Chris Izzo
Research Subjects
Research Interests
Chris Izzo has a total of 175 co-authors. Here are the top co-authors by number of shared publications:
- C. M. Ireland
Facility for Rare Isotope Beams
5 shared publications - Ryan Ringle
Facility for Rare Isotope Beams, East Lansing, MI, USA
5 shared publications - Scott E. Campbell
Facility for Rare Isotope Beams
5 shared publications - Xiangcheng Chen
Facility for Rare Isotope Beams, East Lansing, MI, USA
5 shared publications - Franziska Maier
Facility for Rare Isotope Beams
4 shared publications - H. Erington
Facility for Rare Isotope Beams, East Lansing, MI, USA
4 shared publications
Latest Publications
- 20 October 2026
- Published by American Physical Society (APS) in Physical Review C
- Vol. 114 (4) , 044327
High-precision mass measurements of Ni 52 and Co 51 reveal breakdown of the isobaric multiplet mass equation in the f p shell
We performed high-precision mass measurements of the proton-rich nuclei $^{52}\mathrm{Ni}$ and $^{51}\mathrm{Co}$ with the LEBIT Penning trap at the Facility for Rare Isotope Beams. For $^{52}\mathrm{Ni}$, a mass excess of $\ensuremath{-}22474.8(2.2)$ keV was determined, which is consistent with a recent storage-ring measurement at the Cooler-Storage Ring (CSRe) but has a factor 37 improved precision. For $^{51}\mathrm{Co}$, we obtained a mass excess of $\ensuremath{-}27375.1(5.7)$ keV, agreeing with a recent CSRe result, while reducing the uncertainty by a factor 2. Combining our mass value for $^{52}\mathrm{Ni}$ with the known two-proton decay energy of $^{54}\mathrm{Zn}$, we determined the mass excess of $^{54}\mathrm{Zn}$ to be $\ensuremath{-}6463(42)$ keV. These new mass values reveal a substantial breakdown of the isobaric mass multiplet equation for $A=52$ and $A=54$, and provide stringent benchmarks for isospin-symmetry-breaking effects in the proton-rich $fp$-shell, favoring theoretical descriptions that omit the Coulomb-exchange term.- 20 October 2026
- Published by American Physical Society (APS) in Physical Review C
- Vol. 114 (4) , 044327
High-precision mass measurements of Ni 52 and Co 51 reveal breakdown of the isobaric multiplet mass equation in the f p shell
We performed high-precision mass measurements of the proton-rich nuclei $^{52}\mathrm{Ni}$ and $^{51}\mathrm{Co}$ with the LEBIT Penning trap at the Facility for Rare Isotope Beams. For $^{52}\mathrm{Ni}$, a mass excess of $\ensuremath{-}22474.8(2.2)$ keV was determined, which is consistent with a recent storage-ring measurement at the Cooler-Storage Ring (CSRe) but has a factor 37 improved precision. For $^{51}\mathrm{Co}$, we obtained a mass excess of $\ensuremath{-}27375.1(5.7)$ keV, agreeing with a recent CSRe result, while reducing the uncertainty by a factor 2. Combining our mass value for $^{52}\mathrm{Ni}$ with the known two-proton decay energy of $^{54}\mathrm{Zn}$, we determined the mass excess of $^{54}\mathrm{Zn}$ to be $\ensuremath{-}6463(42)$ keV. These new mass values reveal a substantial breakdown of the isobaric mass multiplet equation for $A=52$ and $A=54$, and provide stringent benchmarks for isospin-symmetry-breaking effects in the proton-rich $fp$-shell, favoring theoretical descriptions that omit the Coulomb-exchange term.- Open Access
- 15 July 2026
- Published by Springer Nature in Nature
- Vol. 655 (8124) , 875-878
Magnetic character of the low-energy enhancement in 70Zn
The transition of an atomic nucleus from an excited state to a state of lower energy is typically accompanied by the emission of photons. The likelihood of photon emission is a function of the photon energy and of properties of the initial and final nuclear states and is known as the photon (or γ-ray) strength function (γSF)1,2. Of the features present in the γSF, an enhancement in the low-energy region has been observed in some nuclei, but the electromagnetic nature of this enhancement remains an open question3,4. This low-energy enhancement in the γSF significantly impacts our understanding of how elements are created in stars and the structure of the nucleus5,6. Here we present the results from an experiment on the γSF of 70Zn that show that the enhancement in the γSF of this nucleus is of magnetic nature. This observation helps address a long-open question about γSFs in atomic nuclei and directly impacts our predictive capabilities in nuclear science.
