The CD Panels: An Inquiry into the Spatial, the Sonic and the Public was released at the occasion of a symposium with the same name, which took place in Maastricht in October 2010. The CD contains an abridged version of Rayons de son.
More information can be found here:
https://www.bureau-europa.nl/nl/manifestations/112/
https://www.discogs.com/Various-Panels-An-Inquiry-Into-The-SpatialSonic-And-The-Public/release/3207617