Lutetium-177 radio-pharmaceutical has become an important theranostic candidate in cancer treatment. Its availability from bench-to-bed requires strategic implementation of isotope-enrichment, neutron-irradiation and radio-chemical techniques. In this paper, the need for enrichment of lutetium-176 is emphasized by estimating specific activity of lutetium-177 as a function of enrichment percentage for typical neutron flux available at Dhruva reactor, India. A novel Atomic Vapour Laser Isotope Separation (AVLIS) module for lutetium-176 enrichment is designed to meet the above requirement. The paper documents its characteristics and production estimates. The design is carried out after critical assessment and evaluation of available AVLIS-infrastructure in the country. Outline of lutetium-177 enrichment, capable of producing non-carrier-added lutetium is also provided. This work concludes that India has taken a step forward towards self-reliance (Atmanirbhar Bharat) in securing the supply chain of lutetium-177.

In this article, a 1-D electrostatic particle-in-cell (PIC) code is developed in an object-oriented paradigm with a computationally improved Poisson Solver. The performance of a Poisson solver plays a vital role in the computational cost of an electrostatic PIC. Therefore, to reduce the overall cost of the system, the Gauss–Seidel with a modified Chebyshev acceleration scheme is implemented as a Poisson solver. This method is designed by altering the standard Chebyshev acceleration scheme and executed with the optimal spectral radius. A separate program is written to optimize the spectral radius and to investigate its impact on the rate of convergence. Subsequently, a comparative analysis of this solver with the Gauss–Seidel, Gauss–Seidel with successive over-relaxation, and Gauss–Seidel with the Chebyshev acceleration factor is carried out, which implies that the modified solver converges fast. This article also provides the object-oriented architecture, including some key features of C++. The developed code is benchmarked with the two-stream instability, which evolved self-consistently. The performance of the overall code is evaluated by considering up to two million particles on two different CPUs and it is observed that the standard CPU is capable to solve the 1-D PIC problem. This code is implemented to study various characteristics of a finite-size photoplasma like plasma sheath formation, ion phase response, and electron dynamics when it is subjected to a uniform electric field.

Plasma is the fourth state of matter. Broadly, it can be classified into two categories first one is natural occurring plasma and another one is laboratory plasma. Laboratory plasma has variety of application in the field of material synthesis, controlled fusion, thruster, plasma-based lighting and display systems. In this paper an exhaustive literature survey on generation of laboratory plasma is provided. The objective of this paper is to provide an overview of various plasma generation methods that include plasma generation using electrical fields, electron beams and laser beams.

Photoexcitation dynamics in a three-step photoionization of atomic uranium has been investigated using time-resolved two-color three-photon and delayed three-color three-photon photoionization signals. Investigations are carried out in an atomic beam of uranium coupled to a high-resolution time-of-flight mass spectrometer using three tunable pulsed dye lasers. Dependence of both the signals on the second-step laser photon fluence is studied. Excited-level-to-excited-level photoexcitation cross section and photoionization cross section from the second excited level are simultaneously determined by analyzing the two-color three-photon and three-color three-photon photoionization signals using population rate equation model. Using this methodology, photoexcitation and photoionization cross sections at seven values of the second-step laser wavelength have been measured. From the measured values of the photoexcitation cross sections, we have obtained excited-level-to-excited-level transition probabilities and compared these with the values reported in the literature.

Laser-induced photoionization and fluorescence signals were simultaneously observed in atomic samarium using Nd:YAG-pumped dye lasers. Two-color, three-photon photoionization and two-color fluorescence signals were recorded simultaneously as a function of the second-step laser power for two photoionization pathways. The density matrix formalism has been employed to analyze these signals. Two-color laser-induced fluorescence signal depends on the laser powers used for the first and second-step transitions as well as the first and second-step transition probability whereas two-color, three-photon photoionization signal depends on the third-step transition cross-section at the second-step laser wavelength along with the laser powers and transition probability for the first and second-step transitions. Two-color laser-induced fluorescence was used to measure the second-step transition probability. The second-step transition probability obtained was used to infer the photoionization cross-section. Thus, the methodology combining two-color, three-photon photoionization and two-color fluorescence signals in a single experiment has been established for the first time to measure the second-step transition probability as well as the photoionization cross-section.

