A 500 MeV booster has been designed at the Argonne National Laboratory to increase the beam intensity from the Zero Gradient Synchrotron (ZGS). Many turns of H ions from the 50 MeV lirac will be injected into the booster and stripped to H so that the ring will contain the maximum useful charge in each booster pulse. Several booster pulses will be injected into the ZGS to form one ZGS pulse. This machine is now under construction.