The key reactions to study the Generalised Parton Distributions are Deeply Virtual Compton
Scattering (DVCS) and Deeply Virtual Meson Production (DVMP). At COMPASS, these pro-
cesses are investigated using a high intensity muon beam with a momentum of 160 GeV/c and
a 2.5 m-long liquid hydrogen target. In order to optimize the selection of exclusive reactions at
these energies, the target is surrounded by a new barrel-shaped time-of-flight system to detect
the recoiling particles. COMPASS-II covers the up to now unexplored x B domain ranging from
0.01 to 0.15. From the sum of cross sections measured with positive and negative beam polar-
ities, the pure DVCS cross-section and its t-dependence have been extracted resulting in a first
model-independent determination of the transverse size of the partonic distribution of the nucleon