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ELECTRON BEAM EXTRACTION ON PLASMA CATHODE ELECTRON SOURCES SYSTEM. The electron beam extraction through window of Plasma Generator Chamber (PGC) for Pulsed Electron Irradiator (PEI) device and simulation of plasma potential has been studied. Plasma electron beam is extracted to acceleration region for enlarging their power by the external accelerating high voltage (Vext) and then it is passed foil window of the PEI for being irradiated to any target (atmospheric pressure). Electron beam extraction from plasma surface must be able to overcome potential barrier at the extraction window region which is shown by estimate simulation (Opera program) based on data of plasma surface potential of 150 V with Ueks values are varied by 150 kV, 175 kV and 200 kV respectively. PGC is made of 304 stainless steel with cylindrical shape in 30 cm of diameter, 90 cm length, electrons extraction window as many as 975 holes on the area of (15 65) cm 2 with extraction hole cell in 0.3 mm of radius each other, an cylindrical shape IEP chamber is made of 304 stainless steel in 70 cm diameter and 30 cm length. The research result shown that the acquisition of electron beam extraction current depends on plasma parameters (electron density ne, temperature Te), accelerating high voltage Vext, the value of discharge parameter G, anode area Sa, electron extraction window area Se and extraction efficiency value .

The development of silver (Ag) thin films and the fabrication of Ag nanosquare arrays with the use of an anodic aluminum oxide (AAO) template and leaf extracts were successfully carried out using the DC sputtering and spin coating deposition methods. Ag thin films and Ag nanosquare arrays are developed to monitor cancer prognosis due to the correlation between serum albumin levels and prognostic factors, as well as the binding of serum albumin to the surface of these electrodes. Nanosquare structures were fabricated using AAO templates with varying diameters and a gap distance between adjacent unit cells of 100 nm. The nanosquare array with a diameter of 250 nm and irradiated with electromagnetic waves with a wavelength of around 800 nm possessed the greatest electric field distribution compared to the other variations of diameters and wavelengths. The results of the absorption measurement and simulation showed a greater shift in absorption peak wavelength when carried out using the Ag nanosquare array. The absorption peak wavelengths of the Ag nanosquare array in normal blood and blood with cancer lymphocytes were 700–774 nm and 800–850 nm, respectively. The electrochemical test showed that the sensitivity values of the Ag thin-film electrode deposited using DC sputtering, the Ag thin-film electrode deposited using spin coating, and the Ag nanosquare array in detecting PBS+BSA concentration in the cyclic voltammetry (CV) experiment were 1.308 µA mM−1cm−2, 0.022 µA mM−1cm−2, and 39.917 µA mM−1cm−2, respectively. Meanwhile, the sensitivity values of the Ag thin film and the Ag nanosquare array in detecting the PBS+BSA concentration in the electrochemical impedance spectroscopy (EIS) measurement were 6593.76 Ohm·cm2/mM and 69,000 Ohm·cm2/mM, respectively. Thus, our analysis of the optical and electrochemical characteristics of Ag thin films and Ag nanosquare arrays showed that both can be used as an alternative biomedical technology to monitor the prognosis of blood cancer based on the concentration of serum albumin in blood.

Abstract:Objective:This research aims to determine corrosion behavior of SS316L biomaterial metals after plasma nitriding process. Methods:The plasma nitriding process on the surface of SS316L was performed at 350oC, 400oC, 450oC, 500oC, 550oC and 1.8 mbar nitrogen gas pressure for 3 hours. The surface Nitrogen concentration level distribution from the surface was examined using Energy Dispersive X-ray Spectroscopy, the phases formed after nitriding process were determined using X-ray Diffraction. The corrosion resistance was investigated using three-electrode cell polarization method. Result:The results showed that the percentage of nitrogen concentration atoms on the surface of the SS316L after plasma nitriding process was in range of 7.61-21.73%, in which the highest number 21.73% occurred at 500oC. Metal nitride formed on the surface of SS316L for all temperature variations are Fe4N, CrN and β-Cr2N phases were formed after nitriding process. Optimum corrosion resistance (8.21 x 10-4 mm/yr) occurs at 350oC.

