摘要:

In a previous paper by Razdan, Brennan, and Grossweiner, it was shown that theoretical thermoluminescence (TL) glow curves for first‐order kinetics and the temperature‐independent preexponential factor can be successfully generated using an analog computer. The present work was undertaken to extend the computer program to include second‐order kinetics as well as the temperature dependence of the preexponential factor in both the first‐ and second‐order kinetics. The theoretical TL glow curves obtained with the new programs are reported here. Also reported are the details of the programs developed: the amplitude and time scaling procedures, sample calculations of the initial conditions, and potentiometer settings.

ISSN:0021-8979    

DOI:10.1063/1.1662181

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The simple Drude‐Zener theory has been used to ascertain the behavior of microwave reflectivity of a semiconductor in a magnetic field. Magnetoreflectivity of the circular mode TE11at 34 GHz has been measured with an experimental setup which is described. The Hall mobility results are given for Ge and Si samples. The interest and potentiality of the method are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1662182

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Intense broadband emission in the visible is observed from crystals of Bi4Ge3O12under optical and x‐ray excitation. From measurements of absorption, reflection, fluorescence, and excitation spectra, the emission is assigned to3P1→1S0transitions of Bi3+. The Stokes shift is large,[inverted lazy s]14 000 cm−1. The temperature dependences of the fluorescence intensity and lifetime in the range 77–400 °K establish that nonradiative decay becomes significant at temperatures ⪞250°K. Comparison of the properties of Bi4Ge3O12with those of Bi12GeO20and other bismuth‐activated materials demonstrates the importance of the Stokes shift and the1S‐3Penergy difference in determining the luminescence behavior. The use of Bi4Ge3O12as a laser host crystal for rare‐earth and iron group activator ions, and as a scintillator material is discussed briefly.

ISSN:0021-8979    

DOI:10.1063/1.1662183

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A simple test is developed to establish the existence of an Ohmic thermally activated conductivity in a chalcogenide glass which is carrying uniform current densities sufficient to cause current‐controlled negative differential resistance. The technique involves proper plotting of the turnover voltage data, taken as a function of ambient temperature, according to a theoretical relation obtained for a Joule‐heated thin‐film sandwich structure. This technique is of particular value in the event that insufficient information is available for a detailed analysis of the current‐voltage curve. Experimental data from a thin‐filma‐As2SeTe2device are plotted according to this relation and evidence is presented that the chosen conductivity function does not obtain for this glass at high current densities, even though this behavior is observed at low current densities.

ISSN:0021-8979    

DOI:10.1063/1.1662184

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

We have investigated material initiated air breakdown using a long 10.6‐&mgr;m pulse (tens of microseconds) and attributed the breakdown initiation to a thermal mechanism. In particular, breakdown initiated on glass fibers after irradiation times up to 35 &mgr;sec with power densities of 106−107W/cm2is reported. Measured parameters included breakdown threshold, time to breakdown, plasma expansion dynamics, and transmission of 10.6‐&mgr;m radiation through the plasma.

ISSN:0021-8979    

DOI:10.1063/1.1662185

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A method has been found for introducing ions into SiO2that are highly mobile at room temperature. This is done by contaminating the surface of the oxide with a salt containing the ion to be introduced, followed by charging with a corona discharge. Positive ions move rapidly through a thin layer of oxide and accumulate at the silicon interface where their presence is detected by means ofC‐Vmeasurements. Charge introduced in this way can be subsequently removed by charging with a negative corona, followed by washing in water and annealing.

ISSN:0021-8979    

DOI:10.1063/1.1662186

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

We explore the uniformity of energy deposition from the primary (ionizing) beam from the electron‐beam‐controlled discharge laser, especially considering the magnetic deflections and the scattering collisions. We find the addition of a parallel guide magnetic field to be useful.

ISSN:0021-8979    

DOI:10.1063/1.1662187

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

We have developed a set of computer codes to treat the transport of the high‐energy (primary) electrons in gas discharge lasers of the Los Alamos type. Such electron transport requires no new physical ideas, but must be applied without any of the common restrictions. In contrast to existing theory, we may not specialize to total turning without energy loss; we may not specialize to energy loss without turning or tortuous paths; we are interested in observations other than just those made far from the interaction region; and we must include applied electric and magnetic fields. Our codes meet these requirements and still permit the computation of cases of interesting complexity with the investment of a modest amount of machine time. Several examples are reported as verification of the computation and as its application to laser design.

ISSN:0021-8979    

DOI:10.1063/1.1662188

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The design features and operating parameters of a cold‐cathode gas plasma electron beam apparatus for bombardment excitation of semiconductor samples is described. The gas plasma apparatus is capable of electron beam energies > 50 keV and current densities ≳50A/cm2, which are sufficient for semiconductor laser operation. Although photopumping and high surface losses do not permit the observation of anA‐line peak in0.4<x≲0.8 GaAs1−xPx:N+(N>1019/cm3), the deeper pumping of the gas plasma electron beam source permits observation of theA‐line, as is demonstrated onx= 0.53 material. The deeper excitation afforded by the gas plasma electron beam apparatus, and lower over‐all surface losses have permitted laser operation of indirect crystal (x>xc) made quasidirect by the N trap, as is shown (77 °K) on theA‐line transition inx= 0.47 (x>xc≈ 0.46) GaAs1‐xPx: N−(N < 1019/cm3).

ISSN:0021-8979    

DOI:10.1063/1.1662189

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Properties of the reflection and mode conversion of the fundamental TM surface wave at a guiding structure deformation are investigated in this paper with the boundary perturbation technique. In order to obtain each order of the scattered fields, it is found that a separate boundary value problem has to be solved. A brief outline of the formulation is given. Numerical results from an example are presented in graphs to show the effect of the geometric shape of the deformation.

ISSN:0021-8979    

DOI:10.1063/1.1662190

出版商:AIP    

年代:1973

数据来源: AIP