Production of prompt electrons in the charm P sub t -region at radical s=630 GeV

The production of prompt electrons at {radical}s=630 GeV has been measured in the p{sub t} range 0.5--2.0 GeV/c using a Ring Imaging CHerenkov (RICH) counter installed in the UA2 experiment at the CERN p{bar p} collider. From our measurement of the electron/hadron ratio in the pt range 0.9--1.5 GeV/c we conclude that the charm production cross-section does not exceed 1.9 mb at 95% CL. As best estimate we obtain {sigma}(c{bar c})=684{plus minus}557(stat){plus minus}253(sys,exp){plus minus}205(sys,theory) {mu}b. The RICH counter was operated successfully at the collider providing an electron/pion separation capability of better than 8--10{sup {minus}5} at momenta below the pion threshold.