Calculation of D/XB Values of Hydrocarbon Molecules in Tokamak Edge Plasmas

In order to investigate the dependence of effective inverse photon-efficiency D/XB values on the plasma parameters, we have been performed calculations of effective D/XB values by Monte Carlo method. Photon fluxes are converted into particle fluxes with aid of D/XB values. A D/XB value is critical factor in the study of chemical erosion by spectroscopic measurement. In modeled tokamak edge plasma, transfer of hydrocarbon molecules (CH4, C2Hx (x = 2,4,6), C3Hy (y = 4,6,8)) and CH and C2 emissions have been simulated. The plasma temperature ranged from 1 eV to 100 eV and the plasma densities are 1018 m−3, 1019 m−3 and 1020 m−3. In the temperature region of less than 3 eV, the calculated D/XB values increase with decreasing temperature due to decreasing of emission counts. In the high temperature region (≥ 10 eV), the D/XB values increase with a rise in the temperature due to decrease of number of fragment of type CH and C2.