Jacek Kaczmarczyk

Mobile stands for multi-channel high bandwidth acquisition of transient electrical signals

Mobile stands for multi-channel recording of fast transient electrical signals are presented in this paper. The design of the mobile stands and all additionally employed equipment provides efficient shielding against electromagnetic interference and allows carrying out data acquisition in a harsh electromagnetic environment. Some examples are given of the results obtained by means of the data acquisition system based on the mobile stands.

Application of high-speed photography to the study of the plasma-focus PF1000 device

This paper presents the multi-frame image-capturing system based on a few simultaneously operating high-speed photography subsystems, capable of acquiring plasma images in different parts of radiation spectra, i.e. in a visible as well as soft X-ray spectral range. The passive optical diagnostic subsystem allows recording frame sequence and streak images of plasma in visible spectrum. It consists of the streak camera and the high-speed four-frame camera. The high-speed four-frame camera is based on of the first generation image intensifiers and is able to acquire images of plasma originating in plasma-focus phenomena with minimal estimated optical gate time of about 1 ns. The two cameras based on an open microchannel plate devices allow recording four-frame plasma images in a soft X-ray range with estimated X-ray gate time of about 2 ns. All presented high-speed photography subsystems are equipped with digital readout. Some examples of the results obtained by means of the multi-frame image-capturing system, are given in the final part of the paper.

Nanosecond x-ray frame cameras for plasma-focus device imaging applications

This paper presents the construction details of the X-ray frame cameras and the gating pulse generating systems applied to the dynamic supplying of open microchannel plate-based devices. Presented cameras are equipped with digital readout and are able to acquire one-frame or four-frame images of plasma originating in plasma-focus phenomena with minimal estimated X-ray gate time of about 800 ps. Some examples of the results obtained by means of the nanosecond X-ray frame cameras, are given in the final part of the paper.

Comparison of silicon drift detectors made by Amptek and PNDetectors in application to the PHA system for W7-X

Abstract The paper presents comparison of two silicon drift detectors (SDD), one made by Amptek, USA, and the second one by PNDetector, Germany, which are considered for a soft X-ray diagnostic system for W7-X. The sensitive area of the first one is 7 mm2 × 450 μm and the second one is 10 mm2 × 450 μm. The first detector is cooled by a double-stage Peltier element, while the second detector is cooled by single-stage Peltier element. Each one is equipped with a field-effect transistor (FET). In the detector from Amptek, the FET is mounted separately, while in the detector from PNDetector, the FET is integrated on the chip. The nominal energy resolution given by the producers of the first and the second one is 136 eV@5.9 keV (at -50°C) and 132 eV@5.9 keV (at -20°C), respectively. Owing to many advantages, the investigated detectors are good candidates for soft X-ray measurements in magnetic confinement devices. They are suitable for soft X-ray diagnostics, like the pulse height analysis (PHA) system for the stellarator Wendelstein 7-X, which has been developed and manufactured at the Institute of Plasma Physics and Laser Microfusion (IPPLM), Warsaw, in collaboration with the Max Planck Institute for Plasma Physics (IPP), Greifswald. The diagnostic is important for the measurements of plasma electron temperature, impurities content, and possible suprathermal tails in the spectra. In order to choose the best type of detector, analysis of technical parameters and laboratory tests were done. Detailed studies show that the most suitable detector for the PHA diagnostics is the PNDetector.

Application of High-Speed Photography Methods to the Studies of the Plasma Sheath Structure in Plasma-Focus Phenomenon

This paper presents the two methods enabling to determine distributions of electron density and/or electron temperature of the plasma sheath originating in plasma-focus phenomenon. These methods are based on theoretical considerations and processing of experimental results taken by means of high-speed frame photography in narrow band of visible spectrum and multi-frame laser interferometry. Both high-speed photography subsystems can operate simultaneously with sub nanosecond accuracy and allow recording frame sequence of plasma with temporal resolution of about 1 ns and spatial resolution of about 0.1 mm. They are also equipped with digital readout. The detailed explanations and considerations concerning presented methods are exemplified by results obtained in experimental investigations.

Multiframe optical cameras for visualization of ultrahigh-speed phenomena

This paper presents the construction details of the multi-frame optical cameras and the gating pulse generating system applied to the dynamic supplying of the first generation image intensifiers. Presented cameras are equipped with digital readout and are able to acquire multi-frame images of investigated object with minimal estimated optical gate time of about 1 ns. The special method and suitable experimental arrangement are proposed in order to determine an actual optical gate time of the gated image intensifiers. Some examples of the results obtained by means of the multi-frame optical cameras, are given in the final part of the paper.