Measurements of Mo I S/XB values

The number of ionization events per photon, i.e. S/XB value, of Mo I lines has been determined by taking a ratio of the sputtered Mo flux, Gamma(Spt)(Mo), to the line-of-sight integrated Mo I emission intensity in weakly ionized (ionization degree of similar to 1-10%) He plasmas in the linear divertor plasma simulator PISCES-B under the following plasma parameters: electron density n(e) similar to (0.6-1.3) x 10(19) m(-3), electron temperature T(e) similar to 10-30 eV, ion flux Gamma(i) similar to (0.9-1.2) x 10(23) m(-2) s(-1) and incident ion energy to the Mo target E(i) similar to 60 eV. For these conditions, most of the sputtered Mo atoms are ionized in the plasma column. While measured S/XB values for z (5)P degrees -> a (5)S (550.6, 553.3 and 557.0 nm) are systematically higher than theoretically calculated values provided in the Atomic Data and Analysis Structure database by a factor of similar to 2-5, agreement for the other transitions, y (7)P degrees -> a (7)S (313.3, 317.0 and 319.4 nm) and z (7)P degrees -> a (7)S (379.8, 386.4 and 390.3 nm), is more satisfactory (within a factor of 2).