Re-publication of the data from the BILL magnetic spectrometer: The cumulative $\beta$ spectra of the fission products of $^{235}$U, $^{239}$Pu, and $^{241}$Pu

In the 1980s, measurements of the cumulative $\beta$ spectra of the fission products following the thermal neutron induced fission of $^{235}$U, $^{239}$Pu, and $^{241}$Pu were performed at the magnetic spectrometer BILL at the ILL in Grenoble. This data was published in bins of 250 keV. In this paper, we re-publish the original data in a binning of 50 keV for $^{235}$U and 100 keV for $^{239}$Pu and $^{241}$Pu.