| 摘要 |
An atomic absorption spectrometer in which each sample is analyzed for all desired elements before starting the next sample. New features include the grating drive, lamp-carousel alignment, pulsed atom source, lamp-drift compensation, and dynamic range control. The grating (G) is driven by an arm (A), the arm (A) by a taut band (B) wound on a drum (D), and the drum (D) directly by a motor. The lamp carousel (C) mounts on an ''L''-shaped rocker with one horizontal and one vertical arm. The carousel (C) rotates on a horizontal axis (P1) at the end of the vertical arm. The rocker itself pivots on a horizontal axis (P2) at the corner of the L; it is driven about its axis by a motor (M2) and screw (W) at the other end of the L. Carousel (C) rotation on its axis moves the right lamp into position and adjusts it accurately in vertical direction. Pivoting of the rocker simultaneously on its corner axis positions the lamp accurately in the horizontal direction. The pulsed atom source is a combined angled-gas-jet- and discharge unit. During pulses it yields high absorption with better detectability limits; average power is lower. The lamp-drift compensator makes double duty of the absorber pulsation to obtain a lamp-intensity reading between pulses. Dynamic range control is obtained by even further exploiting the pulsation, namely by taking measurements at a known delay (and decay) time after each pulse. |
