2004-2006 activity report of Dapnia

This document presents the research programs of the Department of Astrophysics, Particle Physics, Nuclear Physics and the related Instrumentation (Dapnia) of the French atomic energy commission (CEA). These programs deal with: 1 -the ultimate constituents of matter (standard model, physics at the LHC, neutrinos, hadrons structure); 2 - the energy content of Universe (dark matter, dark energy, antimatter and CP violation); 3 - the Universe's structuration (cosmology and structures formation in the Universe, formation and evolution of galaxies); 4 - structure and evolution of stars (formation of stars and planets, stellar and laboratory plasmas, compact objects, cosmic ray sources); 5 - nuclear matter in its extreme states (quarks and gluons plasma, exotic nuclei); 6 - innovation for detection systems (development of detectors, signal processing and real-time systems, intensive calculation and simulation); 7 - magnets and accelerators (particle accelerators, superconducting magnets, test facilities, new developments for magnets and accelerators instrumentation); 8 - physics for nuclear energy (nuclear data and modeling, fusion research technology); 9 - Dapnia's expertise for the society (physics and health, dismantling and aid to the design of nuclear facilities, light sources, environment). A list of publications completes the document. (J.S.)