摘要:

Deposit thickness profiles obtained from a set of parallel strip sources were investigated to determine the optimum conditions of strip spacing relative to source‐substrate distance needed for the production of smooth thickness profiles. The study was motivated by a desire to produce homogeneous alloy deposits by sputtering from a target consisting of sets of interspersed parallel strips of the alloying elements. Calculated and experimental profiles revealed a rapid decrease in deposit thickness variation with decreased distance between the strips in the source and with increased distance from strip source to substrate. The percentage composition variation (VA′) of a binary alloy deposit produced from interspersed strips was found to depend on the composition for a given thickness variation according to the equationVA′≃(1−CA)2t′.CAis the average concentration ofAin the deposit, andt′ is the percentage variation in the thickness of a deposit from a single set of parallel strip sources. Thus the variation in concentration is always less than twice the thickness variation because 1−CA<1 for all alloys. It was found that a strip spacing to source‐substrate distance ratio of 0.5 or less would give sufficient uniformity of thickness for homogeneous alloys to be made from an easily constructed target‐substrate arrangement. The maximum composition variation for a source‐substrate distance ratio of 0.5 was calculated to be 0.012%.

ISSN:0021-8979    

DOI:10.1063/1.1658576

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A model is proposed to explain the reduction in work function of an Na‐covered W (112) surface by oxygen adsorption. It is proposed that oxygen atoms are adsorbed directly to the W (112) substrate, forcing the Na atoms to the second layer. Since the dipole moment of an O&sngbnd;Na bond is much larger than that of a W&sngbnd;Na bond, it is believed that the W&sngbnd;O&sngbnd;Na bonding has larger dipole moment than that of the W&sngbnd;Na bond thus causing a decrease in work function. LEED results consistent with the proposed model is presented.

ISSN:0021-8979    

DOI:10.1063/1.1658577

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The theory for an asymmetric Langmuir probe is developed for the case of a collisionless streaming high‐density (ai>Rp>30&lgr;d) plasma withTi<Te. The results are used to analyze the response of the probe to a mildly turbulent drifting plasma. Ion saturation current is a function of the angle between the streaming direction and the probe asymmetry axis and has the formVdi=(Te/Ti)1/2(Vs/4)(&Dgr;Isi/Isi).The operation of the probe is verified by measurements of a known plasma‐drift velocity and found to be accurate within a factor of three.

ISSN:0021-8979    

DOI:10.1063/1.1658578

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A model is presented for the one‐dimensional thermoelastic response of homogeneous isotropic metals to pulsed relativistic electron beam absorption. The effect of the time dependence of the electron power pulse was examined for two cases: a delta function and a rectangular pulse of duration &tgr;0. Equations were obtained in both cases which explicitly relate properties of the electron beam (energy absorption profile, total energy, and pulse duration) to properties of the material (density, dilatational wave velocity, and Gru¨neisen parameter). Experiments were performed to test the developed model for polycrystalline aluminum, copper, and tantalum. Electron beam dosimetry was accomplished by means of calorimetry and a passive film technique. Material response data was obtained by measuring the back surface motion by means of a laser interferometer. The experimental results indicated that an assumption of instantaneous energy deposition was incorrect except possibly for the case of the lowest Z metal, i.e., aluminum The assumption of a rectangular power pulse was adequate to correlate the experimental results for all of the metals. The experiments afforded a direct determination of the Gru¨neisen parameters which agree with the values calculated from thermodynamic data.

ISSN:0021-8979    

DOI:10.1063/1.1658579

出版商:AIP    

年代:1970

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1658580

出版商:AIP    

年代:1970

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1658581

出版商:AIP    

年代:1970

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1658582

出版商:AIP    

年代:1970

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1658583

出版商:AIP    

年代:1970

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1658584

出版商:AIP    

年代:1970

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1658585

出版商:AIP    

年代:1970

数据来源: AIP