To provide Monte Carlo calculated beam quality correction factors (k ) for monoenergetic proton beams using [Formula: see text], a toolkit based on the Monte Carlo code [Formula: see text]. Monte Carlo simulations of six plane-parallel and four cylindrical ionization chambers were carried out. The latest ICRU 90 recommendations on key data for ionizing-radiation dosimetry were used to calculate the electronic stopping powers and to select the mean energy necessary to create an ion pair in air ([Formula: see text]). [Formula: see text] factors were calculated for a Co spectrum at a depth of 5 g cm. f factors and [Formula: see text] ratios as well as k factors were calculated at the entrance region of monoenergetic proton beams with energies between 60 MeV and 250 MeV. Additionally, perturbation correction factors for the Exradin A1SL ionization chamber at an energy of 250 MeV were calculated. [Formula: see text] factors agreed within 0.7% or better, f factors within 1.7% or better and [Formula: see text] ratios within 2.2% or better with Monte Carlo calculated values provided in the literature. Furthermore, k factors calculated in this work were found to agree within 1% or better with experimentally determined k factors provided in the literature, with only two exceptions with deviations of 1.4% and 2.4%. The total perturbation correction factor for the Exradin A1SL chamber was 0.969(7) and hence significantly different than unity in contrast to the assumption from the IAEA TRS-398 code of practice (CoP). [Formula: see text] can be used to calculate k factors in clinical proton beams. k factors for six plane-parallel and four cylindrical ionization chambers were calculated and provided for the upcoming update of the IAEA TRS-398 CoP.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1088/1361-6560/ab6e53 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
State shifts in the deep Critical Zone drive landscape evolution in volcanic terrains.
Proc Natl Acad Sci U S A
January 2025
Department of Earth Sciences, University of Oregon, Eugene, OR 97403.
Volcanic provinces are among the most active but least well understood landscapes on Earth. Here, we show that the central Cascade arc, USA, exhibits systematic spatial covariation of topography and hydrology that are linked to aging volcanic bedrock, suggesting systematic controls on landscape evolution. At the Cascade crest, a locus of Quaternary volcanism, water circulates deeply through the upper [Formula: see text]1 km of crust but transitions to shallow and dominantly horizontal flow as rocks age away from the arc front.
View Article and Find Full Text PDFReviving the Lieb-Schultz-Mattis theorem in open quantum systems.
Natl Sci Rev
January 2025
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
In closed systems, the celebrated Lieb-Schultz-Mattis (LSM) theorem states that a one-dimensional locally interacting half-integer spin chain with translation and spin rotation symmetries cannot have a non-degenerate gapped ground state. However, the applicability of this theorem is diminished when the system interacts with a bath and loses its energy conservation. In this letter, we propose that the LSM theorem can be revived in the entanglement Hamiltonian when the coupling to the bath renders the system short-range correlated.
View Article and Find Full Text PDFTemperature-dependent pathways in carbon dioxide electroreduction.
Sci Bull (Beijing)
January 2025
Beijing National Laboratory for Molecular Sciences, CAS Laboratory of Colloid and Interface and Thermodynamics, CAS Research/Education Centre for Excellence in Molecular Sciences, Centre for Carbon Neutral Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; School of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, China; Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China. Electronic address:
Temperature affects both the thermodynamics of intermediate adsorption and the kinetics of elementary reactions. Despite its extensive study in thermocatalysis, temperature effect is typically overlooked in electrocatalysis. This study investigates how electrolyte temperature influences CO electroreduction over Cu catalysts.
View Article and Find Full Text PDFPhase transitions, Dirac and Weyl semimetal states in MnGeBiTe.
Sci Rep
January 2025
Saint Petersburg State University, St. Petersburg, 198504, Russia.
Using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT), an experimental and theoretical study of changes in the electronic structure (dispersion dependencies) and corresponding modification of the energy band gap at the Dirac point (DP) for topological insulator (TI) [Formula: see text] have been carried out with gradual replacement of magnetic Mn atoms by non-magnetic Ge atoms when concentration of the latter was varied from 10% to 75%. It was shown that when Ge concentration increases, the bulk band gap decreases and reaches zero plateau in the concentration range of 45-60% while trivial surface states (TrSS) are present and exhibit an energy splitting of 100 and 70 meV in different types of measurements. It was also shown that TSS disappear from the measured band dispersions at a Ge concentration of about 40%.
View Article and Find Full Text PDFA python approach for prediction of physicochemical properties of anti-arrhythmia drugs using topological descriptors.
Sci Rep
January 2025
Department of Mathematical Sciences, Faculty of Science, Somali National University, Mogadishu Campus, Mogadishu, Somalia.
In recent years, machine learning has gained substantial attention for its ability to predict complex chemical and biological properties, including those of pharmaceutical compounds. This study proposes a machine learning-based quantitative structure-property relationship (QSPR) model for predicting the physicochemical properties of anti-arrhythmia drugs using topological descriptors. Anti-arrhythmic drug development is challenging due to the complex relationship between chemical structure and drug efficacy.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!