Characteristics of fast timing MCP-PMTs in magnetic fields

TL;DR

This study investigates how different design parameters of MCP-PMTs influence their performance in magnetic fields, aiming to guide the development of more magnetically tolerant photomultiplier tubes.

Contribution

It demonstrates that independently biased voltage MCP-PMTs significantly outperform resistor chain designs in magnetic field tolerance, highlighting the importance of adjustable voltages.

Findings

Independently biased MCP-PMTs tolerate magnetic fields up to 0.7 T.

Signal amplitude peaks at a tilt angle of ±8°, aligned with MCP pore bias angle.

Maximum signal amplitude varies with magnetic field strength and bias voltage.

Abstract

The motivation of this paper is to explore the parameters that affect the performance of Microchannel Plate Photomultiplier Tubes (MCP-PMTs) in magnetic fields with the goal to guide their design to achieve a high magnetic field tolerance. MCP-PMTs based on two different designs were tested.The magnetic field tolerance of MCP-PMT based on a design providing independently biased voltages showed a significant improvement (up to 0.7 T) compared to the one utilizing an internal resistor chain design (up to 0.1 T), indicating the importance of individually adjustable voltages. The effects of the rotation angle of the MCP-PMT relative to the magnetic field direction and of the bias voltage between the photocathode and the top MCP were extensively investigated using the MCP-PMT based on the independently biased voltage design. It was found that the signal amplitude of the MCP-PMT exhibits an enhanced performance at a tilt angle of $\pm$8$^{\circ}$, due to the 8$^{\circ}$ bias angle of the MCP pores. The maximum signal amplitude was observed at different bias voltages depending on the magnetic field strength.