Ivan Novikov

Results of field trials for the PELAN system

PELAN (Pulsed ELemental Analsys with Neutrons) is a man-portable system for the detection of explosives and chemical warfare agents, weighing 40 kg. It is based on the principle that explosives and other contraband contain various chemical elements such as H, C, N, O, etc. in quantities and ratios that differentiate them from ot her innocuous substances. The pulsed neutrons are produced with a pulsed 14 MeV (d-T) neutron generator. Separate gamma-ray spectra from fast neutron, thermal neutron and activation reactions are accumulated and analyzed to determine elemental content. Data analysis is performed in an automatic manner and a final result of whether a threat is present is returned to the operator. Since 1999, PELAN has undergone several field trials and demonstrations, including in 2001, demonstrations in Belgium andin the US of its ability to identify chemical warfare agents. We will review the results of these tests and also discuss the modifications made to the system.

Material Analysis Using Characteristic Gamma Rays Induced by Neutrons

Neutron interrogation based methods of non-destructive analysis are well established techniques employed in the field of bulk material analysis. These methods utilize a source of neutrons (a neutron probe) to irradiate objects under scrutiny. Nuclear reactions initiated by neutrons in the volume of the irradiated sample include the following: inelastic neutron scattering, thermal neutron capture, and neutron activation. As a result of nuclear reactions with the material inside the object, the “fingerprint” -rays are emitted with characteristic energies. These characteristic gamma rays are used for the elemental identification. By measuring and counting the number of -rays emitted with a specific energy, one can deduce the amount of the associated chemical element in the sample. The amounts of chemical elements measured allow specifying the chemical composition of the analyzed sample.

PELAN 2001: Current Status of the PELAN Explosives Detection System

PELAN (Pulsed ELemental Analysis with Neutrons) is a portable system for the detection of explosives, weighing less than 45 kg. It is based on the principle that explosives and other contraband contain various chemical elements such as H, C, N, O, etc. in quantities and ratios that differentiate them from other innocuous substances. Neutrons are produced with a pulsed 14 MeV (d-T) neutron generator. Separate gamma-ray spectra from fast neutron, thermal neutron and activation reactions are accumulated and analyzed to determine elemental content. Data analysis is performed in an automatic manner and a final result of whether a threat is present is returned to the operator. Recently, a number of modifications were performed to improve PELAN. Since the bismuth germanate detectors light output changes with temperature, an automatic gain stabilization system has been designed. Also, the signal-to-noise ratio has been increased by the innovative use of a veto shield placed around the bismuth germanate detector. This shield reduces Compton-continuum as well as the background gamma rays. Results from tests of the gain stabilization and the veto shield will be shown.

Neutron Interrogation System For Underwater Threat Detection And Identification

Wartime and terrorist activities, training and munitions testing, dumping and accidents have generated significant munitions contamination in the coastal and inland waters in the United States and abroad. Although current methods provide information about the existence of the anomaly (for instance, metal objects) in the sea bottom, they fail to identify the nature of the found objects. Field experience indicates that often in excess of 90% of objects excavated during the course of munitions clean up are found to be non‐hazardous items (false alarm). The technology to detect and identify waterborne or underwater threats is also vital for protection of critical infrastructures (ports, dams, locks, refineries, and LNG/LPG). We are proposing a compact neutron interrogation system, which will be used to confirm possible threats by determining the chemical composition of the suspicious underwater object. The system consists of an electronic d‐T 14‐MeV neutron generator, a gamma detector to detect the gamma signal from the irradiated object and a data acquisition system. The detected signal then is analyzed to quantify the chemical elements of interest and to identify explosives or chemical warfare agents.

