The experimental results of the arc lifetime, the arc voltage, the cathode spot velocity and the erosion structure influenced by the cathode surface microstructure for low-current DC vacuum arcs are presented. The correlation between the arc voltage instability peak and the discontinuity in the cathode erosion trace has been shown when applying a transversal magnetic field. With increasing cathode surface roughness, an increase (of about a factor of 100) in the arc lifetime and a 30% decrease in arc voltage at the most, has been found for a drawn arc. The increase of the cathode spot velocity of the retrograde motion by cathode roughness is significant (a hundred times different at most) for triggered arcs. The mechanism of the cathode surface microstructure influence on the DC arc stability is discussed.

An electrode configuration with microhollow array dielectric and anode was developed to obtain parallel vacuum arc discharge. Compared with the conventional electrodes, more than 10 parallel microhollow discharges were ignited for the new configuration, which increased the discharge area significantly and made the cathode eroded more uniformly. The vacuum discharge channel number could be increased effectively by decreasing the distances between holes or increasing the arc current. Experimental results revealed that plasmas ejected from the adjacent hollow and the relatively high arc voltage were two key factors leading to the parallel discharge. The characteristics of plasmas in the microhollow were investigated as well. The spectral line intensity and electron density of plasmas in microhollow increased obviously with the decease of the microhollow diameter.

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.

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.

A scintillator detector consisting of LaBr3(Ce) (0.5%) scintillator and PMT, and an oscilloscope were used to study the neutron sensitivities of LaBr3(Ce) scintillator at the CSNS Back-n white neutron source in the double-bunch and single-bunch operation modes, respectively. Under the two operation modes, the relative neutron sensitivity curves of the LaBr3(Ce) scintillator in the energy region between 1 and 20 MeV, and 0.5 and 20 MeV were obtained for the first time. In the energy range of 1-20 MeV, the two curves were nearly identical. But the relative neutron sensitivity uncertainties of the double-bunch experiment were higher than those of the single-bunch experiment. The above results indicated that the single-bunch experiment's neutron sensitivity curve has a lower minimum measurable energy than the double-bunch experiment. Above the minimum measurable energy of the double-bunch experiment, there is little difference between the measured relative neutron sensitivity curves of the single-bunch and double-bunch experiments of the LaBr3(Ce) scintillator and those of other scintillators with a similar neutron response signal intensity.