- 15 July 2026
- Published by Springer Nature in Nature
- Vol. 655 (8124) , 875-878
Open AccessMagnetic character of the low-energy enhancement in 70Zn
The transition of an atomic nucleus from an excited state to a state of lower energy is typically accompanied by the emission of photons. The likelihood of photon emission is a function of the photon energy and of properties of the initial and final nuclear states and is known as the photon (or γ-ray) strength function (γSF)1,2. Of the features present in the γSF, an enhancement in the low-energy region has been observed in some nuclei, but the electromagnetic nature of this enhancement remains an open question3,4. This low-energy enhancement in the γSF significantly impacts our understanding of how elements are created in stars and the structure of the nucleus5,6. Here we present the results from an experiment on the γSF of 70Zn that show that the enhancement in the γSF of this nucleus is of magnetic nature. This observation helps address a long-open question about γSFs in atomic nuclei and directly impacts our predictive capabilities in nuclear science.
- 17 February 2026
- Published by American Physical Society (APS) in Physical Review C
- Vol. 113 (2)
Mass of Sn 101 and Bayesian extrapolations to the proton drip line
- 17 February 2026
- Published by American Physical Society (APS) in Physical Review C
- Vol. 113 (2)
Mass of Sn 101 and Bayesian extrapolations to the proton drip line
- Open Access
- 15 August 2025
- Published by Elsevier in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- Vol. 1082
The upgraded summing NaI(Tl) (SuN++) absorption spectrometer
- 15 August 2025
- Published by Elsevier in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- Vol. 1082
Open AccessThe upgraded summing NaI(Tl) (SuN++) absorption spectrometer
- 23 January 2025
- Published by American Physical Society (APS) in Physical Review C
- Vol. 111 (1)
Precision mass measurements of using the multiple reflection time-of-flight mass spectrometer at TITAN- 23 January 2025
- Published by American Physical Society (APS) in Physical Review C
- Vol. 111 (1)
Precision mass measurements of using the multiple reflection time-of-flight mass spectrometer at TITAN- 9 January 2025
- Published by American Physical Society (APS) in Physical Review C
- Vol. 111 (1)
High-precision mass measurement of restores smoothness of the mass surface- 9 January 2025
- Published by American Physical Society (APS) in Physical Review C
- Vol. 111 (1)
High-precision mass measurement of restores smoothness of the mass surface- Open Access
Exploring the Nuclear Chart via Precision Mass Spectrometry with the TITAN MR-TOF MS
Isotopes at the limits of nuclear existence are of great interest for their critical role in nuclear astrophysical reactions and their exotic structure. Experimentally, exotic nuclides are challenging to address due to their low production cross-sections, overwhelming amounts of contamination, and lifetimes of typically less than a second. To this end, a Multiple-Reflection Time-of-Flight mass spectrometer at the TITAN-TRIUMF facility was built to determine atomic masses. This device is the preferred tool to work with exotic nuclides due to its ability to resolve the species of interest from contamination and short measurement cycle times, enabling mass measurements of isotopes with millisecond half-lives. With a relative precision of the order 10−7, we demonstrate why the TITAN MR-TOF MS is the tool of choice for precision mass surveys for nuclear structure and astrophysics. The capabilities of the device are showcased in this work, including new mass measurements of short-lived tin isotopes (104–107Sn) approaching the proton dripline as well as 89Zr, 90Y, and 91Y. The last three illustrate how the broadband surveys of MR-TOF MS reach beyond the species of immediate interest.
Open AccessExploring the Nuclear Chart via Precision Mass Spectrometry with the TITAN MR-TOF MS
Isotopes at the limits of nuclear existence are of great interest for their critical role in nuclear astrophysical reactions and their exotic structure. Experimentally, exotic nuclides are challenging to address due to their low production cross-sections, overwhelming amounts of contamination, and lifetimes of typically less than a second. To this end, a Multiple-Reflection Time-of-Flight mass spectrometer at the TITAN-TRIUMF facility was built to determine atomic masses. This device is the preferred tool to work with exotic nuclides due to its ability to resolve the species of interest from contamination and short measurement cycle times, enabling mass measurements of isotopes with millisecond half-lives. With a relative precision of the order 10−7, we demonstrate why the TITAN MR-TOF MS is the tool of choice for precision mass surveys for nuclear structure and astrophysics. The capabilities of the device are showcased in this work, including new mass measurements of short-lived tin isotopes (104–107Sn) approaching the proton dripline as well as 89Zr, 90Y, and 91Y. The last three illustrate how the broadband surveys of MR-TOF MS reach beyond the species of immediate interest.
