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Ion Beam Materials Analysis and Modifications At keV to MeV Energies at the University of North Texas

Description: This paper provides an overview of the Ion Beam Modification and Analysis Laboratory facilities and some of the current research projects.
Date: February 25, 2014
Creator: Rout, Bibhudutta; Dhoubhadel, Mangal; Poudel, Prakash R.; Kummari, Venkata C.; Lakshantha, Wickramaarachchige J.; Manuel, J. E. et al.
Partner: UNT College of Arts and Sciences

Charge State Dependence of M-Shell X-Ray Production in 67Ho by 2-12 MeV Carbon Ions

Description: The charge state dependence of M-shell x-ray production cross sections of 67HO bombarded by 2-12 MeV carbon ions with and without K-vacancies are reported. The experiment was performed using an NEC 9SDH-2 tandem accelerator at the Ion Beam Modification and Analysis Laboratory of the University of North Texas. The high charge state carbon ions were produced by a post-accelerator stripping gas cell. Ultra-clean holmium targets were used in ion-atom collision to generate M-shell x rays at energies from 1.05 to 1.58 keV. The x-ray measurements were made with a windowless Si(Li) x-ray detector that was calibrated using radiative sources, particle induced x-ray emission (PIXE), and the atomic field bremsstrahlung (AFB) techniques.
Date: August 1994
Creator: Sun, Hsueh-Li
Partner: UNT Libraries

Analysis of Biological Materials Using a Nuclear Microprobe

Description: The use of nuclear microprobe techniques including: Particle induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) for elemental analysis and quantitative elemental imaging of biological samples is especially useful in biological and biomedical research because of its high sensitivity for physiologically important trace elements or toxic heavy metals. The nuclear microprobe of the Ion Beam Modification and Analysis Laboratory (IBMAL) has been used to study the enhancement in metal uptake of two different plants. The roots of corn (Zea mays) have been analyzed to study the enhancement of iron uptake by adding Fe (II) or Fe (III) of different concentrations to the germinating medium of the seeds. The Fe uptake enhancement effect produced by lacing the germinating medium with carbon nanotubes has also been investigated. The aim of this investigation is to ensure not only high crop yield but also Fe-rich food products especially from calcareous soil which covers 30% of world’s agricultural land. The result will help reduce iron deficiency anemia, which has been identified as the leading nutritional disorder especially in developing countries by the World Health Organization. For the second plant, Mexican marigold (Tagetes erecta), the effect of an arbuscular mycorrhizal fungi (Glomus intraradices) for the improvement of lead-phytoremediation of lead contaminated soil has been investigated. Phytoremediation provides an environmentally safe technique of removing toxic heavy metals (like lead), which can find their way into human food, from lands contaminated by human activities like mining or by natural disasters like earthquakes. The roots of Mexican marigold have been analyzed to study the role of arbuscular mycorrhizal fungi in enhancement of lead uptake from the contaminated rhizosphere.
Date: December 2014
Creator: Mulware, Stephen Juma
Partner: UNT Libraries

Fabrication of silicon-based optical components for an ultraclean accelerator mass spectronomy negative ion source

Description: Article discussing the fabrication of silicon-based optical components for an ultraclean accelerator mass spectonomy negative ion source.
Date: May 1994
Creator: Kirchhoff, J. F.; Marble, D. K.; Weathers, Duncan L.; McDaniel, Floyd Del. (Floyd Delbert), 1942-; Matteson, Samuel E.; Anthony, J. M. et al.
Partner: UNT College of Arts and Sciences

High Sensitivity Measurement of Implanted as in the Presence of Ge in Ge(x)Si(1-x)/Si Layered Alloys Using Trace Element Accelerator Mass Spectrometry

Description: This article discusses high sensitivity measurement of implanted As in the presence of Ge in Ge(x)Si(1-x)/Si layered alloys using trace element accelerator mass spectrometry.
Date: December 11, 2000
Creator: Datar, Sameer A.; Wu, Liying; Guo, Baonian N.; Nigam, Mohit; Necsoiu, Daniela; Zhai, Y. J. et al.
Partner: UNT College of Arts and Sciences

Low-level copper concentration measurements in silicon wafers using trace-element accelerator mass spectrometry

Description: This article discusses low-level copper concentration measurements in silicon wafers using trace-element accelerator mass spectrometry.
Date: June 8, 1998
Creator: McDaniel, Floyd Del. (Floyd Delbert), 1942-; Datar, Sameer A.; Guo, Baonian N.; Renfrow, Steve N.; Anthony, J. M. & Zhao, Z. Y.
Partner: UNT College of Arts and Sciences

