The MAC-TMFD: Novel multi-armed Centrifugally Tensioned Metastable Fluid Detector (Gamma-Blind) — Neutron-alpha recoil spectrometer

Centrifugally Tensioned Metastable Fluid Detector systems (CTMFDs) have a number of valuable advantages over other conventional, state of the art systems (e.g., ³He tubes). CTMFDs can be configured to attain intrinsic efficiencies over 90% for neutron energies from the thermal to the fast region (ev to MeV). TMFDs can detect alpha and fission recoil interactions exceeding 10 times lower activity than that of conventional spectrometers (i.e., <; ~0.05 Bq/g). The tension pressures used for detection (-10 bars) are over 1000 times greater than the fluctuations resulting from even extreme external events such as during earthquakes. TMFDs are also inherently gamma blind making them ideal for use in high gamma fields where traditional detectors fail such as in active interrogation applications. Unlike current state of the art active and passive interrogation systems, the CTMFD relies on simple to use, straightforward, and inexpensive electronics with lab-prototypes costing around ~$100-1000. Finally, the CTMFD system can switch between detection of neutrons, alpha recoils, and fission products with simplicity within the same system. As a novel transformational advancement, the CTMFD has been re-configured to now allow for multiple detectors enclosed within the envelope of a single system, resulting in the Multi-Arm Centrifugally Tensioned Metastable Fluid Detectors (MAC-TMFDs). This system embodiment now allows for the creation of several independently operating sensing regions within a single TMFD. In this way, a single detector can effectively be converted into multiple situation-specific sensors within a simple package. This advancement allows for rapid neutron/alpha spectroscopy with a single system. As part of capability validation, alpha spectroscopy has been performed with a two sensitive volume region apparatus. This system´s sensitivity shows significant improvement over state-of-the-art liquid scintillation counters ~ 1 to 10 times more sensitiv- than a Beckman LS6500^TM spectrometer. Also, gamma blind neutron detection using (n, alpha) Pu-Be and fission ²⁵²Cf neutron sources have been possible to attain along with discrimination of each source. The resulting detection data has been shown to remain compatible with the underlying science of a traditional CTMFD system. Further analysis shows that the leap-ahead MAC-TMFD is amenable for on-demand scalability.