Evaluation of the Doppler‐Broadening of Gamma‐Ray Spectra from Neutron Inelastic Scattering on Light Nuclei

Neutron‐induced gamma‐ray reactions are extensively used in the nondestructive analysis of materials and other areas where the information about the chemical composition of a substance is crucial. The common technique to find the intensity of the gamma ray is to fit gamma‐ray line shape with an analytical function, for example, a Gaussian. However, the Gaussian fitting may fail if the gamma‐ray peak is Doppler‐broadened since this leads to the miscalculation of the area of the peak and, therefore, to misidentification of the material. Due to momentum considerations, Doppler‐broadening occurs primarily with gamma rays from neutron‐induced inelastic scattering reactions with light nuclei. The recoiling nucleus of interest must have excited states whose lifetimes are much smaller than the time of flight in the material. We have examined various light nuclei bombarded by 14 MeV neutrons to predict when the peak shape of a neutron‐induced gamma ray emitted from these nuclei will be Doppler‐broadened. We have f...

Remote sensing of neutron and gamma radiation using aerial unmanned autonomous system

The system based on unmanned aerial vehicles was designed for remote sensing of neutron and gamma radiation. A swarm of small-scale quadcopters with navigational and sensing capabilities was studied to perform radiation monitoring with dynamically tracked measurements that could be used for analysis and prognostics in temporal and space domains. A Cs2LiYCl6:Ce3+ scintillation detector equipped with a digital data analysis system was developed for simultaneous gamma-ray spectroscopy and neutron sensing. Pulse shape discrimination was used to segregate neutron and photon signatures. The maximum likelihood estimation technique was employed to search for unattended radiation sources using the data obtained cooperatively by multiple UAVs.

A Radiation Laboratory Curriculum Development at Western Kentucky University

We present the latest developments for the radiation laboratory curriculum at the Department of Physics and Astronomy of Western Kentucky University. During the last decade, the Applied Physics Institute (API) at WKU accumulated various equipment for radiation experimentation. This includes various neutron sources (computer controlled d‐t and d‐d neutron generators, and isotopic 252 Cf and PuBe sources), the set of gamma sources with various intensities, gamma detectors with various energy resolutions (NaI, BGO, GSO, LaBr and HPGe) and the 2.5‐MeV Van de Graaff particle accelerator. XRF and XRD apparatuses are also available for students and members at the API. This equipment is currently used in numerous scientific and teaching activities. Members of the API also developed a set of laboratory activities for undergraduate students taking classes from the physics curriculum (Nuclear Physics, Atomic Physics, and Radiation Biophysics). Our goal is to develop a set of radiation laboratories, which will streng...

Characterization of a Pulse Neutron Source Yield under Field Conditions

Technique of rapid evaluation of a pulse neutron sources such as neutron generators under field conditions has been developed. The phoswich sensor and pulse‐shape discrimination techniques have been used for the simultaneous measurements of fast neutrons, thermal neutrons, and photons. The sensor has been calibrated using activation neutron detectors and a pulse deuterium‐tritium fusion neutron source.

Monte Carlo analysis of pulse neutron based cargo interrogation system

The nondestructive method to detect explosive and chemical threats hidden in a cargo is based on determination of its bulk isotopic content under the fast neutron irradiation using the neutron-induced fingerprint photons. The computational analysis of nuclear processes in the active interrogation system consisting of a 14-MeV pulse neutron generator, neutron and photon detectors, and a cargo truck was carried out. The systems geometry, material composition of the cargo, and the mass of TNT and HD objects hidden in the cargo were varied to study the time structure of the interrogating neutron flux and energy distributions of neutron and gamma-ray flux in the detectors. The results of the Monte Carlo analysis are discussed.

A Pressurized Tank Car Inspection System for Railroad Transportation Security

Pressurized rail tank cars transport large volumes of volatile liquids and gases throughout the country, much of which is hazardous and/or flammable. Our group is developing a trackside inspection system for these tank cars. It consists of five narrow frequency band pressure sensors with center frequencies of 40 and 75 kHz, a broad band microphone for sound normalization and three video cameras. In addition, a 5 cm times 5 cm NaI(Tl) radiation detector provides radiological data on the passing trains every 60 seconds. During operation, an audio frequency spectrum is associated with each frame of the video camera as the train passes by the system at normal speeds, and the spectra are inspected for high frequency sounds associated with leaks. A 10 m tall tower houses the system positioned approximately 10 m from the center of a rail line and siding located in Bowling Green, KY (USA). The system is controlled by a website and server located at the tower and the Internet connection utilizes WiFi (802.11 g) radios.