isotope
GAMMA_FLOW: Guided Analysis of Multi-label spectra by MAtrix Factorization for Lightweight Operational Workflows
Rädle, Viola, Hartwig, Tilman, Oesen, Benjamin, Kröger, Emily Alice, Vogt, Julius, Gericke, Eike, Baron, Martin
GAMMA_FLOW is an open-source Python package for real-time analysis of spectral data. It supports classification, denoising, decomposition, and outlier detection of both single- and multi-component spectra. Instead of relying on large, computationally intensive models, it employs a supervised approach to non-negative matrix factorization (NMF) for dimensionality reduction. This ensures a fast, efficient, and adaptable analysis while reducing computational costs. gamma_flow achieves classification accuracies above 90% and enables reliable automated spectral interpretation. Originally developed for gamma-ray spectra, it is applicable to any type of one-dimensional spectral data. As an open and flexible alternative to proprietary software, it supports various applications in research and industry.
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- Health & Medicine > Pharmaceuticals & Biotechnology (1.00)
- Law (0.68)
Improvement of Nuclide Detection through Graph Spectroscopic Analysis Framework and its Application to Nuclear Facility Upset Detection
Fernández, Pedro Rodríguez, Svinth, Christian, Hagen, Alex
We present a method to improve the detection limit for radionuclides using spectroscopic radiation detectors and the arrival time of each detected radiation quantum. We enable this method using a neural network with an attention mechanism. We illustrate the method on the detection of Cesium release from a nuclear facility during an upset, and our method shows $2\times$ improvement over the traditional spectroscopic method. We hypothesize that our method achieves this performance increase by modulating its detection probability by the overall rate of probable detections, specifically by adapting detection thresholds based on temporal event distributions and local spectral features, and show evidence to this effect. We believe this method is applicable broadly and may be more successful for radionuclides with more complicated decay chains than Cesium; we also note that our method can generalize beyond the addition of arrival time and could integrate other data about each detection event, such as pulse quality, location in detector, or even combining the energy and time from detections in different detectors.
- North America > United States (0.28)
- Asia > Japan > Honshū > Tōhoku > Fukushima Prefecture > Fukushima (0.04)
- Europe > Belgium > Flanders > Antwerp Province > Antwerp (0.04)
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- Government > Military (1.00)
- Energy > Power Industry > Utilities > Nuclear (1.00)
Further Exploration of Precise Binding Energies from Physics Informed Machine Learning and the Development of a Practical Ensemble Model
Bentley, I., Tedder, J., Gebran, M., Paul, A.
Sixteen new physics informed machine learning models have been trained on binding energy residuals from modern mass models that leverage shape parameters and other physical features. The models have been trained on a subset of AME 2012 data and have been verified with a subset of the AME 2020 data. Among the machine learning approaches tested in this work, the preferred approach is the least squares boosted ensemble of trees which appears to have a superior ability to both interpolate and extrapolate binding energy residuals. The machine learning models for four mass models created from the ensemble of trees approach have been combined to create a composite model called the Four Model Tree Ensemble (FMTE). The FMTE model predicts binding energy values from AME 2020 with a standard deviation of 76 keV and a mean deviation of 34 keV for all nuclei with N > 7 and Z > 7. A comparison with new mass measurements for 33 isotopes not included in AME 2012 or AME 2020 indicates that the FMTE performs better than all mass models that were tested.
- North America > United States > Massachusetts > Suffolk County > Boston (0.04)
- North America > United States > District of Columbia > Washington (0.04)
- North America > United States > Michigan > Kent County > Grand Rapids (0.04)
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Discovering Nuclear Models from Symbolic Machine Learning
Munoz, Jose M., Udrescu, Silviu M., Ruiz, Ronald F. Garcia
Numerous phenomenological nuclear models have been proposed to describe specific observables within different regions of the nuclear chart. However, developing a unified model that describes the complex behavior of all nuclei remains an open challenge. Here, we explore whether novel symbolic Machine Learning (ML) can rediscover traditional nuclear physics models or identify alternatives with improved simplicity, fidelity, and predictive power. To address this challenge, we developed a Multi-objective Iterated Symbolic Regression approach that handles symbolic regressions over multiple target observables, accounts for experimental uncertainties and is robust against high-dimensional problems. As a proof of principle, we applied this method to describe the nuclear binding energies and charge radii of light and medium mass nuclei. Our approach identified simple analytical relationships based on the number of protons and neutrons, providing interpretable models with precision comparable to state-of-the-art nuclear models. Additionally, we integrated this ML-discovered model with an existing complementary model to estimate the limits of nuclear stability. These results highlight the potential of symbolic ML to develop accurate nuclear models and guide our description of complex many-body problems.
