  Recently, S.W. Kahler studied the solar energetic particle (SEP) event
timescales associated with coronal mass ejections (CMEs) from spacecraft data
analysis. They obtained different timescales of SEP events, such as TO, the
onset time from CME launch to SEP onset, TR, the rise time from onset to half
the peak intensity (0.5Ip), and TD, the duration of the SEP intensity above
0.5Ip. In this work, we solve SEPs transport equation considering ICME shocks
as energetic particle sources. With our modeling assumptions, our simulations
show similar results to Kahler's spacecraft data analysis that the weighted
average of TD increases with both CME speed and width. Besides, from our
simulation results, we suggest TD is directly dependent on CME speed, but not
dependent on CME width, which were not achieved from the observation data
analysis.
