As the accumulation current of positrons increases in the KEKBring, the injection time is becoming longer. It will thus be one of themost important issues affecting the accumulation of the integratedluminosity. As one of the steps, we introduced a high-intensitytwo-bunch acceleration scheme at the KEKB linac to intensify positronsby means of doubling the primary electrons. We recently obtained testresults of 0.54 nC for the first bunch and 0.49 nC for the second bunchat the linac end. This scheme increased the positron intensity by nearly65%. Since the linac frequency is not a harmonic number of the LERfrequency, the best time interval between two bunches is 96.29 ns,corresponding to 49 LER-buckets. Even with this limitation, it isundoubtedly a very useful scheme for increasing the positron injectionrate. The beam test results are described
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