P G Reyes

Experimental study of single-electron loss by Ar + ions in rare-gas atoms

Absolute differential and total cross sections for single-electron loss were measured for Ar+ ions on rare-gas atoms in the laboratory energy range of 1.5 to 5.0 keV. The electron loss cross sections for all the targets studied are found to be in the order of magnitude between 10-19 and 10-22 cm2, and show a monotonically increasing behaviour as a function of the incident energy. The behaviour of the total single-electron loss cross sections with the atomic target number, Zt, shows different dependences as the collision energy increases. In all cases the present results display experimental evidence of saturation in the single-electron loss cross section as the atomic number of the target increases.

Biodistribution in rats and estimates of doses to humans from 64CuCl2, a potential theranostic tracer

The aim of this study was to obtain data on the biodistribution of (64)CuCl2 in rats and to obtain estimates of the radiation doses to humans by extrapolating the animal data. MicroPET imaging and biodistribution studies were carried out with Wistar rats, and the doses were estimated with OLINDA/EXM. The lower large intestine wall was found to be the critical organ with an absorbed dose of 139±34 and 125±32µGy/MBq for females and males, respectively. The corresponding effective doses were estimated as 47±4 and 39±4µSv/MBq.

Paschen law for argon glow discharge

Electric discharge between two electrically charged surfaces occurs at a well-defined, gas-dependent combination of atmospheric pressure and the distance between those surfaces, as described by Paschens law. The understanding of when the discharge will occur in an Ar discharge is essential basic knowledge. A glow discharge apparatus was used in this experiment of Ar discharge at a pressure range between 2.0 Torr and 12 Torr, a power of 20 W and 40 l/min flow rate of gases. The optical emission spectroscopy was carried out in the wavelength range of 200 to 1100 nm. Here, we present experimentally measured plasma Paschen curves for Ar gas and compare our results of breakdown voltages with the literature. The minimum voltage measured for a discharge in Ar atmosphere was 215 ± 2.2 at 0.7 Torr-cm, which agree with previous measurements.

Study of the Rogowski coil response in a plasma focus device

In plasma physics is very important understand the behaviour and amplitude of high intensity currents. The high intensity current pulses are measured by resistive and inductive sensors. Coil configurations are employed in the same form as inductive sensors. Rogowski coil is a representative example; that coil consists of a toroidal-shaped winding. In this work we built a Rogowski coil. The coil operation was realized in a plasma focus device. The results show a good performance. We also used the coil to measure the current and voltage changes with respect to time, during the normal operation of the plasma focus device. The maximum value of the current (348kA) was obtained. As a complementary work, we analysed the results by changing the central electrode of the device (needle electrode, gap electrode and plane electrode). It founds that the pinch time is independent of the configuration of the central electrode.

Measurements of electron temperature, and ion density, in a mixture of O2 and Ar plasma

Optical emission spectroscopy was applied for plasma characterization of a gas mixture glow discharge of O2 and Ar at a total pressure of 1.0 Torr, power of 150 W, and with 40 l/min flow rate of gases. The main diagnostic techniques applied to determine the plasma parameters were optical and probe diagnostics. We study the dependence of the electron density and temperature as a function of the relative O2 concentration. The emission bands and lines were measured using a monochromator in the wavelength range from 200 to 1000 nm. We also study the dependence of the principal band intensities observed as the relative O2 concentration was increasing from 0 to 100 % of the mixture.

Characterization of Ethanol Plasma Glow Discharge, Decomposition in Several Species and Solid Film Formation

Ethanol plasma produced in low pressure with constant flux has been characterized in situ by optical emission spectroscopy (OES) and a Langmuir probe. From these methods, hydrogen and carbon monoxide are the main products from the ethanol decomposition in the plasma. In addition, C2, OH, CH, O+2 , and Hα species were identified. The values obtained for electron density and temperatures were 1.26 × 1018 m-3 and 1.16 eV, respectively. The mass deposited (MD) on the electrode was analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy (FT-IR) techniques. The morphology of the MD changes as a function of the discharge time from thin film to a cluster formation. The FT-IR results show that the main absorbance corresponds with C-H bonds, indicating that the mass deposit is formed mainly by this molecular fraction, which agrees with the CH species identified as the less abundant molecule in the plasma by OES. In addition, C≡C, O-H, C-H, C=C, and C-O bonds were identified.

Striations in an ethyl alcohol glow discharge

This research shows the behavior of striations in glow discharge generated with high purity ethyl alcohol at a pressure of 0.6 Torr. This paper present the number of striations as a function of the of current and voltage discharge.

Analysis of green fluorescent protein bioluminescence in vivo and in vitro using a glow discharge

The discovery of fluorescent proteins has been a revolution in cell biology and related sciences because of their many applications, mainly emphasizing their use as cellular markers. The green fluorescent protein (GFP) is one of the most used as it requires no cofactors to generate fluorescence and retains this property into any organism when it is expressed by recombinant DNA techniques, which is a great advantage. In this work, we analyze the emission spectra of recombinant green fluorescent protein in vivo and in vitro exposed to a glow discharge plasma of nitrogen in order to relate electron temperature to fluorescence intensity.

Study of N2/He DC glow discharge

Optical emission spectroscopy and mass spectrometry measurement were used to study a gas mixture glow discharge of He and N2 at total pressure of 2.0 Torr, a power of 10 W and a flow of 16.5 l/min. The emission bands were measured in the wavelength range of 200 to 1100 nm. The principal species observed were N2+ (B2Σ+u→X2Σ+g), N2 (C3Πu→B3Πg), and He, which agree with mass spectrometry measurement.

Electrical and optical characterization of CO2/He glow discharge

Glow discharge studies are produced in a atmosphere of CO2/He mixture at a pressure of 1.5 Torr . The experiment was conducted to observe the optical emission spectroscopy of the plasma, and determined the electron temperature and ion density by the use of a double Langmuir probe. The electron temperature of the mixture was found in the range of 4.54 to 5.37 eV, and the ion density values between 2.15 and 12.00 × 109 particles/cm3. The principal species observed were: CO2+ CO+, CO, C2, O2+ O*, and He*.