- 23 February 2023
- Published by American Physical Society (APS) in Physical Review C
- Vol. 107 (2) , 024313
Measurements and computational analysis of the natural decay ofBackground: Mainly because of its long half-life and despite its scientific relevance, spectroscopic measurements of forbidden decays are very limited and lack formulation of shape factors. A direct precise measurement of its Q value is also presently unreported. In addition, the description of forbidden decays provides interesting challenges for nuclear theory. The comparison of precise experimental results with theoretical calculations for these decays can help to test underlying models and can aid the interpretation of data from other experiments.- 23 February 2023
- Published by American Physical Society (APS) in Physical Review C
- Vol. 107 (2) , 024313
Measurements and computational analysis of the natural decay ofBackground: Mainly because of its long half-life and despite its scientific relevance, spectroscopic measurements of forbidden decays are very limited and lack formulation of shape factors. A direct precise measurement of its Q value is also presently unreported. In addition, the description of forbidden decays provides interesting challenges for nuclear theory. The comparison of precise experimental results with theoretical calculations for these decays can help to test underlying models and can aid the interpretation of data from other experiments.- 18 February 2022
- Published by American Physical Society (APS) in Physical Review C
- Vol. 105 (2) , 025804
Improved nuclear physics near refines urca neutrino luminosities in accreted neutron star crustsWe performed Penning trap mass measurements for at the National Superconducting Cyclotron Laboratory and NuShellX calculations of the and structure using the GXPF1A Hamiltonian to obtain improved estimates of the and reaction rates. Surveying astrophysical conditions for type-I x-ray bursts with the code mesa, implementing our improved reaction rates, and taking into account updated nuclear masses for and from the recent literature, we refine the neutrino luminosity from the important mass number urca cooling source in accreted neutron-star crusts. This improves our understanding of the thermal barrier between deep heating in the crust and the shallow depths where extra heat is needed to explain x-ray superbursts, as well as the expected signature of crust urca neutrino emission in light curves of cooling transients.- 18 February 2022
- Published by American Physical Society (APS) in Physical Review C
- Vol. 105 (2) , 025804
Improved nuclear physics near refines urca neutrino luminosities in accreted neutron star crustsWe performed Penning trap mass measurements for at the National Superconducting Cyclotron Laboratory and NuShellX calculations of the and structure using the GXPF1A Hamiltonian to obtain improved estimates of the and reaction rates. Surveying astrophysical conditions for type-I x-ray bursts with the code mesa, implementing our improved reaction rates, and taking into account updated nuclear masses for and from the recent literature, we refine the neutrino luminosity from the important mass number urca cooling source in accreted neutron-star crusts. This improves our understanding of the thermal barrier between deep heating in the crust and the shallow depths where extra heat is needed to explain x-ray superbursts, as well as the expected signature of crust urca neutrino emission in light curves of cooling transients.- 25 February 2021
- Published by American Physical Society (APS) in Physical Review C
- Vol. 103 (2) , 025811
Mass measurements of neutron-rich indium isotopes for -process studiesA new series of neutron-rich indium mass measurements is reported from the TITAN multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). These mass measurements cover () and include ground states as well as isomeric states. The masses of nuclei in this region are known to be of great importance for accurately modeling -process nucleosynthesis, and the significance of the reported neutron-rich indium masses is discussed in this context. Results are compared with earlier experimental data where available as well as theoretical mass models. The measurements reported here include the first mass measurements of , as well as the first direct mass measurement of . The masses of ground states and several isomers were previously measured to higher precision by Penning trap mass spectrometry, which also resolved some low-lying isomers that could not be resolved in this work. The earlier Penning trap measurements serve as excellent cross-checks for the MR-TOF-MS measurements, and in some cases the MR-TOF-MS measurements improve the literature uncertainties of higher-lying isomer masses and excitation energies. A new isomeric state for , recently reported for the first time by the JYFLTRAP group, is also confirmed by the TITAN MR-TOF-MS, with a measured excitation energy of 1813(17) keV.- 25 February 2021
- Published by American Physical Society (APS) in Physical Review C
- Vol. 103 (2) , 025811
Mass measurements of neutron-rich indium isotopes for -process studiesA new series of neutron-rich indium mass measurements is reported from the TITAN multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). These mass measurements cover () and include ground states as well as isomeric states. The masses of nuclei in this region are known to be of great importance for accurately modeling -process nucleosynthesis, and the significance of the reported neutron-rich indium masses is discussed in this context. Results are compared with earlier experimental data where available as well as theoretical mass models. The measurements reported here include the first mass measurements of , as well as the first direct mass measurement of . The masses of ground states and several isomers were previously measured to higher precision by Penning trap mass spectrometry, which also resolved some low-lying isomers that could not be resolved in this work. The earlier Penning trap measurements serve as excellent cross-checks for the MR-TOF-MS measurements, and in some cases the MR-TOF-MS measurements improve the literature uncertainties of higher-lying isomer masses and excitation energies. A new isomeric state for , recently reported for the first time by the JYFLTRAP group, is also confirmed by the TITAN MR-TOF-MS, with a measured excitation energy of 1813(17) keV.