Mar 18 – 22, 2021
Stony Brook, NY
US/Eastern timezone

Options for gain elements and gas mixtures in a high rate EIC Time Projection Chamber

Mar 18, 2021, 12:40 PM
Stony Brook, NY

Stony Brook, NY

Online [US/EST Timezone]
Gaseous Detectors Gaseous Detectors


Dr Bob Azmoun (BNL)


 In order to investigate options for a future high rate TPC we have tested various gas gain structures and gas mixtures. Our goal was to focus on crucial TPC parameters: ion back flow, energy resolution (dE/dx), electron and ion drift speed, electron diffusion (in E- and B-fields), and stability. We concentrated on two options for the gain structure: 4 GEMs and MMG+2GEMs. For the hybrid option we achieve simultaneously an ion back flow below 0.3% and an energy resolution better than 12% for 55Fe X-rays at a gain of ≈2000 in a variety of gas mixtures. A few gas mixtures that we studied haven’t typically been used in a TPC, but appear promising, and further testing is recommended. Additionally, we investigated a potential instability (especially for MMGs) that occurs primarily from a high voltage (HV) power supply (PS) voltage drop in reaction to a discharge. It was demonstrated that a resistive protection layer on a pad / strip readout structure reduces the HV PS voltage drop after a spark to practically negligible levels. The hybrid micro-pattern gas amplification stage allows for a TPC design that can operate in a continuous mode, serves as a viable option to limit space charge distortions in high-rate TPCs, and guarantees that dE/dx, ionization cluster space reconstruction resolution, drift parameters and detector stability will not be compromised.

Primary authors

Dr Bob Azmoun (BNL) Nikolai Smirnov (Yale University) Prof. John Harris (Yale University) Dr Craig Woody (BNL) Mrs Caitlin Beattie (Yale University)

Presentation materials