摘要:

The 4‐in. hydrogen bubble chamber has been used as a neutron spectrometer in the 5‐ to 30‐Mev region. A fast data‐reduction system for the analysis of the recoil‐proton tracks was developed, utilizing a commercial electronic coordinate‐measuring device, the IBM punch‐card system, and the IBM 650 digital computer. The resolution of the entire spectrometer system was determined by measuring the monoergic (14.1‐Mev) neutron spectrum from the t(d, n)He4reaction with different neutron collimators. The full width at half maximum of the measured peak was 10% of the peak energy.

ISSN:0034-6748    

DOI:10.1063/1.1716782

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A time‐to‐pulse height converter covering the range from millimicroseconds to minutes is described. A simple 5‐component passive circuit for scanning times above 50 &mgr;sec is included also. The converters can measure several events per time scan related to one starting event. They are designed as plug‐in units for an oscilloscope, and utilize its sweep and other circuits. The use of the converters is discussed and includes scanning of negative time and inverted operation for reduction of counting losses. Notes on testing, calibration, and dead times are given, as well as examples of nuclear experiments to which they have been applied.

ISSN:0034-6748    

DOI:10.1063/1.1716779

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A sampling oscilloscope with a rise time of 3×10−10sec is described. It may be used with carrier or noncarrier periodic signals having a high fixed repetition rate. A novel coincidence circuit employed in the device for displaying the envelope of 1‐m&mgr;sec bursts of 10‐kMc energy is also presented.

ISSN:0034-6748    

DOI:10.1063/1.1716780

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A method for the precise measurement of surface tension and density of molten salts in one apparatus at temperatures up to 1000°C is reported. The essential features of the apparatus are a density bob of special design to enable surface tension data to be obtained simultaneously, and a continuously variable height crucible arrangement for the liquid sample. A description of the apparatus and the calibration procedures are given in detail. The results for molten potassium nitrate up to 470°C are reported to illustrate the method.

ISSN:0034-6748    

DOI:10.1063/1.1716781

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A method for making use of the Laue diffraction technique rather than the Bragg symmetric technique in the design of multichannel x‐ray spectrochemical analysis instruments is described. The method uses only one analyzing crystal, but with individual detectors for simultaneous registration of the relative amounts of the elements in the sample to be analyzed. Thus a compact instrument with no moving parts, which may often be designed so as to reduce spectral interferences, is possible. The method is compared with other well‐known methods and some experimental tests of the principle are described.

ISSN:0034-6748    

DOI:10.1063/1.1716783

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

An experimental camera has been devised capable of viewing a gamma‐ray or x‐ray source both statically and dynamically with a kinescope readout suitable for quantitative measurements. Experiments are described indicating sensitivities to x‐rays of about 1 to 2 r/hr.

ISSN:0034-6748    

DOI:10.1063/1.1716784

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

An investigation has been made of the possibility of using an oxide‐coated cathode as an electron source for the M.I.T. 320‐Mev electron synchrotron. A button cathode originally designed by Sperry Gyroscope Company was redesigned slightly to meet our specifications. With this new cathode, we have obtained an average lifetime of 330 hrs, operated at peak‐pulsed current of 200 ma in vacuums as poor as about 10−5mm Hg. This represents a factor of about 20 improvement in lifetime‐current product over directly heated cathodes.

ISSN:0034-6748    

DOI:10.1063/1.1716785

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

The attenuation of the low energy component (below 50 Mev) of the bremsstrahlung beam of a high energy electron accelerator by several low‐Z absorbers is studied. In particular, the advantages and construction of a lithium hydride absorber are described. The experimentally measured attenuation is compared with that calculated from a single interaction model, and several further suggestions are offered.

ISSN:0034-6748    

DOI:10.1063/1.1716786

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

A carbon arc‐image furnace has been designed and employed for the growth of single crystals of refractory compounds. The image furnace is a unique facility for this application since it provides a sharply defined hot zone, excellent atmosphere control, and complete freedom from contamination during crystal growth. General operating and performance characteristics of this furnace are described.

ISSN:0034-6748    

DOI:10.1063/1.1716787

出版商:AIP    

年代:1960

数据来源: AIP

摘要:

Energy loss spectra for gamma rays incident on sodium‐iodide crystals have been calculated by the Monte Carlo method. The calculations have been carried out for point sources, disk sources, and broad parallel beams of monoenergetic gamma rays varying in energy from 0.279 to 8 Mev. The crystals considered were right circular cylinders varying from small crystals of height and diameter one inch to large crystals of height and diameter 6 inches. Also calculated simultaneously with the energy loss spectra were the efficiencies and total absorption fractions.

ISSN:0034-6748    

DOI:10.1063/1.1716788

出版商:AIP    

年代:1960

数据来源: AIP