Measurement of narrow beam attenuation coefficients using a broad beam geometry configuration for 145.4 keV photons

• Published in: Applied radiation and isotopes 1993-09, Vol.44 (9), p.1248-1252
• Main Authors: Jahagirdar, H.A., Hanumaiah, B., Thontadarya, S.R.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; X- and γ-ray instruments and techniques
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/0969-8043(93)90072-I

Narrow beam attenuation coefficients, μ ρ , of 145.4 keV γ-rays, emitted from the 141Ce radioisotope have been measured in various high Z materials such as Pb; (CH 3COO) 2. Pb · 3H 2O; Pb(NO 3) 2; PbO 2; PbO; Na 2 WO 4 · 2H 2O; BiPO 4 for the first time using a broad beam geometrical configuration, employing a 5.10 cm × 2.54 cm NaI (T1) detector spectrometer system coupled to a 1 K multichannel analyser. The measured μ ρ values, in cm 2/g for the above materials in the transmission range from 50% to 20% respectively are 2.12 ± 0.02 (2.2); 1.25 ± 0.03 (1.27); 1.40 ± 0.01 (1.43); 1.78 ± 0.06 (1.92); 1.96 ± 0.03 (2.05); 0.97 ± 0.02 (1.04) and 1.52 ± 0.03 (1.6). The corresponding theoretical values estimated from the mixture rule using tabulated values of Hubbell (1982), are given in parentheses. It is observed that for high Z compounds at 145.4 keV energy, the exponential law of attenuation will be valid even for a broad beam geometry configuration in the transmission range from 50% to 20%. The attenuation coefficients of elements derived from this method were compared with the tabulated narrow beam attenuation coefficients indicating the validity of the mixture-rule in the above region of transmission.