Atom and Nuclear Physics
A Nuclear Science Research Facility has been established at UTPA comprising 100 microgram Californium-252 neutron source and High Purity Germanium Detector (HPGE) with gamma ray spectrometer and gamma vision software. This equipment enhances students knowledge in Nuclear Science and Engineering through the processes of Neutron Activation Analysis (NAA) and neutron flux characterization. The facility is located at the Academic Support Facilities Complex in ASFC 1.312 A.
Dr. Hannan, with the assistance of student researcher (Gary Hanson) determined concentration levels of radio nuclides in soil samples from a chemical plant in the Rio Grande Valley, TX using neutron activation technique. This chemical plant has been closed for years but people living nearby have been complaining of many infectious diseases. The results were presented at the annual nuclear conference in 2006.
Dr. Hannan has also used the UTPA Californium facility to determine mercury levels in fish samples consumed mostly by the Rio Grande Valley people to verify whether this heavy metal has carcinogenic level. The mercury was determined in detection limits which did not give information about its carcinogenic effect. NAA is not a suitable method to determine mercury in sample and the UTPA Californium source strength is low to identify this metal. The result was presented at the HESTEC annual meeting.
Dr. Hannan in collaboration with the Hidalgo county WIC Center (Norma Longoria) in Edinburg , Dr. Bob Faraji and R.C.Rodriguez (student) from the Dietetics department measured concentration levels in zinc, iron, selenium, and iodine in samples of mothers milk using Neutron Activation method and Atomic Absorption technique. The objective was to identify whether these heavy elements are within the Recommended Dietary Allowance (RDA) intake values as specified by the American Academy of Pediatrics. The results were published in the peer reviewed journal in 2009.
Dr. Hannan is currently measuring thermal neutron flux of this facility by loading the Californium source into the UT Austin shielding cascade (4 ft diameter X 5 ft height) donated by the UT Austin Nuclear Engineering Teaching laboratory (NETL). Water extended Polyester (WEP) is used as a moderator (Moderator thermalizes fast neutrons into thermal neutrons). The thermal flux at a distance of ~ 20 cm was determined as 2.2 x 104 n/cm2 s-1. The measured reaction rate determined by different neutron activation foils will be used to unfold the UTPA Californium neutron flux spectrum using the MAXED unfolding program.
The UTPA Californium facility, the gamma counting system, and spectrum analysis are shown in figures below:
Figure 1:100 microgram Californium 252 neutron source facility at the University of Texas Pan American Figure 2: HPGe Gamma Detector at the Nuclear Research Laboratory for neutron activation analysis and neutron flux characterization to enhance students knowledge in Nuclear Science and Engineering.
Figure 3: Gamma spectrum of calibrated sources.