In this paper we present measurements performed with a Micromegas X-ray detector setup. The detector is a prototype in the context of the BabyIAXO helioscope, which is under construction to search for an emission of the hypothetical axion particle from the sun. An important component of such a helioscope is a low background X-ray detector with a high efficiency in the 1-10 keV energy range. The goal of the measurement was to study techniques for background discrimination. In addition to common techniques we used a multi-layer veto system designed to tag cosmogenic neutron background. Over an effective time of 52 days, a background level of 8.6×10−7counts keV−1cm−2s−1 was reached in a laboratory at above ground level. This is the lowest background level achieved at surface level. In this paper we present the experimental setup, show simulations of the neutron-induced background, and demonstrate the process to identify background signals in the data. Finally, prospects to reach lower background levels down to 10−7counts keV−1cm−2s−1 will be discussed.
@article{arxiv.2403.06316,
title = {Background discrimination with a Micromegas detector prototype and veto system for BabyIAXO},
author = {K. Altenmüller and J. F. Castel and S. Cebrián and T. Dafni and D. Díez-Ibañez and A. Ezquerro and E. Ferrer-Ribas and J. Galan and J. Galindo and J. A. García and A. Giganon and C. Goblin and I. G. Irastorza and C. Loiseau and G. Luzón and X. F. Navick and C. Margalejo and H. Mirallas and L. Obis and A. Ortiz de Solórzano and T. Papaevangelou and O. Pérez and A. Quintana and J. Ruz and J. K. Vogel},
journal= {arXiv preprint arXiv:2403.06316},
year = {2024}
}