[en] In STP-3(M) reversed-field pinch plasma, the bursts of soft X-rays are periodically observed in association with the toroidal flux regeneration (dynamo action) using surface barrier diode (SBD). The soft X-ray bursts result from high energy electrons colliding with the surface of metal liner and limiters. The energy of colliding electrons analyzed by the absorber method assuming a monochromatic distribution, is found to have a distribution of 2 ∼ 8 keV. The energy of 8 keV is observed at about 100 μs before the termination of the plasma current. The mechanisms of the acceleration and the anomalous diffusion for these high-energy electrons are discussed. (author)

[en] Silicon Surface Barrier detector has been used to study the invariance of alpha decay rate under lattice compression using unstable Astatine ions implanted in Palladium and Silicon foils. To study the change in alpha decay rate with high precision, it was necessary to achieve a good energy resolution of the detector. The detector and preamplifier were placed inside the vacuum chamber and cooled up to 213 K. An enhancement in the energy resolution of Silicon Surface Barrier detector has been achieved from 110 keV at 300 K to 40 keV at 213 K for 5869.5 keV alpha line. The cooling technique and the results will be presented.

[en] Surface barrier diodes have been prepared by chemical deposition of thin gold film on samples of GaAssub(1-x)Psub(x) with x=0.3. The spectrum of the photo-response over a spectral range covering the photo-injection from the metal and the intrinsic absorption regions of the semiconductor has been measured. From the photo-threshold corresponding to each region, the height of the energy barrier and the forbidden gap width of the semiconductor have been determined and are found to be 0.96 e.v. and 1.78 e.v. respectively for the investigated composition. (author)

[en] A diagnostic system of soft x-ray diode-array was set up for HT-7 superconducting tokamak. The system consists of two slot-aperture cameras and is capable of measuring the soft x-ray emission from the plasma on HT-7 device with a high resolution in space and a high response in time. Both cameras, located separately in a horizontal port and a vertical port each with thirty-seven detectors of Au-Si surface-barrier diode (SBD) can view the same toroidal cross-section of the plasma from different poloidal chords. The structure, principle and performance of the diagnostic system are described and some experimental results observed are presented

No abstract available

[en] A thermal activation mechanism of dislocations in the gallium arsenide surface barrier structures was considered on the base of the lattice mismatch accommodation model. (author). 4 refs., 5 figs

[en] Taylor's theory of relaxed states, which defines relaxed Reversed Field Pinch equilibria independently of the mechanism of relaxation is briefly reviewed. An account is then given of a number of mechanisms put forward to explain relaxation and reversed field generation, processes which can also lead to anomalous transport. Finally, studies of fluctuations in the HBTX1A Reversed Field Pinch using edge coils, insertable probes and surface barrier diode X-ray detectors are described in which a variety of unstable modes are identified. The questions of the origin of these modes, their possible role in relaxation and field generation and their effect on transport is discussed in a preliminary fashion

No abstract available

[en] A Si semiconductor detector, surface barrier type, with a slim film of a converter material capable to produce charged particles was used as a sensor of neutrons in an environment of a zero power reactor. Two types of converters were used to improve the detection efficiency: (1) the polyethylene, n(CH₂), which produces recoil protons from the (n,p) interaction and, (2) the ¹⁰B which generates a particle from the (n,alpha) reaction. The optimal thickness of those converters was determined experimentally and specifically for the polyethylene a mathematical model R(ips) = ε_p · N₀ ·(1-e^-Σ·Χ) ·e ^-μ·Χ + ε_n · N₀ · ^-Σ · Χ was used to fit to the experimental data. For the polyethylene converter the thickness was of 0.058 cm (62.64 mg.cm^-2) while for the ¹⁰B it was equal to 6.55 [μm (1.54 mg.cm^-2). The converter of polyethylene or ¹⁰B improved the detection efficiency to a factor of 4.7 and 3.0 respectively. The comparison of the spectrum of the background radiation with the spectra of the recoil protons and the a radiation from the ¹⁰B it was concluded that the polyethylene presented better performance than the ¹⁰B converter. (author)

[en] Large amplitude low frequency (0.7-2.5 kHz) oscillations which are in phase across the minor radius have been observed in soft X-ray emission since the removal of limiters from HBTX1B Reversed Field Pinch for plasmas with small field reversal, F, at all toroidal currents. These oscillations, due to variations in electron temperature, are in antiphase with oscillations in plasma resistance and ion temperature and occur in the majority of discharges where the resistance is closest to its lowest value. Correlated magnetic oscillations indicate cyclic behaviour in the F-θ plane similar to that observed at high values of θ on other experiments, where θ is the pinch parameter. (author)