THE IMPORTANCE OF POSITIVE IONS IN OPTOGALVANIC DETECTION WITH THE THERMIONIC DIODE AND THE GLOW DISCHARGE LAMP L.R. Pendrill, M. Pettersson and U. Österberg J. Phys. Colloques, 44 C7 (1983) C7-489-C7-496 DOI: 10.1051/jphyscol:1983748