摘要:

The delay error distribution of the parallel plate spark counter has been measured and the average delay is found to be 6×10−9sec. The counters are, therefore, applicable to the measurement of lifetimes as short as 10−9sec. Auxiliary circuits, including a fast synchroscope, for short time interval measurements are described, and the resolution limitations of the counters and circuits are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1745602

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A rapid differential analyzer of accuracy about 0.5 percent is discussed and its performance reviewed. Extensions to differential equations other than that of Schro¨dinger are mentioned.

ISSN:0034-6748    

DOI:10.1063/1.1745603

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

This paper describes the design and construction of compact iron‐free solenoid magnets cooled by immersion in liquid nitrogen. Construction details and performance data are given for two such magnets, which produce a magnetic field of 4000 gauss with a power expenditure of 2.7 to 3.3 kw. Heat transfer coefficients between copper wire and boiling liquid nitrogen have been measured for temperature differences between the wire and the liquid of 2 to 11°K.

ISSN:0034-6748    

DOI:10.1063/1.1745604

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An analog computer has been built which determines (e12+e22)½and Arc Tane2/e1two thousand times a second with an accuracy of about five percent. Using amplified electrocardiographic voltages proportional to three perpendicular components of the dipole moment of the hearts electric field, a pair of computers of this type will be able to produce other voltages proportional to the magnitude and two directional angles of the dipole. This may simplify considerably the study of fluctuations in the direction of the dipole and the neutralization of the effects of abnormal heart positions.

ISSN:0034-6748    

DOI:10.1063/1.1745605

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

This paper describes a convenient scheme for detecting and measuring vibration as related to the performance of an RCA electron microscope (Type EMU). The procedure involves the use of a Webster Model F5P2 phonograph pick‐up arm in conjunction with a cathode‐ray oscillograph. The cathode‐ray oscillograph signal amplitude which represents the vibration of the location being investigated was calibrated by means of a Brush Development Company Type BL‐301 vibration pick‐up whose voltage output is proportional to the product of the vibration amplitude and the square of the frequency. An audio oscillator was used to calibrate the voltage output of the Webster (rochelle salt) pick‐up as a function of frequency. After calibration, these oscillographic measurements may be used to determine absolute mechanical displacements.Electron micrographs are included to illustrate the image displacements due to several different amplitudes of vibration. Cognizance of vibration is often necessary, especially in high resolution electron microscopy. This scheme may be used as a guide in high resolution electron microscopy.

ISSN:0034-6748    

DOI:10.1063/1.1745606

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The quantitative evaluation of crystallite orientation in textile fibers by x‐ray methods is discussed. It is found that photographic recording and photometering of the resulting films can be replaced by automatic recording on a strip chart with the aid of an x‐ray spectrometer with Geiger‐Mueller counter. The design and details are given for a specimen holder capable of properly positioning and rotating a bundle of fibers in the x‐ray beam so that the 002 or other selected diffraction arc passes before the window of the counter. A tentative procedure is outlined for evaluating, with the aid of this apparatus, the crystallite orientation of a bundle of cellulose fibers. Some typical recordings of the intensity curves of the 002 arcs from ramie, cotton, and high tenacity rayon are presented.

ISSN:0034-6748    

DOI:10.1063/1.1745607

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A description of the radiofrequency system of the Berkeley synchrotron is given.

ISSN:0034-6748    

DOI:10.1063/1.1745608

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An application of x‐rays for determination of active slip systems based on a comparison of distortion of Laue spots is described.

ISSN:0034-6748    

DOI:10.1063/1.1745609

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A new type of pair spectrometer is described. The rotation of the image in a short magnetic lens is used to separate negatrons and positrons by putting the pair converter a little aside from the optical axis of the lens. It is then possible to obtain coincidence ``lines.'' The apparatus has been tried on the 2.62‐Mev &ggr;‐ray of ThC″ and the 2.76‐Mev &ggr;‐ray of Na24.

ISSN:0034-6748    

DOI:10.1063/1.1745610

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A device has been constructed to focus the external beam of the 184‐in. cyclotron at Berkeley. The device consists of a cylindrical tube 4 ft. in length and 3 in. in diameter, which contains a longitudinal arc of nearly uniform current density. Such a device will focus any beam of cylindrical symmetry. Owing to the large power requirements of such a device it is applicable only to very short pulsed beams.

ISSN:0034-6748    

DOI:10.1063/1.1745611

出版商:AIP    

年代:1950

数据来源: AIP