Extension of the Ultra-Violet Wave-Length Limit

Abstract

THE best light source for the spectroscopy of the extreme ultra-violet region is the hot spark. In the spectroscopic work at this Institute, the electrodes of the spark are usually connected through short straight leads to four condensers having a capacity C of 0.4 F. together. These are charged to a tension V = 5070 kv. The discharge through the spark is periodic with a period T of about 8 sec. (corresponding to a wave-length of 2,400 metres). The maximum current in the spark is If in our case, V = 50 kv., we have i_max. = 16,000 amp. If we wish to increase the current in the spark we have to increase the tension V, which is possible only to a certain extent. Further, we can increase the capacity C, but this gives a rather slow increase in i. Finally, we can decrease the inductance in the circuit.