April 12, 2023 ~
A new DOE Office of Science Highlight features the first experimental results from FRIB from a team led by NSD’s Heather Crawford. See also our recent News Article.
The FRIB Decay Station initiator, with the VANDLE neutron detectors on the far side and the gamma-ray detectors on the near side. These detectors were installed for the first FRIB experiment.
Image courtesy of FRIB Laboratory.
In February, the final results from the MAJORANA DEMONSTRATOR were published in Physical Review Letters. The results set a limit on the half-life of the neutrinoless double beta decay of Ge-76.
NSD Senior Scientist Volker Koch has been named as an Outstanding Referee by the Physical Review journals, as chosen by the journal editors for 2023. Instituted in 2008, the Outstanding Referee program recognizes the number, quality, and timeliness of referee reports and honors a small fraction of the journal’s 82,000 referees each year.
NSD Postdoctoral Researcher Weronika Wolszczak has been selected as the co-chair of the Berkeley postdoc association.
NSD welcomes new hires Adan Esparza (Research Associate), Lei Pan (Postdoctoral Researcher), Kushant Patel (Senior Scientific Research Associate), Celine Li (Senior Scientific Engineering Associate), Michael Gorin (Administrative Assistant), Ryan Heller (Research Scientist), and Dayle Silverio (Administrative Assistant).
Several NSD employees were recently promoted. Mark Bandstra, Alexey Drobizhev, Yue Shi Lai, Marco Salathe, and Jayson Vavrek were all promoted to Research Scientist.
Congratulations to all of you for your achievements!
In 2019, the American Physical Society (APS) formed an Ethics Committee (EC), charged to provide guidance on how the APS can promote ethical behavior by members, and police unethical behavior, including scientific ethics (fabrication, falsification or plagiarism) and interpersonal misbehavior – sexual harassment or bullying, for example. EC member and NSD Senior Scientist Spencer Klein discussed EC activities at a recent NSD staff meeting and summarizes those activities here.
Under the guidance of the APS Board, the committee works in several areas. They review APS statements on ethics and propose new ones, as appropriate. They provide ethics education, through presentations and workshops at APS meetings, and articles in different publications, such as Physics Today.
The EC develops policies and procedures for the APS to handle reports of misconduct. There are two categories: incidents at APS meetings, and everything else. For incidents at APS meetings, the APS will immediately (i.e., during the meeting) investigate and react as appropriate, and can remove the perpetrator from the meeting if needed.
Other complaints are dealt with in a longer, more involved process, starting with an initial review by the APS Ombudsperson (an outside lawyer), review by the EC, and then by the APS Board. Appeals are also possible. The APS also asks nominators (and, later, nominees) if nominees for APS committees, offices, prizes or fellowships are known to have committed misconduct. Positive answers are followed up and action may be taken.
For non-meeting complaints, the APS will not investigate, but will react to complaints which include an investigatory report by other agencies, such as the employer or other agency. The non-investigation policy can be problematic, since investigatory reports are usually private, and not available to would-be complainants or the APS.
Although many people think that the APS should conduct investigations when needed, there are real challenges in doing so. It would require significant resources, and could open the door to lawsuits. Incidents reported to the APS will likely have previously been investigated by one or more groups. Witnesses (especially victims of sexual harassment) may not want to tell their story many times, and not everyone will trust or cooperate with a U. S.-based organization. There is also some risk that different investigations reach different conclusions.
But, with outside investigatory reports generally unavailable, without its own investigation, the APS may be unable to act, even against pervasive behavior. And that is clearly extremely awkward. The EC is continuing to grapple with this.
January 10, 2023 – Update on the Mental Health Initiative and WD&E Deadlines
January 24, 2023 – Effective Teams
February 7, 2023 – APS Ethics Committee
February 21, 2023 – Outreach Opportunities
March 7, 2023 – K-12 Stem Programs
March 21, 2023 – Women’s History Month and Transgender Day of Visibility
April 4, 2023 – Inclusion and Equity in Science Publications
To recognize their efforts in the area(s) of Inclusion, Diversity, Equity, and Accountability, the following people received a Luminary Card:
Spencer Klein
From 1955–1988, low-level waste solutions from the processing of uranium and irradiated nuclear fuel were discharged into unlined earthen storage basins at the Savannah River Site (SRS) F-Area [1]. Over the decades, radioactive contaminants including uranium and iodine-129 (I-129) have leaked out of the basins and into the groundwater of the surrounding wetlands, and are now present at levels that exceed regulatory thresholds.
