Calvey, J.R. Borland, M. Harkay, K.C. Lindberg, R.R. Yao, C. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-WEA1CO03 English 647-650 WEA1CO03 ion booster lattice injection simulation Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-WEA1CO03 https://jacow.org/napac2016/papers/wea1co03.pdf The APS-Upgrade will require the injector chain to provide high single bunch charge for swap-out injection. One possible limiting factor to achieving this is an observed reduction of injection efficiency into the booster synchrotron at high charge. We have simulated booster injection using the particle tracking code elegant, including a model for the booster impedance and beam loading in the RF cavities. The simulations point to two possible causes for reduced efficiency: energy oscillations leading to losses at high dispersion locations, and a vertical beam size blowup caused by ions in the particle accumulator ring. We also show that the efficiency is much higher in an alternate booster lattice with smaller vertical beta function and zero dispersion in the straight sections.