Fluorine K-Shell X-Ray Cross-Section Measurements for Lithium, BORON-10, Carbon, Nitrogen, and Oxygen Ions on Ultra-Clean Ultra-Thin Yttrium Trifluoride Solid Target Foils

Flourine K-shell x-ray cross sections have been measured for 1-6 MeV ^7Li ^{+1,+2,+3}, 1.5-11 MeV ^{10}B^{+1,+2,+3,+4,+5 }, 1-10 MeV ^{12} C^{+1,+2,+3,+4,+5,+6+} , 2-9 MeV ^{14}N ^{+1,+3}, and 3-12 MeV ^{16}O^ {+1,+2,+3,+4,+5,+6,+7,+8} incident ions on ultra-clean, ultra-thin YF_3 solid target foils. Previously, fluorine x-ray cross section measurements existed only for a few ions due to the difficult nature of measuring inner-shell ionization under these conditions. Consequently, procedures were developed to produce ultra-clean, ultra-thin target foils and to remove x-ray interference from electron bremsstrahlung and low energy K-shell xrays from contaminant elements. Fluorine x-ray cross sections were subsequently measured using target foils of thicknesses <=2 mug/cm^2. X-ray cross section measurements were compared with the ECPSSR theory over the range of 0.3 < Z_1/Z_2 < 0.9 and 0.2 < v _1/v_{rm 2K} < 0.8 which test the validity of the ECPSSR's approximation for both direct ionization and electron capture. For ^7Li, the ECPSSR was found to correctly predict the data for reduced ion velocities, xi_{rm K} >= 0.3. However, the ECPSSR theory mildly overpredicts the ^7 Li data at lower velocities. For ^ {10}B and ^{16} O ions, the ECPSSR is also found to predict the data at higher reduced ion velocities: xi _{rm K} >= 0.35 for ^{10}B and xi_{rm K} >= 0.5 for ^{16 }O. However, for ^{12 }C and ^{14}N ions, the ECPSSR overpredicts the data by more than a factor of two at higher reduced ion velocities. In addition, for all ions except ^7Li, the ECPSSR underpredicts data at low ion velocities. This effect is probably attributed to increased vacancy production due to molecular promotion processes. Finally, the electron capture contribution to the x-ray cross section has been inferred from the charge state dependence of the data and compared to the ECPSSR. The ECPSSR theory is seen to overpredict electron capture by more than a factor of 2 at all energies.