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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Nuclear Data Sheets for A = 71

The evaluated spectroscopic data are presented for experimentally known nuclides of mass 71 (Mn,Fe,Co,Ni,Cu,Zn,Ga,Ge,As,Se,Br,Kr). Excited-state data are nonexistent for {sup 71}Mn, {sup 71}Fe, {sup 71}Co and {sup 71}Kr. Significant new data have been added since the last evaluation of A=71 nuclides by M. Bhat (1993Bh02). Excited states are now known in {sup 71}Ni and {sup 71}Cu, and enhanced information about high-spin excitations is available for {sup 71}Ga, {sup 71}As and {sup 71}Br. The decay schemes of radioactive isotopes {sup 71}Mn and {sup 71}Fe are not known at all, and those for {sup 71}Co, {sup 71m}Ni and {sup 71}Kr are not known well. For the decay of {sup 71}Cu, {sup 71g}Ni, and {sup 71}Br, extensive data are available, but in the opinion of the evaluators the decay schemes still seem incomplete. This work supersedes earlier full evaluations of A=71 published by 1988Bh01, 1979Ke06 and 1973Al33, and the last one published in 'update' mode by 1993Bh02.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Direct Mass Measurements of Short-Lived A=2Z-1 Nuclides {sup 63}Ge, {sup 65}As, {sup 67}Se, and {sup 71}Kr and Their Impact on Nucleosynthesis in the rp Process

Mass excesses of short-lived A=2Z-1 nuclei {sup 63}Ge, {sup 65}As, {sup 67}Se, and {sup 71}Kr have been directly measured to be -46 921(37), -46 937(85), -46 580(67), and -46 320(141) keV, respectively. The deduced proton separation energy of -90(85) keV for {sup 65}As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of {sup 65}As suggest that the majority of the reaction flow passes through {sup 64}Ge via proton capture, indicating that {sup 64}Ge is not a significant rp-process waiting point.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

β Decay in the Region of Neutron-deficient {sup 69,70,71}Kr

Decay spectroscopy was performed for neutron-deficient nuclei ranging from zinc to krypton with isospin −3/2 ≤T{sub z}≤0. Measurements of correlated β-delayed protons allowed us to determine the isobaric analog states fed from the decay of {sup 65}Se and {sup 69}Kr, constraining the spin of the {sup 69}Kr ground state. Preliminary results regarding the half lives for the T{sub z}=−1 systems, relevant to the rapid proton capture (rp) process, are discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

32.8-nm X-ray laser produced in a krypton cluster jet

We have interpreted the well-known experimental quantum yield data for a 32.8-nm X-ray laser operating at the 3d{sup 9}4d (J = 0) – 3d{sup 9}4p (J = 1) transition of Kr{sup 8+} with the use of gaseous krypton or a krypton cluster jet. Proceeding from our model we propose a novel scheme for the 32.8-nm laser produced in a krypton cluster jet. The quantum yield is shown to saturate for a plasma length of ∼300 μm, a krypton ion density n{sub Kr} ∼ (4 – 9) × 10{sup 19} cm{sup -3}, and an electron temperature Te ∼ 5000 eV. In this case, the energy conversion coefficient amounts to ∼5 × 10{sup -3} of the pump pulse energy. We propose the experimental setup for producing a highefficiency subpicosecond X-ray laser in a krypton cluster jet. (lasers)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Dust Particle Growth in a Sputtering Discharge with Krypton

Dust particles are grown in the PKE chamber by sputtering materials. The sputtering efficiency and the gas phase reactions can be affected by the gas type and particularly by the ion mass. Due to the presence of growing dust particles, the huge loss of electrons can trigger many instabilities in the plasma. These instabilities, the growth kinetics and the structure of the dust cloud, are compared by using two different gases: argon and krypton.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

Ellipsometry with polarisation analysis at cryogenic temperatures inside a vacuum chamber

