摘要:

A 256‐channel pulse‐height analyzer using a magnetic core memory is now in use at the Argonne National Laboratory. This analyzer uses a form of the Wilkinson method of generating numbers in response to input pulses. These numbers are proportional to the amplitudes of the input pulses, and correspond to the channel numbers into which the individual counts are to be recorded. The digital data processing circuits comprise a simple computer, with an internal memory which can store 256 sixteen digit binary numbers. A cathode‐ray tube display of the data in the form of a plot of countsversuschannel number is available during and after operation. Permanent readout is in the form of a similar curve traced by a recording potentiometer. Printed decimal readout is also available. The normal average analyzer dead time is 80 &mgr;sec, and pulse rates in excess of 5 million per minute at the input circuit can be tolerated without appreciable data distortion.

ISSN:0034-6748    

DOI:10.1063/1.1715670

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A 1024‐channel time‐of‐flight analyzer for recording data obtained in neutron time‐of‐flight experiments has been placed in operation at the Argonne National Laboratory. Channel widths are adjustable from ½ &mgr;sec to essentially any higher value. The analyzer dead time is 16 &mgr;sec following each recorded count. The storage circuits may be divided into two sections for recording events detected by two separate counters. The analyzer may also be divided into four groups of 256 channels each. These groups may be independently located in any time region up to 4096×T, whereTis the channel width in use. Readout is by means of simultaneous teletype punched tape and analog pen recording. There is a linear cathode ray tube display of countsvschannel number. The device uses a magnetic core memory system similar to that used in the 256 channel pulse height analyzer described in the preceding article.

ISSN:0034-6748    

DOI:10.1063/1.1715671

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A little trick is described, which facilitates the carrying out of anatomical or physiological preparations that are extremely delicate to handle with free hands. It consists mainly in a support and a screwdriver acting as a lever to reduce the movements of the hands.For very fine micromanipulations, where even touching the operating table must be avoided, an air‐driven micromanipulator has been built, in which a small air‐driven turbine rotates the adjusting screws of the manipulator. Movement in various directions can be performed by pressing keys which open air pressure valves. All the movements can be programmed in advance by means of prepunched holes in a paper strip of the type used in teletype systems.

ISSN:0034-6748    

DOI:10.1063/1.1715672

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The apparatus described here permits the study of phase diagrams either by heating or cooling. One temperature control circuit permits a preset temperature gradient, either positive or negative, to be maintained between the sample and bath with the temperature of the bath being controlled by that of the sample. The appearance or disappearance of solids in the sample is followed by measurement of the light transmission of the sample. A second control circuit provides constant bath temperatures. A step‐wise approach to the liquidus point, with the light transmission used to indicate the establishment of equilibrium between solid and liquid at each step, offers a means of determining this point under equilibrium conditions.

ISSN:0034-6748    

DOI:10.1063/1.1715673

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

Two Faraday‐cup electron collectors have been developed which are capable of measuring the absolute integrated beam current of the Stanford linear accelerators to better than 0.5&percent; at electron energies ranging from 4 to 300 Mev. A description of these instruments is given and complete design criteria are offered which allow the extension of the range to Bev energies.

ISSN:0034-6748    

DOI:10.1063/1.1715674

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

A modification of the Beckman DU spectrophotometer is described which is capable of observing absorption spectra of liquid systems up to 650°C.

ISSN:0034-6748    

DOI:10.1063/1.1715675

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

Expressions are derived relating counting rate measured with quantum detectors to the dosage rate in roentgens. The number of quanta/cm2per roentgen is strongly energy dependent. In the x‐ray region 5 to 50 kv, however, the variation of the quantum counting efficiency with wavelength of some counters (e.g., argon Geiger counter) matches fairly closely the energy dependence factor, and hence such detectors can be used asr‐meters.

ISSN:0034-6748    

DOI:10.1063/1.1715676

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The square‐wave principle for electromagnetic flow recording offers several theoretical advantages over the dc or ac systems, particularly for blood flow recording from intact vessels. The degree to which these advantages may be obtained in practice depends upon the extent to which the equipment meets the specific requirements of the principle. This paper considers the objectives that should be considered in design and construction of a practical equipment.

ISSN:0034-6748    

DOI:10.1063/1.1715677

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

The importance of Compton backscattering in gas proportional spectrometry in the energy range 10 to 100 kev is pointed out. If the backscattered photons are unresolved from the main peak, a large error may be introduced under certain conditions in absolute and relative intensity measurements based on theoretical quantum efficiency (geometry×absorption); if the backscattered peak is resolved, failure to recognize its origin may result in the ``discovery'' of a new gamma ray. The effect is especially pronounced when a collimator is used to establish geometry; for example, the intensity of backscattered photons can amount to as much as half the intensity of the main peak at 46.5 kev with a ¼‐in. diameter collimator.

ISSN:0034-6748    

DOI:10.1063/1.1715678

出版商:AIP    

年代:1956

数据来源: AIP

摘要:

An apparatus is described which provides a simple means of obtaining stirring or pumping action in a pressurized system. Since no packing glands are employed, the device is leak‐proof. The required mechanical action is provided by reciprocating motion of a soft‐iron armature enclosed in the system and driven by a pair of electromagnetic coils. Input to the coils is provided by a thyratron‐controlled circuit. The circuit and constructional details are given.

ISSN:0034-6748    

DOI:10.1063/1.1715679

出版商:AIP    

年代:1956

数据来源: AIP