PMT Large-Signal Response and Waveform Correction

Measured PMT response, coupled transport and circuit modeling, and correction of detector waveforms.

Research Question

How can measured and modeled PMT response help recover signals distorted by saturation and suppression in liquid-xenon detector data?

Experimental Foundation

I measured nonlinear PMT responses over approximately 1–100,000 photoelectrons per channel, with pulse separations of 5–100 μs, to study large-signal saturation, consecutive-pulse suppression, and temporal recovery. Part of the R12699 base and circuit work was published in IEEE Transactions on Nuclear Science with co-first authorship.

Coupled Response Modeling

I proposed and developed a framework coupling PMT base-circuit simulation with a custom 2.5D electron-transport model. It investigates the relationship between internal multiplication and external circuitry and reproduces key features of small-signal multiplication and large-signal nonlinearity. This is a diagnostic framework; it is not a fully validated three-dimensional PMT model.

Application to Detector Data

I derived waveform corrections from measured and simulated response curves and applied them to saturated and suppressed signals in detector data. With the same event selection before and after correction, the difference between multi-site (MS) and single-site (SS) reconstructed energy peak positions decreased by 85%.

This metric describes the alignment of reconstructed energy peaks. It does not quantify an improvement in energy resolution.

  • Published R12699 PMT-base study
  • Manuscript in preparation (working title): Coupled PMT Electron-Transport and Base-Circuit Modeling for Saturation and Suppression Correction in Liquid-Xenon Detector Data.