{"525881":{"#nid":"525881","#data":{"type":"news","title":"New Technique Could Improve Detection of Concealed Nuclear Materials","body":[{"value":"\u003Cp\u003EResearchers have demonstrated proof of concept for a novel low-energy nuclear reaction imaging technique designed to detect the presence of \u201cspecial nuclear materials\u201d \u2013 weapons-grade uranium and plutonium \u2013 in cargo containers arriving at U.S. ports. The method relies on a combination of neutrons and high-energy photons to detect shielded radioactive materials inside the containers.\u003C\/p\u003E\u003Cp\u003EThe technique can simultaneously measure the suspected material\u2019s density and atomic number using mono-energetic gamma ray imaging, while confirming the presence of special nuclear materials by observing their unique delayed neutron emission signature. The mono-energetic nature of the novel radiation source could result in a lower radiation dose as compared to conventionally employed methods. As a result, the technique could increase the detection performance while avoiding harm to electronics and other cargo that may be sensitive to radiation.\u003C\/p\u003E\u003Cp\u003EIf the technique can be scaled up and proven under real inspection conditions, it could significantly improve the ability to prevent the smuggling of dangerous nuclear materials and their potential diversion to terrorist groups.\u003C\/p\u003E\u003Cp\u003ESupported the National Science Foundation and the U.S. Department of Homeland Security, the research was reported April 18 in the Nature journal \u003Cem\u003EScientific Reports\u003C\/em\u003E. Scientists from the Georgia Institute of Technology, the University of Michigan, and the Pennsylvania State University conducted this research, which is believed to be the first successful effort to identify and image uranium using this approach.\u003C\/p\u003E\u003Cp\u003E\u201cOnce heavy shielding is placed around weapons-grade uranium or plutonium, detecting them passively using radiation detectors surrounding a 40-foot cargo container is very difficult,\u201d said \u003Ca href=\u0022http:\/\/www.me.gatech.edu\/faculty\/erickson\u0022\u003EAnna Erickson\u003C\/a\u003E, an assistant professor in Georgia Tech\u2019s \u003Ca href=\u0022http:\/\/www.me.gatech.edu\/\u0022\u003EGeorge W. Woodruff School of Mechanical Engineering\u003C\/a\u003E. \u201cOne way to deal with this challenge is to induce the emission of an intense, penetrating radiation signal in the material, which requires an external source of radiation.\u201d\u003C\/p\u003E\u003Cp\u003EThe technique begins with an ion accelerator producing deuterons, heavy isotopes of hydrogen. The deuterons impinge on a target composed of boron, which produces both neutrons and high-energy photons. The resulting particles are focused into a fan shaped beam that could be used to scan the cargo container.\u003C\/p\u003E\u003Cp\u003EThe transmission of high-energy photons can be used to image materials inside the cargo container, while both the photons and neutrons excite the special nuclear material \u2013 which then emits gamma rays and neutrons that can be detected outside the container. Transmission imaging detectors located in the line of sight of the interrogating fan beam of photons create the image of the cargo.\u003C\/p\u003E\u003Cp\u003E\u201cThe gamma rays of different energies interact with the material in very different ways, and how the signals are attenuated will be a very good indicator of what the atomic number of the hidden material is, and its potential density,\u201d Erickson explained. \u201cWe can observe the characteristics of transmission of these particles to understand what we are looking at.\u201d\u003C\/p\u003E\u003Cp\u003EWhen the neutrons interact with fissile materials, they initiate a fission reaction, generating both prompt and delayed neutrons that can be detected despite the shielding. The neutrons do not prompt a time-delayed reaction with non-fissionable materials such as lead, providing an indicator that materials of potential use for development of nuclear weapons are inside the shielding.\u003C\/p\u003E\u003Cp\u003E\u201cIf you have something benign, but heavy \u2013 like tungsten, for instance \u2013 versus something heavy and shielded like uranium, we can tell from the signatures of the neutrons,\u201d Erickson said. \u201cWe can see the signature of special nuclear materials very clearly in the form of delayed neutrons. This happens only if there are special nuclear materials present.\u201d\u003C\/p\u003E\u003Cp\u003EEarlier efforts at active detection of radioactive materials used X-rays to image the cargo containers, but that technique had difficulty with the heavy shielding and could harm the cargo if the radiation dose was high, Erickson said. Because it uses discrete energies of the photons and neutrons, the new technique minimizes the amount of energy entering the container.\u003C\/p\u003E\u003Cp\u003EResearchers at Georgia Tech \u2013 led by Erickson \u2013 and at University of Michigan and Penn State University \u2013 led by Igor Jovanovic, professor of nuclear engineering and radiological sciences \u2013 demonstrated that the technique works in a laboratory setting by detecting uranium plates and rods.\u003C\/p\u003E\u003Cp\u003EIn testing conducted in collaboration with the Massachusetts Institute of Technology at the Bates Linear Accelerator Center, the researchers used a fan-like pattern of particles created by an ion accelerator and emitted at 4.4 and 15.1 MeV. The particles passed through a shielded radioactive material, and were measured on the other side with Cherenkov quartz detectors connected to photomultiplier tubes.