HUMANITARIAN DEMINING NUCLEAR TECHNIQUES MAY HELP THE SEARCH FOR LANDMINES

BY ULF ROSENGARD,THOMAS DOLAN, DMITRI MIKLUSH, AND MASSOUD SAMIEI

bout 60 million The Convention requires, modern landmines contain abandoned landmines among other things that: “Each very small amounts or no Aare distributed in more State Party in a position to do metal at all. than 70 countries in all parts of so shall provide assistance for Increasing the sensitivity of the world. They are lethal mine clearance and related the detector to detect smaller remnants from often forgotten activities”. In recognition of amounts of metal also makes it armed conflicts during the last the inabilities of some very sensitive to metal scrap century. Landmines kill about countries to do so, the often found in areas where 26,000 persons every year and Convention also states that mines may be located. maim even more, leaving “State Parties may request the Furthermore, metal detectors, behind dismembered victims United Nations, other State however sophisticated, can requiring extensive healthcare Parties, regional organizations only succeed in finding and rehabilitation. or other competent anomalies in the ground The victims are usually intergovernmental or non- without providing information women, children and farmers governmental organizations to about whether an explosive in developing countries. For assist its authorities in the agent is present or not. example, in Angola one of elaboration of a national One major problem in 16 every 334 individuals is a demining program.” humanitarian demining is to landmine amputee and discriminate between a Cambodia has more than MINE DETECTION “dummy” object and a 25,000 amputees due to mine METHODS landmine. Identifying and blasts. Furthermore, the In military demining the removing a harmless object is a landmine problem has vast objective is to clear a minefield time-consuming and costly socio-economic consequences as fast as possible using brute process. Dogs have extremely as it undermines peace and force, and usually a clearance well-developed olfactory senses stability in whole regions by rate of 80% to 90% is accepted. and can be trained to detect displacing people and Humanitarian demining, on explosives in trace quantities. inhibiting the use of land for the other hand, is more This technique, however, agricultural production. The difficult and dangerous, as it requires extensive training of daily lives of more than 22 requires the complete removal the dogs and their handlers, million people are directly of all mines and the return of and the dog’s limited attention affected by abandoned the cleared minefield to normal span makes it difficult to landmines. use. Today, most humanitarian maintain continuous In December 1997, a total of demining is done using hand- operations. 123 countries signed the held metal detectors and/or “Convention on the sniffer dogs. Metal detectors Mr. Rosengard is a staff member Prohibition, of the Use, find objects containing metal in the IAEA Physics Section, Stockpiling, Production and by utilizing a time-varying Division of Physical and Transfer of Anti-Personnel electromagnetic field to induce Chemical Sciences. Mr. Dolan is Mines and on Their eddy-currents in the object, the Section Head. Mr. Miklush Destruction” in Ottawa, which in turn generate a is a staff member in the IAEA’s Canada. Since then, 16 detectable magnetic field. Old Europe Section, Department of additional countries have landmines contain metal parts Technical Cooperation. Mr. IAEA BULLETIN, 43/2/2001 signed the Convention. (e.g. the firing pin), but Samiei is the Section Head. Electronic chemical sniffers matter depend strongly on emitted in ten-microsecond imitating the dog’s natural their kinetic energy. Fast bursts. During the bursts, senses are also used. However, neutron “scattering” prompt gamma rays are minefields are often saturated (bouncing) off a nucleus and emitted from inelastic with vapors from detonated slow neutron absorption into a scattering reactions on carbon explosives, which limit the use nucleus can both increase the and oxygen. During the of sniffer techniques for mine energy of the nucleus roughly 100 microsecond detection. (“excitation”), which leads to interval between the bursts, the emission of a gamma ray. gamma rays resulting from EMERGING The neutron’s interaction thermal neutron reactions are TECHNOLOGIES FOR probability with a nucleus recorded. HUMANITARIAN (capture cross section) is very Using sophisticated spectral DEMINING high at certain incident analysis software, elemental A number of mine detection neutron energies, which are ratios such as carbon/nitrogen, techniques are emerging as unique for each