This article reports on the development and the first applications of a new spectrometer which enables the precise and time-resolved measurement of both the energy loss and the charge-state distribution of ion beams with 10 < Z < 30 at energies of 4-8 MeV/u after their interaction with a laser-generated plasma. The spectrometer is based on five 20 × 7 mm(2) large and 20 μm thick polycrystalline diamond samples produced via the Chemical Vapour Deposition (CVD) process and was designed with the help of ion-optical simulations. First experiments with the spectrometer were successfully carried out at GSI using (48)Ca ions at an energy of 4.8 MeV/u interacting with a carbon plasma generated by the laser irradiation of a thin foil target. Owing to the high rate capability and the short response time of the spectrometer, pulsed ion beams with 10(3)-10(4) ions per bunch at a bunch frequency of 108 MHz could be detected. The temporal evolution of the five main charge states of the calcium ion beams as well as the corresponding energy loss values could be measured simultaneously. Due to the outstanding properties of diamond as a particle detector, a beam energy resolution ΔEE ≈ 0.1% could be reached using the presented experimental method, while a precision of 10% in the energy loss and charge-state distribution data was obtained.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1063/1.4798539 | DOI Listing |
J Chem Inf Model
January 2025
Ecole Nationale Supérieure de Chimie de Paris, Université PSL, CNRS, Institute of Chemistry for Life and Health Sciences, 75 005 Paris, France.
In this contribution, we examine the interplay between target definition, data distribution, featurization approaches, and model architectures on graph-based deep learning models for thermodynamic property prediction. Through consideration of five curated data sets, exhibiting diversity in elemental composition, multiplicity, charge state, and size, we examine the impact of each of these factors on model accuracy. We observe that target definition, i.
View Article and Find Full Text PDFJ Proteome Res
January 2025
Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.
Proteo-SAFARI is a shiny application for fragment assignment by relative isotopes, an R-based software application designed for identification of protein fragment ions directly in the / domain. This program provides an open-source, user-friendly application for identification of fragment ions from a candidate protein sequence with support for custom covalent modifications and various visualizations of identified fragments. Additionally, Proteo-SAFARI includes a nonnegative least-squares fitting approach to determine the contributions of various hydrogen shifted fragment ions ( + 1, + 1, - 1, - 2) observed in UVPD mass spectra which exhibit overlapping isotopic distributions.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA.
We theoretically investigate how the intranuclear environment influences the charge of a nucleosome core particle (NCP)-the fundamental unit of chromatin consisting of DNA wrapped around a core of histone proteins. The molecular-based theory explicitly considers the size, shape, conformation, charge, and chemical state of all molecular species-thereby linking the structural state with the chemical/charged state of the system. We investigate how variations in monovalent and divalent salt concentrations, as well as pH, affect the charge distribution across different regions of an NCP and quantify the impact of charge regulation.
View Article and Find Full Text PDFbioRxiv
November 2024
Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA.
We theoretically investigate how the intranuclear environment influences the charge of a nucleosome core particle (NCP) - the fundamental unit of chromatin consisting of DNA wrapped around a core of histone proteins. The molecular-based theory explicitly considers the size, shape, conformations, charges, and chemical states of all molecular species - thereby linking the structural state with the chemical/charged state of the system. We investigate how variations in monovalent and divalent salt concentrations, as well as pH, affect the charge distribution across different regions of an NCP and quantify the impact of charge regulation.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!