摘要:

The use of an electrically calibrated pyroelectric detector for accurately measuring periodically pulsed (∼3‐ns duration) energy with an average power level in the microwatt to milliwatt range was investigated. Sources of error especially important in this application were the pyroelectric’s acoustic response, its linearity, and possible deterioration of its gold black coating. The detector had a thin polymer film that isolated the radiation receiver from the pyroelectric material. This film temporally resolved the pyroelectric response from the piezoelectric response to the acoustic energy that is associated with the absorption of an impulse of energy. Thus it was demonstrated that the acoustic response was not a serious source of error. The film also reduced the requirement of linearity on the on the pyroelectric transducer by about 5 orders of magnitude from the conditions of a bare transducer. It is concluded that periodic pulsed energy measurements with 5% uncertainties are readily achievable with the detector described.

ISSN:0003-6951    

DOI:10.1063/1.88713

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A 1‐MeV 40–80‐kA 60‐nsec 40‐cm2electron beam was injected into a 3‐eV 2×1015‐cm−3‐density plasma. Plasma density and temperature within the beam channel were measured by Thomson scattering, and local time‐dependent magnetic probe measurements were made across a plasma diameter. The observed plasma heating rate was an order of magnitude larger than can be explained on the basis of classical collisional processes.

ISSN:0003-6951    

DOI:10.1063/1.88690

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A simple phenomenological theory of alloy sputtering is developed which suggests that in some instances the depth resolution of depth profiling measurements is limited by the time it takes to create a layer of altered chemical composition at the surface.

ISSN:0003-6951    

DOI:10.1063/1.88714

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The retention of hydrogen isotopes in Mo at room temperature after ion implantation damage has been studied by measurements of H depth profiles and total D retained in the near‐surface region. Implantations of He, O, Ne, and Bi in a fluence range 3×1014–2×1017/cm2were followed by 8‐keV hydrogen bombardment to fluences of 2×1015–2×1017/cm2. Large enhancements in the amount of hydrogen retained in preimplanted samples over samples without prior implantation have been observed and are interpreted in terms of damage trapping. For a given predamage ion fluence hydrogen retention increases linearly with hydrogen fluence until a saturation level is reached. Increased predamage fluence results in increased saturation level for hydrogen trapping, with average concentrations as high as ∼10 at.% achieved. An ion‐mass dependence indicates that the lighter ions, which create fewer primary displacements, are more effective in hydrogen trapping, suggesting a dependence on the damage density in the ion cascades.

ISSN:0003-6951    

DOI:10.1063/1.88715

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Depth profiles for 60‐keV Al+implanted in Si have been measured by SIMS analysis as a function of implant fluence and anneal temperature. A pronounced structure has been observed in the annealed profiles for fluences ⩾1015cm−2. Comparison of the Al profiles with those of implanted B and Ga established that the structure is species dependent. The results of measurements designed to isolate damage effects indicate that the observed structure is induced by the reordering of the amorphous layer.

ISSN:0003-6951    

DOI:10.1063/1.88716

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A new model for boron diffusion in silicon is proposed in which it is assumed that the dominant diffusing species is a neutral boron‐vacancy pair (B−V+). Analysis of the model shows that whenCBis not the dominant species, the solution of the diffusion equation for constant surface concentration is a complementary error function. WhenCBis the dominant species during at least part of the diffusion, the diffusion equation must be solved numerically. It is shown that in this latter case, the variation of positively charged vacancy concentration with Fermi level causes the boron diffusivity to appear to be concentration dependent.

ISSN:0003-6951    

DOI:10.1063/1.88717

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

We have succeeded in generating cw laser sidebands at wavelengths tunable from ∼5.5 to ∼6.5 &mgr;m. The behavior of the power output of the generated radiation is described quantitatively by using the equivalence between four‐photon mixing and Raman scattering from coherent spin motion in a spin‐flip Raman laser.

ISSN:0003-6951    

DOI:10.1063/1.88691

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Laser performance of twinned 90% Nd–10% Y‐pentaphosphate (0.9 Nd–0.1 YP5O14) crystals with dimensions typically 4.5×3 mm in diamond‐shaped cross‐section by 2 mm thick is reported. Power conversion efficiencies of ≈24% and peak power outputs of approximately 240 mW were obtained under optical excitation with a repetitively pulsed argon laser. Samples of 0.75 Nd–0.25 InP5O14, 0.1 Nd–0.9 YP5O14, 0.1 Nd–0.9 CeP5O14, and 0.1 Nd–0.9 GdP5O14were also lased.

ISSN:0003-6951    

DOI:10.1063/1.88718

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Grating couplers between low‐refractive‐index (n≈1.5) optical fibers and high‐refractive‐index (n≈2.2) electro‐optic planar guides have been analyzed and demonstrated. Coupling efficiencies of 6% between single modes of a film and a fiber have been observed. Efficiencies of approximately 86% between single‐mode fibers and films using blazed backward‐wave gratings are predicted. In addition, low‐loss low‐optical‐aperture multimode fibers may be coupled to single‐mode films with efficiencies greater than 50% and angular spreads less than 0.5°.

ISSN:0003-6951    

DOI:10.1063/1.88692

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A single pass gain of ∼0.9% p/m (at 8446 A˚ in atomic oxygen) has been measured for a3He‐Ne‐O2plasma generated by the volumetric3He(n,p)3H reaction induced by neutrons from a pulsed nuclear reactor. The plasma was contained in an optical cavity containing a chopping fan that permitted a measurement of the ratio of output 8446 A˚ from the normal cavity to that with the back mirror blocked. This ratio, called the unblocked‐blocked ratio, was used to study the gain dependence on total pressure and concentration. The maximum gain observed was for a concentration of 0.048% O2and 1.5% Ne, at a total pressure of 600 Torr. The peak gain remained fairly constant with neutron fluxes from 1013to 2.5×1015n/cm2 sec. Results of other concentration studies are also discussed. The laser medium is pumped by thermal neutrons from the Illinois TRIGA reactor that impinge on a 80‐cm by 0.8‐cm‐i.d. glass tube containing from 50 to 800 Torr3He‐Ne‐O2.

ISSN:0003-6951    

DOI:10.1063/1.88693

出版商:AIP    

年代:1976

数据来源: AIP