paper

The effects of a passive Bi-Polar Grid (BPG) on Ion Back-Flow (IBF) and resolution

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Published 20 June 2023 © 2023 IOP Publishing Ltd and Sissa Medialab
, , Citation V. Zakharov et al 2023 JINST 18 C06024 DOI 10.1088/1748-0221/18/06/C06024

1748-0221/18/06/C06024

Abstract

Time Projection Chambers (TPC)s are excellent tracking detectors for high multiplicity events and can intrinsically be high-rate, but are limited by the ions created in their avalanche stage. GEMs and Micromegas can reduce IBF through their geometry and -field ratios, but these can lead to gain fluctuations and still leave IBF as the dominant source of space charge. An active BPG can block all IBF ions, but their slow drift speed creates too much dead time. A passive BPG will overcome this limitation by using an external -field to allow the electrons to pass through while still blocking all ions. Since the grid changes the electron's trajectory, a loss of resolution will occur. The trajectory is shifted symmetrically along the wires so the wire alignment with respect to the detection pads is a specific question not studied before. We present completed IBF analysis from data collected at Weizmann Institute of Science (WIS), along with an intro to our test on wire resolution.

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