element. carbon/oxygen and complements to presently used Most of the neutron-based carbon/hydrogen can be methods. They include techniques for detection of established. This enables real- ground penetrating radar, explosives in bulk form rely on time identification of the infrared thermography and the detection of these explosive material by advanced metal detectors. A characteristic gamma rays comparison with reference data common feature of these emitted by excited nuclei. By stored in the computer. The techniques is that they detect measuring the energies and the additional detection of “anomalies” in the ground but intensities of the gamma rays, backscattered neutrons gives an are unable to indicate the the elemental composition of indication on the density of presence of an explosive agent. the interrogated object can be hydrogen in the soil, which can Methods based on established, and characteristic be used for further enhancing penetrating radiation offer gamma ray spectra for most the mine detection probability. 17 features that can be utilized for elements are well known. By using an electrostatic landmine detection and Several different techniques neutron generator, this identification. However, in have been developed along technique minimizes the risk contrast to conventional these lines. of accidental release of radiographic methods, one ■ Thermal Neutron Analysis radioactive material to the cannot utilize radiation (TNA) utilizes the fact that all environment. Small portable transmission, as this requires explosive materials contain a electrostatic neutron generators access to two opposing sides of large fraction of nitrogen. The are commercially available the investigated object. capture of a thermal neutron from several companies. Instead, emission of secondary by a nitrogen nucleus results in By using a neutron-based radiation or scattering of the the emission of a gamma ray method for elemental interrogating radiation have to with the energy 10.8 MeV. As characterization of a buried be used. this is the highest energy object, the demining procedure gamma ray emitted by a could be done considerably ELEMENTAL ANALYSIS naturally occurring isotope, it faster and more efficiently. BY NEUTRONS gives a very clear indication on This is because most of the Analysis by neutron irradiation the presence of nitrogen. An alarms, from, for example, is one of the few methods isotopic neutron source, such metal detectors, are emanating available for elemental as californium-252, is often from harmless scrap metal characterization of hidden used for TNA applications. pieces, abundant on former objects. Due to their zero ■ The Pulsed Fast and battlefields. charge, even low-energy Thermal Neutron Analysis neutrons can penetrate thick (PFTNA) technique uses a IAEA ACTIVITIES layers of material and interact small sealed tube electrostatic Many national, international directly with atomic nuclei. D-T neutron generator. In this and non-governmental Neutron interactions with method, the neutrons are organizations are devoting tens IAEA BULLETIN, 43/2/2001 of millions of dollars for removing landmines and helping mine victims. On the recommendations of an international advisory group the IAEA Department of Nuclear Sciences and Applications has initiated a Coordinated Research Project (CRP) on the “Application of Nuclear Techniques to Anti- personnel Landmines Identification”. Twelve research groups, from both developed and developing Member States, are participating in the CRP. The CRP has shown that methods based on neutron interrogation can identify the explosive content of a buried mine. Several devices based on TNA, PFTNA techniques and neutron backscattering are being developed. A flexible approach is used by assessing these and other nuclear 18 methods applicable for humanitarian demining regularly as they mature. Although several methods have potential, it is clear that a suite of sensors will be needed for any real life demining operation. The development of better demining instruments is a demanding task, as the instruments have to be sensitive, fast, reliable, cost effective, and easy to operate and maintain in all parts of the world. For example, they have to operate reliably in all types of terrains, including hot sandy Photos: In Bosnia & Herzegovina, another country suffering from deserts and wet rice fields. A landmines, a PMN mine has been exposed on a steep rocky hillside. single technology will not be (Credit: Prof. James Trevelyan, University of Western Australia, Australia). able to meet all the In Afghanistan, a country affected heavily by war and mines, a deminer requirements. Methods based probes the terrain with a metal prodder every three centimeters. (Credit: on neutrons may be Prof. James Trevelyan, University of Western Australia). complementary to The compact PELAN system, developed in the United States, is being conventional techniques, as considered for deployment in an IAEA-supported field testing programme. one of many tools in a IAEA BULLETIN, 43/2/2001 (Credit: Prof. George Vourvopoulos, Western Kentucky University, USA). deminer’s toolbox. ❐ FIELD TESTING FOR HUMANITARIAN DEMINING THROUGH IAEA TECHNICAL COOPERATION PROJECTS

