REU Program at Michigan State Un

Abstract: A physicist's dream - place a single particle freely in space and study it. Such a dream has become reality at LEBIT at the NSCL (http://groups.nscl.msu.edu/lebit/ ). LEBIT - the Low Energy Beam and Ion Trap facility - allows us to slow down rare isotopes produced at the NSCL at half the speed of light such that we can capture and bring them to rest in devices called ion traps. Using such devices we determine the mass of trapped ions with very high precision. This allows us to determine nuclear binding energies, an important and basic information about rare isotopes, needed for example for the understanding of their structure or in nuclear astrophysics. The construction of LEBIT is completed and a number of interesting rare isotopes, with half-lives as short as 100 ms, has already been investigated.

We are looking for a highly motivated and experimentally skilled student who wants to gain hands-on experience at a high-tech precision instrument. Themes for individual projects range from the design, building and test of dedicated electronics components, development work for the computer-based control system, ion optics simulations and their comparison with measurements using the LEBIT facility, to systematic investigations of the properties of LEBIT components.

TITLE: Intercepting Highly-Enriched Uranium at Points of Entry to Our Country

Abstract: One proposed method of intercepting highly-enriched uranium at airports and seaports is to irradiate suitcases and containers with thermal neutrons. Thermal neutrons are readily absorbed by ²³⁵U, and it is that process that produces the chain reaction that leads to slow energy release in power reactors and to explosions in atomic bombs. The nuclei of uranium atoms and of transuranic elements emit fast neutrons, but there is no source of thermal neutrons. Repeated collisions of fast neutrons, such as those emitted by ²⁵²Cf with light nuclei can produce thermal neutrons. The lighter the nuclei, the fewer the number of collisions required. In this sense, hydrogen is the best. Thermal neutrons do emerge from the surface of a ball of polyethylene (CH₂) that has a ²⁵²Cf source at its center. Unfortunately, hydrogen absorbs many of the thermal neutrons before they reach the surface of the ball.

A slight modification might produce a much better result. A Monte–Carlo calculation will be required to investigate the possibility, and the REU student will have to write the program. The modification is to use a ball of CD₂, deuterated polyethylene. Because deuterons have twice the mass of neutrons, the number of collisions to achieve neutron thermalization will be larger than with ordinary polyethylene, and the diameter of the ball will be correspondingly greater. The advantage of using CD₂ instead of CH₂ is the reduced probability of neutron capture in deuterium—by a factor of ~ 650.

The National Superconducting Cyclotron Laboratory is one of the leading laboratories world-wide in the production of new forms (isotopes) of atomic nuclei. The new nuclei are used for studies that help us to understand the many-body atomic nucleus. The REU project will be to improve the techniques used to identify single ions. The amount of ionization created as an ion passes through a volume of gas can be used to determine the atomic number of the ion. Single nuclei can be identified in this way, and this is part of the technique used to identify new isotopes. The goal will be to determine whether or not the current equipment can be used to identify very heavy elements near uranium (atomic number 92). The project will be to model and analyze this process and to determine what contributes to a limitation in atomic number resolution. The results of the study will be published in Nuclear Instruments and Methods.

Abstract: We recently commissioned two major devices necessary to study the decay very neutron-rich nuclei. The combination of the superconducting 4 T sweeper magnet and the Modular Neutron Detector Array (MoNA) allows us to detect charged fragments and neutrons in coincidence. We are scheduled to run a major experiment to populate a broad range of neutron-rich nuclei in July. This run offers a unique opportunity for the REU students because they can get involved in all of the final preparations, including scintillation detectors, gas detectors, electronics, data acquisition and data analysis. Within these areas there several different opportunities for REU projects which the students can choose from depending on their interest.

Abstract: The giant dipole resonance (GDR) in hot nuclei has been studied extensively in many nuclei under a variety of conditions over the last 30 years. While a very nice summary of the GDR parameters for cold nuclei has been published, an equivalent compilation for hot nuclei has been missing until recently. We have completed such a compilation and it now can be used to proceed with a uniformed analysis of all existing data. The project first involves the parameterization of the GDR width for all nuclei. Subsequently the data have to analyzed to search for common trends and dependencies. In particular the temperature dependence of the GDR width is of high current interest to nuclear structure physics.

