Accelorator Laboratory
Dr. Ron R. Hart and Dr. Pavel V. Tsvetkov
The Accelerator Laboratory of the Department of Nuclear Engineering at Texas A&M University is primarily used for research in ion beam modification and analysis of materials, particularly as related to radiation effects. The laboratory is a modern research facility equipped with two primary accelerators having maximum voltages of 150 KV and 200 KV, respectively, and a secondary low-energy accelerator. All three accelerators provide mass-analyzed ion beams of most of the elements of the periodic table. Measurements are especially based on Rutherford backscattering and channeling analysis of the near-surface region (100 nm) of solids. Pulsed-beam time-of-flight detection of backscattered ions is used for high depth resolutions of less than 1.5 nm. Using doubly-ionized He ions (alpha particles) analysis can be performed with energies up to 400 keV. Emphasis is on radiation damage, the depth distribution of heavy impurities, and thin-film interactions. However, a variety of research topics have been investigated. These include the measurements of ion stopping powers, transmitted energy and angular distributions of ions that are channeled through thin films, lattice damage and self-annealing phenomena, low-energy implantations and film deposition, and ion-beam lithography. Recent work has also included the study of Ga interactions with stainless steel for the safe storage of weapons grade Pu and investigations of alpha particle interactions with cladding metals of Pu pits. The pulsed-beam time-of-flight approach also offers excellent sensitivity and depth resolution measurements of forward-scattered light atoms such as H. This unique capability may be applied to problems such as hydrogen embrittlement of cladding materials.
Past work has involved the use of the 1 MW Triga Research Reactor that is associated with the Department of Nuclear Engineering. Neutron transmutation doping of semiconductors and annealing of the associated neutron damage were performed. The results were very successful and led to improved infrared detectors that were fabricated by Hughes Research Laboratories.
Present investigations as part of a DOE-funded Nuclear Engineering Research Initiative with Sandia National Laboratories are directed toward direct conversion of fission fragment kinetic energies to electrical power using the “Collimator” approach. Fission fragments may be transported out of a reactor core along magnetic field lines, collimated into a beam by expansion of the magnetic field, and then converted into electrical power by impact of the fission fragments on collector plates. Such an approach is not limited by normal thermal conversion efficiencies. Our computer modeling work indicates that high overall efficiencies greater than 60% are possible. In addition to the use of the accelerators in the Accelerator Laboratory, this work involves the modern K500 Superconducting Cyclotron at Texas A&M University. With an advanced ECR ion source, a diverse range of particle beams and energies are available for radiation effects testing and for the production or simulation of fission fragments. A recently installed beam line incorporates a 7 Tesla superconducting solenoid which will be used in the present work on direct conversion.
In summary the Ion Beam Laboratory, in association with the 1 MW Triga Research Reactor and the K500 Superconducting Cyclotron, offers wide-ranging capabilities for the production and investigation of radiation effects in materials.