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Christopher Wrede, Ph.D., Professor of Physics
Chris is a tenured Professor in the Department of Physics and Astronomy at Michigan State University working at the Facility for Rare Isotope Beams. His primary research interest is in the field of experimental nuclear astrophysics. He has taught courses in Astronomy, Electronics, Thermodynamics, Modern Physics, and Nuclear Astrophysics. Prior to joining MSU in 2011, Chris received a Ph.D. in Physics from Yale University in 2008 followed by three years as a Research Associate based at the University of Washington's Center for Experimental Nuclear Physics and Astrophysics.
Research Associates:
Ruchi Mahajan, Ph.D., Research Associate
Ruchi received her Ph.D in 2019 from the Department of Physics, Panjab University Chandigarh-India in the field of Experimental Nuclear Physics, researching the dynamics of fusion-fission reactions using neutron multiplicity as a probe. She carried out her experiments using the National Array of Neutron Detectors (NAND) facility, which is one of the largest neutron detector arrays in India consisting of 100 organic scintillator detectors. During her Ph.D., she was actively involved in the handling, testing and installation of the NAND detectors and published experimental results for 48Ti induced reactions [ Phys. Rev. C 98, 034601 (2018), Acta Physica Polonica B. Vol. 49, 645 (2018)], technical methods to produce 144,154Sm targets [ Vacuum 150, 203 (2018)], and statistical model calculations for 210Po [ EPJ Web of Conferences 86, 00025 (2015)] as the first author. Her Ph.D. thesis was selected as one of the top three best theses in the International Symposium on Nuclear Physics held at Bhabha Atomic Research Center-Mumbai in December 2018 organized by Department of Atomic Energy, India. Ruchi joined NSCL/FRIB in November 2020, where she has expanded her scientific and technical expertise by upgrading the Gaseous Detector with Germanium Tagging (GADGET) detector into a time projection chamber (TPC) for nuclear astrophysics experiments, the first of which ran succesfully at FRIB in November, 2022.
Lijie Sun, Ph.D., Research Associate
Lijie received his Ph.D. at China Institute of Atomic Energy in July 2017. Then he joined Shanghai Jiao Tong University, where he worked as a postdoctoral researcher. His research in China focused on the experimental study of beta decay of nuclei close to the proton-drip line and their astrophysical implications. In China, he participated in several beta-decay spectroscopy studies by implanting nuclei into a silicon detector array surrounded by germanium detectors and published the results for 36,37Ca [ Chin. Phys. Lett. 32, 012301 (2015)], 23Al, 24Si [ Nucl. Instrum. Methods Phys. Res. A 804, 1 (2015)], 20Mg [ Phys. Rev. C 95, 014314 (2017)], 27S [ Phys. Rev. C 99, 064312 (2019)], [ Phys. Lett. B 802, 135213 (2020)], and 26P [ Phys. Rev. C 101, 024305 (2020)] as the (co-)first author. He was with us at NSCL as Research Associate from October 2018 to October 2021. At NSCL, he performed a detailed analysis of 25Si beta-decay data acquired using GADGET including a Doppler Broadening technique [ Phys. Rev. C 103, 014322 (2021)] and led the first application of Markov chain Monte Carlo-based Bayesian data analysis to the Doppler-Shift Attenuation Method [accepted for publicatoin in Phys. Lett. B, arXiv:2203.10336v2]. He also played a major role in the design of the Doppler Shift Lifetimes 2 (DSL2) upgrade and worked on adapting and expanding upon the Particle-X-ray Coincidence Technique for the measurement of resonances of interest to Type I X-ray bursts on accreting neutron stars. He recently re-joined us to continue work on the PXCT project after a position as a Research Associate at Shanghai Jiao Tong University.