Laser-induced photoionization and fluorescence signals were simultaneously observed in atomic samarium using two Nd:YAG-pumped dye lasers. Two-color, three-photon photoionization and two-color fluorescence signals were recorded simultaneously under similar experimental conditions and their dependence as a function of the second-step laser power was studied to understand the behavior of these signals. The laser-induced fluorescence and photoionization techniques have been used simultaneously for the first time to understand the behavior of these signals so that these techniques can be used efficiently in complementary manner to investigate the high-lying energy levels. The even-parity energy levels of atomic samarium in the energy region 36 510–36 875 cm-1 have been investigated based on these experiments. Total 21 high-lying even-parity energy levels have been identified and the two energy levels amongst them are reported as new energy levels after comparing our results with those reported in the literature.

In this paper, we report the investigations of lifetime measurement of odd-parity energy level 19009.52 cm −1 of Sm I using simultaneous detection of laser-induced fluorescence and laser-induced photoionization signals employing pump–probe technique. To the best of our knowledge, this is for the first time that the results obtained using laser-induced fluorescence and photoionization techniques have been compared with each other. The obtained results match well with those reported in the literature.

Radiative lifetimes of ten even-parity energy levels of atomic uranium in the 15,500–19,000 cm−1 region and branching ratios of six transitions originating either from ground level (5L 6 o ) or from lowest metastable level (5K 5 o ) at 620.32 cm−1 are measured employing three-step delayed photoionization technique. The lifetimes of five energy levels and branching ratios of five transitions are measured for the first time. By combining the experimentally measured values of radiative lifetimes and branching ratios, we have determined the absolute transition probabilities of six transitions of uranium and compared with those previously reported in the literature.

Laser-induced steel plasma is generated by focusing a Q-switched Nd:YAG visible laser（532 nm wavelength） with an irradiance of 1 x 109 W/cm2 on a steel sample in air at atmospheric pressure.An Echelle spectrograph coupled with a gateable intensified charge-coupled detector is used to record the plasma emissions.Using time-resolved spectroscopic measurements of the plasma emissions,the temperature and electron number density of the steel plasma are determined for many times of the detector delay.The validity of the assumption by the spectroscopic methods that the laser-induced plasma（LIP） is optically thin and is also in local thermodynamic equilibrium（LTE） has been evaluated for many delay times.From the temporal evolution of the intensity ratio of two Fe I lines and matching it with its theoretical value,the delay times where the plasma is optically thin and is also in LTE are found to be 800 ns,900 ns and 1000 ns.

We report the quantitative elemental analysis of a steel sample using calibration-free laser-induced breakdown spectroscopy (CF-LIBS). A Q-switched Nd:YAG laser (532 nm wavelength) is used to produce a plasma by focusing it onto a steel sample in air at atmospheric pressure. The time-resolved spectra from atomic and ionic emission lines of the steel elements are recorded by an echelle grating spectrograph coupled with a gated intensified CCD camera and are used for the plasma characterization and quantitative analysis of the sample. The time delay at which the plasma is in local thermodynamic equilibrium as well as optically thin, necessary for elemental analysis, is deduced. An algorithm for the CF-LIBS relating the experimentally measured spectral intensity values with the basic physics of the plasma is developed and used for the determination of Fe, Cr, Ni, Mg, and Si concentrations in the steel sample. The analytical results obtained from the CF-LIBS technique agree well with the certified values of the elements in the sample, with relative uncertainties of less than 5%.

