Status of the prototype Pulsed Photonuclear Assessment (PPA) inspection system
The Idaho National Laboratory, in collaboration with Idaho State University's Idaho Accelerator Center and the Los Alamos National Laboratory, continues to develop the Pulsed Photonuclear Assessment (PPA) technique for shielded nuclear material detection in large volume configurations, such as cargo containers. In recent years, the Department of Homeland Security has supported the development of a prototype PPA cargo inspection system. This PPA system integrates novel neutron and gamma-ray detectors for nuclear material detection along with a complementary and unique gray scale, density mapping component for significant shield material detection. This paper will present the developmental status of the prototype system, its detection performance using several INL Calibration Pallets, and planned enhancements to further increase its nuclear material detection capability.
Active Neutron Interrogation to Detect Shielded Fissionable Material
Portable electronic neutron generators (ENGs) may be used to interrogate suspicious items to detect, characterize, and quantify the presence fissionable material based upon the measurement of prompt and/or delayed emissions of neutrons and/or photons resulting from fission. The small size (<0.2 m3), light weight (<12 kg), and low power consumption (<50 W) of modern ENGs makes them ideally suited for use in field situations, incorporated into systems carried by 2-3 individuals under rugged conditions. At Idaho National Laboratory we are investigating techniques and portable equipment for performing active neutron interrogation of moderate sized objects less than ~2-4 m3 to detect shielded fissionable material. Our research in this area relies upon the use of pulsed deuterium-tritium ENGs and the measurement of die-away prompt fission neutrons and other neutron signatures in-between neutron pulses from the ENG and after the ENG is turned off.
Conception of a Language Learning Environment Based on the Communicative and Actional Approaches
This paper's aim is to give a conceptual framework about the conception of a Computer Assisted Language Learning environment based on the communicative and actional approaches. In this environment, the learner is implicated in a task that he/she has to complete by interacting with a partner using his/her language competencies. Given a task, different ways exist to accomplish it and the different competencies of the learner can then be solicited with different types of interaction. Works accomplished in human computer dialogue give models to manage this interaction.