Study of the continuous internal bremsstrahlung spectrum from Tl-204 by using singular value decomposition

Internal bremsstrahlung (IB) accompanying the beta(-) decay of Tl-204 was measured using a 5.08 x 5.08 cm(2) NaI(Tl) detector employing a magnetic deflection method in the range of 10-760 keV. A novel approach, the Singular Value Decomposition (SVD), is applied to unfold the raw detector spectrum of Tl-204. Unfolded IB spectrum is compared with the KUB theory. The measured spectrum is found to show fairly good agreement with the KUB theory in the energy range of 100-600 keV. The distribution beyond the 600 keV takes a positive deviation from the theory. (C) 2015 Published by Elsevier Ltd