V. Bohacek

Soft X-ray emission of a fast-capillary-discharge device

The paper reports on some technological modifications of the capillary discharge device, especially in the spark gap region. Passively generated pre-pulse plasma was replaced by an external driver, which can independently control a pre-ionisation capillary current. The time development of the axial soft X-ray radiation of the modified capillary discharge device is reported as well.

Comparison of computed and measured parameters of a driver for fast capillary discharge

The authors were attracted by numerous applications of coherent soft X-rays and decided to build a fast capillary discharge, despite it is generally understood as a relatively sophisticated apparatus. From the beginning they paid great attention to its design: they performed a lot of modelling and optimisation. The present paper aims at comparison of the designed (computed) parameters with the measured value.

Amplification of spontaneous emission of neon-like argon in a fast gas-filled capillary discharge

The evolution of the CAPEX facility and its basic diagnostics are described. The experiments carried out in the last modification of this facility accomplished with the demonstration of amplified spontaneous emission of neon-like argon (Ar8+) at the wavelength 46.88 nm. The first version of the facility, CAPEX1, operated with a plastic capillary and had a short high-power passive prepulse and an imperfect gas-filling system. In the second version, CAPEX2, a ceramic capillary was used, the prepulse amplitude was lowered, and the gas-filling system was improved. In the third, most successful version, CAPEX3, the capillary bending was reduced, a longer external prepulse was used, and the gas-filling system was further optimized. For each version, results of X-ray measurements are presented and interpreted.

Design of a laser-triggered driver for fast capillary discharge

We are developing a new upgraded capillary discharge device. The assembled set-up consists of a Marx generator, a pulse forming line, a gas-filled laser-triggered spark gap and a ceramic capillary. The special attention has been paid to the design of the spark gap. The laser triggering of this spark gap ensures a very low jitter in comparison with the present capillary discharge device CAPEX, where the main spark gap works in a self-breakdown regime. The description of the assembled apparatus, the main predicted parameters of the designed device (such as capillary current, capillary current rise-rte, and/or voltage at the end of pulse forming line) are presented.

Strong Amplification of Ne-like AR line in the Source Based on Capillary Discharge

For the first time we have used a surveillance homemade flat field XUV spectrograph for the measurement of soft X-ray emission from the capillary discharge device CAPEX when using of an external capillary pre-pulse driver. The time-resolved XUV spectrum is presented. It was found that a very short intense spike that had been measured by a vacuum photodiode likely corresponds to a laser pulse. Modifications/assemblies of the spark gap switch the capillary, and the fast electromagnetic shutter are described as well.

Gas-filled laser-triggered spark gap

We report 200 ps jitter operation of high-voltage air/nitrogen pressurized spark gap triggered by 850 mJ/5 ns Nd:YAG laser. It is studied the delay and the jitter of this spark gap as a function of voltage, energy of laser pulse, gas pressure and angle of incidence of the laser beam. These experiments will resulted in recommendation for construction of low-jitter spark gap in our new pulse-capillary-discharge driver.

Soft X-ray radiation of fast-capillary-discharge CAPEX 2

The paper reports on technological modifications of the capillary discharge experiment CAPEX, especially in capillary region. A temporal evolution of axial soft X-ray radiation and a spectroscopic measurement in the soft X-ray region on the modified capillary are presented as well. The strong spectral line at the wavelength of laser transition (Ne-like Ar, γ=46.9 nm) was observed.

Properties of soft X-ray emission from a fast capillary discharge

Results are presented from experimental studies of the time resolved, spatially resolved, and spectrally resolved soft X rays emitted along the axis of a fast capillary discharge.

A laser-triggered driver for fast capillary discharge device

We are developing a new upgraded capillary discharge device. The assembled set-up consists of a Marx generator, a pulse forming line, a gas-filled laser-triggered spark gap and a ceramic capillary. Special attention has been paid to the design of the spark gap. The laser triggering of this spark gap ensures a very low jitter in comparison with the present capillary discharge device CAPEX, where the main spark gap works in a self-breakdown regime. The description of the assembled apparatus, the main predicted parameters of the designed device (such as capillary current, capillary current rise-rate, and voltage at the end of pulse forming line) are presented

Interactive system for the interpretation of atomic spectra

A method described in this paper enables the simplification and specification of the process of interpreting some spectroscopic measurements. Tabulated spectroscopic data are transformed into the form that provides a clear idea of mutual proportions of spectral line intensities of the given element depending on the selected temperature.