Improved apparatus for a radio communication network having mobile transceiver units in communication with base transceiver units. The binder is transparent to the scintillator emission. The impact modifier is characterized in that it takes the form of microgranules having a diameter of less than 1500 \u03bcm, and preferably between 400 and 1000 \u03bcm. Inter-enclosure paths respectively link the first arrays in the first and second storage enclosures and the second arrays in the first and second storage enclosures and are enabled during normal operation of the storage system.