$^{144}$Ce–$^{144}$Pr electron antineutrino spectrum measurement with silicon semiconductor detectors

In this work we present $\beta$-spectrum studies for $^{144}$Ce–$^{144}$Pr source spectra with endpoint energy of 2997 keV. The spectral studies were performed with two spectrometer types: target-detector scheme and a $4\pi$ spectrometer. The spectra were fitted with the spectrometer response functions derived through Monte-Carlo simulations. As a result of the study, we have derived the nuclear shape factor necessary for the $\beta$-spectrum calculation. The obtained parameters of the shape factor arge between the spectrometers within statistical uncertainties. Also, we have evaluated electron antineutrino spectrum of $^{144}$Pr decay with the most precise up to date rate expected for IBD on protons of (0.47091 $\pm$ 0.00003$_{stat}$+0.00022$_{syst}$)$\cdot$10$^{-43}$ cm$^2$ decay$^{-1}$.