摘要:

Magnetic flux trapped in the rotor of a superconducting gyroscope can cause the rotor to lose energy through dissipation in a readout loop encompassing the rotor and by the generation of eddy currents in the support electrodes. These losses are calculated and shown to be negligible for the rotor in the gyroscope‐relativity experiment, a proposed satellite experiment which is to test predictions of the theory of general relativity.

ISSN:0021-8979    

DOI:10.1063/1.324699

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The design of a gravitational antenna consisting of a relatively large piezoelectric quartz crystal cooled to 3 m °K is presented. Calculations show that the use of the piezoelectric output to detect signals results in a simplification of the apparatus with no loss in sensitivity as compared to that attainable with similar antennas employing magnetic‐displacement detectors. For both types of antennas the sensitivity is considerably better than that required to detect thermal oscillations at 3 m °K and compares favorably with that attainable with massive room‐temperature antennas.

ISSN:0021-8979    

DOI:10.1063/1.324736

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A focusing system which utilizes twof/0.47 doublets in conjunction with ellipsoidal mirrors produces two focusing cones with half‐angles of 81.5°. This system has been used with the Lawrence Livermore Laboratory Janus 1.06‐&mgr;m laser to irradiate and implode DT‐filled glass microshells of ∼70 &mgr;m diameter. The purpose of the system was to provide more uniform heating of the pusher and more uniform compression of the DT fuel than had been obtained when irradiating targets usingf/1 lenses. Neutron yields of ∼107per event have been obtained at power levels of ∼0.4 TW. X‐ray micrographs show that improved uniformity of heating and implosion sphericity are achieved. Data are also presented which add further confirmation of the importance of absorption by plasma wave resonance for non‐normal incidence of the laser light on the target surface.

ISSN:0021-8979    

DOI:10.1063/1.324692

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Depth profiles of 20–60‐keV3He ions incident on surfaces of C, Al, Si, V, Ni, and Zr have been measured using the3He(d,&agr;)1H reaction. A comparison of the results with theoretical predictions shows rather large discrepancies.

ISSN:0021-8979    

DOI:10.1063/1.324693

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Experimental measurement of the first‐ and second‐overtone spontaneous‐emissions spectrum in a low‐pressure CO/He plasma has enabled determination of the vibrational distribution up tov=30. The variation in the CO distribution as a function of CO and He partial pressure and plasma current has been correlated by a detailed model of the steady‐state energy‐transfer dynamics. The agreement between calculated and measured distributions has generated a consistent set of rate coefficients for CO/He mixtures for a temperature around 150 K.

ISSN:0021-8979    

DOI:10.1063/1.324694

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Stimulated emission at 15.88 and 15.95 &mgr;m has been obtained in14NH3utilizing two‐photon excitation. Total output energies on the order of 1 mJ have been observed in configurations which can be readily scaled to higher values. A discussion of the parameters available to control the operation of this system is given along with experimental data on laser output energy, divergence, the role of the optical Stark effect, pressure dependence, and spectral control with absorbing gases. These mechanisms can be generally applied for efficient down‐conversion throughout the infrared.

ISSN:0021-8979    

DOI:10.1063/1.324695

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The interaction of neutron beams with3He gas is of interest for nuclear pumped lasers. The effects of spectral dependence of the neutron beam, neutron attenuation in the gas‐filled laser tube, and transport of the charged‐particle3He(n,p)3H reaction products are treated in detail. An expression for the energy density as a function of position within the tube, tube radius, operating pressure, and neutron fluence is given. The maximum energy density within the optical cavity is achieved when the tube radiusa(cm) is given bya=3.26/PwhereP(atm) is the operating pressure. The variation of radius by 50&percent; above and below optimum will change the energy density at most by 10&percent;, although performance degrades quickly for radii outside this range. If the optimum tube radius is used for each operating pressure, then the power density on the centerline (kW/cm3) is given as &xgr;CL=9.3×10−18Pf0in a thermal neutron environment off0(n/cm2 sec).

ISSN:0021-8979    

DOI:10.1063/1.324696

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Pumping gas lasers by the235U(n,ff)FFreaction has the advantage of depositing large energies per reaction (∼200 MeV), and by using235UF6, a volumetric energy source is achieved. Factors in235UF6pumping of a He gas relating to neutron attenuation and fission product transport within a laser tube are treated in detail. Neutron attenuation is found not to be significant for tube sizes and pressure ranges anticipated for laser applications. Maximum power can be deposited in a laser tube when the tube radius is at least as large as the range of the fission fragments. The maximum power is deposited in the helium gas when the tube radius equals the fission‐fragment range and the UF6partial pressure to total pressure ratio is 0.15 corresponding to a UF6‐He mixing ratio of approximately 1 : 6.

ISSN:0021-8979    

DOI:10.1063/1.324697

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The reflected and refractive fields are calculated for a very rough surface which is assumed to be a set of tangent planes with small corrections due to the local finite radii of curvature. A perturbation technique similar to those used in the moderately rough surface calculations is developed to treat the solution for the tangent planes as the unperturbed solution with the curvature correction as the perturbation. Our results are expressed in terms of the slope distribution function of the tangent planes and the average radius of curvature. Numerical results for scattering of both polarizations are obtained. The depolarization calculation is shown to be consistent with the experimental data. Further, the relationship between the surface model and the conventional Gaussian model is discussed, and a comparison with previous works is given.

ISSN:0021-8979    

DOI:10.1063/1.324698

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The mean irradiance reflected from a randomly rough dielectric surface is calculated using the vector Kirchoff integral. The tangent‐plane approximation is used to relate the fields on the boundary to the incident fields through the Fresnel reflection coefficients. The averages involving the random surface variables are performed exactly using a spectral representation for the scattering function. The special case of a corrugated surface is treated numerically to gain insight into the more general problem. Our results are compared with previous solutions. An empirical formula is presented for practical applications. Finally, a general expression for the depolarization matrix is derived, retaining terms up to second order in the surface slopes. Our solution is compared with available theories.

ISSN:0021-8979    

DOI:10.1063/1.325037

出版商:AIP    

年代:1978

数据来源: AIP