Performance Test and Circuit Simulation for R12699-406-M4 Photomultiplier Tube Base

TL;DR

This paper presents a comprehensive performance test and circuit simulation of the R12699-406-M4 photomultiplier tube base, optimizing its dynamic range for next-generation liquid xenon experiments and providing a model for improved detector response.

Contribution

It introduces a detailed circuit simulation model validated by experimental data, aiding in the design and optimization of PMT bases for enhanced detector performance.

Findings

Accurate simulation of saturation and suppression responses.

Optimized voltage-divider base for broad dynamic range.

Guidance for detector design and data correction strategies.

Abstract

The next-generation liquid xenon experiments like PandaX-xT target an energy range from sub-keV to multi-MeV to address the requirement of multiple physics searches. The Hamamatsu R12699-406-M4 photomultiplier tubes (PMTs) were developed and selected as photon sensors for PandaX-xT. Their voltage-divider base is optimized for a broad dynamic range, from single-photoelectron (SPE) sensitivity to 30~nC collected charge (matching the 2.5~MeV Q-value of $^{136}$Xe neutrinoless double beta decay~(NLDBD)). Using a dedicated test bench, we characterize the saturation and suppression responses of R12699-406-M4 PMTs with this base design. Based on measured PMT-base responses, we develop a circuit simulation model that accurately reproduces the physical mechanisms underlying these effects with key parameters tuned via experimental data. The combined simulation and bench-test approach guides base design and optimization, enabling improved detector dynamic range and supporting future saturation and suppression correction studies in data analysis.