The Practicality of Pulsed Fast Neutron Transmission Spectroscopy for Aviation Security (1999) / Chapter Skim
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5 Tensor Technology Report on the Multidimensional Neutron Radiometer Airline Security System
5 Tensor Technology Report on the Multidimensional Neutron Radiometer Airline Security System
Pages 19-25
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From page 19... ...
Although this approach has some advantages, it also raises some questions because all of the previous tests on the detection capabilities of PFNTS were conducted on equipment with a linear accelerator as the neutron source. Furthermore, the cyclotron-based design still has weight and space requirements that may preclude integration into the passenger baggage line at existing airports.
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From page 20... ...
Differences in Pfa may be related to the use of an open two-dimensional detector at the University of Kentucky rather than the linear array used at the University of Oregon, to differences in the explosives-detection algorithms, or to differences in the test protocols. In any event, these laboratory test results indicate that the MDNR would probably not meet the EDS detection performance requirements for Class A explosives.3 Results indicate that the MDNR would meet the EDS detection requirements for Class B explosives and, indeed, for all classes of explosives in the FAA EDS specifications except Class A explosives.
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From page 21... ...
A potential disadvantage of the cyclotron is that the rotating, accelerating charged particles produce much more gamma radiation than linearly accelerated particles with the same energy and charge. The MDNR overcomes this disadvantage by placing an 80-cm (32-in.~-thick berated concrete shield around the compact cyclotron, in addition to the concrete vault enclosure used to shield both linear and cyclotron accelerators.
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From page 22... ...
But, like the cyclotron magnets, the bending magnets used with a linear accelerator are a localized radiation source that can be shielded efficiently with a small volume of materials. The potential advantages of a cyclotron over a linear accelerator size and compact neutron source for easier shielding may not carry over into an MDNR if it is housed in a separate facility rather than integrated into the baggage line.
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From page 23... ...
The panel concluded that the Tensor shielding is a reasonable baseline configuration for a conceptual design. Although much more detailed radiation transport calculations will be required to support an engineering-level design, the MDNR shielding mass of 637 tonnes (109 + 528)
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From page 24... ...
Even if the activation levels are low enough that the shielding materials do not require disposal as activated material, material surveys or clear bounding radiation transport calculations will be necessary to deter 7As part of a large-scale personnel monitoring program, the cost of thermoluminescent dosimeters is between $5 and $50 per unit with new units provided on a quarterly basis. PA thermal neutron analysis system uses thermal neutrons, which have a much larger typical activation cross section than fast neutrons (> 1 MeV)
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From page 25... ...
CARGO INSPECTION The Tensor report discusses the potential of PFNTS for use in scanning cargo but does not provide a conceptual design consistent with cargo-scanning requirements. The panel concluded that PFNTS technology does not have significant potential for the inspection of thick containers of hydrogenousl° materials for explosive amounts consistent with the FAA' s EDS detection requirements because neutron attenuation is too great.
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