Benchmark Nifty closed above the 9,300-mark for the first time in its history on Tuesday, while the sensex soared 287 points to a three-week high on widespread buying, spurred by strong results and upbeat global cues.The 50-share Nifty rallied 88.65 points, or 0.96 per cent, to reach its new lifetime closing high of 9,306.60, surpassing the previous record close of 9,265.15 on April 5.Intra-day, it surged to 9,309.20, breaking its previous intra-day record of 9,273.90 reached on April 5.The BSE 30-share sensex surged 287 points to end at a three-week high of 29,943.24, after shuttling between 29,961.82 and 29,780.84. The gauge had gained 290.54 points on Monday.This is the highest closing for sensex since April 5, when it had ended on 29,974.24.