Neutron based measurements planned in SPARC early campaigns

The SPARC mission of demonstrating Q > 1 in its first year of operations requires accurate neutron yield measurements, and multiple instruments are being designed for use in early campaigns. A set of 15 flux monitors at various locations in the tokamak hall will deliver yield data on fast (dt~10 ms) timescales for real-time control. They use 235U and 238U fission chambers and 10B based proportional counters and compensated ion chambers. A neutron activation system, with foil irradiation locations re-entrant into the vacuum vessel and pneumatic retrieval tools, will monitor the neutron yield per pulse. A radial neutron camera with ≥ 7 collimated lines of sight, served with spectrometric detectors (diamond and liquid organic scintillator), will provide emissivity profiles with spatial resolutions of a/8 (~7 cm), and support in reconstruction of Ti and ni profiles and potentially also the confined fusion product distribution functions. Finally, a magnetic proton recoil spectrometer providing dE/E~1% at DT/DD peak, is planned for a radial, midplane line of sight. Detectors' optimization for over 4-5 decades wide dynamic range is discussed here, and engineering design for the port components and the neutron laboratory (part of SPARC diagnostics hall) are also highlighted.