~50% for a reconstructed five-neutron event at 1 GeV (see tabels below) will constitute a major step forward. Neutron separation matrices for multiplicities of 1 to 5 neutrons. The final design described in [...] will be limited, especially for very heavy projectiles, to about 10 5 s –1 or less, luminosities of the order of 10 28 cm –2 sec -1 , as expected for EXL, will not be reachable with external active targets [...] of stability, and consequently have half-lives much shorter than 1 s, and relatively low production rates considerably below 10 5 s –1 . For such cases the technique of active targets is presently considered