Abstract: Projectile fragmentation is one of the means to produce rare isotopes in the Coupled Cyclotron Facility (CCF) at the National Superconducting Cyclotron Laboratory at MSU. To understand the mechanisms of producing extremely neutron rich isotopes, we have carried out comprehensive cross-section measurements in the projectile fragmentation of Ca40, Ca48, Ni58, Ni64, Ni68, Cu69 and Zn72. We found that by adding 8 neutrons to the projectile of Ca40, fragmentation of Ca48 produces nearly twice as many (~200) isotopes as the fragmentation of Ca40 (~100 isotopes). This summer we would like to work with an REU student to work on the theoretical understanding of the fragmentation mechanisms by describing the data with different models. It is especially exciting that with the availability of the high performance computer center at MSU, it is now possible to do sophisticated simulations of nuclear collisions of heavy ions.

Abstract: The 1963 Nobel Prize in Physics was awarded to Maria Goeppert Mayer and Hans Jensen for their explanation of the structure of nuclei. The success of the Shell Model to explain the existence of the magic numbers of 2, 8, 20, 28, 50, 82 and 128 in neutron and protons has prompted the speculations that the closed shell can be treated as an inert core and the valence nucleons outside this core can be treated as independent particles. Such simple model allows the understanding of many observed nuclear properties. It also prompted many studies in the past four decades to describe the configuration of single particle orbits.

Recent advance in radioactive beams by using nuclei far away from stability has revived interest in measuring single particle structure in nuclei. There is evidence that the traditional view of the simple shell models will be modified for these exotic nuclei. Currently the only technique to study the single particle configuration of a wide range of nuclei from stable to very unstable isotopes is to use transfer reactions. Thus it is important to establish reference points in the stable nuclei region allowing reliable extrapolations to rare isotopes.

The objective of this project is to use a consistent analysis procedure that our group has developed to analyze the past transfer reaction data published in the literature [see for example, http://meetings.nscl.msu.edu/DREB2005/TALKS/lee.pdf. ] The extracted data will be invaluable for nuclear model development. Early next year, an experiments on transfer reactions is scheduled to run at the National Superconducting Cyclotron Laboratory.. The REU student is encouraged to participate in the preparation of this experiment.

Abstract: Theoretically, it is predicted that, under right conditions, nuclear matter undergoes the liquid-to-gas phase-transition and that an excess of neutrons accumulates in the low-density (gaseous) phase. This phenomenon can be used to study the symmetry energy which is the energy penalty paid when the number of neutrons and protons in a nucleus is not the same. Symmetry energy is a fundamental property not only in describing normal nucleus but also in understanding properties of the neutron stars. To study the problem, we have measured the ratios of the free neutron (n) yields to free proton (p) yields from the more proton-rich 112Sn+112Sn collisions and the more neutron-rich 124Sn+124Sn collisions. In this project, we would like to work with an REU student to study the yield ratios of n/p from models utilizing transport equations. It is important that the student is proficient in programming and familiar with the Linux operating systems. See for example: http://groups.nscl.msu.

Condensed Matter Physics

Abstract: Giant Magnetoresistance (GMR) in Magnetic Multilayers is of interest both for the underlying physics and for technology--the read heads in modern computer hard drives are now GMR multilayers. The MSU group pioneered measurements of Giant Magnetoresistance in Metallic Magnetic Multilayers with Current Flow Perpendicular to the Layer Planes, a geometry that usually gives more direct access to the physics underlying GMR. A specific project will be chosen after discussion with the REU student. The project will involve sample preparation (using a state-of-the-art sputtering system), sample characterization, and measurement of magnetoresistance. The project might also involve optical and electron-beam lithography in collaboration with a Ph.D. student or Postdoc.

Abstract: Ultrafast molecular imaging represents an emerging frontier. In particular, recent developments in the ultrafast electron diffraction (UED) have demonstrated the ability to image the rearrangements of chemical bonds in complex systems with resolutions of ~0.01A and ~1 ps, respectively. These new limits provide the means for the determination of transient structures of molecules, surfaces and nanostructures, including reactive intermediates and nonequilibrium structures of complex energy landscapes. Recent development of ultrafast electron crystallography (UEC) for studying condensed phase reactions and phase transitions in the nanometer scale reveal the transient phenomena at interfaces and in nanophases. Atomic scale processes of both coherent and incoherent energy conversions through carrier-phonon, phonon-phonon and configurational interactions in systems of finite size were imaged.