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.14)
- Europe > Italy > Marche > Ancona Province > Ancona (0.04)
Blood vessels made with 3D-printed ice could improve lab-grown organs
Complex artificial organs could be created by 3D printing a mould of veins, arteries and capillaries in ice, casting that in organic material and then allowing the ice to melt away, resulting in a delicate, hollow network. This leaves a space for the intricate artificial blood vessels that are required to develop lab-grown internal organs. Researchers have been working on artificial organs for decades to help meet the high global demand for transplants of the likes of hearts, kidneys and livers. But creating the blood vessel networks needed to keep them alive is still a challenge. Existing techniques can grow artificial skin or ears, but any flesh or organ material dies off if more than 200 micrometres from a blood vessel, says Philip LeDuc at Carnegie Mellon University in Pennsylvania.
Precision Spectroscopy of Fast, Hot Exotic Isotopes Using Machine Learning Assisted Event-by-Event Doppler Correction
Udrescu, Silviu-Marian, Torres, Diego Alejandro, Ruiz, Ronald Fernando Garcia
We propose an experimental scheme for performing sensitive, high-precision laser spectroscopy studies on fast exotic isotopes. By inducing a step-wise resonant ionization of the atoms travelling inside an electric field and subsequently detecting the ion and the corresponding electron, time- and position-sensitive measurements of the resulting particles can be performed. Using a Mixture Density Network (MDN), we can leverage this information to predict the initial energy of individual atoms and thus apply a Doppler correction of the observed transition frequencies on an event-by-event basis. We conduct numerical simulations of the proposed experimental scheme and show that kHz-level uncertainties can be achieved for ion beams produced at extreme temperatures ($> 10^8$ K), with energy spreads as large as $10$ keV and non-uniform velocity distributions. The ability to perform in-flight spectroscopy, directly on highly energetic beams, offers unique opportunities to studying short-lived isotopes with lifetimes in the millisecond range and below, produced in low quantities, in hot and highly contaminated environments, without the need for cooling techniques. Such species are of marked interest for nuclear structure, astrophysics, and new physics searches.
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.14)
- South America > Colombia > Bogotá D.C. > Bogotá (0.04)
- Europe > Netherlands (0.04)
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Data Isotopes for Data Provenance in DNNs
Wenger, Emily, Li, Xiuyu, Zhao, Ben Y., Shmatikov, Vitaly
Today, creators of data-hungry deep neural networks (DNNs) scour the Internet for training fodder, leaving users with little control over or knowledge of when their data is appropriated for model training. To empower users to counteract unwanted data use, we design, implement and evaluate a practical system that enables users to detect if their data was used to train an DNN model. We show how users can create special data points we call isotopes, which introduce "spurious features" into DNNs during training. With only query access to a trained model and no knowledge of the model training process, or control of the data labels, a user can apply statistical hypothesis testing to detect if a model has learned the spurious features associated with their isotopes by training on the user's data. This effectively turns DNNs' vulnerability to memorization and spurious correlations into a tool for data provenance. Our results confirm efficacy in multiple settings, detecting and distinguishing between hundreds of isotopes with high accuracy. We further show that our system works on public ML-as-a-service platforms and larger models such as ImageNet, can use physical objects instead of digital marks, and remains generally robust against several adaptive countermeasures.
- Information Technology > Security & Privacy (1.00)
- Health & Medicine (0.67)
- Law (0.67)
Do quantum effects play a role in consciousness? – Physics World
The role of biophotons in the brain is a growing area of research in neurobiology – and where there are photons there might be quantum mechanics. The light of the mind is blue, wrote the poet Sylvia Plath ("The Moon and the Yew Tree" 1961). But it seems it may actually be red. That's because recent research suggests a link between intelligence and the frequency of biophotons in animals' brains. In 2016 Zhuo Wang and colleagues at the South-Central University for Nationalities in China studied brain slices from various animals (bullfrog, mouse, chicken, pig, monkey and human) that had been excited by glutamate, an excitatory neurotransmitter.
