Pulsed neutron differential die away analysis for detection of nuclear materials

Field Prototype of the ENEA Neutron Active Interrogation Device for the Detection of Dirty Bombs

“…As an alternative to DDAA, other different techniques could have potentially been adopted for detecting plutonium and uranium fertile isotopes (e.g., Neutron Coincidence Counting, Neutron Multiplicity Counting), but they all imply longer measurements for obtaining statistically significant data [14]. Jordan et al [15][16][17][18] experimentally proved the ability of the fast neutron interrogation technique and the DDAA for a prompt detection of fissile material. Experiments were carried out providing evidence that the approach allows the detection of hundreds of grams of 235 U in laboratory setups although they are heavy in weight, with large masses of moderator and structural materials.…”

“…In particular, the main target for the designer of such kind of devices should be the Minimum Detectable Activity (MDA) of fissile material, i.e., the minimum quantity of fissile material for triggering the alarm as a nuclear threat. The NAI device is intended to overcome the limitations of similar systems [15][16][17][18] by (1) decreasing the MDA, (2) lowering the device in weight, and (3) getting real-time responses.…”

Development of a novel neutron detection technique by using a boron layer coating a Charge Coupled Device

“…These sources are, nuclear research reactor and spallation sources, big facilities mainly dedicated to the neutron production [6]. Other applications that motivated the development of the neutron detection techniques are the instrumentation required for the operation of nuclear reactors [3], and the detection of concealed substances in port containers [7][8][9][10][11][12]. Due to the present international context, during the last decade this last application has become of importance for homeland security.…”

Using electronic neutron generators in active interrogation to detect shielded fissionable material

“…Using an external neutron radiation source to probe a suspect SNM-containing object produces additional SNM signatures, generally stronger and less ambiguous than the passive signatures, which can allow positive/negative determinations to be made quicker and with lower material detection limits than with passive screening alone. [5][6][7][8][9][10][11][12][13][14][15][16][17] The most commonly used active neutron interrogation techniques for SNM detection involve the use of electronic neutron generators (ENGs), which produce nearly monoenergetic fast neutrons at either 2.5 or 14.1 MeV, operating as pulsed neutron sources. For these measurements the ENGs generate short pulses of neutrons, ranging from 0.01 ms to 1 ms, and typically pulse at frequencies on the order of ~100 Hz.…”

“…[7][8][9][12][13][14]16,17] During this period fission is still occurring and detectors suited for measuring these fission signatures directly can be used. The intensity of these prompt fission signatures is much stronger than those from the fission products used in the delayed measurements.…”