Photodetachment cross-section evaluation using asymptotic considerations
الموضوعات : Journal of Theoretical and Applied PhysicsPhilippe Babilotte 1 , Mickael Vandevraye 2
1 - Laboratoire Aimé Cotton, UPR 3321 CNRS, LAC, Université Paris Sud XI;UMR 6303 CNRS, ICB, Université de Bourgogne Franche-Comté, UBFC
2 - Laboratoire Aimé Cotton, UPR 3321 CNRS, LAC, Université Paris Sud XI;French Ministry of Education
الکلمات المفتاحية: Other topics in mathematical m, Metrology, Determination of fundamental c,
ملخص المقالة :
AbstractMathematical calculations are given concerning the evaluation of the negative ions photodetachment cross-section σdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$sigma $$end{document}, into a so-called saturation regime. The interaction between a negative ion particle beam and a laser beam is examined under theoretical aspects. A quantitative criterion S is proposed to define the saturation threshold between the linear and the saturated domains, which are both present in this saturation regime. The asymptotic behaviours extracted at the low and high energy limits are used to determine this threshold quantitative criterion S and to evaluate also the photodetachment cross-section σdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$sigma $$end{document}. The case of a symmetric gaussian photodetachment laser beam shape is examined according to the proposed formalism, which can be used either for the photo-detachment or photo-ionization processes, and could be potentially used into technological solutions for negative ion neutralisation processes (such as neutral beam injector) in the future fusion energy devices. Estimations onto the errors related to the use of this methodology are given.