Titanium nitride (TiN) thin film was successfully grown on the surface of stainless steel 304 (SS 304) and preparate glass using the direct current sputtering method. The fabrication was done at high voltage 2.5 kV, sputtering current 40 mA, and deposition time 1 hour. The characterization was carried out using a Micro Hardness Tester and UV-Vis Spectrophotometer. Based on mechanical properties, the hardness results of deposition on SS 304 obtained vickers hardness value of 153.59 HVN and thin film thickness was preparate glass 172.61 nm. Whereas optical properties, from testing the transmittance of thin films TiN measured at a wavelength range of 300 nm - 800 nm, the thin film TiN optical gap energy is 3.51 eV.

The fabrication of a ZnO/Au nanosquare-array electrode was successfully carried out for the detection of glucose concentration in biomedical applications. The fabrication of the ZnO/Au nanosquare array using an ultra-thin alumina mask (UTAM) based on the imprinted anodic aluminum oxide (AAO) template and the direct current (DC) sputtering method was able to produce a very well-ordered nanosquare arrangement with a side size of 300 nm and a thickness of 100 nm. Tests were done to evaluate the performance of the electrode by means of cyclic voltammetry (CV) which showed that the addition of glucose oxidase (GOx) increased the sensitivity of the electrode up to 1180 ± 116 μA mM−1cm−2, compared with its sensitivity prior to the addition of GOx of 188.34 ± 18.70 mA mM−1 cm−2. A iox/ired ratio equal to ~1 between the peaks of redox reactions was obtained for high (hyperglycemia), normal, and low (hypoglycemia) levels of glucose. The ZnO/Au nanosquare-array electrode was 7.54% more sensitive than the ZnO/Au thin-film electrode. Furthermore, finite-difference time-domain (FDTD) simulations and theoretical calculations of the energy density of the electric and magnetic fields produced by the ZnO/Au electrode were carried out and compared to the results of CV. From the results of CV, FDTD simulation, and theoretical calculations, it was confirmed that the ZnO/Au nanosquare array possessed a significant optical absorption and that the quantum effect from the nanosquare array resulted in a higher sensitivity than the thin film.

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Abstrak – Telah dilakukan penentuan  parameter elektron plasma dalam Bejana Emiter (BE) berbasis besar arus lucut busur gas udara pada tegangan 10 kV untuk Ignitor Discharge Power Supply (IDPS) dan tegangan anoda 1 kV untuk Arc Discharge Power Supply (ADPS).  Tekanan gas udara divariasi mulai dari 5,70 × 10-3 Torr  hingga 7,90 × 10-3 Torr.  BE terbuat dari Stainless Steel-304 (SS-304) silinder berdiameter ф = 4,00 cm dan panjang l = 66 cm, dipasangi grid berukuran 60 cm × 2,6 cm dan ditutup dengan frame yang terdiri dari 15 grup lubang (masing-masing berisi 10 lubang kecil berdiameter ф = 0,4 cm).  Dari hasil eksperimen pada tekanan gas udara sekitar 6,8 × 10-3 Torr diperoleh arus berkas elektron pulsa terekstraksi sebesar 4,17 A pada tegangan tinggi ekstraksi 5 kV.  Berdasarkan arus elekton terekstraksi tersebut, diperoleh kerapatan elektron plasma ne sebesar 3,15 × 1012 partikel/cm3 dan suhu elektron plasma Te  sebesar 1,77 × 104 K ≈ 1,50 eV.Kata kunci: emitter, plasma, bejana emiter (BE), lucutan, kerapatan, suhu Abstract – The determination of plasma electron parameters in the Emitter Vessel (EV) based on arc dischage value of air gas has been conducted at 10 kV of Ignitor Discharge Power Supply (IDPS) and 1 kV of anode voltage for Arc Discharge Power Supply (ADPS).  The air gas pressure was varied from 5.70 × 10-3 Torr to 7, 90 × 10-3 Torr.  The EV was made from Stainless Steel-304 (SS-304) cylindrical shape with diameter ф of 4.00 cm and length l of 66 cm, fitted with 60.00 cm × 2.60 cm grid and covered with a frame consisting of 15 groups of holes (each containing 10 holes small diameter ф of 0.4 cm).  From the experiment result at the average air gas pressure of about 6.80 × 10-3 Torr, it was obtained 4.17 A of extracted pulse electron beam current at 5 kV of extracted high voltage.  Based on that extracted electron beam current, it was obtained 3.15 × 1012 particles/cm3 of plasma electron density ne and 1.77 × 104 K ≈ 1.50 eV of plasma electron temperature Te. Key words: emitter, plasma, emmiter vessel (EV), discharge, density, temperature