In the REU summer projects, we seek one or two students to participate our experiments. One project will be related to studying the real-time functional transformation of gold nano-particles in the nonscalable size (1 –10 nm) regimes. The other project will be related to the search for the medium range order in the potential energy landscape of amorphous system, such as silicon, supercooled liquid… . The former project aims to provide a real-time functional probe to examine the fundamental physical and chemical processes in the nanoscaled systems. The second project aims to solve one of the main mysteries in directionally coordinated liquid and amorphous states with many technological implications. Both projects will have ample hands-on opportunities to assist the experimental operations in the laboratory as well as performing novel atomic modeling for determining dynamical structural evolutions.

Astrophysics

TITLE: SOAR Telescope Remote Observing Software Development

SUPERVISOR: Prof. Jack Baldwin

MSU is a partner in the new 4m-diameter SOAR Telescope. The telescope is located in South America, but we will be using it remotely from East Lansing, starting again in August. In the meantime, we need somebody with a strong aptitude for computer software to help test and smooth out the software used in his remote observing. Most of the software runs under the Linux operating system. Previous knowledge of Linux would be a major asset. Knowledge of the Fortran and Perl computer languages would also be very helpful.

TITLE: Giant HII regions in the Hubble Space Telescope data archives.

SUPERVISOR: Prof. Jack Baldwin

Stars form within dense interstellar gas clouds and then ionize the outer skin of the remaining interstellar gas to form H II regions. These H II regions produce very luminous emission lines that can be studied out to huge distances, so they are an important means of following the history of star formation and chemical enrichment in galaxies over much of the history of the universe. When we look at distant galaxies, only the very largest of these H II regions are luminous enough to be detected, so in order to interpret their spectra we need to understand what happens when you scale H II regions up to very large masses of gas and large numbers of newly-formed stars. The distant H II regions are so far away that we see them only as points of light, so we cannot see any of the details of what is happening inside them. The solution is to study in detail the very few nearby examples of these Giant Extragalactic H II Regions, and then assume that the distant examples have the same things going on inside them. The summer research project would consist of retrieving from the Hubble Space Telescope data archives a wide range of data about one or two nearby Giant H II Regions, and assesing the quality and relevance of that data for this particular research project. This is an OBSERVATIONAL astronomy project.

TITLE: Pulsating Stars

ADVISOR: Prof. Horace Smith

Abstract: Pulsating stars are keys to the galactic and extragalactic distance scales, tests of stellar evolution, and probes of the formation of the galaxy. This project will use photometric observations to study the changes in brightness and color of mainly old variable stars. Some of these data will be newly acquired using the campus 60-cm telescope, so that the REU student would both analyze observations obtained elsewhere and obtain new observations.

The chief focus of the work will be pulsating stars of the RR Lyrae and type II Cepheid varieties. These are giant stars, but they are also old, low mass stars. Their properties provide information on conditions in the early days of the Milky Way Galaxy, at the time of the formation of the galactic halo.

High Energy Physics

TITLE: Parton Distribution Functions

SUPERVISOR: Prof. Daniel Stump

Abstract: Baryons and mesons are bound states of fundamental fields - the quarks and gluons. The internal structure of the nucleon has been studied for over 30 years using deep-inelastic lepton scattering and other short-distance scattering processes. The theoretical description of the quark and gluon content of the nucleon is called the parton model. The parton (i.e., quark and gluon) distribution functions are constructed by fitting the theoretical model to data from a large collections of experiments. The best model available today is the set of CTEQ6 parton distribution functions (PDFs), which was developed at Michigan State University. A new generation of PDFs will be developed in the next few months, based on new more accurate data that has recently become available.

An REU student could be involved in research on the CTEQ parton distribution functions. The project would have two parts. First, using Mathematica to make detailed graphical comparisons between theory and data; this work is necessary to determine the precision and uncertainties of the new model. Second, making a web site showing the results of the new model; this part of the project is important for disseminating the results to the community of high-energy physics. Prior knowledge of Mathematica or web page design is not necessary, but an interest in scientific graphics is necessary. Also, the REU student should be interested in science writing for web publication.

Theoretical Physics

TITLE: Fragmentation Models of Gene Lengths

SUPERVISORS: Prof. Wolfgang Bauer and Prof. Scott Pratt

Abstract: The human genome consists of approximately 30 thousand genes, and each gene might contain many thousands of codons. The lengths of the genes vary widely, from a few hundred codons to tens of thousands. By applying ideas and models used for understanding the fragmentation of nuclei, we will investigate whether the length distribution for genes can be explained from simple principles. The project will involve both algebraic and numerical work. Programming experience is not necessary, just an eagerness to learn it.

