The 2001 Mars Odyssey spacecraft was launched towards Mars on April 7, 2001. Onboard the spacecraft is the Martian radiation environment experiment (MARIE), which is designed to measure the background radiation environment due to galactic cosmic rays (GCR) and solar protons in the 20-500 MeV/n energy range. We present an approach for developing a space radiation-shielding model of the spacecraft that includes the MARIE instrument in the current mapping phase orientation. A discussion is presented describing the development and methodology used to construct the shielding model. For a given GCR model environment, using the current MARIE shielding model and the high-energy particle transport codes, dose rate values are compared with MARIE measurements during the early mapping phase in Mars orbit. The results show good agreement between the model calculations and the MARIE measurements as presented for the March 2002 dataset.
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http://dx.doi.org/10.1016/s0273-1177(03)00527-1 | DOI Listing |
J Phys Chem A
January 2025
Laboratoire de Chimie et Physique Quantique, UMR 5626 CNRS - Université Toulouse III-Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse, France.
In this work, we reexamine the Dailey-Townes model by systematically investigating the electric field gradient (EFG) in various chlorine compounds, dihalogens, and the uranyl ion (). Through the use of relativistic molecular calculations and projection analysis, we decompose the EFG expectation value in terms of atomic reference orbitals. We show how the Dailey-Townes model can be seen as an approximation to our projection analysis.
View Article and Find Full Text PDFEJNMMI Phys
January 2025
Sherbrooke Molecular Imaging Center and Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 12th Avenue N, Sherbrooke, J1H 5N4, Québec, Canada.
Background: The renewed interest in BGO scintillators for TOF-PET is driven by the improved Cherenkov photon detection with new blue-sensitive SiPMs. However, the slower scintillation light from BGO causes significant time walk with leading edge discrimination (LED), which degrades the coincidence time resolution (CTR). To address this, a time walk correction (TWC) can be done by using the rise time measured with a second threshold.
View Article and Find Full Text PDFSci Rep
January 2025
School of Electrical Engineering, University of Tehran, Tehran, 14179-35840, Iran.
This paper introduces an analytical method for studying power transmission through an infinite array of helical-shaped metal particles in a lossy dielectric medium. While the assessment of composite slabs' transmitted power has been extensively researched in the electromagnetic interference (EMI) shielding field, many studies lack an adequate problem description. The primary inadequacy of these studies is the need for an analytical framework.
View Article and Find Full Text PDFJ Orthop Surg Res
January 2025
University of Marburg, Marburg, Germany.
Background: Total knee arthroplasty (TKA) is one of the most common orthopaedic procedures and the number of patients which undergo TKA will continue to rise in the coming years. Consecutively, the number of necessary revision surgeries will increase. One of the main reasons for revision surgery is aseptic loosening because of a so-called stress-shielding effect.
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