摘要:

In slab or cylindrical geometry, it is shown that the total heat flow through parallel, homogeneous channels is the same, regardless of the state of thermal contact between them, even if the channels have conductivities which are different functions of temperature.

ISSN:0034-6748    

DOI:10.1063/1.1718182

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The characteristics of some EMI photomultipliers when operated continuously with large cathode and collector currents are described. It is shown that cathode currents up to about 10 &mgr;A/cm2are possible with some types of tubes, the only limitation being cathode deterioration under intense illumination. In other types surface resistivity and space charge prevent operation above about 0.02 &mgr;A/cm2. Data on collector saturation are given and the effect of dynode heating by large currents with consequent reduction in secondary emission factor is also described.

ISSN:0034-6748    

DOI:10.1063/1.1718183

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A pulsed, capacitively loaded helical line capable of generating 5000‐G pulses is described. The line velocity is 15 cm/&mgr;sec. Titanate ceramics are used as the dielectric elements. The analysis and design take into account the often overlooked effect of inductive coupling between line elements. A formalism suitable for numerical computation of complicated systems is illustrated. The design can be extended to give a variable velocity 9‐kG line.

ISSN:0034-6748    

DOI:10.1063/1.1718184

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A simple automatic frequency control system for reflex klystrons is described. A sample of the microwave power is reflected from a reference cavity that has a modulated resonant frequency. The detected signal is phase sensitively demodulated in a transistorized demodulator that can be inserted directly into the reflector lead of the klystron.

ISSN:0034-6748    

DOI:10.1063/1.1718185

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

An inexpensive streak camera was designed and built with the specific purpose of examining laser emissions. A 10‐ft sweep radius and a 6‐ft film plane provided good spatial resolution and at the same time recorded the entire event. Sweep rates were variable to greater than 0.5 in./&mgr;sec. Periodic self‐modulation, mode variations, and changes in emitting points have been observed.

ISSN:0034-6748    

DOI:10.1063/1.1718186

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The clevage plane grating spacing of potassium acid phthalate (KAP) has been measured in nine orders of diffraction andd∞found to be (13289.51±0.05 xu) at 26°C. The use of these crystals as diffraction elements for the wavelength range 6 to 25 Å is discussed. Measurement of the lattice spacing is by diffraction angle determinations in many orders with Cu K&agr;1radiation. An angular precision of 0.1″ is attained. The index of refraction was calculated from the crystal constants and is consistent with the observed orders of diffraction.

ISSN:0034-6748    

DOI:10.1063/1.1718187

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

An apparatus, enclosed in a sand‐cast aluminum vacuum chamber capable of retaining pressures of 10−5–10−6Torr, was used to measure the thermal conductivity of powder samples in vacuum. The base of the sample was heated by the temperature bath on which it rested and the top surface of the sample radiated into a cavity which was maintained at liquid nitrogen temperature (77°K). The thermal conductivity of the powders was calculated from the emitted flux, the sample thickness, and the bath temperature.

ISSN:0034-6748    

DOI:10.1063/1.1718188

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

Eddy current magnetic shielding by a rotating conductor has been utilized to create a low magnetic field region in the interior of a hollow cylinder. The enhancement of this effect by cooling to the superconducting state has been studied and applied to a superconducting device which easily generates and maintains an extremely low magnetic field region as a laboratory environment. The operation of certain commercial Hall probes at helium temperatures is discussed, and a novel method of measuring bulk resistivities as low as 10−14&OHgr;‐m is suggested.

ISSN:0034-6748    

DOI:10.1063/1.1718189

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

A high temperature vacuum furnace using electron bombardment heating has been designed and constructed for studies of diffusion in refractory materials. The furnace is designed to operate in the temperature range of 1200 to 2300°C for prolonged periods of time. The specimen temperature is controlled to ±2°C by a servo system using a thermocouple attached to the specimen crucible for the servo input.

ISSN:0034-6748    

DOI:10.1063/1.1718190

出版商:AIP    

年代:1963

数据来源: AIP

摘要:

The use of a lead sulfide detector in a device for monitoring the intensity distribution of high energy electron beams from a linear accelerator is described. Experimental measurements of the beam profile for a 6‐MeV linear accelerator are presented.

ISSN:0034-6748    

DOI:10.1063/1.1718191

出版商:AIP    

年代:1963

数据来源: AIP