Effects, Determination, and Correction of Count Rate Nonlinearity in Multi-Channel Analog Electron Detectors

TL;DR

This paper addresses the common issue of count rate nonlinearity in multi-channel electron detectors used in photoemission spectroscopy, proposing a rapid detection and correction method to improve data accuracy.

Contribution

It introduces a novel algorithm to detect and correct count rate nonlinearity, enhancing the quantitative reliability of spectroscopic measurements.

Findings

The nonlinearity causes artificial spectral sharpening.

The proposed method effectively corrects the nonlinearity.

Improved spectral analysis accuracy demonstrated.

Abstract

Detector counting rate nonlinearity, though a known problem, is commonly ignored in the analysis of angle resolved photoemission spectroscopy where modern multichannel electron detection schemes using analog intensity scales are used. We focus on a nearly ubiquitous "inverse saturation" nonlinearity that makes the spectra falsely sharp and beautiful. These artificially enhanced spectra limit accurate quantitative analysis of the data, leading to mistaken spectral weights, Fermi energies, and peak widths. We present a method to rapidly detect and correct for this nonlinearity. This algorithm could be applicable for a wide range of nonlinear systems, beyond photoemission spectroscopy.