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Nuclear Science Division

Nuclear Science Division Newsletter, January 2024

In this issue:

  • Director’s Corner

    2023 has been an important year for Nuclear Science in the U.S. with the roll out of the new NSAC Long Range Plan (LRP) on Nuclear Science “A New Era of Discovery”. The research portfolio and strategic priorities developed for LBNL’s Nuclear Science Division, are well aligned with the priorities and recommendations articulated in the LRP, including the Electron Ion Collider (EIC) and Neutrinoless Double Beta Decay as top construction priorities. LBNL plans to make leading contributions to the EIC ePIC detector and is supporting two next generation Neutrinoless Double Beta Decay experiments, CUPID – as lead lab – and LEGEND. The November Division Retreat was a successful occasion to bring the whole division together and discuss not only our strategic goals but also focus on conversations around People Stewardship. It was great to see so many members of the NSD team in person and the engaged interactions during the session and the breaks.

    This issue of the NSD Newsletter introduces the newly formed Neurodiversity Working Group, part of the Lab’s AllAccess Employee Resource Group (ERG), which aims to celebrate that diversity, develop community, and influence lab policy to hire, support, and retain neurodivergent employees.

    On the technical side, the Newsletter introduces the recently launched modernized version of the Berkeley Lab Scintillator Library, which provides measured properties of many scintillating materials, and will advance modeling of scintillator response in support of a variety of applications. It also summarizes the exciting technical development of a graphene field-effect transistor (GFET) for applications as cryogenic signal amplifier and photo sensor.  

    We also learn about the advances in producing a new, innovative closed-loop coil for the MARS-D project, a 4th Generation Electron Cyclotron Resonance Ion Source (ECRIS). MARS-D will be able to achieve stronger fields than the current VENUS source at the 88-Inch cyclotron, further enhancing the already impressive current ion-beam capabilities. The end of the year saw the first delivery of a high-intensity 50Ti beam from the 88-Inch CCyclotron to the Berkeley Gas-filled Separator (BGS), using a new induction oven in VENUS. This sets us up for an exciting year ahead in the heavy element program.

    It is great to see these science and technology developments as well as the advancement of our workplace culture. I am looking forward to an exciting year and wish everyone a healthy, safe,  and successful year 2024.

  • MARS-D: Progress Towards 4th Generation ECRIS

    The MARS-D project will produce a 4th Generation Electron Cyclotron Resonance Ion Source (ECRIS). MARS-D is expected to outperform the 88-Inch Cyclotron’s world leading 3rd Generation VENUS ECRIS. The transition from a 3rd Generation to a 4th Generation ECRIS means that both higher intensity beams and higher charge state beams can be provided to the 88-Inch Cyclotron for experiments, and this is made possible with stronger plasma confining magnetic fields. In an ECRIS, the plasma confining fields are typically provided by a conventional configuration that uses a combination of solenoids and a set of six racetrack coils. Using this conventional configuration, the upper limits of the superconducting NbTi wire, for use in an ECRIS, have been reached.  MARS-D will be able to achieve stronger fields than VENUS, while also using NbTi superconductor wire, because of its novel magnet configuration that will replace the six racetrack coils which provide the radial confining field. The novel magnet configuration is a closed-loop coil that will provide both a radial confining field as well as solenoidal fields that will add to the axial confinement of the plasma [1].

    The 88-Inch ECRIS Group and the SMP group received funding through a DOE Office of Science Funding Opportunity Announcement (FOA) in 2023. The two year project will produce the coldmass (sextupole and solenoid magnets) for the MARS-D ECRIS, to be built at a later date. Recently, the group successfully completed a full size 4 layer test wind using NbTi, shown in Figure 1. The winding of the final coil will begin in January of 2024 and consist of 24 layers. The test wind allowed the group to perfect the winding tooling, test the epoxy impregnation, and observe effects of cooling down on the coil.

    Figure 1: The completed NbTi 4 layer test coil is shown after epoxy impregnation is completed.

    The success of the test wind is owed to the hard work of the technicians at the 88-Inch Cyclotron and ATAP: Brian Bell, Patrick Coleman, John Garcia, Roman Nieto, Matthew Reynolds, Nathan Seidman, Chet Spencer, James Swanson, Sixuan Zhong, the lead designer Lianrong Xu, and the 88-Inch Mechanical Engineer Jaime Cruz-Duran.

    References: [1] M. Juchno et al., Shell-based support structure for the 45 GHz ECR Ion Source MARS-D,” IEEE Trans. Appl.  Supercond., vol. 32, no. 6, Sept. 2022.

  • Empowering Detector Development: Introducing the Upgraded Scintillator Library

    Until recently, the compilation of scintillator properties has largely proceeded as a side project to detector development efforts for fundamental physics and applications. The recently launched modernized version of the Berkeley Lab Scintillator Library is poised to change this landscape. 

