Efficiency calibration of γ-ray detector for extended sources

• Published in: Pramāṇa Vol. 92; no. 4; pp. 1 - 5
• Main Authors: Chakraborty, Animesh Kumer, Uddin, Md Shuza, Shariff, Md Asad, Latif, Shaikh Abdul, Rashid, Md Abdur, Khandaker, Mayeen Uddin
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 2019; Springer Nature B.V
• Subjects: Astronomy; Astrophysics and Astroparticles; Attenuation; Efficiency; Observations and Techniques; Photopeak; Physics; Physics and Astronomy; Point sources; Power efficiency; Radioactivity; Radioisotopes; Sensors; ray spectrometry; efficiency; efficiency loss in extended samples; standard point source; HPGe; 29; source–detector geometry; solid angle
• ISSN: 0304-4289; 0973-7111
• DOI: 10.1007/s12043-019-1735-1

Precise identification and quantification of radioisotope in a sample largely depend on the accuracy of the full-energy peak efficiency of the detector. It is generally observed that the efficiency for a given energy of point-like sources is not the same as the extended source. However, number of correction factors such as detector geometry, photon attenuation, coincidence-summing, etc. may reduce such a difference in efficiency regardless of sources, or they should be considered in the measurement of extended samples. In connection to this, the variation of absolute photopeak efficiency of a high-purity germanium (HPGe) detector with the distances from the surface of the detector as well as with the γ -ray energies were investigated using γ -ray standard point sources. We present a method to determine the loss of efficiencies in radioactivity measurement of the thin extended radioactive disc samples in comparison to point source.