There is a change in philosophy when measuring with a TAS. Instead of detecting the individual gamma rays (as high-resolution detectors do), it will detect the gamma cascades emitted in the decay. Then, the final energy spectrum will not be a collection of different energy peaks coming from the different transitions (as can be expected in the case of a germanium detector), but a collection of peaks situated at an energy that is the sum of the different energies of all the gammas of the cascade emitted from each level. This means that the energy spectrum measured with a TAS will be in reality a spectrum of the levels of the nuclei, where each peak is a level populated in the decay. Since the efficiency of these detectors is close to 100%, it is possible to see the feeding to the high excitation levels that usually can not be seen by high-resolution detectors. This makes total absorption spectroscopy the best method to measure beta feedings and provide accurate beta intensity (I β) distributions for complex decay schemes.