  The IBF and the transparent rate of electrons are two essential indicators of
TPC, which affect the energy resolution and counting rate respectively. In this
paper, we propose several novel strategies of staggered multi-THGEM to suppress
IBF, where the geometry of the first layer THGEM will be optimized to increase
the electron transparent rate. By Garfield++ simulation, the electron
transparency rate can be more than 90% of single THGEM with a optimized large
hole. By simulating these configurations of triple and quadruple THGEM
structures, we conclude that the IBF can be reduced to 0.2% level in an
optimized configuration denoted as "ACBA". This strategy for staggered THGEM
could have potential applications in future TPC projects.
