摘要:

A proton‐recoil methane proportional counter has been used as a neutron energy spectrometer in the presence of conversion electrons from background gamma rays. A difference in the rise time of the voltage profile for conversion‐electron and recoil‐proton events of the same total ionization was made the basis for an electronic gamma‐neutron discrimination technique. Use of the gamma rejection technique was equivalent to an effective reduction in gamma sensitivity of the detector by a factor of 450. Spectroscopic information on a broad incident neutron spectrum was extended from the region above 350 keV to that above 80 keV.

ISSN:0034-6748    

DOI:10.1063/1.1717719

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

An NMR spectrometer system is described which incorporates the use of magnetic field modulation for the simultaneous purpose of baseline stabilization and stabilization of the resonance condition. Several other modulation techniques are briefly described.

ISSN:0034-6748    

DOI:10.1063/1.1717720

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A microtechnique for measuring the magnetic susceptibility of paramagnetic compounds in solution is described. Solutions containing less than 10−8mole of solute have been measured, which represents a sensitivity increase of more than 104over the classical Gouy method. The method depends upon balancing magnetic forces in an inhomogeneous magnetic field against density gradients in the solution.

ISSN:0034-6748    

DOI:10.1063/1.1717721

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A simple apparatus is described which provides a heating rate proportional to the square of the absolute temperature (T2). The apparatus is based on a Wheatstone bridge having a platinum heating coil in one arm and a variable resistor which changes linearly with time in the opposite arm. An example of a recorded glow peak is given and compared to the theoretical curve.

ISSN:0034-6748    

DOI:10.1063/1.1717722

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A contaminated fluid is charged and pumped into an electrodeless collection space, where particulates are precipitated. An approximate theory of precipitation is given; it is supported by experimental evidence. The method is especially suited for cleaning insulating liquids.

ISSN:0034-6748    

DOI:10.1063/1.1717723

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A photoengraving technique is described for the preparation of tensile specimens from rolled copper foil down to ∼2 &mgr; in thickness. The tensile testing procedure gives a complete stress‐strain analysis of the foils to the point of fracture. Yield stress, ultimate tensile strength, and elongation to fracture are measured.

ISSN:0034-6748    

DOI:10.1063/1.1717724

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A dynamic mechanical properties tester is described for use in the low audio and subaudio frequency range on various types of flabby material, including biological tissue. The moving element of the device is supported by a gas bearing with negligible springiness and friction and contains about 2.5 g of mass. A single coil in a magnetic field is used for both driving the moving element and measuring the vibration response.

ISSN:0034-6748    

DOI:10.1063/1.1717725

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

An apparatus is described with various modifications for the observation of chemical relaxation upon fast temperature rises, 2 to 4° within a few microseconds. Several types of concentric and thermostated discharge tubes are described. The smallest type holds only 50 &mgr;l, which is thus ideal for investigating biological systems with the temperature jump method. Fast temperature rises are produced by discharges of capacitances through an electrolytic solution. Changes of the chemical system are detected spectrophotometrically by means of fast photomultipliers. The signal is amplified and observed oscillographically. Special emphasis is placed on high geometric flux (use of conical lenses).

ISSN:0034-6748    

DOI:10.1063/1.1717726

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A measuring stage for bubble chamber film, having some interesting features in both its film transfer mechanism and its stage motor drive, is described. Power for the stage motion is supplied by pairs of motors geared to differentials, the speed of one motor being controllable. Lead screw speed is, therefore, continuously variable in both directions. Measurement of coordinates of points on a track with the assistance of a track centering device is outlined in principle; details are given elsewhere in this issue. The film transfer mechanism will accomodate four stereo‐views on separate films on any width from 35 to 70 mm and any length from 100‐ft spools to 1000 ft, wound on cores, with the maximum ease of convertibility.

ISSN:0034-6748    

DOI:10.1063/1.1717727

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A means for automatically determining the coordinates of a point, quickly and accurately, at the center of a bubble chamber track is described. A coarse setting of operator‐controlled cross hairs, supported by a toolmaker's stage, is made and the distance between the cross hairs and the track center is found by means of a system based on a vibrating slit which scans a portion of the track. The distance is reduced to digital form and printed out on tape along with the coordinates of the coarse stage setting. A computer routine then determines the true position of the point on the track.

ISSN:0034-6748    

DOI:10.1063/1.1717728

出版商:AIP    

年代:1962

数据来源: AIP