Test of \textit{Topmetal-${II}^-$} In Liquid Nitrogen For Cryogenic Temperature TPCs

TL;DR

This paper demonstrates that the Topmetal-II- sensor functions effectively at cryogenic temperatures in liquid nitrogen, maintaining low noise levels suitable for use in liquid argon and xenon TPCs in particle physics experiments.

Contribution

It is the first to test and confirm the cryogenic performance of Topmetal-II- sensors, showing their viability for advanced particle detection applications.

Findings

Topmetal-II- operates well at cryogenic temperatures with low noise.

Noise level at cryogenic temperature is 12 e-, lower than 13 e- at room temperature.

Suitable for next-generation liquid argon and xenon TPC readouts.

Abstract

\textit{Topmetal-${II}^-$} is a highly pixelated direct charge sensor that contains a 72${\times}$72 pixel array of 83${\mu}$m pitch size. The key feature of \textit{Topmetal-${II}^-$} is that it can directly collect charges via metal nodes of each pixel to form two-dimensional images of charge cloud distributions. \textit{Topmetal-${II}^-$} was proved to measure charged particles without amplification at room temperature. To measure its performance at cryogenic temperature, a \textit{Topmetal-${II}^-$} sensor is embedded into a liquid nitrogen dewar. The results presented in this paper show that \textit{Topmetal-${II}^-$} can also operate well at this low temperature with a noise (ENC) of 12 e$^-$ lower than that at room temperature (13 e$^-$). From the noise perspective, \textit{Topmetal-${II}^-$} is a promising candidate for the next generation readout of liquid argon and xenon Time Projection Chamber (TPC) used in experiments searching for neutrinoless double beta decay and dark matter.