Modulation effect in the differential rate for Supersymmetric Dark Matter detection

The modulation effect in the direct detection of supersymmetric Cold Dark Matter (CDM) particles is investigated. It is shown that, while normally the modulation effect in the total event rate is small, $\leq 5% $, in some special cases it becomes much larger. It also becomes more pronounced in the differential event rate. It may thus be exploited to discriminate against background.