. The American journal of roentgenology, radium therapy and nuclear medicine . the facts superficially,the sudden acceleration of the electronsalong an extremely short path—practicallyon the surface of the cathode itself—may,from the standpoint of the theory ofelectromagnetism, be held responsible for afurther new phenomenon w hich is the emis-sion of a roentgen-radiation from the activesurfaces of the cathode, while the otherparts of the cathode do not emit any radia-tion whatever. This is proven by pinholecamera pictures of energized tubes exposedtwenty times or more longer than would berequ
. The American journal of roentgenology, radium therapy and nuclear medicine . the facts superficially,the sudden acceleration of the electronsalong an extremely short path—practicallyon the surface of the cathode itself—may,from the standpoint of the theory ofelectromagnetism, be held responsible for afurther new phenomenon w hich is the emis-sion of a roentgen-radiation from the activesurfaces of the cathode, while the otherparts of the cathode do not emit any radia-tion whatever. This is proven by pinholecamera pictures of energized tubes exposedtwenty times or more longer than would berequired to obtain a picture of the radiation from the cathode is a weakone and specifically negligible if comparedwith that of the anode. Furthermore, theradiation is much softer. If a tube isoperated with a ij cm. spark gap, theregular radiation of the anode is butslightb allectcd by a two millimeter alumi-num filter. The cathodal radiation, how-ever, is completely absorbed by such afilter. Through so thin an aluminum layerno impression of the cathode radiation. Fig. 2. edges only can be seen. The tube was oper-ated on a rectified direct current. A reliablehighly evacuated hot cathode valve and ahigh tension resistance of 10 megohms ofcarbon-coated glass tubes was inserted inseries with the tube studied, in order toexclude any inverse voltage which mighthave possibly arisen from some electricoscillation. The picture has been taken byexposing a glass plate, provided with anintensifying screen, to a radiation gener-ated by 2 ma., 180 minutes at a focaldistance of 25 cm., through a pinhole mm. The distance of the pinhole tothe plate was 10 cm. i4(7i). Another fact appearing to beclosely connected to those under para-graphs 11 and 12 concerns the pondero-motive force of attraction between theelectrodes. One of the electrodes—forinstance the cathode—may be held at acertain distance from the anode by a springof such dimensions that the regular elec-trostatic att
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Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1900, bookyear1906