Graduate Students:
Tyler Wheeler, B.S., 5th year dual Ph.D. candidate in Physics and Computational Math, Science, and Engineering at MSU
Tyler earned his B.S. in Physics from Grand Valley State University in 2018. As an undergraduate, he investigated molecular networks and metal-organic frameworks using positron annihilation lifetime spectroscopy. His work is published in the journal Macromolecules under the title, Tunability of Free Volume and Viscoelastic Damping of Thiol-ene Networks Deep in the Glassy StateÂ. At NSCL, he is investigating the influence of a particularly important thermonuclear reaction rate on X-ray Burst light curves. His goal is to determine the thermonuclear rate of the 15O(α, γ)19Ne reaction by measuring the beta delayed charged particle emissions in the decay of 20Mg. The data for these measurements has been succesfully acquired at FRIB following an upgrade of GADGET's Proton Detector to time-projection chamber operation. He is pursuing a joint degree in Physics and Computational Math, Science, and Engineering. The CMSE component will enhace his data analysis via machine-learning techniques.
Joseph Dopfer, B.S., 3rd year Ph.D. candidate in Physics at MSU
Joseph graduated summa cum laude with a B.S. in physics from the University of Massachusetts, Lowell in 2020. His undergraduate thesis was characterizing 6Li depleted CLYC inorganic scintillation detectors for applications in simultaneous fast neutron and gamma ray spectroscopy. At NSCL, Joseph has performed analysis on GRETINA data of 52Fe for Professor Gade's research group, and is currently working assembling the experimental set up for Particle-X-Ray Coincidence Technique (PXCT) measurements with Professor Wrede's group after completing the conceptual and mechanical design. Associated with this technical development, Joe is pursuing MSU's new Graduate Certificate for Instrumentation in High Energy Physics.
Lexanne Weghorn, B.S., 2nd year Ph.D. candidate in Physics at MSU
Lexie received her B.S. degree with Honors in Physics from the University of Wisconsin - La Crosse in 2021. Her undergraduate work included the preparation and characterization of implanted 14N solid targets to be used in an experiment constraining the lifetime of the 6.79 MeV state in 15O. She also assisted in the production of the podcast My Nuclear Life, which aims to make nuclear physics topics accessible to both the broader scientific community and the general public. She has worked on developing the Doppler Shift Lifetimes 2 (DSL2) setup and successfully ran the first DSL2 experiment at TRIUMF-ISAC in Canada in December 2022.
Alexander Adams, B.S., 2nd year Ph.D. candidate in Physics at MSU
Alex received a B.S in Computer Engineering with a minor in Physics from UC Santa Barbara with high honors in 2012, and a M.S. in Astronautical Engineering from University of Southern California in 2013. As an undergraduate he performed modelling and analysis of data from an integral field spectrometer to help resolve gas flows in starburst galaxies, and as a masters student he built and tested liquid propellant rocket engines. He then worked in industry on spacecraft fluid and propulsion systems from 2014-2021. He is currently working on using GADGET II and the Particle X-Ray Coincidence Technique setup to make measurements of half lives and branching ratios of resonances in 59Cu+p reactions of interest to X-ray bursts.
Undergraduate Students:
Logan transferred to MSU from Lansing Community College to MSU in the Fall of 2020. He has completed an analysis of the proton spectra of 32Ar beta decay taken with GADGET's Proton Detector and set upper limits on the intensities of low energy protons. He is now contributing to GADGET II TPC analysis and development work to test various gas mixtures in the TPC.
Ari is an undergraduate research assistant who started research in October 2021 and is part of the class of 2024. He is majoring in Astrophysics and minoring in Computer Science and Japanese. He graduated his British-Curriculum high school with a primary in physics and mathematics. He is currently working on simulations of the GADGET II system, including high-purity germanium arrays and charge dispersion in the TPC Micromegas readout.
Adam is an undegraduate at MSU working on simulations of particle tracks in the GADGET II TPC.
Former Graduate Students and Research Associates:
Jason Surbrook, B.S., Ph.D. (MSU, 2023)
Jason earned a B.S. degree in Physics from the University of North Carolina in 2016. As an undergraduate, he worked on mechanical drawings for a new accelerator of high current, pulsed proton beams for nuclear astrophysics and measured background neutron activation of germanium in consideration of a precision neutrino measurement at SNS. At NSCL, he dedicated about a year on precision mass measurements with the LEBIT Penning Trap. He was the spokesperson for a successful NSCL LEBIT experiment to investigate isospin symmetry breaking by measuring the mass of 36Ca and has published a paper on that measurement as the first author [ Phys. Rev. C 103, 014323 (2020)]. Currently, he preparing a paper based on experiments with the GADGET system to search for exotic decay modes of 11Be, and leading an effort to perform complementary experiments using Accelerator Mass Spectrometery.
