Towards the definition of the optimum height of voluminous cylindrical sources in gamma-ray spectroscopy

We show that for cylindrical voluminous sources in gamma-ray spectroscopy t he relative error of the spectral intensity of a low-energy spectral line, as the height of the source increases, saturates faster than the spectral i ntensity itself. This significantly reduces the quantity of the required sa mple material as compared to that based on the usual considerations of the spectral intensity only. We also demonstrate that there exists a weakly pro nounced height of the source (the sourer size) which minimizes the relative error of the intensity of a given low-energy spectral line, Due to the sma llness of the effect the benefit of introducing the concept of the truly op timum size of the source is more on a psychological side, one should feel e asier using an optimum quantity of the source material than merely a suffic ient one, as is otherwise the case. (C) 1999 Elsevier Science Ltd. All righ ts reserved.