The Mass Response of Ilford Q 2 Plates Used in Mass Spectrography

The mass response of Ilford Q 2photographic plate sensitivity to singly charged ions has been investigated by using 16 keV ions of 7 elements with the mass number ranging from6through 198. Exposure(Em1)for a singly charged ion only was calculated from the exposure(Em)measured by the monitor electrode placed at the entrance of the magnetic field by eliminating the contribution by doubly charged ions which are simultaneously measured by the monitor and by taking into account the isotopic abundance. Correction was also made for the line width. Logarithm Em1was plotted against logarithm Seidel function(Δ)calculated from transmittance measurements made on suitably exposed spectra. The relative value of the mass response is the reciprocal of the value of E atΔ=0. The mass response of the Q 2 emulsion sensitivity was found to decrease with 0.4 th power of the ion mass. Disagreement with Owens'value of 0.5 and apparent good harmony with the values obtained by Woolston et al. are considered.