Tamas Budner, B.S., Ph.D. (MSU, 2022)
In 2016, Tamas graduated from Ursinus College summa cum laude, earning his B.S. with Honors in Physics and minors in computer science and mathematics. His senior thesis was a continuation of his computational atomic physics research related to the field ionization of Rydberg atoms [Phys. Rev. A 92, 043412 (2015)] and involved developing a genetic algorithm for selective state ionization. At Michigan State, he has been supported by the NSCL Graduate Fellowship and the College of Natural Science Recruiting Fellowship. He ran a successful experiment at NSCL to experimentally constrain the thermonuclear rate of the 30P(p, γ)31S reaction by measuring the branching ratios of low energy proton emissions following the decay of 31Cl using the Gaseous Detector with Germanium Tagging (GADGET) and recently published a paper [Phys. Rev. Lett. 128, 182701 (2022)] on the first results. He is now a Research Associate at Argonne National Laboratory.
Brent Glassman, B.S., Ph.D. (MSU, 2019)
Brent received his B.S. in Physics at James Madison University in 2013. His undergraduate research dealt with the analysis of one-proton-removal reactions of proton-rich psd-shell nuclei for reactions relevant to novae. At NSCL, he planned and ran a 20Mg beta decay experiment to study the CNO-cycle breakout reactions occurring on accreting compact stars and isospin-symmetry breaking related to tests of the Standard Model of particle physics. The astrophysics results have been disseminated in three recent contributions: [Phys. Lett. B 778, 397 (2018)], [Phys. Rev. C 96, 032801(R) (2017)], and [Phys. Rev. C 99, 065801 (2019)], the last of which involved a detailed analysis of the Doppler shifts of gamma-rays emitted following beta delayed proton emission. Regarding isospin symmetry breaking, he has published a paper demonstrating the revalidation of the isobaric multiplet mass equation in the A=20 quintet [Phys. Rev. C, 92, 042501(R) (2015)] and submitted a related paper on the superallowed beta decay of 20Mg [arxiv:1910.12965]. He is now working as a Data Scientist at Frequence.
Moshe Friedman, Ph.D., Research Associate
Moshe finished his Ph.D. research at the Hebrew University of Jerusalem in 2016: a measurement of the proton elastic form factor ratio at low momentum transfer (Q2 = 0.02-0.08 GeV2) at the Thomas Jefferson National Accelerator Facility (JLAB), Newport News, VA. Moshe was also involved in the modeling and commissioning of a quasi-stellar neutron source for s-process measurements at SARAF (Israel). He published a stand-alone C++ code, SimLiT, for calculating the resulting neutron spectrum from the 7Li(p,n)7Be reaction, an important neutron source for s-process measurements and medical purposes (BNCT). He was also involved in the modeling of a detector for prompt fission neutron emission spectrum of 235U(n,f), which is relevant for reactor physics. Moshe played a lead role in the recent assembly and commissioning of, and first experiments with GADGET, which is used to study the rp-process in novae and x-ray bursts and search for exotic decay modes. He is lead author of a technical paper on GADGET [Nucl. Instrum. Methods Phys. Res., Sect. A, 940, 93 (2019)] and disseminated the first science results related to the produciotn of the radioactive 22Na in classical novae [Phys. Rev. C 101, 052802(R) (2020)]. He is now a Faculty Member at the Hebrew University of Jerusalem.
