The recent advances in attosecond physics revealing an emission delay between electrons emitted from valence states and deeper bound 4f states in tungsten [1] and from the 2p and 2s subshells in neon [2] have provoked and will continue to provoke questions about the physics of photo-ionization. However, in the aforementioned experiments a relative phase ambiguity remained, because of the spectral separation of the respective emitted wavepackets. We present experimental data obtained using this method from an atomic system, xenon, from which more different electron wavepackets including shake-up electron wavepackets are emitted, and where a spectral overlap of some of these wavepackets can be observed. The spectral overlap of the different emitted electronic wavepackets can eliminate the relative phase ambiguity, and thus allows for a more reliable measurement of the relative emission phase and delay. In the experimental data we present here, the streaking of the 5p, 5s and 4d photoelectrons and the 5p -2 5d shake-up satellite from xenon is well resolved, and the Auger lines and corresponding sidebands are individually resolved. Isolated attosecond pulses with a central photon energy of 94 eV and a full-width at half-maximum of 6 eV are generated by loosely focusing carrier envelope phase (CEP) stable 5-fs pulses with a central wavelength of ~750 nm and ~250 µJ on a neon target. The few-cycle pulses are spatially separated from the generated soft x-ray pulses using an annular filter consisting of a pellicle with a central hole that is covered with a Zr foil. The delay between the attosecond pulse and the few-cycle pulse is controlled via translation of the inner component of the double mirror. The double mirror focuses both pulses on a xenon gas jet, and the ejected photoelectrons are analyzed using a time-of-flight (TOF) spectrometer [5]. Center-of-mass analysis of the spectral shift of the 4d, 5p -2 5d, 5s and 5p emission lines in the CEP stable laser field yields an upper limit of 50 as for the relative emission delay between these electrons. In order to obtain a better temporal resolution, we carried out a FROG-CRAB reconstruction of our measured spectrogram [ Fig. 1(a)]. This analysis reveals that the 5p -2 5d shake-up emission precedes the 5s emission by ~20 as, and that the emission from the 5p subshell is delayed by ~30 as with respect to the 5s electrons. Furthermore, we observe, similarly to Ref.[3] a phase-sensitive behavior of the sidebands to the Auger emission [see Fig 1(b)]. 60 65 70 75 80 85 90 0.0 0.2 0.4 0.6 0.8 1.0 -0.5 0.0 0.5 0 50 retrieved spectrum measured spectrum Normalized Intensity E kin (eV) Phase (π rad) Group Delay (as) -15 -10 -5 0 Signal (arb. un.) XUV-IR delay (fs)Fig. 1. (a) FROG-CRAB reconstruction of the photo-electron spectrum (black) and corresponding spectral phase (red) and group delay (blue). The emission from the 5p-25d electrons precedes the 5s emission by ~20 as and the 5p emission by ~50 as. (b) Strength of the up-(red) and down-shifted (blue) Auger-sidebands. A weak 18...

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