The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. $^{92}$Rb makes the dominant contribution to the reactor spectrum in
the 5-8 MeV range but its decay properties are in question. We have studied $^{92}$Rb decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed.
Double Chooz main target is to measure Theta13 oscillation parameter by comparing reactor neutrino fluxes in two identical detectors located respectively at 400 m and 1 km away from the 2 Chooz reactor cores. The far detector is now under constructio
n, while we have just completed the design phase of the near one. In this report I will discuss the detector principle, sensitivity and its present construction status.