\u003C\/p\u003E\u003Cp\u003E\u201cThis provided proof that the physics works, and that we can use these particles to actually distinguish among various materials, including special nuclear materials,\u201d Jovanovic said. The technique has not yet been tested under the real-world conditions of a steel cargo container, but such demonstration may take place in the near future.\u003C\/p\u003E\u003Cp\u003EBeyond the potential homeland security uses, the technology could also find application in materials science, medical imaging, low-energy nuclear physics and industrial imaging. In addition to Erickson and Jovanovic, the research included graduate students Paul Rose, Jr. (Georgia Tech) and Jason Nattress (University of Michigan) and postdoctoral research associate Michael Mayer (Penn State University).\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis work was supported by the National Science Foundation under Grant No. ECCS-1348366 and ECCS-1348328 and by the U.S. Department of Homeland Security under Grant Award Number 2014-DN-077-ARI079-02 and 2014-DN-077-ARI078-02. The research of Jason Nattress was performed under appointment to the Nuclear Nonproliferation International Safeguards Graduate Fellowship Program sponsored by the National Nuclear Security Administration\u2019s Next Generation Safeguards Initiative (NGSI). The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the NSF or the U.S. Department of Homeland Security.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Paul Rose, Anna Erickson, Michael Mayer, Jason Nattress and Igor Jovanovic, \u201cUncovering Special Nuclear Materials by Low-energy Nuclear Reaction Imaging,\u0022 (\u003Cem\u003EScientific Reports\u003C\/em\u003E, 2016). \u003Ca href=\u0022http:\/\/www.dx.doi.org\/10.1038\/srep24388\u0022\u003Ehttp:\/\/www.dx.doi.org\/10.1038\/srep24388\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia 30332-0181\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) (404-894-6986) or Ben Brumfield (\u003Ca href=\u0022mailto:ben.brumfield@comm.gatech.edu\u0022\u003Eben.brumfield@comm.gatech.edu\u003C\/a\u003E) (404-358-1933).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EResearchers have demonstrated proof of concept for a novel low-energy nuclear reaction imaging technique designed to detect the presence of \u201cspecial nuclear materials\u201d \u2013 weapons-grade uranium and plutonium \u2013 in cargo containers arriving at U.S. ports. The method relies on a combination of neutrons and high-energy photons to detect shielded radioactive materials inside the containers.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have demonstrated proof of concept for a novel low-energy nuclear reaction imaging technique designed to detect the presence of \u201cspecial nuclear materials.\u201d"}],"uid":"27303","created_gmt":"2016-04-16 20:12:20","changed_gmt":"2016-10-08 03:21:21","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2016-04-18T00:00:00-04:00","iso_date":"2016-04-18T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"525841":{"id":"525841","type":"image","title":"Nuclear Reaction Cherenkov Detector","body":null,"created":"1461074400","gmt_created":"2016-04-19 14:00:00","changed":"1475895298","gmt_changed":"2016-10-08 02:54:58","alt":"Nuclear Reaction Cherenkov Detector","file":{"fid":"205501","name":"nuclear-reaction1.jpg","image_path":"\/sites\/default\/files\/images\/nuclear-reaction1.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/nuclear-reaction1.jpg","mime":"image\/jpeg","size":1110102,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/nuclear-reaction1.jpg?itok=L8tuxQKC"}},"525851":{"id":"525851","type":"image","title":"Nuclear Reaction Ion Acclerator","body":null,"created":"1461074400","gmt_created":"2016-04-19 14:00:00","changed":"1475895298","gmt_changed":"2016-10-08 02:54:58","alt":"Nuclear Reaction Ion Acclerator","file":{"fid":"205502","name":"nuclear-reaction2.jpg","image_path":"\/sites\/default\/files\/images\/nuclear-reaction2_0.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/nuclear-reaction2_0.jpg","mime":"image\/jpeg","size":1148156,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/nuclear-reaction2_0.jpg?itok=Yill6dzR"}},"525861":{"id":"525861","type":"image","title":"Nuclear Reaction Imaging Schematic","body":null,"created":"1461074400","gmt_created":"2016-04-19 14:00:00","changed":"1475895298","gmt_changed":"2016-10-08 02:54:58","alt":"Nuclear Reaction Imaging Schematic","file":{"fid":"205503","name":"nuclear-reaction-schematic.jpg","image_path":"\/sites\/default\/files\/images\/nuclear-reaction-schematic_1.jpg","image_full_path":"http:\/\/tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/nuclear-reaction-schematic_1.jpg","mime":"image\/jpeg","size":225258,"path_740":"http:\/\/tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/nuclear-reaction-schematic_1.jpg?itok=h-0eKKWq"}}},"media_ids":["525841","525851","525861"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"147","name":"Military Technology"},{"id":"135","name":"Research"}],"keywords":[{"id":"171927","name":"ion accelerator"},{"id":"170124","name":"nuclear materials"},{"id":"170125","name":"nuclear reaction imaging"},{"id":"170128","name":"radioactive materials"}],"core_research_areas":[{"id":"145171","name":"Cybersecurity"},{"id":"39451","name":"Electronics and Nanotechnology"},{"id":"39471","name":"Materials"},{"id":"39481","name":"National Security"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}