MAC-TMFD: A novel, Multi-Armed Centrifugally Tensioned Metastable Fluid Detector (gamma-blind) – neutron-alpha recoil-fission spectrometer

Abstract This paper describes the physics, design, and qualification of a novel, parallel-processing mode spectroscopy enabled sensor system architecture for the detection of fundamental nuclear particles interacting with fluids placed under tensioned metastable states. Our past studies have described gamma-blind spectroscopic detection of neutrons, alphas and fission events using the Centrifugally Tensioned Metastable Fluid Detectors (CTMFDs) allowing for high intrinsic efficiencies over 80% for neutron energies spanning 0.02eV to 15 MeV, and efficiencies of over 95% for detection of alpha and fission fragment recoils. As a novel advancement, the CTMFD was radically redesigned such that a single unit effectively works as several detectors operating in parallel - resulting in the Multi-Arm Centrifugally Tensioned Metastable Fluid Detectors (MAC-TMFDs). The MAC-TMFD now enables benefits such as several times faster data acquisition, and simultaneous, more rapid spectroscopic detection of neutrons-alphas-fission events within the same apparatus. As a first-of-kind prototype, the dual-arm, aka (2)MAC-TMFD effectively encompassing two TMFDs within one form factor has been designed, constructed and extensively tested for neutron-alpha detection. The MAC-TMFD was tested to show improvement over traditional liquid scintillation counters (LCSs) for alpha spectroscopy and exhibited ∼ 10-to-100 times greater efficiency than a Beckman LS6500 T M spectrometer. Gamma-insensitivity was demonstrated using Co-60 and Cs-137 sources (offering gamma ray exposure doses of up to ∼ 1 R/h (0.01 Sv/h) while showing high sensitivity for neutron detection [for hard Pu-Be(n, α ), and fission 252Cf fission derived neutron spectra; this is in addition to allow for energy profile difference identification. Analysis for neutron detection efficiency reveals that the detection efficiency varies non-linearly with the tension negative pressure (Pneg) ranging from 10% to over 50% of the theoretical interaction rates for the Pneg states tested. The resulting detection data has been shown to remain compatible with the underlying science and physics of a traditional TMFD system; however, with a 0.1 MPa reduced Pneg offset attributed to the tension state being maximized at the wall–fluid interface for the MAC-TMFD vs. in the bulk for the conventional CTMFD design. A follow-on (8)MAC-TMFD architecture (with 8 independent CTMFDs within a single enclosure) has also been constructed and proven promising in scoping studies. This paper presents the various steps involved in consideration of the underlying physics, technical challenges, design, construction, and benchmarking- vetting of the MAC-TMFD sensor architecture.