FANGS: Beam background monitoring during the commissioning phase of the Belle II detector

The FANGS (FE-I4 ATLAS Near Gamma Sensors) detector is one of the components of the BEAST II (Beam Exorcisms for A Stable Experiment) experiment, a pre-experiment of Belle II at the SuperKEKB accelerator in Japan. BEAST II was a dedicated detector system used to study the machine-induced background during the commissioning phase of the SuperKEKB accelerator before the installation of the Belle II inner detector (silicon vertex detectors). The FANGS detector is based on hybrid pixel detector modules used in the ATLAS IBL pixel detector (FE-I4) which are sensitive to low-keV X-rays and can cope with high particle rates. In this presentation, the development and construction of the FANGS detector, the installation in BEAST II at the end of 2017 and the first results from background studies, such as energy distributions of the background, are presented.