It has been shown by WALSH' and other investigators in the field of atomic absorption that a flame can be used as an absorption source for elements that are readily dissociated from their compounds . Except for some work done by RUSSELL AND WALSH 2, GATEHOUSE AND WALSH*, with hollow-cathode absorption tubes, and L'vov with graphite crucibles4, little has been published about the use of an absorption source other than the flame for atomic absorption work .
Because our laboratory is confronted with a variety of samples, some of which are not readily dissociated from their compounds in the flame, and many of which are radioactive, it was decided to investigate sources other than the flame to obtain limits of detection for elements of interest . It was thought that a hollow-cathode tube would serve our need, since the sputtering action of the discharge in the hollow cathode might dissociate even the refractory elements, as indicated by our previous experience of exciting refractory uranium alloys in a Schtiler-Gollnow water-cooled hollow-cathode tube, and, also the radioactivity might be confined to the closed tubes . Since a number of Schdler-Gollnow water-cooled tubes were readily available at this laboratory, it was decided to use one as an emission source, and the other as an absorption source, after it was modified, to study absorption characteristics and limits of detection for a few elements . EXPERIMENTAL Apparatus A schematic diagram illustrating the operation of the atomic absorption technique used for this investigation is shown in Fig . i . The Schfiler-Gollnow water-cooled tubeΒ°Z * Lens-L3 A .C .Amp-Lens-L2 Monochro-lifter end Recorder meter and rectifier detectors Fig . t . Schematic diagram illustrating apparatus used for atomic absorption studies . * . Based on work performed under the