Gated photomultiplier response characterization for DIAL measurements

Area of Science:

• Physics
• Instrumentation Science

Background:

• Systematic biases in detector responses can affect measurements of transient signals with large dynamic ranges.
• Understanding and minimizing these biases are crucial for accurate scientific measurements.

Purpose of the Study:

• To investigate the causes of systematic biases in detector responses.
• To quantitatively evaluate signal-induced bias, gain variation, and linearity of gated photomultiplier tubes (PMTs).
• To identify methods for minimizing these undesirable effects.

Main Methods:

• Quantitative evaluation of signal-induced bias, gain variation, and linearity of gated PMTs in current integrating mode.
• Analysis of photomultiplier tube characteristics over a large dynamic range.
• Development of a new technique for linearity study that avoids absolute calibration.

Main Results:

• Impurity ions within the PMT were identified as the source of signal-induced bias and gain variation.
• Significant differences in bias magnitude and decay behavior were observed between two PMT models.
• Signal-induced bias can be minimized by using an external amplifier to reduce PMT gain and applying a low potential between the cathode and first dynode.
• PMT response linearity is limited to a specific input intensity range below a certain anode current.

Conclusions:

• Impurity ions are a primary cause of systematic biases in PMTs.
• Specific operational adjustments can effectively mitigate signal-induced bias and gain variations.
• PMT linearity is constrained, necessitating careful consideration for large dynamic range measurements.