We report the simultaneous measurements of radiative lifetimes, branching fractions, and absolute transition probabilities in atomic samarium using laser-induced fluorescence. The radiative lifetimes of seven odd-parity energy levels and six step-wise-excited even parity energy levels of atomic samarium have been measured. The lifetime values of odd-parity energy levels agree well with those reported in the literature, and the values of even-parity energy levels are new. Excited-level-to-ground-level branching fractions and absolute transition probabilities for twenty-one transitions in atomic samarium are measured using single-color laser-induced fluorescence, and the results are compared against the values reported in the literature. We also report branching fractions and absolute transition probabilities for fifty-one excited-level-to-excited-level transitions in atomic samarium using two-color laser-induced fluorescence. The existing ambiguity in assigning the total angular momentum values for the six stepwise-excited even-parity energy levels is removed by assigning each of these excited levels a unique J value by identifying known odd-parity lower levels to which a stepwise-excited even-parity level decays via fluorescence decay channels. (C) 2010 Optical Society of America

Spectrally resolved laser-induced fluorescence technique was used to uniquely assign total angular momentum ( J ) values to high-lying even-parity energy levels of atomic samarium. Unique J value assignment was done for seven energy levels in the energy region 34,800–36,200 cm −1 , recently observed and reported in the literature.

A U–Ne hollow cathode discharge tube is used as a source of uranium atomic vapors as well as a photoelectron/photoion detector for carrying out two-color three-photon photoionization spectroscopy of uranium. Using the uranium excitation transition 0 cm −1 ( 5 L 6 0 ) → 16 900.38 cm −1 ( 7 M 7 ) at 591.5-nm laser wavelength as a first step transition and scanning the wavelength of a second laser from 558 to 568 nm, high-lying odd-parity atomic levels of uranium are studied in the energy region 34 500–34 813 cm −1 . All the expected 21 odd-parity atomic levels identified by various researchers in this region are observed in a single spectrum, demonstrating the high sensitivity achieved therein. In addition to this, we have identified eight autoionization resonances of uranium starting from its odd-parity atomic level at 33 801.06 cm −1 pumped by two-photon excitation. Four out of these eight autoionization resonances are observed for the first time.

We report the observation of new high-lying even-parity excited levels of samarium in the energy region 34 814.4 cm(-1) to 35 110.9 cm(-1). These levels are identified with two-color laser-induced fluorescence spectroscopy in an atomic beam. The values of the total angular momentum (J) of these levels are assigned. Our results are compared with the results obtained with two-color, three-photon photoionization spectroscopy in the same energy region reported earlier in the literature [J. Opt. Soc. Am. B 13, 641 (1996)]. The similarities and differences observed in the spectra by two techniques have been discussed, reaffirming the complementary nature of the two techniques for laser spectroscopy of highly excited levels. (c) 2005 Optical Society of America.

The isotope-ratio-enhancement calculations for 138La are carried out using spectral-simulation (SS) and density-matrix (DM) methods for the 5d6s2 2D3/2−5d6s6p 4F3/20 (753.9-nm) transition that was considered by Young and Shaw [J. Opt. Soc. Am. B 12, 1398–1402 (1995)] a first-step transition in their diode-laser-initiated, resonance-ionization mass spectrometry experiments. The results from the two methods are compared with each other and with the reported experimental result. The SS result is noted to be more sensitive to the residual Doppler width but less sensitive to the laser linewidth than the DM result. It is further noted that under exact correspondence with experimental conditions, the DM result is in much better agreement with the experimental result obtained by Young and Shaw in their two-color resonant, three-photon photoionization of La by use of a narrowband, cw diode laser for the first-step excitation and a broadband, pulsed dye laser for further excitation and ionization.

Isotopic selectivity calculations are carried out for minor calcium isotopes against the major isotope 40Ca for the single-resonance two-step and double-resonance three-step photoionization schemes with narrow-band lasers by using spectral simulation (SS) and modified spectrum (MS) approaches. The results of these calculations are compared with the density matrix (DM) results reported in the literature. It is noted that the values of isotopic selectivity from the SS approach do not agree with those from the DM approach whereas the MS approach, considering hole burning in the Doppler-broadened atomic spectrum, predicts selectivity values which are in good agreement with the DM results. It is argued that one can adequately use the simple MS approach rather than the complex DM approach for the calculation of isotopic selectivity of multi-step photoionization with single-frequency lasers.