摘要:

A system of five, equally‐spaced, square coils which provides a uniform magnetic field over a considerable volume is described. The region of uniformity is easily accessible from outside the coils. The method used to design the system is discussed.

ISSN:0034-6748    

DOI:10.1063/1.1770378

出版商:AIP    

年代:1945

数据来源: AIP

摘要:

An improved method for the measurement of alpha‐ray sources, using the luminescence of fluorescent screens, is described. The improvements consist of the use of a multiplier photo‐tube and long lived non‐emanating alpha‐standards. The chief advantage of the multiplier photo‐tube is its great flexibility, allowing quite an extensive range of measurements. Alpha‐ray sources, ranging from110&mgr;Cup to a few curies, can thus be measured, in a much quicker fashion than either the ionization or calorimetric method would permit. The standardization procedure of the photo‐tube for measurements of absolute intensity is described in detail, the accuracy of the results being estimated at 5 percent. New applications of this method to the preparation of photometric standards and to the measurements of strong neutron sources are suggested.

ISSN:0034-6748    

DOI:10.1063/1.1770379

出版商:AIP    

年代:1945

数据来源: AIP

摘要:

There is described the operation and calibration of an electronic stimulator which supplies a unidirectional, rectangular current pulse of variable frequency, amplitude, and pulse length (length of the conducting portion of the cycle). Each of these three variables is independent of changes in the other two, and the amplitude is virtually independent of variations in the resistances of individual subjects. The range of frequencies extends from one cycle in several minutes to 20,000 cycles per second. With the maximum amplitude of 2 milliamperes the resistance of the subject may be as great as 200,000 ohms; smaller amplitudes or a slight modification of the circuit permits the allowable resistance to be increased. The pulse length may be varied from a minimum of110of the cycle to any desired value.

ISSN:0034-6748    

DOI:10.1063/1.1770380

出版商:AIP    

年代:1945

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770381

出版商:AIP    

年代:1945

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770382

出版商:AIP    

年代:1945

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770383

出版商:AIP    

年代:1945

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770384

出版商:AIP    

年代:1945

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1770385

出版商:AIP    

年代:1945

数据来源: AIP