Enhancing accuracy in energy measurement of nuclear spectroscopy signals by identification techniques

In nuclear spectroscopy, mixed analog-digital signal conditioning has proven to be useful to enhance the energy resolution of the instrument. Analog filters are used to preshape the signal in such a way as to minimise the requirements set to the analog-to-digital converter. However, it is necessary to accurately identify the singularities of the analog filter, to make the subsequent digital processing possible. In this paper, we address the problem of identifying the poles of the analog filter. We discuss the required precision of the identification method. We address the problem of the experimental measurement of the filter behaviour without hardware overhead. We implement a subspace-based identification method capable of determining the filter singularities with the required accuracy and precision. Experimental results show that a noticeable enhancement of the setup energy resolution is obtained.