In this paper we describe a new variant of null ellipsometry to determine thicknesses and optical properties of thin films on a substrate at cryogenic temperatures. In the PCSA arrangement of ellipsometry the polarizer and the compensator are placed before the substrate and the analyzer after it. Usually, in the null ellipsometry the polarizer and the analyzer are rotated to find the searched minimum in intensity. In our variant we rotate the polarizer and the compensator instead, both being placed in the incoming beam before the substrate. Therefore the polarisation analysis of the reflected beam can be realized by an analyzer at fixed orientation. We developed this method for investigations of thin cryogenic films inside a vacuum chamber where the analyzer and detector had to be placed inside the cold shield at a temperature of T≈ 90 K close to the substrate. All other optical components were installed at the incoming beam line outside the vacuum chamber, including all components which need to be rotated during the measurements. Our null ellipsometry variant has been tested with condensed krypton films on a highly oriented pyrolytic graphite substrate (HOPG) at a temperature of T≈ 25 K. We show that it is possible to determine the indices of refraction of condensed krypton and of the HOPG substrate as well as thickness of krypton films with reasonable accuracy.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Communication: Nuclear quadrupole moment-induced Cotton-Mouton effect in noble gas atoms

New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: {sup 21}Ne, {sup 83}Kr, and {sup 131}Xe. The magnitude of the resulting ellipticities is predicted to be 10{sup −4}–10{sup −6} rad/(M cm) for fully spin-polarized nuclei. These should be detectable in the Voigt setup. Particularly interesting is the case of {sup 131}Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Effect of Zeeman Slower Beam on Loading of a Krypton Magneto-Optical Trap

We report the studies on the effect of Zeeman slower beam power on the loading rate and collision loss rate in an atomic beam loaded krypton magneto-optical trap (MOT). The results show that an increase in Zeeman slower beam power initially increases the MOT loading rate and reduces the background collision loss rate to increase the number of cold atoms in the MOT to an optimum value. With further increase in the Zeeman slower beam power, the number of cold atoms in the MOT decreases due to increased background collision loss rate and decrease in the trap loading rate. However, the cold collision loss rate is observed to remain unaffected by the variation in the Zeeman slower beam power. Therefore, the study emphasizes the need to optimize the Zeeman slower beam power to trap maximum number of cold atoms in an atomic beam loaded MOT.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Inscription and Visualization of Tilted Fiber Bragg Gratings

Tilted fiber Bragg gratings with different tilt angles have been inscribed in single-mode isotropic optical fiber with an increased photorefractivity using Talbot interferometer and KrF-excimer laser system. Their spectra are studied. Using a confocal laser scanning luminescent microscope the images of gratings in transmitted light were obtained. The calculated dependence of the slope angle of the grating recorded in the Talbot interferometer on the angle between the strokes of the interference pattern created in the interferometer and the transverse section of the optical fiber is experimentally verified.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Equation of state of dense neon and krypton plasmas in the partial ionization regime

The compression behaviors of dense neon and krypton plasmas over a wide pressure-temperature range are investigated by self-consistent fluid variational theory. The ionization degree and equation of state of dense neon and krypton are calculated in the density-temperature range of 0.01–10 g/cm{sup 3} and 4–50 kK. A region of thermodynamic instability is found which is related to the plasma phase transition. The calculated shock adiabat and principal Hugoniot of liquid krypton are in good agreement with available experimental data. The predicted results of shock-compressed liquid neon are presented, which provide a guide for dynamical experiments or numerical first-principle calculations aimed at studying the compression properties of liquid neon in the partial ionization regime.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Evolution of a Diffusion Channel in an Inhomogeneous Electric Field of the KrF-Laser Pump Discharge

The results of studying the 2D-simulation of evolution of a diffusion channel in the KrF-laser pump discharge initiated by the pin on the cathode surface are presented. It is shown that during the pump pulse, the inhomogeneity passes successively through three stages: a plasma spot on the cathode surface, a diffuse channel, and a high-conductivity channel. From the analysis of the dynamics of spatial distribution of spontaneous emission on the B{sub 0}-X transition of the KrF molecule in such a discharge, it is obtained that the channel can work as an amplifying medium while the volumetric form of its glow is maintained. Despite the contraction of the channel into a narrow cord at the end of the pump pulse, the distribution of the radiation energy over the entire pulse has the shape of a torch with the width at the anode of ~0.6 cm.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Formation of a carbon nanofilm on oil-coated KU-1 glass annealed by KrF laser radiation

