E  ~ 0,5-3 МэВ) использовались мониторы NaI(Tl), расположенные снаружи вакуумной камеры в различных сечениях токамака Т-10.…”

A study on the effects of magnetohydrodynamic perturbations on nonthermal beam formation during the current decay phase of disruptions in the T-10 tokamak

“…The nonthermal bursts are analysed using CdTe detectors with toroidal and orthogonal views of the plasma column, standard x-ray tomographic systems [14], x-ray gas detectors [17], silicon absolute extreme ultraviolet (AXUV) detectors [18] and electron cyclotron emission (ECE) radiometers [19] (see figure 2). An additional NaI(Tl) monitor (placed outside the tokamak vessel) is used for measurement of the nonthermal (E γ ∼ 0.5 − 3 MeV) x-ray and neutron radiation.…”