Approach to the Highest HXR Yield in Plasma Focus Device Using Adaptive Neurofuzzy Inference System to Optimize Anode Configuration

Adaptive neurofuzzy inference system (ANFIS) is investigated to optimize the configuration of anode shape in plasma focus devices to achieve the highest X-ray yield. Variables of discharge voltage, filling gas pressure, and angles of anode slopes (Φ1 and Φ2) are chosen as input parameters, while the output is designated to be the radiated hard X-ray intensity. The trained ANFIS has achieved good agreement with the experimental results and has mean relative error percentages (MRE%) 1.12% and 2.18% for training and testing data, respectively. The study demonstrates that adaptive neurofuzzy inference system is useful, reliable, and low-cost way to interpret the highest X-ray yield and corresponding anode configuration in plasma focus devices. 1. Introduction Plasma foci are generally known as efficient, nonexpensive source of various pulsed radiations of high intensity including X-rays [1, 2], ions [3], electrons [4], and neutrons [5]. The onset of radiations coincides with compression of filling gas into pinched plasma which is observed by significant fall in the current signal. Occurrence of instabilities, which compress plasma volume, leads to induced electric field and local micron-sized plasma regions (hot spots) of high density and temperature. Apart from possibility of fusion reactions in the case of deuterium plasma, hot spots are identified as sources of intense X-ray emission as well as ion beams and pulsed electrons [6, 7]. Accelerated electrons often have high energies in excess of the quantity which would be imparted on by the applied voltage. Electron beams mainly hit the central metallic electrode and slightly the chamber’s wall emitting braking X-ray radiation of extensive continuous spectrum from soft up to hard X-ray on which characteristic lines represent the anode’s material mount. Various applications have been exploited from plasma foci’s radiations especially due to characteristics of reproducibility, compact size, and cheapness. Ion beams of desired gas are generally used for surface treatments [8, 9] as well as neutron beams for neutronic detection of hydrogen in samples [10, 11] and lithography by means of electron beams [12, 13]. X-rays, in particular, have extensive applications such as X-ray microscopy, X-ray lithography, micromachining, radiography, and material synthesis [14–21]. Radiography of the biological samples and X-ray imaging of moving metallic objects are two of the most noticeable applications of radiated hard X-ray in PF devices. HXR radiography of the biological samples [18, 22] which needs inevitable source