摘要:

A computation is given of the fluctuations in average temperature of an isolated thin film on a substrate, the noise being due to two causes: (i) fluctuations in blackbody radiation absorbed and emitted by the front surface; (ii) thermal diffusion in the sample and the substrate. The surface source results in a large 1/frange, the level of which decreases with increasing heat conductivity of the substrate; the noise goes over into a 1/f2spectrum at high frequencies. The noise due to the volume source results in a 1/f1/2spectrum, going over into a 1/f3/2spectrum at higher frequencies; the noise also decreases with increasing heat conductivity of the substrate. The integrated total noise is of the orderkT20/C. Under most circumstances the spectrum due to the volume source dominates.

ISSN:0021-8979    

DOI:10.1063/1.328104

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A previous calculation of neutral‐beam divergence due to imperfect magnetic shielding of the gas‐cell neutralizer is generalized to include the case in which the intrinsic magnetic‐field–free divergence of the beam is finite.

ISSN:0021-8979    

DOI:10.1063/1.328105

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Strong fluorescence is observed on the XeI (B→X) excimer band upon excitation of a mixture containing an iodine compound and Xe with 193 nm photons. This emission is observed when I2, CH2I2, CH3I, or CF3I are used as iodine donors. Radiative lifetime and two‐body collisional quenching rate of XeI(B) by Xe, I2, and CH3I have been measured. The relevance of these results with regards to use of this excimer as a source of UV stimulated emission is discussed.

ISSN:0021-8979    

DOI:10.1063/1.328106

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Relationships between partial pressures and shifts of blue wing and red wing maxima of the self‐reversedDlines in a high‐pressure sodium‐mercury discharge have been calculated. A van der Waals model is used in the calculation of the interaction between sodium and mercury atoms. A useful and convenient formula has been derived for estimating mercury pressure in a sodium‐mercury discharge from easily measured parameters (the shift of red wing maximum and the shift of blue wing maximum).

ISSN:0021-8979    

DOI:10.1063/1.328107

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Vacuum ultraviolet absorption cross sections for the compounds Cl2, Br2, I2, HCl, HBr, HI, CCl4, CCl3Br, CF3Br, CF3I, HgCl2, HgBr2, and HgI2have been measured between 170 and 230 nm. Studies of the Xe*2discharge lamp used are reported. The absorption bands of various mercuric halides are identified.

ISSN:0021-8979    

DOI:10.1063/1.328108

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The thermal pulsing technique gives information about the spatial distribution of charge and polarization through the thickness of electrets. This paper discusses methods by which this technique is applied in practice to the problem of determining these distributions. Several possible sources of systematic error in the experimental data are identified, and methods are discussed for eliminating these errors. A physical approach to data analysis is discussed which is complementary to a previously published mathematical analysis. Examples are given where this approach has yielded useful information about the charge or polarization distribution in insulators.

ISSN:0021-8979    

DOI:10.1063/1.328109

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Two model analyses are constructed in order to determine the influence of bonding materials on the propagation of electromagnetic waves in otherwise bilaminated composites. The geometric arrangement of the composite with the bond is treated as a special type of a trilaminated composite in which each of its major constituents is sandwiched between two bonding layers. In the first model, a recently developed continuum mixture theory of electromagnetic wave propagation in bilaminated composites is extended to treat the trilaminated composite. Here, details of the propagation process in the major components and also in the bonding layers are derived. In the second model, the entire effect of the bonds is treated as a modifier to interfacial continuity conditions. In this model the details of the propagation process in the bonding material are ignored. It is found that the results of both models correlate well with each other and also with some exact solutions for a rather wide range of frequencies.

ISSN:0021-8979    

DOI:10.1063/1.328110

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

This paper presents experimental results in the development of low‐emittance relativistic electron beams with finite energy spread, which—among other applications—is suitable for suppressing collective instabilities in an electron‐ring accelerator. The measurements were performed with a divided cathode in an electron‐beam gun, one half of which is connected via a resistor with the high‐voltage terminal. The energy difference can be varied up to 100 keV in proportion to the resistance, with equal subcurrents. The beam parts are well separated, and their radial distance is about equal to the radial difference of the corresponding electron closed orbits, such that electron‐ring formation with minimum radial betatron oscillations should be possible. The beam emittance is as small as about 100 mrad cm and the current is 800 A.

ISSN:0021-8979    

DOI:10.1063/1.328111

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

We present a nonlinear analysis of the single‐particle dynamics in an electron cyclotron maser oscillator and show that the efficiency can be dramatically enhanced by appropriately contouring the system parameters. The beam electrons can be prebunched in phase to form a macroparticle in phase space such that beam kinetic energy is not extracted. After forming a phase‐bunched electron beam, either the applied magnetic field or the cavity electromagnetic field can be spatially varied in such a way as to extract virtually all the electron transverse kinetic energy. Without such contouring, the transverse efficiency is typically ?40%. An example is presented in which the transverse efficiency is increased from 36% (in uniform fields) to 75% by increasing the applied magnetic field by ∼6%. The present analysis can readily be extended to the case of a maser amplifier.

ISSN:0021-8979    

DOI:10.1063/1.328112

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The optical extraction characteristics of homogeneously broadened cw lasers with nonsaturating losses are calculated exactly and compared with previous analytic approximations. The extraction efficiency as a function of the output coupling is discussed in detail for medium parameters appropriate to high‐gain rare‐gas‐halide lasers. It is found that contrary to expectations, the output is comparatively insensitive to the medium parameters and output coupling, and that it is a poor diagnostic tool for laser medium characterization.

ISSN:0021-8979    

DOI:10.1063/1.328113

出版商:AIP    

年代:1980

数据来源: AIP