摘要:

A high-intensity, high-resolution neutron velocity selector system, employing the Nevis synchrocyclotron as asource of pulsed neutrons, is described. Detector counts are accumulated in a 2000-channel analyzer with 0.1-&mgr;secchannel width. Punch card data reduction techniques are discussed. Resonance spectra ofPbI2obtained using a35-m flight path provide an example of the resolution and illustrate the use of the self-indication capture &ggr;-raydetector scheme extensively employed. A planned flight path of 200 m is expected to provide a resolution of <1nsec/m for neutron energies above 1000 ev.

ISSN:0034-6748    

DOI:10.1063/1.1931231

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A 2000-channel time-of-flight analyzer for neutron spectroscopy is described. The analyzer is designed for usewith pulsed accelerators operating at approximately 60 cps. Channel widths of 0.1 &mgr;sec and a Head time of 0.8 &mgr;secare obtained. A fast electrostatic memory is used to record data with a minimum of dead time, and a slower largercapacity magnetic drum memory is used to read out the electrostatic memory and accumulate data betweenbursts. The electrostatic memory system which was developed at Columbia University is described in detail.

ISSN:0034-6748    

DOI:10.1063/1.1931232

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The properties of continuous variable capacitance liquid level gauges are analyzed, and the interrelations ofhydraulic and electrical properties are examined. The analysis covers both conductive and nonconductive liquidsand considers the “flowback” effects found in dynamic level fluctuations (such as waves and slosh). Design rulesare given.

ISSN:0034-6748    

DOI:10.1063/1.1931234

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

It is demonstrated that a linear sweep of the magnetic field reduces the requirement for precise 180° rotations ina Carr-Purcell spin echo experiment.

ISSN:0034-6748    

DOI:10.1063/1.1931235

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The high pressure optical cell previously described in the literature has been modified to permit measurementsto 400°C and 200 000 atm. The operating details and methods of temperature and pressure calibration are discussed.The absorption edges of sulfur and of olivine are presented as a function of temperature and pressure.

ISSN:0034-6748    

DOI:10.1063/1.1931236

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A new type of instrument for the size classification of airborne particulate matter is described. This apparatusoperates on an aerodynamic principle and effects ordered size separation of both liquid and solid particles. Calculationsof the spatial separation as a function of size for spherical particles of unit density are in accord withpreliminary experimental data for diameters between 10 and 100 &mgr;. Application of this principle to aerosol size-frequencyanalyses is discussed briefly.

ISSN:0034-6748    

DOI:10.1063/1.1931237

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The problem of making electrical contact to apparatus at very low temperatures is discussed, with particularreference to dielectric constant measurements in a situation where multiple shielding is required. Examples aregiven of easily constructed rigid electrode leads suitable for use at low temperatures, which have low thermal conduction,low and stable inter-conductor capacitance and conductance, and which provide for more than two coaxialconductors.

ISSN:0034-6748    

DOI:10.1063/1.1931238

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A unique voltage clamp circuit for certain biological investigations, which features the provision of maintainingthe clamped region at ground potential with the residual error balanced about ground, is discussed. Theoreticalconsideration of the circuit function indicates that the possibility of error arising from stray current pathways andloading of the electrodes is reduced by holding the clamped region close to ground. An additional secondary feedbackloop, in conjunction with this circuit, reduces switching transients and other high frequency noise and allowsdynamic balance of the clamped region about ground potential despite assymmetries in the experimental circuit.This circuit has been employed, using commercially available operational amplifier units, to clamp the isolatedfrog skin for measurement of sodium transport flux. In this application, the assembly clamped the skin to wellwithin 1 mv, with excellent dc stability and a theoretical error of 0.1% in response to 1-msec transients.

ISSN:0034-6748    

DOI:10.1063/1.1931239

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

An experimental high temperature high vacuum furnace with self-supported tungsten resistance heating elementsis described. The furnace is assembled from readily obtainable parts, and knife-edge vacuum seals are used through-out.The volume of the hot chamber is approximately 2 in. diameter by 8 in. high; the uniform zone is 2 in. long.A temperature of 2000°C can be attained at a pressure of∼10−5 mm Hgand at a power expenditure of 12 kw.

ISSN:0034-6748    

DOI:10.1063/1.1931240

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A velocity analyzer has been constructed for use in the diffraction of fast electrons by gases as well as solids. Theangular distributions of elastically and of inelastically scattered electrons are electrostatically separated and aresimultaneously recorded on photographic plates. Coherent inelastic scattering patterns fromCCl4vapor andC6H6vapor have been obtained.

ISSN:0034-6748    

DOI:10.1063/1.1931241

出版商:AIP    

年代:1960

数据来源: AIP