Description: OBJECTIVE: Conventional means of detecting radiological and nuclear threats (e.g., scintillator, semiconductor, ionization detectors) are limited by the range of the emitted particle (i.e., gamma, neutron, alpha, beta) between the source and detector. As an alternative to this constraint, we seek proposals to develop new modalities or improve upon previously investigated concepts for locating or sensing radiological or nuclear threats by means of indirect signatures that utilize non-atmospheric effects. While a heavy investment has been and continues to be made in conventional detection methods, this topic aims to complement those methods with additional or improved capabilities. Indirect signatures detection is a category that could include a number of modalities. As such, specific capabilities and parameters are difficult to identify; however, means are being sought to extend the detection range, increase sensitivity, and/or reduce size/weight/cube beyond that of traditional detectors. DESCRIPTION: DTRA seaks to improve capabilities for detecting nulear and radiological material of interest by innovative means. A previous SBIR solicitation, DTRA122-014, called for"the detection of a radioactive material by means other than by the direct interaction of gammas or neutrons emitted by the source."In addition to the persuit of indirect detection of such sources, DTRA is now following-up with the additional requirement that such detection be performed by means utizing non-atmospheric effects. For the purposes of this topic, atmospheric effects refers to the changes induced on atmospheric species from ionizing radiation that can be observed. Examples include O3 production via radiolysis and N2 and NOX excitation by secondary electrons. It has been proposed that the detection of these species or their spectral lines can indicate the presence of radiation. As an alternate approach, this topic seeks to locate or detect the presence of materials of interest by alternative means other than those indicated by atmospheric effects. As an example, in recent years several efforts have been undertaken to investigate gravity gradiometric approachs for detecting radiological material. Other concepts investigated have included RF and thermographic signatures. It is envisioned that this will most likely occur by observing physical or chemical characteristics of radioactive material (e.g. density, temperature, acustic) or their non-atmospheric effects of the surrounding environment. PHASE I: Development of the proof-of-concept through a laboratory device/setup or equivalent environment for the capability of locating or detecting radiological or nuclear material of interest or other strong indicators such as shielding material or configurations. In this phase, the proof-of-concept must be able to show that further development is likely to lead to a product with one or more capabilities that improve operational utility beyond current COTS detectors. A design concept for a prototype will be delivered and an evaluation of its feasibility and utility will be a key decision point for continuation to Phase II. PHASE II: Phase II must develop a prototype detector that can be validated independently. The results should be quantitatively compared to those of existing technologies in the same environments. Relative cost/benefit studies should be performed to demonstrate the advantages of the new technology. The Phase II final report should include a development plan and partnering approach for follow-on production and fielding along with a roadmap that takes the development through Phase III. PHASE III: Explore marketing and production alliances with existing technology equipment firms that currently have market share in these various commercial markets and under the prevue of export restrictions that may apply. For the military applications, continue the development of the technology and equipment design so that it can be transitioned to a counter-WMD program of record.