Please justify your answer!

1. (35 marks total) 103 102 we hurlandi Counts 101 100 10-1 0 2 4 10 6 8 Energy Element Critical Energy (K) K KB IP 2.145 2.010 S 2.472 2.309 Ar 3.205 2.956 Ca 4.038 3.690 4.013 Ti 4.966 4.510 4.933 Mn 6.539 5.900 6.492 Fe 7.112 6.400 7.059 Cu 8.979 8.030 8.903 Zn 9.659 8.620 9.570 Ba (L1) 5.989, (L3) 5.247 (Lal) 4.467\LB3) 4.926 Above is an EDS spectrum in keV of the thigh bone (femur) of a 125 million year old fossilized bird, taken in air with 12.5 keV incident X-rays at a synchrotron. Also given is a table showing critic energies and characteristic emission lines for several elements. Note all data in the table pertain to the K-edge except the entry for Ba, which gives important details for the L-edge excitation and emission process. a. (10 marks) The composition of bone is typically thought of as slightly modified hydroxyapatite: Cas(PO4)3(OH). Explain the collected spectrum with reference to this simple formula. (Note that the intensity is a log scale.) b. (15 marks) Explain the analytical problems encountered in this use of EDS for elemental analysis as shown in this spectrum, and describe a way that one might deal with those problems if the specimen could be analyzed within an electron microprobe. c. (10 marks) Certain elements do not appear in this spectrum although they are known to be present by other means. List and explain the 3 most probable reasons for this. 1. (35 marks total) 103 102 we hurlandi Counts 101 100 10-1 0 2 4 10 6 8 Energy Element Critical Energy (K) K KB IP 2.145 2.010 S 2.472 2.309 Ar 3.205 2.956 Ca 4.038 3.690 4.013 Ti 4.966 4.510 4.933 Mn 6.539 5.900 6.492 Fe 7.112 6.400 7.059 Cu 8.979 8.030 8.903 Zn 9.659 8.620 9.570 Ba (L1) 5.989, (L3) 5.247 (Lal) 4.467\LB3) 4.926 Above is an EDS spectrum in keV of the thigh bone (femur) of a 125 million year old fossilized bird, taken in air with 12.5 keV incident X-rays at a synchrotron. Also given is a table showing critic energies and characteristic emission lines for several elements. Note all data in the table pertain to the K-edge except the entry for Ba, which gives important details for the L-edge excitation and emission process. a. (10 marks) The composition of bone is typically thought of as slightly modified hydroxyapatite: Cas(PO4)3(OH). Explain the collected spectrum with reference to this simple formula. (Note that the intensity is a log scale.) b. (15 marks) Explain the analytical problems encountered in this use of EDS for elemental analysis as shown in this spectrum, and describe a way that one might deal with those problems if the specimen could be analyzed within an electron microprobe. c. (10 marks) Certain elements do not appear in this spectrum although they are known to be present by other means. List and explain the 3 most probable reasons for this