The Intrinsic Energy Resolution of Organic Scintillators
Imagine trying to measure the weight of an object using scales that slightly "jitter" themselves. Even if you eliminate all external interference, this internal jitter will limit the accuracy of your measurements. Similarly, the intrinsic energy resolution limits the accuracy with which physicists can measure the energy of particles in scintillation detectors.
The presence of an unaccounted contribution to the energy resolution is particularly critical for cutting-edge scientific experiments that use organic scintillators and require high-energy resolution. These include, for example, study of neutrino properties in the large-scale JUNO project or the search for neutrinoless double beta decay.
The author analyzed laboratory data on the energy resolution of organic scintillators previously presented by various research groups. The analysis reliably established that even in an ideal detector based on an organic scintillator, there exists a fundamental, unavoidable limit to the accuracy of particle energy measurement. It is associated with the so-called intrinsic energy resolution, caused by statistical fluctuations in the light generation process within the scintillating material.
Data analysis for various organic scintillators showed that the contribution of the intrinsic resolution to the total error ranges from 1.5% to 2.2% for particles with an energy of 1 MeV. Furthermore, the behavior of this contribution as a function of energy, within the studied range up to 4 MeV, is successfully described by a simple model proposed by the author. It turns out that the contribution of the intrinsic resolution has the same energy dependence as the primary statistical contribution, which is why precise calibration of experimental setups using photomultiplier tubes is important. The paper provides specific recommendations for minimizing sources of error in future experiments.
"My work is a reminder that nature has its own 'rules of the game'," says O. Yu. Smirnov, the author of the study. "We cannot circumvent this limit, but we can accurately measure and account for it. Only knowing the error of a measuring instrument can give confidence in the obtained result. The contribution of the intrinsic resolution may prove critical for the success of the new generation of experiments, where the answers to fundamental questions about the structure of our Universe are at stake."
Link to the article: Eur. Phys. J. Plus (2025) 140:1114