Title: Quantum Cryptography and Entanglement

Supervisor: Prof. Carlo Piermarrochi

Abstract: On April 21^st 2004 an Austrian scientist has used for the first time a quantum cryptography protocol in a $3500 bank transaction (see Nature Apr. 29 2004 p 883). The protocol is based on sharing a pair of entangled photons to create the encoding key. Upon arrival, both photons are measured by their respective owners. This act of measurement determines the state of the photons, and thus the state of the key. One important issue for the success of quantum cryptography is related to the availability of efficient devices to generate entangled pairs. Quantum dots are man-made semiconductor nanostructures that are very promising for these applications.

The project consists of two parts: (i) introduction to quantum cryptography protocols, in particular the ones based on sharing EPR pairs. (ii) Investigation of semiconductor quantum dots as a source of entangled photons and single photon emitters.

Biological Physics and Biophysics

TITLE: Dynamics of Sudden Movement in Plants and Animals

SUPERVISORS: Prof. Michael Harrison (MSU) and Dr. Edward Landa (US Geological Survey)

Abstract: Rapid movements in plants and animals has been the focus of much recent research attention in the journals Science and Nature [ “Physical Limits and Design Principles for Plant and Fungal Movements”, J.M. Skotheim and L. Mahadevan, Science Vol 308, 27 May 2005; “How the Venus flytrap snaps”, Y Forterre, et al, Nature Vol 433, 27 Janusry 2005 ; “Conical dislocations in crumpling”, E. Cerda, et al, Nature Vol 401, 2 September 1999 ; “A record-breaking pollen catapult”, J. Edwards, et al, Nature Vol 435, 12 May 2005 ; “Power at the Tip of the Tongue”, U.K. Muller and S. Kranender, Science Vol 304, 9April 2004 ]. The research cited concluded that the chameleon’s tongue acquires rapid acceleration through an ingenious catapult system. The sudden motion of certain plants in order to efficiently disperse their seeds appears to depend on the rapid release of elastic stored energy arising from a dynamic instability triggered by nonmuscular hydraulically actuated structures.

The study of the sudden pollen release mechanism in Mountain Laurel (Kalmia latifolia) was carried forward by Lyman J. Briggs (1874 – 1963), who is the namesake of the Lyman J. Briggs School at Michigan State University. He was one of the first investigators to examine the biophysics of rapid plant movements. Dr. Briggs was trained initially as a soils physicist, and subsequently had a distinguished career as a physicist at the U.S. Department of Agriculture and then as Director of the National Bureau of Standards, where he designed and built a wind tunnel that figured importantly in early airplane design. He also worked on geophysical experiments using high altitude balloons, and became head of the National Geographic Society. His work on the pollen release mechanism in Mountain Laurel is documented in his notebooks, which are now housed at the National Archives in College Park, Maryland.

It is important to study the mechanism of sudden pollen release from a biophysics perspective. The rapid release of pollen by flowers of Mountain Laurel when touched by a bumblebee or other visiting insect pollinator is a natural object of study by an REU theoretical student. The anthers are inserted into the corolla and held reflexed under tension until they are triggered by a visiting insect pollinator, or released spontaneously when the flower dies. Then the anthers spring inward and throw pollen on the insect’s body, absent any insect, onto the stigma which results in self-pollination. A systematic mathematical study of the dynamical mechanism that may be responsible for the sudden motion will be the focus of this REU project.

TITLE: Protein Folding
SUPERVISOR: Prof. Lisa Lapidus

Proteins are part of all processes of life, such as photosynthesis, respiration and reproduction. Within the cell, proteins are continuously constructed from amino acid building blocks strung together like beads on a necklace using a gene as a template for the sequence. But a protein does nothing until this necklace folds into the native structure necessary for performing its particular function. The process of folding a protein into its native structure is spontaneous and depends in detail on the physical interactions between different residues of the polypeptide chain and with the surrounding water.

In my lab we study protein folding using optical methods. We have recently developed an ultra-rapid mixer to start observing the folding process after only 10 microseconds using fluorescence. An REU student would use this mixer to study the folding of an protein that has been engineered to fold extremely fast. Lab duties would include some simple biochemical preparation of the protein for study, optical observation of the protein during folding and data analysis of the folding process. A background in biology is not required.

REU Program at Michigan State University

Project Abstracts, Summer 2006 (updated list of March 26)

Nuclear Physics

Condensed Matter Physics

Astrophysics

High Energy Physics

Theoretical Physics

Biological Physics and Biophysics