%0 Generic %A Maffei, B %A Aghanim, N %A Aumont, J %A Battistelli, E %A Beelen, A %A Besnard, A %A Borgo, B %A Calvo, M %A Catalano, A %A Chluba, J %A Coulon, X %A De Bernardis, P %A de Jabrun, C %A Douspis, M %A Errard, J %A Grain, J %A Guiot, P %A Hill, JC %A Ishino, H %A Kogut, A %A Lagache, G %A Macias-Perez, J %A Masi, S %A Matsumura, T %A Monfardini, A %A O'Sullivan, C %A Pagano, L %A Patanchon, G %A Pisano, G %A Pitre, L %A Ponthieu, N %A Remazeilles, M %A Ritacco, A %A Savini, G %A Sauvage, V %A Shitvov, A %A Stever, SL %A Tartari, A %A Thiele, L %A Trappe, N %A Aubrun, JF %A Bray, N %A Louvel, S %D 2024 %E Zmuidzinas, Jonas %E Gao, Jian-Rong %F discovery:10197935 %I Society of Photo-Optical Instrumentation Engineers (SPIE) %P 50-50 %T BISOU: A balloon pathfinder for CMB spectral distortions studies %U https://discovery.ucl.ac.uk/id/eprint/10197935/ %V 13102 %X The BISOU (Balloon Interferometer for Spectral Observations of the primordial Universe) project studies the viability and prospects of a balloon-borne spectrometer, pathfinder of a future space mission dedicated to the measurements of the CMB spectral distortions. A balloon concept based on a Fourier Transform Spectrometer, covering a spectral range from about 90 GHz to 2 THz, adapted from previous mission proposals such as PIXIE and FOSSIL, is being studied and modeled. Taking into account the requirements and conditions of balloon flights, we present here the instrument concept together with the results of a CNES Phase 0 study. We forecast a first detection of the CMB Compton y-distortion monopole with a signal-to-noise ratio of at least 5. We also present the future plan and work that will be the subject of a recently awarded two-year Phase A study. %Z This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions.