  Time Projection Chamber (TPC) is one of the main tracking systems for many
current and future collider experiments at RHIC and LHC. It has a capability to
measure the space points of charged tracks for good momentum resolution as well
as the energy loss (dE/dx) for particle identification with good energy
resolution. Both of these features depend strongly on the amount of space
charge in the TPC gas volume, mainly due to the ions from the amplification
stage. An active gating grid has been used thus far to gate the electrons and
ions by switching the polarities of the grid wires. Therefore, active gating
does introduce a limitation for data taking rates in high luminosity
collisions. In this work we propose several options of a passive gating, where
a significant reduction of Ion Back Flow (IBF) is possible in a high luminosity
environment without any dead time issues due to gating operation. Particularly,
the application of a TPC passive gating for the sPHENIX experiment at RHIC is
presented, which is currently under development.
