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A long-standing limitation of semiconductor neutron detectors is the lack of a scalable solution to make large area instruments. Neutron detectors are used in a wide range of applications, including the nuclear industry, safeguarding radioactive material, neutron imaging, non-destructive testing, understanding space weather effects on commercial electronics used in aviation, and for fundamental science such as nuclear and particle physics. Here we demonstrate that a solution processed organic semiconductor technology, which is scalable, can solve this aproblem. We have demonstrated detection of fast neutrons from monoenergetic beams (energies 0.565 and 16.5 MeV), from AmBe sources, and thermal energy (0.025 eV) in devices sensitised with B-10 enriched B_4C. This energy range is of interest for many of the applications listed above. The detector response is found to be linear with flux up to 1.5 x 10^7 n/cm^2/s. As organic semiconductors are a similar density to human tissue, this technology may be of interest for medical physics applications, for example B neutron capture therapy dose monitoring and understanding neutron interactions in human tissue., Comment: 21 pages, 15 figures including supplementary information; 9 pages, 4 figures excluding SI

Numerous techniques and equipment have been developed to provide a capability for the detection of special nuclear materials (SNM), but due to the necessary security measures surrounding these materials alternate, or proxy, neutron sources are often utilised in their stead. In this paper we report the neutron and gamma pulse shape discrimination response of plastic scintillator to mixed neutron/gamma beams produced from two radionuclide neutron sources, and also from an SNM source of weapons-grade plutonium. We discuss the suitability of using radionuclide sources, with appropriate shielding configurations as proxy sources for SNM. A 3σnth-γ discrimination level has been achieved for an SNM source at a low-level energy threshold of ~220 keVee when a shielding configuration of 5 cm of lead was implemented. Varying amounts of lead and high-density polyethylene (HDPE) shielding were also investigated with the 3σ limit being reached by ~240 keVee. This work shows that an AmBe neutron source serves as an appropriate SNM proxy achieving a comparable value for figure of merit above ~1 MeVee. For energies below 1 MeVee down to ~100 keVee a closer approximation of the expected FoM for SNM can be attained when using 252Cf as a proxy source or by utilising an 'enhanced' AmBe source with the addition of a further low energy γ ray source.