摘要:

An optical projector having different magnifications, 5× and 50×, in two rectangular directions is described. Although the device is designed principally for rapid measurement of cloud‐chamber track curvatures, it has been applied to various situations in which plane‐to‐plane imaging at constant magnification is desired. Simple plano‐convex cylindrical lenses are used as the image‐forming elements. These give quite satisfactory linearity and resolution at the maximum magnification.

ISSN:0034-6748    

DOI:10.1063/1.1715484

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A light pulse generator is described which utilizes a flash lamp and a 5000 revolutions per second rotating mirror. A variety of light pulse shapes can be produced having widths from 1.16×10−9seconds to 10−6second.

ISSN:0034-6748    

DOI:10.1063/1.1715485

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A new mass spectrometer, which constitutes essentially a low‐resolution 180° instrument and a cyclotron in series, is proposed. The instrument appears to have substantial merits in freedom from space charge, discrimination, and gas scattering, in signal available, and in the possibility of differential pumping, while retaining the important features that the fine resolution depends only on the instrument parameters and thee/mof the ion involved.

ISSN:0034-6748    

DOI:10.1063/1.1715486

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

An albedometer is described that has the incident radiations entering an integrating sphere instead of falling directly upon a horizontal receiver, as in the albedometers that have been used in the past. In this new albedometer the receiver looks at a small opal glass window in the sphere. Filters with a narrow pass band may be placed between the window and the receiver. This arrangement makes it possible to determine the variation of albedo with wavelength.

ISSN:0034-6748    

DOI:10.1063/1.1715487

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The current‐time method of calibrating beam current integrators has been extended to give reliable calibrations for small currents when used with a feedback electrometer. The method described has given calibrations with absolute standard errors ranging from 0.2% at 10−10amp to 0.3% at 10−11amp. The equipment needed, including a precision 100‐megohm resistance, is described, and some experimental difficulties in making calibrations for small currents are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1715488

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A photometer is described for measuring the peak brightness of light flashes 0.3 &mgr;sec in duration and 10−3in.2in cross‐sectional area. A telescope and beamsplitter arrangement permits convenient and rapid aiming. The light flashes are sensed by an RCA 931‐A multiplier phototube, and the resultant electrical signals are transmitted to a pulse lengthener with appropriate 0.1‐&mgr;sec rise time circuitry. A single transient will fully deflect the output meter for a period of five seconds.

ISSN:0034-6748    

DOI:10.1063/1.1715489

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

An rf ion source of conventional type is shown to yield a current of 2.2 &mgr;a of negative hydrogen ions. This is accomplished by charge exchange of the positive ions emerging from the plasma with the neutral gas in the probe channel. The negative ion beam is well focused, and the performance of the source is 0.22 &mgr;a/cc at NTP/hour. The differential equations for the above charge exchange process are set down and solved, and found to be consistent with the observations to within an order of magnitude using published cross sections. The theory also predicts a sizable neutral beam (∼60 &mgr;a) of energy 2–3 kev. According to the equations and the published positive ion performance of these sources, many times larger negative hydrogen ion yields should be obtainable if required.

ISSN:0034-6748    

DOI:10.1063/1.1715490

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A photometer for recording the absorption spectra of microscopic samples in the visible and ultraviolet regions is described. Light intensities are measured by counting the pulse output of a cooled photomultiplier tube. Double‐beam operation is achieved through the use of a rotary shutter and a gating circuit which sorts the beams into separate scaling channels. Optimum signal‐to‐noise levels are obtained by pulse‐height discrimination. In typical operation the noise level is approximately 20 photoelectrons per minute, the signal level at 100% transmission is approximately 20 000 photoelectrons per minute, and approximately 50 absorption points are recorded per hour at an accuracy of ±1%. The system minimizes the errors which result from fluctuations in light source intensity, amplifier drift, and variations in photomultiplier plate voltage so that accuracies of ±0.1% can be achieved with the photometer (but not with the microspectrometer). With appropriate correction for noise and resolving time the system can be operated over four decades of light intensity. Application of this type of photometer to other spectrographic problems is suggested and representative data are presented.

ISSN:0034-6748    

DOI:10.1063/1.1715491

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715473

出版商:AIP    

年代:1956

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715474

出版商:AIP    

年代:1956

数据来源: AIP