Cdのスペクトル線の形

II: Cd¹¹⁴ランプ

抄録

Several electrodeless lamps with Cd-114 isotope (isotope reduced from Oak Ridge's Cd¹¹⁴O by the use of hydrogen, known to be of 98.2% isotope purity), and with natural Cd for comparison, are prepared. These lamps are heated at 250 to 360°C by a small heater and excited by a 60 MHz, 100 W high frequency oscillator. The temperature dependences of spectral profile and intensity of visible triplet lines of Cd, λ5086, 4800 and 4678, are measured and shown in a figure. The halfintensity width of each line of Cd-114 lamp is smaller than that of natural Cd lamp, but this difference is not so remarkable as in the case of Hg-198. The broadening of each line is caused mainly by the Doppler effect when the temperature is low (250°C) and, as the temperature rises, self-absorption furthers the broadening. The temperature dependence of spectral profile can be explained by theorizing the self-absorption which will be reported later. Self-reversal temperature and optimum condition of Cd lamp for interferometry use are given.