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The pervasiveness of deep space radiation remains a confounding factor for the transit of humans through our solar system. Spacecraft shielding both protects astronauts but also contributes to absorbed dose through galactic cosmic ray interactions that produce secondary particles. The resultant biological effects drop to a minimum for aluminum shielding around 20 g/cm2 but increase with additional shielding. The present work evaluates for the first time, the impact of secondary pions on central nervous system functionality. The fractional pion dose emanating from thicker shielded spacecraft regions could contribute up to 10% of the total absorbed radiation dose. New results from the Paul Scherrer Institute have revealed that low dose exposures to 150 MeV positive and negative pions, akin to a Mars mission, result in significant, long-lasting cognitive impairments. These surprising findings emphasize the need to carefully evaluate shielding configurations to optimize safe exposure limits for astronauts during deep space travel.

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., RST/Fundamental Aspects of Materials and Energy

Refraction-based x-ray imaging can overcome the fundamental contrast limit of computed tomography (CT), particularly in soft tissue, but so far has been constrained to high-dose ex vivo applications or required highly coherent x-ray sources, such as synchrotrons. Here we demonstrate that grating interferometry (GI) is more dose efficient than conventional CT in imaging of human breast under close-to-clinical conditions. Our system, based on a conventional source and commercial gratings, outperformed conventional CT for spatial resolutions better than 263 µm and absorbed dose of 16 mGy. The sensitivity of GI is constrained by grating fabrication, and further progress will lead to significant improvements of clinical CT.

The quest for new materials for thermoluminescence (TL) and optically stimulated luminescence (OSL) dosimetry continues to be a central line of research in luminescence dosimetry, occupying many groups and investigators, and is the topic of many publications. Nevertheless, it has also been a research area with many pitfalls, slow advances in our understanding of the luminescence processes, and rare improvements over existing materials. Therefore, this paper reviews the status of the field with the goal of addressing some fundamental questions: Is there a need for new luminescence materials for TL/OSL dosimetry? Can these materials be designed and, if so, are there strategies or rules that can be followed? What are the common pitfalls and how can they be avoided? By discussing these questions, we hope to contribute to a more guided approach to the development of new luminescent materials for dosimetry applications., RST/Fundamental Aspects of Materials and Energy

Radiation exposures from accidents, nuclear detonations or terrorist incidents are unlikely to be homogeneous; however, current biodosimetric approaches are developed and validated primarily in whole-body irradiation models. A workshop was held at the Armed Forces Radiobiology Research Institute in May 2008 to draw attention to the need for partial-body biodosimetry, to discuss current knowledge, and to identify the gaps to be filled. A panel of international experts and the workshop attendees discussed the requirements and concepts for a path forward. This report addresses eight key areas identified by the Workshop Program Committee for future focus: (1) improved cytogenetics, (2) clinical signs and symptoms, (3) cutaneous bioindicators, (4) organ-specific biomarkers, (5) biophysical markers of dose, (6) integrated diagnostic approaches, (7) confounding factors, and (8) requirements for post-event medical follow-up. For each area, the status, advantages and limitations of existing approaches and suggestions for new directions are presented.

The thermal history of a material with initially filled trap states may be probed using thermoluminescence. Since luminescent microparticles are composed of robust oxides, they are viable candidates for sensing temperature under conditions where all other types of direct-contact sensors fail. Mg(2)SiO(4) : Tb, Co particles with two thermoluminescent peaks have been heated using micromachined heaters over a 232 degrees C to 313 degrees C range on time scales of less than 200 ms. The effect of maximum temperature during excitation on the intensity ratio of the two luminescent peaks has been compared with first-order kinetics theory and shown to match within an average error of 4.4%.

The thermal history of a material with initially filled trap states may be probed using thermoluminescence. Since luminescent microparticles are composed of robust oxides, they are viable candidates for sensing temperature under conditions where all other types of direct-contact sensors fail. Mg(2)SiO(4) : Tb, Co particles with two thermoluminescent peaks have been heated using micromachined heaters over a 232 degrees C to 313 degrees C range on time scales of less than 200 ms. The effect of maximum temperature during excitation on the intensity ratio of the two luminescent peaks has been compared with first-order kinetics theory and shown to match within an average error of 4.4%.