摘要:

A calibration curve for the response of commercial Manganin gauges upon unloading in plane dynamic experiments is presented. The data obtained from 18 plane impact experiments cover shock stresses in the 1.5–15 GPa range and involves various materials. The calibration curve was drawn through normalized data points. The normalization is based on the assumption that the ratio between resistances of the gauge at the shock and unloading states depends on the ratio of the respective stresses.

ISSN:0021-8979    

DOI:10.1063/1.327635

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The pressure, density, and velocity distributions within a cylindrical heat‐pipe oven are analyzed for inviscid, compressible flow in either the radial or axial direction. For sufficiently large but readily attainable heat flows, density variations within the heat pipe as large as 50% which can lead to inaccuracies in quantitative spectroscopic investigations are predicted.

ISSN:0021-8979    

DOI:10.1063/1.327636

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The quality of the confinement and thermonuclear burn of inertial confinement fusion targets scales as the density‐radius product &rgr;Rof the fuel. Neutron activation of trace elements placed in the fuel can be used to directly measure &rgr;R. This concept and several candidate tracers,14N,40Ar, and79Br, are discussed.

ISSN:0021-8979    

DOI:10.1063/1.327637

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

In order to obtain the pusher attenuation length (&rgr;&Dgr;R) of inertial confinement fusion targets by neutron activation, it is necessary to know what fraction of the target debris is counted. One method of measuring this quantity experimentally is by means of a radioactive tracer. We demonstrate the usefulness of this technique by experiments utilizing a24Na tracer.

ISSN:0021-8979    

DOI:10.1063/1.327638

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A means of collectively accelerating an intense electron beam is demonstrated. A long pulse (800 ns) electron beam is propagated through cavity structures which redistributed the energy in the beam such that most of the beam energy is transferred to a short segment (6 ns) in the tail of the beam. Electrons are accelerated in a two cavity system from 200 keV to energies of 2.4–3.0 MeV at a beam current of ∼8 kA. The extension of this principle to larger number of cavities appears feasible.

ISSN:0021-8979    

DOI:10.1063/1.327639

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Many practical laser amplifiers exhibit anisotropic gain due to polarization of the pumping fields or to a fixed preferential alignment of the active dipoles. Several specific causes and consequences of gain anisotropy are discussed in detail. In the analysis, the emphasis is placed on dye‐laser systems including arbitrary amplitudes, phases, and polarizations of the pump and signal fields. Analytical results are presented for a unidrectional molecular distribution, and it is found that the polarization states of the pump and signal fields change with distance in the amplifier.

ISSN:0021-8979    

DOI:10.1063/1.327640

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

In a previous study a general semiclassical formalism has been developed for lasers with arbitrary orientational distributions of the active molecules. Here that formalism is applied to the important case of an isotropic distribution of molecules, and this limit is especially relevant to liquid dye lasers. Extensive analytical and numerical results are presented for the polarization properties of such dye lasers. It is found that in general the polarization states of the pump and signal fields are coupled together and both change with distance in a laser amplifier.

ISSN:0021-8979    

DOI:10.1063/1.327629

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

In a pulsed discharge in a He‐Hg gas mixture favorable for laser oscillation of Hg ion at the green line, the temporal and spatial behavior of the population densities of Hg(63P2) and He(21S0) atoms has been studied experimentally. These reactants are thought to be responsible for the Penning‐like excitation process. It is found that the depression of the population of reactants coincides in space and time with the occurrence of the laser oscillation.

ISSN:0021-8979    

DOI:10.1063/1.327630

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The absorption, emission, and gain spectra of In0.72Ga0.28As0.6P0.4(&lgr;g=1.3 &mgr;m), which lattice matches InP, is calculated using a Gaussian fit to Halperin‐Lax band tails and Stern’s matrix element. The calculation is done both forp‐ andn‐type material at various impurity concentrations. The spectral width of emission increases both with increasing doping and impurity concentration. All results are for 297 K. The gain‐versus‐excitation rate is given by the equationg (cm−1)=0.057 (Jnom−2400), whereJnomis the nominal current density in the active layer expressed in A/cm2 &mgr;m. Also, the photon energy at maximum gain increases with increasing excitation rate.

ISSN:0021-8979    

DOI:10.1063/1.327631

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

We describe the analysis, design, and construction of a large aperture, wide‐field‐of‐view modulator at 10.8 &mgr;m using the Stark effect in ammonia (NH3). The modulator configuration incorporates a longitudinal electric field produced between closely spaced, large‐diameter germanium windows. The windows are antireflection coated for high transmission, and their relatively low resistivity allows their direct use as (transparent) Stark electrodes. Enhanced modulation depth and improved electrical breakdown performance are obtained by using multiple interaction regions. The modulator is mounted at the entrance aperture of a corner cube reflector, thus allowing two passes of the signal beam in a configuration which is retroreflecting and polarization insensitive. This completed device has an aperture of 5.5 cm, a field of view of 38°, and a measured modulation depth of 25% at 1.4 MHz.

ISSN:0021-8979    

DOI:10.1063/1.327632

出版商:AIP    

年代:1980

数据来源: AIP