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

Internal bremsstrahlung (IB) accompanying the β− decay of 204Tl was measured using a 5.08×5.08 cm2 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 204Tl. 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.