WEAK-LINE DETECTION IN THE X-RAY-SPECTRUM OF A NIOBIUM PLASMA PRODUCED BY A LOW-INDUCTANCE VACUUM SPARK

A number of weak lines have been detected by spectral correlation analysis of independent photographic records of the X-ray spectrum of a low-inductance vacuum spark with Nb-electrodes taken by means of a curved crystal spectrograph. Comparing the measured wavelengths to results of relativistic energy level calculations, they are identified as belonging to electronic transitions within singly excited He-like NbXL and doubly excited Li-like NbXXXIX ions. The nonlinear detection technique used is described in detail. © 1979 Springer-Verlag.