Energy and angle resolved measurements have been performed in the double photoionization of helium. Whereas the angular distributions do not depend much on the energy sharing (E~, E&):at 4 eV above threshold, a strong effect is observed at F. = 18.6 eV. These results can be analyzed qualitatively if the total amplitude is split into two parts which are, respectively, symmetric (a") and antisymmetric (a, ) in the interchange of E& and Ez, showing that the relative contribution of the latter increases with the excess energy. Dynamical effects of the energy on a"are also noticeable in the measurements with equal sharing.PACS numbers: 32.80.FbThe double photoionization of a helium atom by a single photon offers the simplest situation for studying the correlations between two continuum electrons. This fundamental process is of main interest from the theoretical point of view, being a pure three-body problem on the atomic scale. A full treatment would involve the ab initio quantal calculation of an accurate sixdimensional wave function for the electron-ion-electron system, valid for short as well as long distances between the two electrons and the ion. Although such a goal is still out of reach, decisive progress has been accomplished recently and different approaches to obtaining the differential cross sections have been proposed [1,2].On the experimental side complete information can be obtained if the two electrons are detected in coincidence after energy and angle selection, so that the tripledifferential cross section (TDCS) is measured. Because of the extreme weakness of the latter, such measurements have become feasible only very recently [3 -5]. If E~h is the photon energy and I = 79 eV the double-ionization potential, then the two electrons share the excess energy above threshold: E: Eph I: E] + E2, Most of the previous measurements were limited to the restricting case Ej = E2 = E/2 [3,4], where only one component of the ionization amplitude is involved (see below), but very recently a first experiment [5] at unequal sharing E& 4 E2 was also performed far from threshold (E = 52.9 eV).The aim of the present Letter is to report on experimental TDCS's that were obtained, for the first time, down to 4 eV above threshold and for energy sharing such as Ei/E2 = 0.2 or 5, together with TDCS for equal sharing measured in the same conditions and at the same values of the total energy E. These measurements were performed using the highly polarized photon beam from the SU6 undulator line of Super Aco (Orsay, France), and the toroidal analyzer described in Ref. [4]. However, in contrast with the experiments reported in [4], only the second electron is detected here in the toroidal analyzer for many angles simultaneously.The first electron Aies through a tube which is placed inside the dead angle of the toroidal analyzer, and is detected by an additional 127 cylindrical analyzer, at right angles with respect to the photon beam. This arrangement allows one to make E] = E2, as well as El 4 E2 measurements, in an extended ang...