摘要:

An electron bombardment furnace temperature controller is described which operates over a wide temperature range with excellent stability. The controller uses a high gain servo amplifier system to maintain constant bombardment current. The bombardment voltage is held fixed over a wide current range by a constant voltage power supply. Temperature constancy of about 0.1% at 1600–1800°C is maintained over a several hour period.

ISSN:0034-6748    

DOI:10.1063/1.1715357

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A densitometer circuit is described which uses two photomultiplier tubes operated at constant anode current as a balanced range compressor, followed by a logarithmic difference amplifier. A density scale linear to ±0.01 density unit over a density range of 2.5 is obtained. The circuit is stable, requires no critical adjustments, and is unaffected by changes in the luminous output of the source.

ISSN:0034-6748    

DOI:10.1063/1.1715361

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The proton beam extraction system of the 450‐Mev Chicago synchrocyclotron is described. The nonlinear theory of LeCouteur has been applied and an external beam of 1011protons per second has been obtained.

ISSN:0034-6748    

DOI:10.1063/1.1715374

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The construction and principle of operation of a new type of quartz fiber torsion balance are described. The quartz suspension fiber used can be as small as 0.5‐&mgr; diameter. This enables magnetic measurements to be made on an individual microscopic magnetic particle of about 1‐&mgr; diameter.

ISSN:0034-6748    

DOI:10.1063/1.1715379

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The conditions for the thicknesses of the foils of a Ross differential x‐ray filter are examined to yield the best accuracy of monochromatic intensity measurement for a given heterogeneous beam of x‐rays. The results are applied to the problem of monochromatizing theK&agr; radiation from a copper target x‐ray tube using nickel and cobalt foils. The improvement in the differential filter as a monochromator when used with a proportional counter and single‐channel pulse‐height discriminator is pointed out.

ISSN:0034-6748    

DOI:10.1063/1.1715354

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A trigger circuit has been developed using a 6BQ7A receiving tube with a recovery time of approximately 1.5×10−7second and an input sensitivity of 0.17 volt. The circuit and test results are described.

ISSN:0034-6748    

DOI:10.1063/1.1715355

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

Four techniques using curved‐crystal focusing monochromators are described: combinations of a reflection specimen and reflection monochromator, a reflection specimen and transmission monochromator, a transmission specimen and reflection monochromator, and a transmission specimen and transmission monochromator. The first technique allows recording of diffraction patterns due toK&agr;1radiation only, and elimination of Compton‐scattered radiation (except at low angles). The second technique provides a back‐reflection diffractometer for measurements at Bragg angles up to 90°. The third technique can be applied to weakly absorbing specimens when a strictly monochromatic diffraction pattern is required. Various aspects of the focusing geometry are analyzed.

ISSN:0034-6748    

DOI:10.1063/1.1715356

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A crystal spectrometer for neutron measurements has been developed which has relatively good resolution over an effective energy range from 0.08 to >20 ev. The figure of merit which has been obtained is 0.171 &mgr;sec/m with Be (123¯1) and 0.127 &mgr;sec/m with Be (224¯2) monochromator. The good resolution is made possible by a multiple channel collimator (Soller slit) of novel design. The collimator is described in detail and the resolution function for the system is derived and discussed. It is shown that the resolution of the system is essentially independent of the mosaic spread of the crystal. Experimental results are presented which illustrate the performance of the instrument.

ISSN:0034-6748    

DOI:10.1063/1.1715358

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The semiautomatic balance used to measure the tensile strength and Young's modulus of glass fibers when bent into a loop has been made fully automatic. A differential transformer and servomotor are used to apply chain‐weight as the tension in the looped fiber is increased by the loading motor.All measurements needed to calculate the tensile strength and Young's modulus are automatically recorded on the drum chart driven by the loading motor. The maximum tensile stress in the looped fiber at the instant of break is proportional to the vertical motion of the recording pen, and the maximum strain is proportional to the rotation of the drum.

ISSN:0034-6748    

DOI:10.1063/1.1715359

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A direct recording Fabry‐Perot interferometer is described which has a high optical speed and provides a direct tracing of spectral line shapes on a linear scale. A photomultiplier views the center spot of the interference pattern. The output of the photomultiplier goes to a vibrating‐reed electrometer and then to a pen recorder. The wavelength of the light at the center of the interference pattern is made to vary with time by changing the index of refraction between the interferometer plates. This is accomplished by enclosing the plates in a gas‐tight housing and admitting an inert gas such as argon or helium to the housing. By the proper choice of gas and of the rate of pressure change, one obtains the desired rate of tracing the line shape. Orders of magnitude reduction in ``exposure'' time are achieved by eliminating the use of photographic plates.

ISSN:0034-6748    

DOI:10.1063/1.1715360

出版商:AIP    

年代:1956

数据来源: AIP