Clas på Hörnet Clas had worked as a waiter and Annika as a manager. They named their own inn first "Browallshof", but it was soon called "Clas på Hörnet", both of them names from the co-founder of the inn. The inn, which was very conveniently positioned close to the Roslagstull customs and the popular health spring "Surbrunnen", quickly expanded into one of the most fashionable in Stockholm, frequented by customers of all social classes. It also offered the biggest dancing parlor in Stockholm, where balls were held by the aristocracy: in 1745, Frederick I of Sweden participated in one of the balls, where
CLAS detector at the center of CLAS. These collisions generally produce new particles, often after the target nucleons (protons and neutrons) are briefly excited to heavier-mass versions of the familiar protons and neutrons. A whole variety of intermediate-mass short-lived particles called "mesons" can be created. Scattered electron as well as the longer-lived produced particles travel through the CLAS detector, where they are measured. Particle physicists use these measurements to deduce the underlying structure of protons and neutrons and to better understand the interactions that create these new particles. The CLAS detector system was operational from 1998 until May 2012. From that time