The Study of Phosphors Efficiency and Homogeneity using a Nuclear Microprobe

Description: Ion Beam Induced Luminescence (IBIL) and Ion Beam Induced Charge Collection (IBICC) have been applied in the study of the luminescence emission efficiency and investigation of the homogeneity of the luminescence emission in phosphors. The IBIL imaging was performed by using sharply focused ion beams or broad/partially-focused ion beams. The luminescence emission homogeneity in samples was examined to reveal possible distributed crystal-defects that may lead to the inhomogeneity of the luminescence emission in samples.The purpose of the study is to search for suitable luminescent thin films that have high homogeneity of luminescence emission, large IBIL efficiency under heavy ion excitation, and can be placed as a thin layer on the top of microelectronic devices to be analyzed with Ion Photon Emission Microscopy (IPEM). The emission yield was found to be low for organic materials, due to saturation of the light output dependence on the energy deposition of heavy ions. The emission yield of a typical Bicron plastic scintillator is about 70 photons/ion/micron. Inorganic materials may have higher IBIL yield under high-energy and heavy-ion excitation, but the challenging problem is the inhomogeneity of the IBIL emission. The IBIL image techniques are applied in the investigation of the homogeneity of a GaN epitaxial thin film, a zircon single crystal and a thin layer coated by Thiogallate(EuII) ceramic.
Date: December 8, 2000
Partner: UNT Libraries Government Documents Department

Investigation of Structural and Optical Properties of Ag Nanoclusters Formed in Si(100) After Multiple Implantations of Low Energies Ag Ions and Post-Thermal Annealing at a Temperature Below the Ag-Si Eutectic Point

Description: This paper investigates the synthesis of Ag NCs in Si(100) substrate by implanting multiple energies and fluences of Ag ions and subsequent thermal annealing.
Date: April 2, 2014
Creator: Dhoubhadel, Mangal; Rout, Bibhudutta; Lakshantha, Wickramaarachchige J.; Das, Sushanta K.; D'Souza, Francis; Glass, Gary A. et al.
Partner: UNT College of Arts and Sciences

Simultaneous measurement of the average ion-induced electron emission yield and the mean charge for isotachic ions in carbon foils

Description: Article discussing the simultaneous measurement of the average ion-induced electron emission yield and the mean charge for isotachic ions in carbon foils.
Date: February 1997
Creator: Arrale, A. M.; Zhao, Z. Y.; Kirchhoff, J. F.; Weathers, Duncan L.; McDaniel, Floyd Del. (Floyd Delbert), 1942- & Matteson, Samuel E.
Partner: UNT College of Arts and Sciences

Ion Beam Analysis of Microcrystalline Quartz Artifacts from the Reed Mound Site, Delaware County, Oklahoma

Description: This paper from the 23rd Conference on Application of Accelerators in Research and Industry conference proceedings evaluates the potential of particle induced X-ray emission spectrometry as a tool for future Ozarks chert provenance studies based on its ability to facilitate discrimination of Ozarks chert materials from different geological formations and identification of discrete groups of artifacts from the same geological formation.
Date: June 18, 2015
Creator: Younger-Mertz, S. B.; Manuel, J. E.; Reinert, Tilo; Szilasi, S. Z.; Hammerstedt, S. W. & Glass, G. A.
Partner: UNT College of Arts and Sciences

Collision-induced interaction cross sections of 1-7 MeV B₂ ions incident on an N₂ gas target

Description: This article describes the measurement of collision-induced interaction cross sections for 1-7 MeV diatomic boron molecular ions incident on a nitrogen gas target by using a differentially pumped gas cell.
Date: May 5, 1995
Creator: Kim, Y. D.; Jin, J. Y.; Matteson, Samuel E.; Weathers, Duncan L.; Anthony, J. M.; Marshall, Paul et al.
Partner: UNT College of Arts and Sciences

