scholarly journals Ion production by lasers using high–power densities in a near infrared region

1996 ◽  
Vol 14 (3) ◽  
pp. 335-345 ◽  
Author(s):  
K. Rohlena ◽  
B. Králiková ◽  
J. Krása ◽  
L. Láska ◽  
K. Mašek ◽  
...  
Keyword(s):  
Charge State ◽  
Near Infrared ◽  
Short Pulse ◽  
Target Surface ◽  
Infrared Region ◽  
Theoretical Explanation ◽  
Ion Production ◽  
Charge States ◽  
Focal Power ◽  
Power Densities

Results are presented of experiments on ion production from Ta targets using a short pulse (350–600 ps in focus) illumination with focal power densities exceeding 1014 Wcm-2 at the wavelength of an iodine photodissociation laser (1.315 μm) and its harmonics. Strong evidence of the existence of tantalum ions with the charge state +45 near the target surface was obtained by X-ray spectroscopy methods. The particle diagnostics point to the existence of frozen high charge states (<53+) of Ta ions in the far expansion zone at about 2 m from the target. The measured charge state-ion energy distribution indicates the highest energy (>4 MeV) for the highest observed charge states. A tentative theoretical explanation of the observed anomalous charge state freezing phenomenon in the expanding plasma produced by a subnanosecond laser pulse is given.

Features of ion generation by a picosecond laser in the range of 1011 – 1013 W/cm2 power densities

2021 ◽  
Author(s):  
Sergey Kondrashev ◽  
Edward Beebe ◽  
Takeshi Kanesue ◽  
Masahiro Okamura ◽  
Robert Scott
Keyword(s):  
Charge State ◽  
Target Surface ◽  
Ion Current ◽  
Total Charge ◽  
Faraday Cup ◽  
Ion Generation ◽  
Target Spot ◽  
External Injection ◽  
Low Charge ◽  
Power Densities

Abstract Picosecond lasers (ps-lasers) have significant advantages for the generation of low charge state ions compared to nanosecond lasers because the influence of heat conductivity on a solid target is almost negligible in the case of ps-laser ablation for laser pulse durations less than 10 ps. However, there is no comprehensive data on ion yields for different elements and target irradiation conditions for laser power densities at the target surface around and below 1013 W/cm2, which is of interest to our study of such plasmas as a source of low charge state ions for various applications, particularly for external injection of those ions into an Electron Beam Ion Source (EBIS). We investigated ion generation from Al, Ti, Cu, Nb and Ta target elements by a ps-laser with power densities in the range of 1011 – 1013 W/cm2 at the target surface. A ps-laser with 1.27 mJ maximum energy within an 8 ps pulse and repetition rate up to 400 Hz has been used to generate a laser-ablated plasma. Dependencies of ion current vs time, total charge of registered ions as well as ion kinetic energy distributions are characterized using a Faraday cup. Significant difference in ion current dynamics between first, second and following shots onto the same target spot was found for all five target elements. The total charge of ions registered by the Faraday cup increases linearly with increasing laser pulse energy and is almost independent of the target element and number of shots onto the same target spot for all five target elements studied. The results obtained give us a basis for specification and design of the source of low charge state ions for external injection into EBIS.

scholarly journals Горячая мишень. Физико-химическая модель реактивного распыления

2019 ◽  
Vol 89 (7) ◽  
pp. 984
Author(s):  
В.И. Шаповалов
Keyword(s):  
Current Density ◽  
Near Infrared ◽  
Thermionic Emission ◽  
Target Surface ◽  
Infrared Region ◽  
Algebraic Equations ◽  
Discharge Current Density ◽  
Rate Region ◽  
Film Synthesis ◽  
A Current

A non-isothermal physicochemical model for the reactive sputtering process is upgraded. The model is used for the description of hot metal target sputtering. The film synthesis on all surfaces of the vacuum chamber is given in a form of a surface chemical reaction. The target temperature is determined from the results of the discharge spectra measurement in the near-infrared region, and is approximated in the form of a function of the discharge current density. In order to provide a mathematical description of the reaction, the basic postulate of chemical kinetics taking into account the equation for Langmuir isotherm and the Arrhenius equation under nonisothermal conditions was used. The model incorporates thermionic emission and evaporation of the target surface. A system of eight algebraic equations describing the model is solved for titanium target sputtering in a nitrogen environment at a current density of 25-600 A/m². It has been shown that the target heating shifts the critical operating points of a target to the lower nitrogen flow rate region and reduces the width of the hysteresis loop as compared to a cold target. The influence of the target evaporation on the process appears at a current density exceeding 400 A/m².

Ligand Influence Versus Electronic Configuration of d-metal Ion in Determining the Fate of NIR Emission from LnIII Ions: A Case Study with CuII, NiII and ZnII Complexes.

2021 ◽  
Author(s):  
Abhineet Verma ◽  
Sk Saddam Hossain ◽  
Sailaja S Sunkari ◽  
Joseph Reibenspies ◽  
Satyen Saha
Keyword(s):  
Metal Ion ◽  
Selection Rule ◽  
Near Infrared ◽  
Electronic Configuration ◽  
Infrared Region ◽  
Direct Excitation ◽  
Characteristic Emission ◽  
Nir Emission ◽  
Near Infrared Region

Lanthanides (LnIII) are well known for their characteristic emission in the Near-Infrared Region (NIR). However, direct excitation of lanthanides is not feasible as described by Laporte’s parity selection rule. Here,...

scholarly journals Phenotypic and genetic variation of ultraviolet–visible-infrared spectral wavelengths of bovine meat