The IAEA serves as one of the key international USA in 2001. After the experts from Member mechanisms for scientific and technical co- States have become thoroughly familiar with operation in the promotion of the peaceful use operation of each PELAN component, they of nuclear energy and plays an important role in would be able to suggest changes in hardware and the transfer of nuclear techniques to the software to adapt this instrument for landmine developing areas of the world for addressing major identification. problems. The main part of the IAEA’s technology At a later stage, PELAN will be transferred to a transfer to Member States is undertaken through Member State in Europe with a suitable research its Technical Cooperation Programme. Very laboratory, and laboratory tests will be performed often, these projects utilize nuclear techniques using various types of soils, dummy mines and developed as a result of successful coordinated explosives. Subsequently, field trials will quantify research work involving the IAEA. the instrument’s speed, sensitivity, accuracy, and For humanitarian demining techniques, reliability, in simulated and real mine fields. however, a new approach is being followed If the results of the adaptation are positive, it is because of the prospect that it will take a very expected that PELAN would be widely used for long time before the results of the research will be humanitarian demining as part of a multi-sensor applied in practice -- bearing in mind the system. For this purpose, the IAEA regional complexity of the task of landmine identification project is complemented by a national technical and the scale of the landmine problem. A new cooperation project in Croatia, “Facility for regional Technical Cooperation project in Europe Testing Nuclear Methods for Landmines and -- “Field Testing and Use of Pulsed Neutron Unexploded Ordnance Detection and Generator for Humanitarian Demining” -- is one Identification”. step towards practical application and the transfer Croatia is a special case right in the middle of 19 of know-how where needed. It focuses on one Europe. It is estimated that 6900 square technique only and one geographical region with kilometers, or 13% of Croatian territory, is a view of being more manageable and realistic. contaminated with landmines and UXO. The The technique selected for the project is Pulsed Government, through the Croatian Centre for Fast and Thermal Neutron Analysis (PFTNA). Demining (CROMAC), operates a large-scale The first project planning and coordination national demining programme, but the process meeting was held in Vienna 12-14 February 2001 is very slow and costly. The Rudjer Boskovic and was attended by experts from more than 20 Institute in Zagreb has a long tradition of Member States. The meeting considered various achievements in nuclear science and technology, alternatives and came to a conclusion that a and is going to establish a laboratory for testing a PFTNA type instrument called PELAN should be number of nuclear methods which could help in procured under the project and deployed in an the detection and identification of landmines and extensive field testing programme. PELAN has UXO, thus speeding up the process and reducing been developed and successfully used in the USA costs. The IAEA will support both the Institute for detection of unexploded ordnance (UXO), and CROMAC in their work related to testing chemical warfare agents and improvised explosive of nuclear techniques for demining. devices. But it needs adaptation for use in If successful, the national and regional IAEA landmine identification and the local conditions, projects will help to significantly improve the and this is where a technical cooperation project efficiency and speed of humanitarian demining. can be valuable. They can thereby contribute to bringing the The purchase of the PELAN system has been mined land back to normal life earlier and initiated. The project started with familiarization reducing the number of people that might be and training on the PELAN system at the Applied killed or maimed by abandoned landmines that Physics Institute in Bowling Green, Kentucky, have yet to be found.

IAEA BULLETIN, 43/2/2001