1) You are given a large sample of glass to try to determine the elemental constituents of the sample. The only tool you have available is X-ray Fluorescence. You use a photon source that has an energy of 25 keV. You run energy calibration standards and find that energy 8.65 keV is at channel 489 and that energy 16.75 keV is located at channel 932. The peaks from your sample are at the following channels. The areas for the peaks are also given Channel number a. a) 489 b. b) 550 c. c) 18500 d. d) 700 e. e) 832 f. f) 932 Peak area 676 counts 4040 counts 18500 counts 3565 counts 2400 counts 435 counts a) give the energy of each of the peaks identified in the spectrum listed above (5 points) b) identify each peak in the spectrum giving the element and the transistion (eg Fe Kal) (5 points) c) List any peaks that are missing in the spectrum given the assignments you have made in part b. (5 points) d) Are the peak intensities consistent with your assignments made in part b. (5 points) e) Assume the detector efficiency is = 1 and that the transmission function for all x- rays = 1 (the analysis was done in vacuum). Calculate the relative amounts (atomic %) of each element present assuming the sample is homogeneous in composition (25 points) f) Name three effects that will cause your calculations in part e) to be in error because the sample is a bulk sample, rather than a thin film (5 points) g) Given the composition you have determined in parte), what is the 50% sampling depth for each of the species present (10 points) h) If the number of counts in channels 400 410 are Channel 400 401 402 Counts 2 3 5 0 3 3 5 403 404 405 406 407 408 409 410 0 1 5 5 Determine the detection limits Lc, Ld, and Lq in counts for a peak that would be at channel 411 assuming you are willing to accept a 10% probability that you will miss a peak that is present and also a 10% chance that you will identify a peak that is not present. (10 points) 1) You are given a large sample of glass to try to determine the elemental constituents of the sample. The only tool you have available is X-ray Fluorescence. You use a photon source that has an energy of 25 keV. You run energy calibration standards and find that energy 8.65 keV is at channel 489 and that energy 16.75 keV is located at channel 932. The peaks from your sample are at the following channels. The areas for the peaks are also given Channel number a. a) 489 b. b) 550 c. c) 18500 d. d) 700 e. e) 832 f. f) 932 Peak area 676 counts 4040 counts 18500 counts 3565 counts 2400 counts 435 counts a) give the energy of each of the peaks identified in the spectrum listed above (5 points) b) identify each peak in the spectrum giving the element and the transistion (eg Fe Kal) (5 points) c) List any peaks that are missing in the spectrum given the assignments you have made in part b. (5 points) d) Are the peak intensities consistent with your assignments made in part b. (5 points) e) Assume the detector efficiency is = 1 and that the transmission function for all x- rays = 1 (the analysis was done in vacuum). Calculate the relative amounts (atomic %) of each element present assuming the sample is homogeneous in composition (25 points) f) Name three effects that will cause your calculations in part e) to be in error because the sample is a bulk sample, rather than a thin film (5 points) g) Given the composition you have determined in parte), what is the 50% sampling depth for each of the species present (10 points) h) If the number of counts in channels 400 410 are Channel 400 401 402 Counts 2 3 5 0 3 3 5 403 404 405 406 407 408 409 410 0 1 5 5 Determine the detection limits Lc, Ld, and Lq in counts for a peak that would be at channel 411 assuming you are willing to accept a 10% probability that you will miss a peak that is present and also a 10% chance that you will identify a peak that is not present. (10 points)
