Passive Gating Grid for Ion Back Flow Suppression in High Luminosity Collider Experiments

TL;DR

This paper proposes passive gating techniques for Time Projection Chambers to reduce ion back flow in high luminosity collider experiments, aiming to improve data rates without dead time limitations.

Contribution

It introduces novel passive gating options for TPCs that significantly reduce ion back flow without the dead time associated with active gating.

Findings

Passive gating reduces ion back flow effectively.

Applicable to high luminosity collider environments.

Enhances TPC performance without dead time.

Abstract

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.