    This database provides measured properties of many scintillating materials along with citations to published papers in which the original measurements were reported. The recent expansion features an Organic Scintillator Library with a current focus on scintillator response to protons and heavy ions. These quenching data are required for modeling scintillator-based detector response to neutrons and charged particles [1] and are useful inputs for kinematic neutron image reconstruction algorithms [2]. The initial library release also includes tabulated data on recoil ion response for EJ-309, a widely-used liquid organic scintillator. The longer-term vision is to provide data on scintillation properties for an array of commercial and custom organic scintillators to facilitate comparison between measurements, provide a basis for theory development, and lay the foundation for future evaluation. 

    This site is an extended version of a library focused on inorganic scintillators originally created by Stephen Derenzo, Martin Boswell, Marvin Weber, and Kathleen Brennan at Lawrence Berkeley National Laboratory (LBNL) with support from the Department of Homeland Security (DHS). The site is currently maintained by Bethany Goldblum and Thibault Laplace at LBNL and the University of California, Berkeley with support from the Nuclear Data Program within the Department of Energy, Office of Science, Nuclear Physics and the Department of Energy, National Nuclear Security Administration, Office of Defense Nuclear Nonproliferation Research & Development via the Nuclear Science and Security Consortium. 

    In 2023, the site was visited by more than 1000 unique users from 47 countries around the globe. Figure 1 shows a world heat map illustrating country demographics of library visitors. 

    For suggested additions to the library, contact Bethany Goldblum at bethany@lbl.gov. 

    Figure 1: Heat map (using a sequential blue scale from the least to the most opaque shades representing low to high values) of visitors to the Scintillator Library by country since January 2023. 

    References

    [1] T.A. Laplace, B.L. Goldblum, J.A. Brown, G. LeBlanc, T. Li, J.J. Manfredi, and E. Brubaker, “Modeling ionization quenching in organic scintillators,” Materials Advances (2022). https://doi.org/10.1039/D2MA00388K 

    [2] J.J. Manfredi, et al., “The Single-Volume Scatter Camera,” Proc. SPIE 11494, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XXII, 114940V (20 August 2020). https://doi.org/10.1117/12.2569995

  • Graphene Amplifier & Sensor Development

    In the early development of the LEGEND-200 low-noise readout electronics (cf. July 2023 NSD newsletter), researchers in the NSD Neutrinos Program realized a supply issue of the junction field-effect transistors (JFETs) implemented in the design. The vendor that manufactured these low-noise devices has stopped making them, as have many of their competitors. NSD Senior Scientist Alan Poon’s group then embarked on a journey to find an alternative to these high-quality devices.    In the summer of 2021, a Science Undergraduate Laboratory Internships (SULI)  student, Jeremy Fleishhacker, from Carleton College, MN, was tasked with simulating the electronic response of a graphene field-effect transistor (GFET). His early findings showed that GFETs could be a viable alternative to JFETs.

    This past summer, another SULI student, Phoebe Andromeda, from Oregon State University, joined the research team to investigate the actual device performance; in particular, the variation of electronic performance for graphene of different sizes, which acts as the “channel,” between the drain and the source of the GFET. They also measured the electronic characteristics at room and liquid nitrogen temperatures. Working with electronics in cryogens was a highlight of Andromeda’s summer term, as “running electrical tests on the GFETs was the culmination of all the hard work earlier in the internship.”

    During the early development of this project, Marcos Turquetti, a staff engineer from the Lab’s Engineering Division, saw an increase in noise when he exposed the GFET device to light in the laboratory. He has since verified that GFETs are indeed sensitive to optical light.  Lisa Schlüter, a postdoctoral fellow in the Neutrino Program since summer 2023, is now investigating the spectral response of GFETs over a broader wavelength spectrum, exploiting its utilities in other photo-sensing applications.

    The team is exploring other practical uses of GFETs.  For example, Lucas Brouwer of the Lab’s Accelerator Technology and Applied Physics  (ATAP) Division is developing a magnetic sensor that exploits graphene’s high charge mobility. The goal is to develop a magnetosensor with nano-Tesla sensitivity for superconducting magnets operating at liquid helium temperature.  

    In 2022, the Department of Energy’s Office of Nuclear Physics funded this GFET development work as a two-year project under its Micro-electronics Initiative.  

    Figure 1.  Layout of a Graphene FET (Image from Graphenea GFET-S31 datasheet).

    Figure 2: SULI undergraduate Phoebe Andromeda presenting their GFET work at the Conference Experience for Undergraduates (CEU)  poster session in Hawaii in November 2023.  Andromeda summed up their poster presentation nicely: “It went exceedingly well. I spoke to many people in the nuclear science community during my presentation who were very interested in my research as it was new and cutting edge!”

  • Inclusion, Diversity, Equity and Accountability Moments

    Recognizing and Celebrating Neurodiversity at the Lab

    We’re happy to highlight a new initiative in our lab community – the Neurodiversity Working Group (NWG), part of the AllAccess Employee Resource Group (ERG). This group is committed to enhancing our understanding of neurodiversity, fostering a supportive network for neurodivergent lab employees, and advocating for inclusive policies that aid in the hiring and retention of neurodivergent individuals.