The Stopping of Energetic Si, P and S Ions in Ni, Cu, Ge and GaAs Targets

Description: Accurate knowledge of stopping powers is essential for these for quantitative analysis and surface characterization of thin films using ion beam analysis (IBA). These values are also of interest in radiobiology and radiotherapy, and in ion- implantation technology where shrinking feature sizes puts high demands on the accuracy of range calculations. A theory that predicts stopping powers and ranges for all projectile-target combinations is needed. The most important database used to report the stopping powers is the SRIM/TRIM program developed by Ziegler and coworkers. However, other researchers report that at times, these values differ significantly from experimental values. In this study the stopping powers of Si, P and S ions have been measured in Ni, Cu, Ge and GaAs absorbers in the energy range ~ 2-10 MeV. For elemental films of Ni, Cu and Ge, the stopping of heavy ions was measured using a novel ERD (Elastic Recoil Detection) based technique. In which an elastically recoiled lighter atom is used to indirectly measure the energy of the incoming heavy ion using a surface barrier detector. In this way it was possible to reduce the damage and to improve the FWHM of the detector. The results were compared to SRIM-2000 predictions and other experimental measurements. A new technique derived from Molecular Beam Epitaxy (MBE) was developed to prepare stoichiometric GaAs films on thin carbon films for use in transmission ion beam experiments. The GaAs films were characterized using X-ray Photoelectron Spectroscopy (XPS) and Particle Induced X-ray Emission (PIXE). These films were used to investigate the stopping powers of energetic heavy ions in GaAs and to provide data for the calculation of Bethe-Bloch parameters in the framework of the Modified Bethe-Bloch theory. As a result of this study, stopping power data are available for the first time for Si and P ions ...
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Date: December 2001
Creator: Nigam, Mohit
Partner: UNT Libraries

Leaf elemental analysis and growth characteristics of mycorrhizal treated post oak seedlings via particle induced X-ray emission spectroscopy.

Description: Growth and element assimilation was investigated in post oak seedlings exposed to four different treatment combinations of fertilization and ectomycorrhizal inoculation. Element concentration in excised leaves was analyzed via particle induced X-ray emission spectrometry with a 1.8 MeV proton macrobeam. Mean growth was significantly different across the treatment groups as well as mean concentration of Mg, Al, S, K, Ca, Fe, Cu, and Zn. The data suggest that fertilization rather than mycorrhizal inoculation had a stronger influence on plant growth and nutrient uptake. A follow up study was conducted with a 3 MeV microbeam. A 850 μm2 scanned area of a post oak leaf produced topographical maps of 11 elements.
Date: May 2006
Creator: Boling, Blake C.
Partner: UNT Libraries

Ion Beam Induced Charge Collection (IBICC) Studies of Integrated Circuits Using a 10MeV Carbon Microbeam

Description: As feature sizes of Integrated Circuits (ICs) continue to shrinlL the sensitivity of these devices, particularly SRAMS and DR4Ms, to natural radiation is increasing. The radiation can lead to the uncontrolled deposition of charge within an IC, which ean alter, for example, the memoty state of a bit and thereby produce what is edled a `SOW error, or Single Event Upset (SEU). The response of ICS to natural background radiation is therefore of great coneem regarding the reliability of Mure devices. In this paper, we present results where Ion Beam Induced Charge Collection (TBICC) technique was used to simulate neutron-induced Si recoil dlkcts in IC test structures. The present wo~ wnducted at the San& National Laboratories, uses a 10 MeV Carbon mierobeam with 1 pm spot to scan test structures on specifically designed ICS. The test structure contains junctions typical of S RAMS and DRAMs. Charge is eolleeted from different areas of the IC under various conditions of junction back bias. The data are digitized and displayed as 3D images combined with KY) coordination. With the aid of IC layout informatio~ the 3D images are sepamted into difTerent layers to allow the identification of charge collection etlciency in the test structures. An analysis of the charge collection efficiency from dillerent test areas is given.
Date: September 29, 1998
Creator: Aton, T.J.; Bouanani, M. E.; Doyle, B.L.; Duggan, J.L.; Guo, B.N.; McDaniel, F.D. et al.
Partner: UNT Libraries Government Documents Department

Microbeam Studies of Diffusion Time Resolved Ion Beam Induced Charge Collection from Stripe-Like Junctions

Description: To design more radiation tolerant Integrated Circuits (ICs), it is essential to create and test accurate models of ionizing radiation induced charge collection dynamics within microcircuits. A new technique, Diffusion Time Resolved Ion Beam Induced Charge Collection (DTRIBICC), is proposed to measure the average arrival time of the diffused charge at the junction. Specially designed stripe-like junctions were experimentally studied using a 12 MeV carbon microbeam with a spot size of 1 {micro}m. The relative arrival time of ion-generated charge is measured along with the charge collection using a multiple parameter data acquisition system. The results show the importance of the diffused charge collection by junctions, which is especially significant in accounting for Multiple Bit Upset (MBUs) in digital devices.
Date: June 14, 2000
Partner: UNT Libraries Government Documents Department