REVEALING INTERMITTENCY IN NUCLEAR MULTIFRAGMENTATION WITH 4-PI DETECTORS

The distortion on the intermittency signal, due to detection efficienc y and to the presence of preequilibrium emitted particles, is studied in a schematic model of nuclear multifragmentation. A clear and genuin e intermittency signal is generated by means of a percolating system, which is assumed to be in a region around the critical one. Mixing of events is considered to simulate the experimental conditions. The effi ciency is schematized by a simple function of the fragment size, and t he presence of preequilibrium particles is simulated by an additional noncritical fragment source. No selection on the events is considered, and therefore all events are used to calculate the moments. It is fou nd that, despite the absence of event selection, the intermittency sig nal is not too much sensitive to the distortion due to the apparatus e fficiency, while the inclusion of preequilibrium particles in the mome nt calculation can substantially reduce the strength of the signal. Pr eequilibrium particles should therefore be carefully separated from th e rest of the detected fragments, before the intermittency analysis on experimental charge or mass distributions is carried out.