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   https://doi.org/10.1088/1748-0221/16/09/C09025  

   Tung, C.F. (September 2021, Journal of Instrumentation)
2. Unsupervised machine learning for unbiased chemical classification in X-ray absorption spectroscopy and X-ray emission spectroscopy

   https://doi.org/10.1039/d1cp02903g  

   Tetef, Samantha; Govind, Niranjan; Seidler, Gerald T. (October 2021, Physical Chemistry Chemical Physics)

   We report a comprehensive computational study of unsupervised machine learning for extraction of chemically relevant information in X-ray absorption near edge structure (XANES) and in valence-to-core X-ray emission spectra (VtC-XES) for classification of a broad ensemble of sulphorganic molecules. By progressively decreasing the constraining assumptions of the unsupervised machine learning algorithm, moving from principal component analysis (PCA) to a variational autoencoder (VAE) to t-distributed stochastic neighbour embedding (t-SNE), we find improved sensitivity to steadily more refined chemical information. Surprisingly, when embedding the ensemble of spectra in merely two dimensions, t-SNE distinguishes not just oxidation state and general sulphur bonding environment but also the aromaticity of the bonding radical group with 87% accuracy as well as identifying even finer details in electronic structure within aromatic or aliphatic sub-classes. We find that the chemical information in XANES and VtC-XES is very similar in character and content, although they unexpectedly have different sensitivity within a given molecular class. We also discuss likely benefits from further effort with unsupervised machine learning and from the interplay between supervised and unsupervised machine learning for X-ray spectroscopies. Our overall results, i.e. , the ability to reliably classify without user bias and to discover unexpected chemical signatures for XANES and VtC-XES, likely generalize to other systems as well as to other one-dimensional chemical spectroscopies. 

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3. Aggregation-induced emission organic metal halide complex for X-ray scintillation

   https://doi.org/10.1039/D4MH00142G  

   Shonde, Tunde Blessed; Liu, He; Olasupo, Oluwadara Joshua; Bouchard, Alexander; Bouchard, Sara; Franklin, Annaliese; Lin, Xinsong; Stand, Luis M; Ma, Biwu (July 2024, Materials Horizons)

   An AIE organic zinc chloride complex scintillator, in which the metal halide serves as X-ray sensitizer for the organic component, is discovered to exhibit a light yield of 13 423 Photon per MeV and a radioluminescence decay lifetime of 5.24 ns. 

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4. Searching for neutrino emission from hard X-ray sources with IceCube

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   Santander, Marcos (January 2020, Pos proceedings of science)
5. Search for Neutrino Emission from Hard X-Ray AGN with IceCube

   https://doi.org/10.3847/1538-4357/ada94b  

   Abbasi, R; Ackermann, M; Adams, J; Agarwalla, S K; Aguilar, J A; Ahlers, M; Alameddine, JM; Amin, N M; Andeen, K; Argüelles, C; et al (March 2025, The Astrophysical Journal)

   Abstract Active galactic nuclei (AGN) are promising candidate sources of high-energy astrophysical neutrinos, since they provide environments rich in matter and photon targets where cosmic-ray interactions may lead to the production of gamma rays and neutrinos. We searched for high-energy neutrino emission from AGN using the Swift-BAT Spectroscopic Survey catalog of hard X-ray sources and 12 yr of IceCube muon track data. First, upon performing a stacked search, no significant emission was found. Second, we searched for neutrinos from a list of 43 candidate sources and found an excess from the direction of two sources, the Seyfert galaxies NGC 1068 and NGC 4151. We observed NGC 1068 at flux ${\varphi }_{{\nu }_{\mu }+{\overline{\nu }}_{\mu }}$= $4.02_{-1.52}^{+1.58}\times 10^{-11}$TeV⁻¹cm⁻²s⁻¹normalized at 1 TeV, with a power-law spectral indexγ= 3.10 ${}_{-0.22}^{+0.26}$, consistent with previous IceCube results. The observation of a neutrino excess from the direction of NGC 4151 is at a posttrial significance of 2.9σ. If interpreted as an astrophysical signal, the excess observed from NGC 4151 corresponds to a flux ${\varphi }_{{\nu }_{\mu }+{\overline{\nu }}_{\mu }}$= $1.51_{-0.81}^{+0.99}\times 10^{-11}$TeV⁻¹cm⁻²s⁻¹normalized at 1 TeV andγ= 2.83 ${}_{-0.28}^{+0.35}$. 

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