摘要:

A sampling oscilloscope is described with a 10 to 90% rise time of 5.6×10−10sec. Maximum useful sweep speed is about 10−10sec/in.; maximum useful sensitivity about 15 mv/in. These are limited solely by the peak time jitter of 2×10−11sec, and apparent input peak noise of about 300 &mgr;v. Unlike prior sampling devices, pulses of constant or random repetition rate are displayed with equal facility. The usual time jitter associated with the display of random pulse heights is eliminated by selecting for display only those pulses that fall within a kicksorter channel. The average wave form of pulses with moderately irregular shapes is particularly easy to measure.

ISSN:0034-6748    

DOI:10.1063/1.1715770

出版商:AIP    

年代:1957

数据来源: AIP

摘要:

An extension of previous work on the analysis of pulse‐height distributions obtained with gamma‐ray sources placed inside well‐type NaI(Tl) crystals is discussed. Two methods are given for the determination of the photopeak efficiency of these NaI spectrometers. It is shown that the summing property of the well‐type crystal can be used to obtain the source strength and to yield information on the decay scheme of gamma‐ray sources.The photofraction, photopeak efficiency, and resolution are given for a 5‐in. diameter by 3‐in. long NaI crystal with a 1‐in. diameter well.

ISSN:0034-6748    

DOI:10.1063/1.1715771

出版商:AIP    

年代:1957

数据来源: AIP

摘要:

Ion optics for Van de Graaff accelerators are reviewed in elementary terms of geometric optics with particular reference to the Oak Ridge 3‐Mv accelerator. This machine produces well‐focused beams of over 100 &mgr;a and pulsed peak currents of several hundred &mgr;a. The beam diameter measured at a distance of 2.7 tube lengths from the accelerator tube exit decreases from 0.26 in. at 0.38 Mv to 0.10 in. at 2.47 Mv. The beam divergence at 1.8 tube lengths from the exit is nearly constant, ≃2.8×10−3rad. The system is analyzed in terms of five separate lenses: (1)einzellens, (2) gap lens, (3) accelerator tube, (4) 90‐degree analyzing magnet, and (5) strong‐focusing lens. It is shown that the crossovers formed in the gap lens and near the exit of the analyzing magnet are of fundamental importance. Brief reference is made to the small energy spread, ≃0.025%, for the beams obtained from this accelerator in spite of the large control slit spacing demanded by a large crossover.

ISSN:0034-6748    

DOI:10.1063/1.1715772

出版商:AIP    

年代:1957

数据来源: AIP

摘要:

The transient containment of high magnetic energy densities in coils of various geometries is discussed. Inherent mechanical and thermal limitations are shown to apply to coils relying solely on the strength of materials. The usefulness of inertial effects is demonstrated. Instrumentation is described for producing 10 &mgr;sec range pulses of amplitude up to 1.6 megagauss in single‐turn coils. Experimental observations document the appearance of ``saw effect'' and Kruskal‐Schwarzschild instabilities at very high fields. The limitations characteristic of conventional coils can be overcome in force‐free geometries. The appropriate mathematics is developed and illustrated with practical examples.

ISSN:0034-6748    

DOI:10.1063/1.1715773

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715774

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715775

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715776

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715778

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715779

出版商:AIP    

年代:1957

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715780

出版商:AIP    

年代:1957

数据来源: AIP