    Understanding Neurodiversity

    Neurodiversity acknowledges the natural diversity of human brains, recognizing the value of cognitive differences. This terminology encompasses every brain’s differences, and also gives space to describe the differences in the brains of “neurodivergent” people. Neurodivergence describes specifically the differences in the brains of individuals with neurodivergent conditions such as autism, ADHD, learning disorders, OCD, and others. Embracing neurodiversity means valuing the unique perspectives and problem-solving approaches of neurodivergent individuals, while understanding their experiences can be largely shaped by their neurotype.

    NWG’s Formation and Leadership

    The NWG, led by Hannah Parrilla (NSD), Melissa Romanus (NERSC), Hannah Ross (NERSC), and Jean Sexton (CCSE), emerged from a collective effort to support neurodiversity. These leaders aim to represent the neurodiverse makeup of our lab and lead the way in celebrating neurodiversity.

    Goals and Initiatives

    The NWG is focused on three main goals:

    1. Celebrating Neurodiversity: Raising awareness about neurodivergent experiences and hosting educational events to foster an inclusive, understanding workplace.
    2. Building a Supportive Network: Creating a community for neurodivergent lab employees to share experiences, access resources, and support personal and professional development.
    3. Influencing Policy: Advocating for inclusive hiring practices and policies that support the career advancement of neurodivergent staff.

    Looking Ahead

    The establishment of the NWG is a progressive step towards recognizing the contributions of neurodivergent individuals in science. It aims to cultivate a diverse and inclusive culture that celebrates the unique skills and perspectives of all members.

    We invite everyone to engage with the NWG, participate in their initiatives, and support their mission to make our division a leader in embracing neurodiversity in science.

    Figure 1: A logo to celebrate the Neurodiversity Working Group.

    Luminary Cards

    To recognize their efforts in the area(s) of Inclusion, Diversity, Equity, and Accountability, the following people received a Luminary Card: Larry Phair

  • Fragments

    In November, NSD held a two-day offsite retreat which brought together the whole division to discuss the goals of the scientific programs and the division’s people stewardship efforts. The agenda included presentations on scientific activities and goals and interactive discussion sessions on topics including career development and the way we work.

    In October, NSD hosted the 11th annual Nuclear Science Day for Scouts. The event provides an opportunity for scouts to earn an event badge and learn about nuclear science through a series of hands-on activities. In the image on the right, NSD Postdoctoral Researcher Emil Rofors describes various radiation detectors on display at the “Detector Expo” station.  A description of this year’s event can be found in this article.

    Several NSD staff members and affiliates attended the Fall Meeting of the American Physical Society Division of Nuclear Physics which was held in Hawaii in late November. Presentations delivered by NSD included topics such as the path to element 120 (Larry Phair), reinforcement learning for ion source control and optimization (Yue Shi Lai), and water coordination chemistry of Nobelium and Lawrencium (Mallory McCarthy).

    Staff and students from the Applied Nuclear Physics (ANP) program attended the IEEE Nuclear Science Symposium and Medical Imaging Conference in Vancouver in November.  The meeting is the largest annual radiation instrumentation conference.  Members of ANP and affiliated graduate students delivered a total of 14 presentations, and served as session chairs and topic conveners.

    At the conference, ANP Postdoctoral Researcher Lei Pan was recognized with an award for the best paper published in IEEE Transactions on Nuclear Science in 2023 for his article entitled Performance of Perovskite CsPbBr3 Single Crystal Detector for Gamma-Ray Detection.

    Andre Walker Loud, a Staff Scientist in the Nuclear Theory Program was recently elected a 2023 APS Fellow. He was recognized for his “definitive contributions to fundamental symmetries in nucleons and nuclei, utilizing lattice QCD and Effective Field Theory, including the high-precision computation of the nucleon axial coupling.” Congratulations, Andre!

    NSD Staff Scientist Brian Quiter and Faculty Scientist Lee Bernstein received 2023 Berkeley Lab Director’s Awards.  Lee received a Tech Transfer award for supporting the “commercialization of his invention, a production method for a groundbreaking but rare cancer drug called AC-225”, and Brian is a member of the  Mentoring@LBNL team, which won the IDEA Award for Mentorship “for building the critical foundations of a complex mentoring ecosystem that fulfills different employee needs around mentorship while also modeling the value of team science and cross-Lab collaboration over a 3 year period.” Congratulations Brian and Lee! 

    Larry Phair, Head of NSD’s 88” Cyclotron Program recently reached 30 years of service. Congratulations to Larry on this major milestone! 

    NSD welcomes new hires Marilena Lykiardopoulou (Postdoctoral Researcher), Antoine Armatol (Postdoctoral Researcher), and Tobin Dean Kramazs (Mechanical Engineering Associate).

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