UC scientists unravel mystery of noble gas properties crucial to dark matter detection
The study carried out at FCTUC clearly shows that the scintillation yield produced in xenon is indeed independent of the type of radiation incident (X-rays, electrons or alpha particles) and its energy, as predicted by theory.
A research team from the Faculty of Sciences and Technology of the University of Coimbra (FCTUC) has successfully solved the puzzle about the properties of xenon and other noble gases, which are essential for studying neutrinos and detecting dark matter.
The study, led by Carlos Henriques, Cristina Monteiro and Joana Teixeira from the Laboratory for Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys), of the UC Physics Department, has been published in the "Journal of Cosmology and Astroparticle Physics".
"Until now, the value of the scintillation yield produced by the interaction of X-rays and electrons in xenon had not been accurately determined. Its value was ambiguous and varied by almost 100% in different studies presented by different research groups. Furthermore, the results seemed to show a dependence of this yield on the energy of X-rays and electrons," explains Carlos Henriques. Cristina Monteiro adds that "these values were significantly higher than those obtained for alpha particle interactions, which are more widely accepted, without any theoretical explanation for such a difference".
The study carried out at FCTUC clearly shows that the scintillation yield produced in xenon is indeed independent of the type of radiation incident (X-rays, electrons or alpha particles) and its energy, as predicted by theory.
"The discrepancies found in previous work are explained by uncertainties in their experimental methods, which tend to be less robust. These findings can be extrapolated to other gases, like krypton and argon," reveal the authors, concluding that the accurate measurement of this parameter has a significant impact on the analysis of signals from noble gas detectors, which are crucial for the study of neutrinos (tiny subatomic particles) and the detection of dark matter.
The scientific article “Understanding the xenon primary scintillation yield for cutting-edge rare event experiments” is available here.