A new method of positive ray analysis.
A new method of positive ray analysis.
复制标题
DOI：
10.1103/physrev.11.316
复制
发表时间：
1918-04-01
期刊：
影响因子：
--
通讯作者：
Dempster, AJ
中科院分区：
文献类型：
--
作者：
Dempster, AJ
正射线的HE分析是以确定各种成分的电荷与质量的比率为基础的。然而，对负粒子的相应测量，已经通过一些方法达到了更高的精确度，这些方法包括使射线大角度偏转，以及使相互之间的角度略有变化的射线重新聚焦。除了测量的精确性外，这些方法在微小的速度差别之间也有很大的分辨力;因此卢瑟福和罗宾逊已经从RaC中分离出不同的p射线群，它们的能量相差2%;克拉森给出的电子照片也显示出这样的清晰度，即如果电子的质量相差只有roo中的I那么小，那么不同的群也会被分离出来。对于正射线，Richard-son 3使用的狭缝法适用于弱源，并能相当精确地测量平均分子量，但上述论文中给出的曲线表明，分离不同元素的能力很小。J. J. Thomson使用的方法能够具有相对较大的分辨能力，在z6中分子量相差I的元素被明显分离，但这仅在强度损失很大的情况下获得。本实验所发展的方法可望在中等分辨率的情况下得到大的强度。发现这种方法也可以发展到在元素之间有很大的分辨能力，这种方法与Classen测定电子e/nz的方法基本相同。来自某个来源的带电粒子通过一个负电位差落下。一个窄束被一个狭缝分开，并被一个强磁场弯曲成一个圆;然后射线通过第二个狭缝，落在一个与静电计相连的板上。电位差（P.D.），磁场
HE analysis of positive rays is based on the determination of the ratio of the charge to the mass of various constituents. The corre-sponding measurement for the negative corpuscle has however been carried to a much greater degree of accuracy by means of methods involving the magnetic deflection of the rays through largeangles, and the refocusing of rays which make slightly varying angles with each other. Apart from the accuracy of the measurement, there is also in these methods a great resolution between slightly di fferent speeds; thus Rutherford and Robinson'have separated distinct groups of p rays from RaC which differ by 2 per cent. in energy; alsothe photo-graphs given by Classen'for electrons show such sharpness that if electrons had masses differing by as little as I in roo, the various groups would beseparated. With positive rays the slit methodused by Richard-son3 is suitable for weak sources and allows a fairly exact measurement of a mean molecular weight, but the curves given in the above paper show that the power of separating different elements is very small. The method used by J. J. Thomson is capable of comparatively great resolving power, elements being sharply separated which differ in molecular weight by I in z6, but this is obtained only with a great loss in intensity. The method developedin the present experiments was expected to give great intensity with moderate resolution. It was found that themethod could also be developed to give a very great resolving power among the elements.The method is essentially identical with that used by Classen in his determination of e/nz for electrons. The charged particles from some source fall through a deGnite potential difference. A narrow bundle is separated out by a slit and is bent into a semicircle by a strong magnetic Geld; the rays then pass through a second slit and fall on a plate connected to an electrometer. The potential difference(P. D.), magnetic field