RESUMEN
Microchannel plate (MCP) photomultiplier tubes (PMTs) are frequently used in experimental diagnostics, where they are operated in single-pulse current measurement mode. However, considering the significant amplitude fluctuations in the measured signal, the resulting output signal from the MCP-PMT is inevitably distorted by gain saturation. Therefore, understanding the correlation between the MCP-PMT output signal and gain saturation is critical in assessing the extent of output signal distortion and determining the MCP-PMT saturation level. This knowledge allows for a more precise assessment of the input signal's features. In this paper, we present an experimental method for restoring the initial waveform from the saturated MCP-PMT signal. To correct the amplitude-drop caused by gain saturation, our technique involves calibrating the MCP-PMT's relative gain as a function of the accumulated output charge using a square-wave light source. We then applied this approach to restore a â¼500 ns saturated pulse from a double-layer 10 mm diameter MCP-PMT. The restored signal showed a deviation of less than 6% from the reference waveform, which validates the effectiveness of the technique.
RESUMEN
A thin film plastic scintillator detector has been developed for the measurement of radiation power and yield of soft x rays produced from Z-pinch implosion. To enable soft x-ray measurements using plastic scintillators, the detector geometry has been specially designed to minimize visible light and alleviate nonlinear behavior. Energy response has been calibrated, and saturation effects have been explored and described in details. The possibility and limitation of its application to such high-density radiation bursts are analyzed. The detector has been fielded on several meters away in vacuum pipes for hundreds of shots at different Z-pinch facilities, and the measured data in these experiments agreed well with the results from other diagnostics, demonstrating the feasibility and reliability of the detector.
RESUMEN
A free-standing thin foil bolometer for measuring soft x-ray fluence in z-pinch experiments is developed. For the first time, we present the determination of its sensitivity by different methods. The results showed great consistency for the different methods, which confirms the validity of the sensitivity and provides confidence for its application in z-pinch experiments. It should be highlighted that the sensitivity of a free-standing foil bolometer could be calibrated directly using Joule heating without any corrections that will be necessary for a foil bolometer with substrate because of heat loss. The difference of the waveforms between the free-standing foil bolometer and that with substrate is obvious. It reveals that the heat loss to the substrate should be considered for the latter in despite of the short x-ray pulse when the peak value is used to deduce the total deposited energy. The quantitative influence is analyzed through a detailed simulation.
RESUMEN
High energy photons are measured for the first time in wire-array Z-pinch experiments on the Primary Test Stand (PTS) which delivers a current up to 8 MA with a rise time of 70 ns. A special designed detecting system composed of three types of detectors is used to measure the average energy, intensity, and pulse waveform of high energy photons. Results from Pb-TLD (thermoluminescence dosimeter) detector indicate that the average energy is 480 keV (±15%). Pulse shape of high energy photons is measured by the photodiode detector consisted of scintillator coupled with a photodiode, and it is correlated with soft x-ray power by the same timing signal. Intensity is measured by both TLD and the photodiode detector, showing good accordance with each other, and it is 10(10) cm(-2) (±20%) at 2 m in the horizontal direction. Measurement results show that high energy photons are mainly produced in pinch regions due to accelerated electrons. PTS itself also produces high energy photons due to power flow electrons, which is one order smaller in amplitude than those from pinch region.
RESUMEN
We report a specially designed type of temporal resolved x-ray spectroscopic diagnostic using a spherically bent quartz crystal for z-pinch plasmas. Registration of time-resolved spectra was accomplished by coupling fast plastic scintillator, an optical fiber array, an optical streak camera, and a charge coupled device as the recording medium of this diagnostic. The diagnostic has been tested in imploding wire array experiments on S-300 pulsed power facility. Time-resolved K-shell lines were successfully obtained for aluminum wire array implosion plasmas.
