K shell X-ray Fluorescence Parameters of Platinum and Lead

Title

K shell X-ray Fluorescence Parameters of Platinum and Lead

Creator

M. T. RAMESHAN

Description

X-ray fluorescence phenomenon (XRF) has gained importance as a tool the fields of atomic, nuclear and radiation physics, material science, medical physics, and in such diverse fields as industry, agriculture, archaeology, forensic science and so on for elemental analysis. This demands for accurate values of XRF parameters such as shell wise and sub-shell wise x-ray fluorescence yield, fluorescence x-ray production cross-section, Auger transition rate, shell and sub-shell intensity ratios, K to L vacancy transfer probabilities and so on. In addition, measurements of these parameters are useful in obtaining physical parameters such as photoelectric cross-sections, jump ratios and x-ray emission rates. Over the years several researchers have measured these parameters employing variety of methods and detectors (Apaydin and Tira?o?lu 2012; Hopman et al. 2012; Kahoul et al. 2011; Cengiz et al. 2011; Cengiz et al. 2010; M??nesguen and M. -C. L??py 2010; S????t et al. 2009a; S????t et al. 2009b; Reyes-Herrera and Miranda 2008; Ertu?rul et al. 2007; Aylikci et al. 2007; Demir and ?ahin 2007; ?ahin et al. 2005; ??zdemir et al. 2002; ?imsek et al. 2002; Durak et al. 2001; 1998; Allawadhi et al. 1993). However these methods involve complicated single and double reflection geometries armed with sophisticated equipments and strong sources of the order of 109 Bq or more. These experiments involve many corrections such as attenuation of x-rays in the target itself (self attenuation correction), attenuation in the window of the detector (window attenuation correction), solid angle correction, photopeak efficiency and total detection efficiency of the detector, etc. Estimation of intensity of radiations incident on the target is a difficult task in these methods. The incident intensity and the total x-ray fluorescence intensity generated in the target are the quantities, which determine the accuracy of the K x-ray fluorescence parameters. Recently Gudennavar et al. (2003a; 2003b) and Horakeri et al. (2011; 1998; 1997) have developed a simple method to measure K-shell fluorescence yields, production cross section and other parameters by adopting a 2geometrical configuration and employing weak radioactive sources. K x-ray fluorescence parameters are independent of angle of emission because K x-rays are emitted isotropically from the target atom. It was found that the method yields K x-ray fluorescence parameter values as accurate as any standard reflection geometry experiment. The simplicity of method helps one to utilize it to develop student laboratory experiments to train students in x-ray fluorescence field. Since the method requires weak sources, it is of great advantage to student laboratories for they do not need special permission to acquire sources and sources can be handled safely without any personal radiation hazards. However the validity of the target thickness criterion and the method needs to checked with other X-ray detectors such as CdZnTe, HPGe as their construction arrangements are different from NaI(Tl) detectors and for all the elements in the periodic table. In the present study, we have measured the K x-ray fluorescence parameters for the elements platinum and lead using HPGe detector spectrometer and 57Co excitation source. The results are compared with the theoretical, semi-empirical fitted and other experimental values.

Source

Physics

Date

2012