In March 2023, scientists from NSD’s Applied Nuclear Physics (ANP) program returned to the SRS F-Area wetlands to conduct handheld gamma-ray surveys in order to map the intensity and spatial distribution of radioactive contaminants in the area. Using ANP’s Scene Data Fusion (SDF) radiological mapping technology (see, e.g., [2]), roughly 0.25 km2 of dense forested wetlands were surveyed. Several uranium hotspots (up to roughly five times higher than the SRS natural background) were identified, and more detailed analysis is ongoing both to refine the mapping results and to examine possible yearly variations compared to measurements from the team’s 2022 campaign. In Fig. 1, a Savannah River National Laboratory (SRNL) scientist can be seen carrying LBNL’s MiniPRISM radiation imager through the SRS-F Area wetlands. Fig. 2 shows SDF results, including a preliminary reconstruction of low energy gamma-ray intensities during one survey. In addition to the SDF mapping systems that are sensitive to uranium radioactivity, LBNL is exploring whether silicon drift detectors are a viable technology to map the I-129 in situ. These efforts are part of the larger DOE-EM ALTEMIS project, which aims to develop long-term remediation and monitoring strategies for contaminated DOE legacy sites and have used the F-Area wetlands as a test bed.
Jayson Vavrek, Brian Quiter and Joanna Szornel collected the data in March 2023 with support from the Savannah River Site. Carol Eddy-Dilek (SRNL) and Haruko Murakami-Wainwright (MIT/LBNL) are Lead and Co-Lead of the DOE ALTEMIS project supporting this work. Zexuan Xu (LBNL EESA) is the LBNL PI.
[1] Biogeochemical gradients as a framework for understanding waste‐site evolution, M. Denham and K. Vangelas, Remediation Journal: The Journal of Environmental Cleanup Costs, Technologies & Techniques 19.1 (2008), DOI: 10.1002/rem.20188
[2] Free-moving quantitative gamma-ray imaging, D. Hellfeld et al., Scientific Reports 11 (2021), DOI: 10.1038/s41598-021-99588-z
In 2021, a collaboration of NSD scientists from the Applied Nuclear Physics, Low-Energy Nuclear Physics, and the 88” Cyclotron programs received funding through a DOE Office of Science FOA for “Data Analytics for Autonomous Optimization and Control of Accelerators and Detectors” to explore application of machine learning approaches to the operations of both the VENUS ion source [1] and the GRETA γ-ray detector array [2].
The primary goal of this project is to explore the best applications of existing machine learning approaches and techniques to optimize and automate operations of both devices. Work has primarily been focused so far on the case of VENUS. The team has established a continuous logging system that has been used to populate a time-series database with relevant control and diagnostic parameters from the operation of the source for over a year. The researchers, supported by a group of undergraduate researchers, are exploring the use of predictive neural networks and Bayesian optimization of the parameter space to tune the ion source.
By providing training data, such as the parameter values that VENUS was operating at and the corresponding beam current produced, the team has begun to develop a neural network which is intended to predict the current for other parameter values and use it to optimize the source. Early indications, however, suggest that in order to do this successfully, the range of input parameters must be extended and the researchers are therefore installing environmental sensors at the ion source in order to measure additional parameters such as temperature and air pressure.
In contrast, the use of Gaussian Process Regression (GPR) to map the parameter space and guide optimization of the VENUS tuning procedure has been very successful. Using this approach, a probability map of the full parameter space is generated from just a few measurements at different parameter values. The probabilistic map can then be used to guess parameter values which are likely to provide a better beam current. By performing the procedure a few dozen times an optimal solution is iteratively approached within a few hours, a similar timescale that would be expected from a human operator. The GPR approach has been shown to robustly produce a maximized beam current within a limited parameter space. Fig. 1 shows the result of using GPR to explore a two-dimensional parameter space during a test run with VENUS. The black circles represent measured observables, while the smooth distribution in the background shows the predictions from the GPR. Work is ongoing to extend this effort and potentially identify useful operational settings for VENUS which have not been considered by human operators.
This project is led by Damon Todd from the Low Energy Nuclear Physics program, Marco Salathe from the Applied Nuclear Physics program and Heather Crawford, from the Low Energy Nuclear Physics program.
[1] Recent progress on the superconducting ion source VENUS, J.Y. Benitez et al., Review of Scientific Instruments 83, 02A311 (2012), DOI: 10.1063/1.3662119
[2] The GRETA Final Design Report, 2020. Available online: GRETA_FDR.pdf
There is so much that we do not yet know about neutrinos. Neutrinos are very light, chargeless, and elusive particles that are involved in a process named beta decay and that can help us to understand the origin of matter in Universe. Beta decay is a type of radioactive decay that involves a neutron converting into a proton emitting an electron and an antineutrino.