Correlations at small relative momenta among protons produced in collisions of 1.8-GeV/nucleon Ar40 with a KC1 target

Correlations between two protons produced in the inclusive reaction Ar+KClp+p+X at 1.8 GeV/nucleon have been measured for proton rapidities near the beam rapidity YB and near YB2. Comparison with model calculations suggests that the size of the region of final scattering is 3.5 fm at YB and corresponds to that expected for a projectile remnant. The sizes we obtain at YB2 (with or without high multiplicity requirements) are smaller (2.4-2.8 fm) and seem inconsistent with a thermalized source containing a large fraction of the available nucleons.