Measurements of Mo IS/XBvalues

Abstract

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, Spt Mo , to the line-of-sight integrated Mo I emission intensity in weakly ionized (ionization degree of ∼1-10%) He plasmas in the linear divertor plasma simulator PISCES-B under the following plasma parameters: electron density n e ∼ (0.6-1.3) × 10 19 m −3 , electron temperature T e ∼ 10-30 eV, ion flux i ∼ (0.9-1.2) × 10 23 m −2 s −1 and incident ion energy to the Mo target E i ∼ 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 • → 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 ∼2-5, agreement for the other transitions, y 7 P • → a 7 S (313.3, 317.0 and 319.4 nm) and z 7 P • → a 7 S (379.8, 386.4 and 390.3 nm), is more satisfactory (within a factor of 2).

Control of high-Z PFC erosion by local gas injection in DIII-D

“…Ref [17]). Hypothesis (ii) is in contradiction with the findings of Ref [19] showing no T e dependence of S/XB for the 386.4 nm MoI line in the T e range of interest. Hypothesis (iii) could not be verified because of lack of the collisional de-excitation cross-section data.…”

Imaging of molybdenum erosion and thermography at visible wavelengths in Alcator C-Mod ICRH and LHCD discharges

“…While the 390nm lines are brightest, the lowest molybdenum reflectivity occurs there 25 , and atomic modeling of the associated ground state transitions is accurate 15 , the low fiber bundle transmission at that range limits the value of these lines for erosion imaging with the present setup. The nearby 410nm lines are much lower intensity, and so also of limited value.…”

Relativistic R -matrix calculations for the electron-impact excitation of neutral molybdenum

“…Experimental investigations using Mo I PFCs have been carried out at Alcator C-Mod [4][5][6]; PISCES-B Mod [7,8]; and the DIII-D tokamak [9]. Furthermore, NSTX-U has plans to install a limited set of molybdenum tiles, with the potential * rsmyth41@qub.ac.uk to upgrade to a fully high-Z wall [10].…”