摘要:

Radiative isotope separation (without lasers) has been achieved using isotopic differences in the rf spectrum of paramagnetic molecules in a supersonic nozzle beam. The combination of molecular‐beam magnetic resonance and supersonic molecular‐beam techniques can be used for isotope separation on a large scale. The principle was demonstrated experimentally for molecular oxygen. The vastly larger isotope spectral differences, the tunability of the spectra by external fields, and the use of the well‐developed technologies are promising starting points for this technique.

ISSN:0021-8979    

DOI:10.1063/1.327409

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

It is shown that (1) if an angular dimension of the supporting structure is large enough, the so‐called modified D‐shaped coil of toroidal magnet differs slightly from the circular one, (2) with the increase of support angle maximum bending moment in a circular toroidal field coil diminishes rapidly. Thus the realistic choice of support angle can guarantee practically pure tension in circular toroidal field coils.

ISSN:0021-8979    

DOI:10.1063/1.327296

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Differential and total cross sections for various competing two‐photon processes in metastable 2shydrogenic atoms are given for several current laser frequencies. Exact calculations are performed within the framework of conventional time‐dependent perturbation theory by using a Sturmian representation of the Coulomb Green’s function. Our results are useful for discussing a recent proposal for obtaining intense vacuum uv light sources from anti‐Stokes Raman scattering.

ISSN:0021-8979    

DOI:10.1063/1.327404

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The main purpose of this paper is the investigation of the rate equations used in the theories of void nucleation and swelling as well as creep, in situations where random displacement cascades are the major source of point defects. The point‐defect concentrations are described by diffusion equations with random source terms to account for the cascades. Using methods from nuclear reactor kinetic theory and averaging over time, the rate equations are derived. It is seen that the rate equations are valid for computing time and spatially averaged point‐defect concentrations, regardless of the cascade statistics, if the observation time is greater than the mean time between cascade events in the irradiated material. An alternate approach is suggested for studying pulsed systems with short pulse widths.

ISSN:0021-8979    

DOI:10.1063/1.327393

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Separation of residual charged particles from neutral particles is typically made by a deflection magnet in a neutral beam injection line for heating fusion plasmas. Ionization of energetic neutrals and neutralization of energetic ions in the deflection magnet region due to collisions with the background gas molecules result in a finite amount of particles that are only partially deflected, which we call a ’’stray particles loss.’’ Quantitative determination of the stray particle loss has been made from calorimetric data of beam power deposited along a beam line employing a 40‐kV 60‐A hydrogen ion source. The stray particle loss is typically 3–5% of the accelerator power and roughly proportional to the background gas pressure. A simple calculation is shown to be in fair agreement with the measurements.

ISSN:0021-8979    

DOI:10.1063/1.327400

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A self‐pinched relativistic electron beam is injected through a thin foil into vacuum with no externally applied magnetic field. The beam is observed to propagate at currents well above the space‐charge‐limiting current (∼3 kA) but limited to the Alfven current (∼30 kA). Propagation results from charge neutralization of the beam by ions accelerated out of the anode plasma as confirmed by various ion diagnostics. Ions are collectively accelerated to greater than the electron energy. The experimental results are in qualitative agreement with a one‐dimensional time‐dependent computer simulation.

ISSN:0021-8979    

DOI:10.1063/1.327414

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The coupling of a spherical‐surfaced LED and a spherical‐ended fiber is analyzed using a model in which a light source and an aperture stop are on the anterior and posterior focal planes, respectively. The launching efficiency is defined as the ratio of the power launched into a fiber to the optical power generated in the LED. The efficiencies for step‐ and graded‐index fibers are derived. Maximum efficiency can be obtained whend0=dc, whered0is the emitting diameter anddcis the critical diameter defined by the focal length and the critical angle of the fiber. Whend0?dc, the ratio &khgr; of improvement in the efficiency for a spherical‐surfaced LED to that for a flat LED is approximately proportional to the square of the lateral magnification &bgr;, which is the image diameter divided byd0. &khgr;?&bgr;2is confirmed experimentally with couplings using spherical‐surfaced and flat LED’s.

ISSN:0021-8979    

DOI:10.1063/1.327372

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Amplification of 0.6‐, 1.6‐, and 100‐ns pulses has been measured in a test amplifier up to 3 atm. total pressure and a small signal gain ranging from 5.5 to 19 dB. A simple model based on a Frantz and Nodvick formulation provides good agreement with the experimental results for 0.6–1.6‐ns pulse duration and can be useful for an iodine laser system design.

ISSN:0021-8979    

DOI:10.1063/1.327382

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

We discuss the theory of Raman‐induced Kerr effect (RIKE) when excited by nonmonochromatic waves. The maxima and minima of the lineshape are shifted farther apart when pumped by linearly polarized nonmonochromatic waves. The shift varies linearly with the sum of the pump and probe linewidths. Certain other features are also predicted in agreement with experimental results.

ISSN:0021-8979    

DOI:10.1063/1.327388

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The dependence of lasing characteristics on stripe width in GaInAsP/InP double‐heterostructure planar stripe lasers, prepared by using sputtered SiO2film as a Zn‐diffusion mask, was investigated. The lasers of 10‐, 15‐, and 20‐&mgr;m‐wide stripes operated in a fundamental‐transverse mode with more than 20% differential quantum efficiencies per facet, while the 5‐&mgr;m‐wide stripe lasers operated in a multi‐transverse‐mode even just above threshold. The threshold current of 5‐&mgr;m‐wide stripe lasers increased greatly, and the lasing wavelengths shifted to shorter than those of stripe lasers with larger stripe widths. The 15‐&mgr;m‐wide stripe lasers showed good mode characteristics to operate in a fundamental‐transverse mode up to the output power of 22 mW per facet and in a single longitudinal mode over a wide range of currents. The cause of this dependence of lasing characteristics on stripe width was discussed, and it was assumed that the Zn diffusion into the stripe region using a sputtered SiO2mask is most responsible for the dependence.

ISSN:0021-8979    

DOI:10.1063/1.327340

出版商:AIP    

年代:1980

数据来源: AIP