- Europe > Italy > Piedmont > Turin Province > Turin (0.05)
- North America > United States > California > Santa Barbara County > Santa Barbara (0.04)
- North America > United States > Arizona (0.04)
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- Research Report > New Finding (0.69)
- Research Report > Experimental Study (0.49)
Automated fragment identification for electron ionisation mass spectrometry: application to atmospheric measurements of halocarbons
Guillevic, Myriam, Guillevic, Aurore, Vollmer, Martin, Schlauri, Paul, Hill, Matthias, Emmenegger, Lukas, Reimann, Stefan
Background: Non-target screening consists in searching a sample for all present substances, suspected or unknown, with very little prior knowledge about the sample. This approach has been introduced more than a decade ago in the field of water analysis, but is still very scarce for indoor and atmospheric trace gas measurements, despite the clear need for a better understanding of the atmospheric trace gas composition. For a systematic detection of emerging trace gases in the atmosphere, a new and powerful analytical method is gas chromatography (GC) of preconcentrated samples, followed by electron ionisation, high resolution mass spectrometry (EI-HRMS). In this work, we present data analysis tools to enable automated identification of unknown compounds measured by GC-EI-HRMS. Results: Based on co-eluting mass/charge fragments, we developed an innovative data analysis method to reliably reconstruct the chemical formulae of the fragments, using efficient combinatorics and graph theory. The method (i) does not to require the presence of the molecular ion, which is absent in $\sim$40% of EI spectra, and (ii) permits to use all measured data while giving more weight to mass/charge ratios measured with better precision. Our method has been trained and validated on >50 halocarbons and hydrocarbons with a molar masses of 30-330 g mol-1 , measured with a mass resolution of approx. 3500. For >90% of the compounds, more than 90% of the reconstructed signal is correct. Cases of wrong identification can be attributed to the scarcity of detected fragments per compound (less than six measured mass/charge) or the lack of isotopic constrain (no rare isotopocule detected). Conclusions: Our method enables to reconstruct most probable chemical formulae independently from spectral databases. Therefore, it demonstrates the suitability of EI-HRMS data for non-target analysis and paves the way for the identification of substances for which no EI mass spectrum is registered in databases. We illustrate the performances of our method for atmospheric trace gases and suggest that it may be well suited for many other types of samples.
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- Research Report (0.50)
- Workflow (0.48)
Quantified limits of the nuclear landscape
Neufcourt, Léo, Cao, Yuchen, Giuliani, Samuel A., Nazarewicz, Witold, Olsen, Erik, Tarasov, Oleg B.
The chart of the nuclides is limited by particle drip lines beyond which nuclear stability to proton or neutron emission is lost. Predicting the range of particle-bound isotopes poses an appreciable challenge for nuclear theory as it involves extreme extrapolations of nuclear masses beyond the regions where experimental information is available. Still, quantified extrapolations are crucial for a variety of applications, including the modeling of stellar nucleosynthesis. We use microscopic nuclear mass models and Bayesian methodology to provide quantified predictions of proton and neutron separation energies as well as Bayesian probabilities of existence throughout the nuclear landscape all the way to the particle drip lines. We apply nuclear density functional theory with several energy density functionals. To account for uncertainties, Bayesian Gaussian processes are trained on the separation-energy residuals for each individual model, and the resulting predictions are combined via Bayesian model averaging. This framework allows to account for systematic and statistical uncertainties and propagate them to extrapolative predictions. We characterize the drip-line regions where the probability that the nucleus is particle-bound decreases from $1$ to $0$. In these regions, we provide quantified predictions for one- and two-nucleon separation energies. According to our Bayesian model averaging analysis, 7759 nuclei with $Z\leq 119$ have a probability of existence $\geq 0.5$. The extrapolations obtained in this study will be put through stringent tests when new experimental information on exotic nuclei becomes available. In this respect, the quantified landscape of nuclear existence obtained in this study should be viewed as a dynamical prediction that will be fine-tuned when new experimental information and improved global mass models become available.
- North America > United States > Michigan > Ingham County > Lansing (0.05)
- North America > United States > Michigan > Ingham County > East Lansing (0.05)
- Europe > Belgium > Brussels-Capital Region > Brussels (0.04)