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giovanni Bittante ◽  
Simone Savoia ◽  
Alessio Cecchinato ◽  
Sara Pegolo ◽  
Andrea Albera
Keyword(s):  
Meat Quality ◽  
Genetic Improvement ◽  
Near Infrared ◽  
Infrared Region ◽  
Phenotypic Variance ◽  
Quality Traits ◽  
Meat Quality Traits ◽  
Infrared Spectral ◽  
Portable Spectrometers ◽  
Absorbance Spectra

AbstractSpectroscopic predictions can be used for the genetic improvement of meat quality traits in cattle. No information is however available on the genetics of meat absorbance spectra. This research investigated the phenotypic variation and the heritability of meat absorbance spectra at individual wavelengths in the ultraviolet–visible and near-infrared region (UV–Vis-NIR) obtained with portable spectrometers. Five spectra per instrument were taken on the ribeye surface of 1185 Piemontese young bulls from 93 farms (13,182 Herd-Book pedigree relatives). Linear animal model analyses of 1481 single-wavelengths from UV–Vis-NIRS and 125 from Micro-NIRS were carried out separately. In the overlapping regions, the proportions of phenotypic variance explained by batch/date of slaughter (14 ± 6% and 17 ± 7%,), rearing farm (6 ± 2% and 5 ± 3%), and the residual variances (72 ± 10% and 72 ± 5%) were similar for the UV–Vis-NIRS and Micro-NIRS, but additive genetics (7 ± 2% and 4 ± 2%) and heritability (8.3 ± 2.3% vs 5.1 ± 0.6%) were greater with the Micro-NIRS. Heritability was much greater for the visible fraction (25.2 ± 11.4%), especially the violet, blue and green colors, than for the NIR fraction (5.0 ± 8.0%). These results allow a better understanding of the possibility of using the absorbance of visible and infrared wavelengths correlated with meat quality traits for the genetic improvement in beef cattle.

scholarly journals Dermacozine N, the First Natural Linear Pentacyclic Oxazinophenazine with UV–Vis Absorption Maxima in the Near Infrared Region, Along with Dermacozines O and P Isolated from the Mariana Trench Sediment Strain Dermacoccus abyssi MT 1.1T

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 325
Author(s):  
Bertalan Juhasz ◽  
Dawrin Pech-Puch ◽  
Jioji N. Tabudravu ◽  
Bastien Cautain ◽  
Fernando Reyes ◽  
...  
Keyword(s):  
Linear Regression ◽  
Density Functional ◽  
Near Infrared ◽  
Linear Regression Analysis ◽  
2D Nmr ◽  
Multiple Linear Regression Analysis ◽  
Infrared Region ◽  
Cellular Level ◽  
Mariana Trench ◽  
Uv Visible

Three dermacozines, dermacozines N–P (1–3), were isolated from the piezotolerant Actinomycete strain Dermacoccus abyssi MT 1.1T, which was isolated from a Mariana Trench sediment in 2006. Herein, we report the elucidation of their structures using a combination of 1D/2D NMR, LC-HRESI-MSn, UV–Visible, and IR spectroscopy. Further confirmation of the structures was achieved through the analysis of data from density functional theory (DFT)–UV–Visible spectral calculations and statistical analysis such as two tailed t-test, linear regression-, and multiple linear regression analysis applied to either solely experimental or to experimental and calculated 13C-NMR chemical shift data. Dermacozine N (1) bears a novel linear pentacyclic phenoxazine framework that has never been reported as a natural product. Dermacozine O (2) is a constitutional isomer of the known dermacozine F while dermacozine P (3) is 8-benzoyl-6-carbamoylphenazine-1-carboxylic acid. Dermacozine N (1) is unique among phenoxazines due to its near infrared (NIR) absorption maxima, which would make this compound an excellent candidate for research in biosensing chemistry, photodynamic therapy (PDT), opto-electronic applications, and metabolic mapping at the cellular level. Furthermore, dermacozine N (1) possesses weak cytotoxic activity against melanoma (A2058) and hepatocellular carcinoma cells (HepG2) with IC50 values of 51 and 38 μM, respectively.

Fast speed switching response and high modulation signal processing bandwidth through LiNbO3 electro-optic modulators

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud M. A. Eid ◽  
Ahmed Nabih Zaki Rashed ◽  
Iraj S. Amiri
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Modulation Bandwidth ◽  
Fast Speed ◽  
Electrooptic Modulators ◽  
High Modulation ◽  
Data Rates ◽  
Electro Optic ◽  
Modulation Signal ◽  
Speed Response

AbstractThis work outlined the fast speed response and high modulation bandwidth through LiNbO3 electro-optic modulators. The refractive index is analyzed to estimate the switching voltage and modulation bandwidth for these modulators. The modulation voltage and data transmission data rates are analyzed and discussed clearly through LiNbO3 electro-optic modulators. The modulator’s performance efficiency is upgraded with the optimum modulator length of 10 mm and its thickness of 2 mm. The proposed modulators are compared with GaAs electrooptic modulators under various electro-optic modulators dimensions at 1300 nm near-infrared region and room temperature.

Highly luminescent InP-In(Zn)P/ZnSe/ZnS core/shell/shell colloidal quantum dots with tunable emission synthesized based on growth-doping

2021 ◽  
Author(s):  
Cong Shen ◽  
Yan Qing Zhu ◽  
Zixiao Li ◽  
Jingling Li ◽  
Hong Tao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Near Infrared ◽  
Infrared Region ◽  
Colloidal Quantum Dots ◽  
High Quality ◽  
Promising Alternative ◽  
Lower Toxicity ◽  
Near Infrared Region ◽  
Inp Quantum Dots ◽  
Tunable Emission

InP quantum dots (QDs) are considered as the most promising alternative to Cd-based QDs with the lower toxicity and emission spectrum tunability ranging from visible to near-infrared region. Although high-quality...

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