The Hope College Nuclear Group will continue its study of neutron-rich unstable nuclei near the drip-line with the Modular Neutron Array (MoNA) at the National Superconducting Cyclotron Laboratory (NSCL) and will continue to apply a variety of nuclear techniques (e.g. Particle Induced X-Ray Emission, Rutherford BackScattering, Nuclear Reaction Analysis, and Ion Beam Induced Luminescence) to a range of interdisciplinary questions with the Hope Ion Beam Analysis Laboratory. This proposal will support two faculty in these efforts, each of which will include undergraduate researchers in all aspects of the research.
The Nuclear Group will investigate unstable neutron-rich nuclei to refine the theoretical understanding of the nuclear shell model. This will involve measurements of excited states and ground states of unstable nuclei created at the NSCL and measured with the MoNA-LISA/Sweeper system. The Nuclear Group, as part of the overall program, will supervise the construction of Large-area multi-Institutional Scintillator Array (LISA) by 12 undergraduate institutions in the MoNA Collaboration (MRI:PHY-0922794). The interdisciplinary portion of the proposed research will examine metalloprotein stoichiometry (deposited on mylar foils), forensic characterization of layered automotive paints and automotive glass fragments, and luminescence studies of feldspars and carbonates. On-going analysis of previous experiments and development projects will continue. Interdisciplinary collaborative efforts will also continue with other Hope researchers (electropolymer characterization, superconductor and electrodeposited thin film stoichiometry) and groups outside Hope College (metal contamination in sediments, provenance of river sediment, detector characterization, and aerosol measurements). All of these initiatives are not only important for the specific science result they yield, but for possible far-reaching impact on the analytical techniques used in many areas.
The Nuclear Group at Hope College carried out significant research that yielded new science with a range of impacts spanning fundamental nuclear physics to strategic national needs, to consumer product testing. In addition to this intellectual merit, the broader impact of the work includes training of the next generation of the STEM workforce, both Hope students and students at the institutions with whom we collaborate, and applying the skills honed by doing cutting-edge research at the National Superconducting Cyclotron Laboratory to a variety of more interdisciplinary question studies with our own accelerator. The Nuclear Group is active in many studies at Hope and is involved in several collaborative efforts with other institutions. Five primary projects are highlighted here. The forces that hold the nucleus together are not yet fully understood, even after decades of study. In order to improve models of the nuclear force, theorists need measurements of nuclei that are very far from stability. The Modular Neutron Array (MoNA) Collaboration, in which Hope plays a leading role and is one of the few undergraduate institutions that is equipped to analyze the data from these experiments, does such work and in recent years the Nuclear Group has provided results to the greater community on the structure of 26O, 13Be, and 24O, in addition to the nuclei studied by others in the collaboration. In collaboration with a DOE-funded project to explore the "harvesting" of radioisotopes from the next generation of accelerators (FRIB), the Hope Nuclear Group collaborates with the medical school at Washington University – St. Louis to harvest long-lived radioisotopes from a water target at the National Superconducting Cyclotron lab. We have designed, constructed and tested a remotely-operated water target system that has successfully collected 24Na and 67Cu beams from the NSCL. These proof-of-principle experiments determine production and extraction limits for the useful long-lived radioisotopes that are predicted to exist in the water cooling lines of the primary target facility at FRIB. The structure and composition of proteins determines their impact and role in living organisms. Many proteins contain a few, or even single, metal atom. Hemoglobin, with iron, is the most well-known example of this. It can be difficult to quantify the type and amount of the metals within most metalloproteins but with a combination of particle induced x-ray emission and nuclear reaction analysis, we have developed a novel way of doing this. This project, interdisciplinary in nature, makes use of fundamental nuclear physics technology in the ion beam analysis of materials of biochemical interest. The forensic analysis of automotive paint fragments left at hit-and-run accidents is currently a difficult and time-consuming process. Ideally, comparing recovered material to the paint from a suspect vehicle should be done in a way that does not alter or destroy the samples in case additional testing is required. Most chemical techniques for measuring the metals in paint layers are destructive. We have developed a protocol, based on scanning electron microscope images of a paint chip combined with particle induced x-ray emission that can quantify and give indication of the sameness of two samples non-destructively. In this case our work will potentially impact on forensic science methodology. Ion beam analysis has also been used to test consumer products for toxic chemicals. We have used particle induced x-ray emission and particle induced gamma-ray emission to measure the halogen (F, Cl, Br) content of various consumer products, to infer the presence of halogenated flame-retardants, as well as perfluorinated compounds in consumer products. We have conducted student-centered research investigations of couch cushions, automotive seating, fabrics, papers, cosmetics and even plastic toys to quantify the extent of toxic chemicals present in these objects. These protocols are a complete novel way to screen large numbers of products in a short period of time, and will help drive the analytical costs down for in-market testing for these chemicals. This will have a positive impact on market forces driving these products off the consumer market and trains students both in nuclear science techniques and scientific public policy.
