Browsing by Author "Chuaqui Kettlun, Hernan"
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- ItemHigh current electron beam generation in a vacuum transient hollow cathode discharge(1993) Chuaqui Kettlun, Hernan; Favre Dominguez, Mario Benjamín; Soto Norambuena, Leopoldo Alejandro; Wyndham Hodder, Edmund SydenhamExperimental observations are presented of prebreakdown electron beam generation in a transient hollow cathode discharge (THCD) in a vacuum. The discharge driver consists of a 400-kV maximum voltage, 25-nF Marx operated at 450-J stored energy coupled to a 120-ns, 1.5- Omega coaxial line. Electron beams with peak currents up to tens of kA are observed when a pulsed Nd:YAG laser is used to produce a plasma at the back of the cathode surface, inside the hollow cathode region (HCR). It is found that a plasma density of a few 10/sup 18/ cm/sup -3/ in a volume of a few mm/sup 3/ is required to generate intense electron beams. Optimal conditions are determined by varying the position of the laser focal spot inside the HCR and the time delay between the laser and the applied voltage. The main features of the electron beams are similar to those observed in conventional THCD at pressures in the 10-200 mtorr range.<>
- ItemReproducibility of a titanium plasma vacuum spark discharge(2005) Wyndham Hodder, Edmund Sydenham; Favre Dominguez, Mario Benjamín; Chuaqui Kettlun, Hernan; Choi, P.; Leñero Marchanat, Ana María; Diaz Poblete, Jorge SamuelThe results of an extensive operation of a vacuum spark plasma using Titanium electrodes in a 120-ns 150-kA discharge are presented. The hot spots are found to form with a regular spacing in a zippering Z-pinch plasma, which forms close to the cathode and extends to approximately two thirds of the anode separation over a period of a few nanoseconds. The axis of the discharge is well defined by an initial plasma from a Nd:YAG laser focussed onto the cathode electrode surface. The statistics of the formation of the hot spots are given for the life of one anode electrode. Between one and three hot spots form and the favored positions are at 1.5 and 3.0 mm from the cathode and the strongest emission, as observed in a filtered X-ray pinhole camera, comes from the hot spot closest to the cathode. The emission spectra resolved between 5 and 35 nm shows a wide range of Ti ionization which allows the temperatures of the anode blow off plasma, the Z-pinch and the hot spot plasma to be distinguished. These results are compared with filtered PIN diode signals and filtered pinhole images. The emission spectrum and the statistics of the axial localization of the hot spots are discussed in the context of potential applications to extreme-ultraviolet lithography.