Durak, Ridvan/0000-0002-3935-176X; DURAK, RIDVAN/0000-0002-3935-176X; Akman, Ferdi/0000-0002-8838-1762 WOS: 000367410300058 PubMed: 26623929 The paper presents the first measurements of the K alpha and K beta excitation factors for some selected elements from Y to Te. To determine the K alpha and K beta excitation factors, the experimental values of K shell X-ray production cross sections and total absorption photoelectric cross sections were used. The measurements were performed using a Si(Li) detector coupled with 2048 multichannel analyzer and an Am-241 annular radioisotope source which is emitted 59.54 keV gamma-photons. It is observed that the Ka excitation factors are 5-6 times larger than the K beta excitation factors. The measured excitation factors were compared only with theoretical calculated ones since there are no other experimental reports for the present elements in the literature. The present experimental values of K alpha and K beta excitation factors are in satisfactory agreement with the theoretical results. (C) 2015 Published by Elsevier Ltd. Bingol University Research FundBingol University [BAP-195-162-2013] This work was done with the support of the Bingol University Research Fund under Project No. BAP-195-162-2013.