  We describe the Compact Accelerator-based Neutron Source SONATE which we are
aiming for to replace the close Orph{\'e}e reactor at Saclay, France. The
SONATE source would serve an instrumental suite of about 10 instruments. The
instruments would be split into low resolution instruments and higher
resolution instruments. Our reference design is based on a proton accelerator
operating at an energy in the range 20-30 MeV. The accelerator would serve 2
target stations. The first one operating at 20Hz with 2ms long pulses serving
low resolution instruments (SANS, reflectivity, imaging, spin-echo) and the
second one operating at 100Hz, 200$\mu$s long pulses serving higher resolution
instruments (powder diffraction, Direct Time-of-flight spectroscopy, Indirect
geometry spectroscopy). The 2 operation modes would be interlaced. The peak
current on the target is aimed at 100 mA with an average power on the target on
the order of 50-80 kW. Numerical Monte-Carlo simulations show that we may
expect instrument performances equivalent to the current instruments around
Orph{\'e}e or ISIS.