The annealing of an oil layer on the output face of a KU-1 glass substrate in air by a high-power 80 ns KrF laser pulse is studied. A polymer-like hydrocarbon film up to 40 nm thick is found to form at laser radiation fluences F above 2 J cm{sup −2} on the glass surface. The upper limit of F ≈ 6 J cm{sup −2} is determined by the damage of the glass samples whose size is approximately equal to the laser spot diameter (1 cm). (interaction of laser radiation with matter. laser plasma)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Experimental capabilities of the GARPUN MTW Ti : sapphire – KrF laser facility for investigating the interaction of subpicosecond UV pulses with targets

This paper describes the first experiments carried out on the GARPUN MTW Ti : sapphire – KrF hybrid laser facility and aimed at gaining insight into the interaction of subpicosecond UV pulses with solid and structured low-density carbon nanotube targets at peak intensities of ∼10{sup 16} W cm{sup −2} in a focal spot ∼70 μm in size. Using X-ray absorbers, the plasma electron temperature has been measured to be ∼850 eV. In our experiments, we used an optimal configuration: direct double-pass ultrashort-pulse (USP) amplification in KrF amplifier stages, with multiple laser beam filamentation suppression in a xenon-filled cell. The highest energy on a target was 0.25 J at a USP contrast relative to amplified spontaneous emission of ∼3 × 10{sup 10} for intensities and ∼3 × 10{sup 5} for fluences. Owing to two-photon resonance in the UV spectral region, the use of xenon, with a negative nonlinear refractive index, allowed us to make the cross-sectional fluence distribution more uniform and reduce the beam divergence to 0.14 mrad (at the 10 % intensity level). Reducing the USP duration via negatively chirped pulse amplification and filamentation suppression and reducing the focal spot size on a target by using parabolic short-focus optics are expected to ensure an increase in the intensity incident on the target by one to two orders of magnitude. (interaction of laser radiation with matter. laser plasma)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Photoionization of noble-gas atoms by ultrashort electromagnetic pulses

The photoionization of atoms of noble gases (Ar, Kr, and Xe) by ultrashort electromagnetic pulses of a corrected Gaussian shape is studied theoretically. Computations are performed in the context of perturbation theory using a simple expression for the total probability of photoionization of an atom by electromagnetic pulses. The features of this process are revealed and analyzed for various ranges of the parameters of the problem.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

High-order harmonic generation enhanced by XUV light

The combination of high-order harmonic generation (HHG) with resonant XUV excitation of a core electron into the transient valence vacancy that is created in the course of the HHG process is investigated theoretically. In this setup, the first electron performs a HHG three-step process, whereas the second electron Rabi flops between the core and the valence vacancy. The modified HHG spectrum due to recombination with the valence and the core is determined and analyzed for krypton on the 3d {yields} 4p resonance in the ion. We assume an 800 nm laser with an intensity of about 10{sup 14} Wcm{sup 2} and XUV radiation from the Free Electron Laser in Hamburg (FLASH) with an intensity in the range 10{sup 13}-10{sup 16} Wcm{sup 2}. Our prediction opens perspectives for nonlinear XUV physics, attosecond x rays, and HHG-based spectroscopy involving core orbitals.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Pulsed hollow-cathode ion lasers: pumping and lasing parameters

Optimal discharge conditions have been experimentally found for ion lasers excited in the hollow-cathode discharge plasma by microsecond current pulses by pumping working atoms in secondkind collisions with ions and metastable buffer-gas atoms. Measurements of the output power of krypton ion and zinc-, cadmium-, mercury-, thallium-, copper-, and gallium-vapour lasers in tubes with cathodes of different diameters showed that the pulse power reaches several tens of watts, and the average power obtained with cathodes 2 cm in diameter and a length of 40 cm or more approaches 1 W. Lasing in most media is observed simultaneously at several lines (the multi-wavelength regime). Lasing on a three-component (He - Kr - Hg) mixture is realised in the multi-wavelength regime at blue, red, and IR lines.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