Microanalysis of Flourine by nuclear reactions: I. 19F(p, α0)16O and19F(p α γ)16O reactions

Abstract

The quantitative determination and depth profiling of fluorine in the surface region of various substrates using nuclear reaction microanalysis was studied. Differential cross sections and excitation functions for the reaction 19 F(p, α 0 ) 16 O and 19 F(p, α γ) 16 O were investigated in great detail, especially in the vicinity of resonances, where automatic energy scanning was used. Resonance widths and positions were measured precisely, in particular for the narrow resonances of 19 F(p, α γ) 16 O. A very narrow, Γ = 150±50 eV, resonance was found at 1088 keV. The excitation curves shown for various resonances allow one to carry out the computer calculations required for converting yield curves into depth profiles. The paper discusses how to choose among the nuclear reactions and resonances available to achieve best sensitivity, selectivity, depth resolution, ease of operation or speed of measurements, according to the problem considered, and to define the corresponding optimal experimental conditions. It appears that, in addition to the strong 872 keV, Γ = 4.2 keV resonance of 19 F(p, α γ) 16 O, the 340 keV, Γ = 2.4 keV resonance may be especially useful. The results are also of interest for hydrogen depth profiling when using the reverse reaction 1 H( 19 F, α γ) 16 O.