In a landmark experiment at the Accelerator Laboratory of the Department of Physics (JYFL-ACCLAB) at University of Jyväskylä, a beam of the short-lived nuclide 85As was produced through nuclear fission. The research group was successful in testing the modular neutron spectrometer (MONSTER) at JYFL-ACCLAB, a new detector array built by an international collaboration with groups from CIEMAT (Spain), VECC (India), JYFL/HIP (Finland), IFIC (Spain), and UPC (Spain).