9Mv Linac Photo-Neutron Interrogation Of Uranium With Advanced Acoustically Tensioned Metastable Fluid Detectors

Active special nuclear material (SNM) photoneutron interrogation research with Acoustically Tensioned Metastable Fluid Detector (ATMFD) sensor technology is discussed which provides evidence for enabling real time detection of special nuclear material (SNM) even when deployed under extreme 15,000 R h-1 (9 MeV endpoint) X-ray beams. Experiments to detect 3.2 kg DU are described with use of two designs of the economical E-ATMFD, viz., E-ATMFD.Ver.0 and E-ATMFD.Ver.1, respectively, at standoffs ranging from 0.1 m to 10 m - including with the E-ATMFD directly within the interrogating beam. Under similar conditions and with 100% photon rejection (i.e., 0 cpm with beam on, and w/o SNM), the E-ATMFD.Ver.1 design was shown capable of ~6x (600%) higher gain at ~10x lower drive powers over E-ATMFD.Ver.0 (with beam on and with SNM). The sensitivity gain rises to ~27x (i.e., 2,700%) with the E-ATMFD.Ver.1 operating at 0.99 W and a background count rate of ~1 cpm. The E-ATMFD.Ver.1 demonstrated 100% photon blindness (0 cpm) while operating at ~0.56 W drive power and placed directly within the beam under 15,000 R/h; including the SNM target led to a count rate of up to 50 cpm - revealing the E-ATMFD.Ver.1 as potentially field-capable for detecting U-based SNMs within seconds from photofission neutron signals, even when deployed directly within the interrogating photon beam.