Cathleen Fry, B.S., Ph.D. (MSU, 2019)
Cathleen received her B.S. in Physics at Tennessee Technological University in 2013. She was involved in a project cataloguing the discovery of the isotopes at Michigan State as an REU student in 2011. In 2012, she was involved in an REU project at Notre Dame studying the feasibility of using deuterons as a probe to study the Isoscalar Giant Monopole Resonance. At Michigan State, she was supported by the NSCL and University Distinguished Fellowships. She planned, executed, an analyzed an experiment to discover and measure 35Ar excited states at Maier-Leibnitz Laboratory in Munich to constrain the 34Cl(p, γ)35Ar reaction rate, which is relevant for nova nucleosynthesis. She published a paper on the results of this work, reporting the discovery of 17 new resonances [Phys. Rev. C 91, 015803 (2015)]. Cathleen also ran an experiment to measure the lifetimes of 30P(p, γ)31S resonances at Canada's national laboratory for nuclear and particle physics, TRIUMF, which complements our group's work on 31Cl beta decay [arXiv:2203.10336v2]. Cathleen is also currently serving as a member-at-large on the APS Forum of Graduate Student Affairs executive board. She is now a Scientist at Los Alamos National Laboratory.
David received his Ph.D. from the University of Santiago de Compostela (Spain) in 2010. His dissertation dealt with the production of medium-mass neutron-rich nuclei using two different mechanisms: the fission of 238U and the projectile fragmentation of fission residues. In this research, the fragmentation of 132Sn was investigated for the first time. After receiving his degree he joined GANIL (France). There, he worked on the development of a next generation active target and time projection chamber (ACTAR TPC). He was mainly involved in the development of a Geant4-ROOT based simulation package to provide reliable simulations of various physics cases. In our group, he worked on the design and development of GADGET in order to investigate resonances of particular interest in explosive stellar nucleosynthesis processes. He performed detailed Geant4 simulations of the gas amplifier detector that helped to define its final geometry. David also performed a comprehensive analysis of 26P decay leading to evidence for a proton halo in 26P [Phys. Rev. C 93, 064320 (2016)] and confirming the recent discovery of an isomeric state in 26P [Phys. Rev. C 96, 014306 (2017)]. He is now an Applied Physicist at the Canadian Nuclear Laboratories.
Mike completed a B.S. cum laude in Physics, with minors in Music and Mathematics, in 2009 at Westmont College in Santa Barbara, California. While at Westmont he performed research with the 24-inch Keck Telescope as well as with the Cosmic Muon Detection Array. After graduating he worked at the Santa Barbara Museum of Natural History as Astronomy Programs Assistant before coming to NSCL in 2011. At MSU, Mike co-led an experiment to constrain the 25Al(p, γ)26Si reaction rate, which influences the amount of 26Al produced in classical novae, and he published paper on that work [Phys. Rev. Lett. 111, 232503 (2013)]. Next, he completed a thesis on the beta decay of 31Cl and the 30P(p, γ)31S reaction rate, which strongly influences nucleosynthesis in classical novae. The first two results from the latter work were recently published [Phys. Rev. Lett. 116, 102502 (2016) and Phys. Rev. C, 93, 064310 (2016)]. Mike also served two terms as the Graduate Outreach Representative for the NSCL and one term as the elected President of the Physics Graduate Organization. He defended his Ph.D thesis on July 25th, 2016 and was subsequently presented with the Sherwood K. Haynes Award for the outstanding graduate student in Physics or Astrophysics at MSU (2017). He is now the Director of Education and Workforce Development at the Q-Sence NSF Quantum Leap Challenge Institute and the Physics Education Research Group at the University of Colorado at Boulder.
Sarah Schwartz, B.S., M.S. (MSU, 2016)
Sarah received a B.S. in Mathematics with a Minor in Physics from the University of Southern Indiana in 2014. She was a participant in Michigan State University's REU program in 2013. During that program she began studying beta delayed proton-gamma emissions from 26P to 25Al to find the absolute intensities of the 25Al gamma rays emitted and also focused on analyzing Doppler-broadening effects from that decay due to the recoil velocity of 25Al. She continued that work in the graduate program at Michigan State and published a paper describing the first observation and application of radiative Doppler broadening in beta delayed proton-gamma decay [Phys. Rev. C 92, 031302(R) (2015)]. This work formed the basis of her M.S. thesis, which she defended successfully on April 26th, 2016. She is now a Scientist with the U.S. Navy.