In this paper we present the experimental results for the mobility of ions in argoncarbon dioxide gaseous mixtures (Ar-CO 2 ) for pressures ranging from 6 to 10 Torr and for reduced electric fields in the 10 Td to 25 Td range, at room temperature.The time-of-arrival spectra of the several mixture ratios studied revealed that the relative abundance of the ions and their mobilities depend on the mixture ratio. For Ar concentrations below 80% only one peak was observed in the spectra which was attributed to CO + 2 , while for Ar concentrations above 80% a second peak appears at the left side of the main peak, which may be due to impurities, probably H 2 O + . In this work, the time-of-arrival spectra from which reduced mobilities were obtained for Ar concentrations of 20% (K 0 = 1.141 ± 0.004 cm 2 V −1 s −1 ), 50% (K 0 = 1.385 ± 0.009 cm 2 V −1 s −1 ), 85% (K 0 = 1.690 ± 0.022 cm 2 V −1 s −1 ) and 95% (K 0 = 1.954 ± 0.043 cm 2 V −1 s −1 ) are displayed as well as other reduced mobilities values obtained similarly. The ion mobility study was performed at reduced electric field values typically used in gaseous detectors.

Towards a novel small animal proton irradiation platformthe SIRMIO project Background: Precision small animal radiotherapy research is a young emerging field aiming to provide new experimental insights into tumour and tissue models in different microenvironments, to unravel the complex mechanisms of radiation damage in target and non-target tissues and assess the efficacy of novel therapeutic strategies. To this end, for photon therapy, modern small animal radiotherapy research platforms have been developed over the last years and are meanwhile commercially available. Conversely, for proton therapy, which holds a great potential for an even superior outcome than photon therapy, no commercial system exists yet. Material and methods: The project SIRMIO (Small Animal Proton Irradiator for Research in Molecular Image-guided Radiation-Oncology) aims at realizing and demonstrating an innovative portable prototype system for precision small animal proton irradiation, suitable for integration at existing clinical treatment facilities. The proposed design combines precise dose application with novel insitu multi-modal anatomical image guidance and in-vivo verification of the actual treatment delivery for precision small animal irradiation. Results and conclusions: This manuscript describes the status of the different components under development, featuring a dedicated beamline for degradation and focusing of clinical proton beams, along with novel detector systems for insitu imaging. The foreseen workflow includes pre-treatment proton transmission imaging for treatment planning and position verification, complemented by ultrasonic tumour localization, followed by image-guided delivery with on-site range verification by means of ionoacoustics (for pulsed beams) and positronemission-tomography (PET, for continuous beams). The proposed compact and cost-effective system promises to open a new era in small animal proton therapy research, contributing to the basic understanding of in-vivo radiation action to identify areas of potential breakthroughs in radiotherapy for future translation into innovative clinical strategies.

Comparative study of alternative Geant4 hadronic ion inelastic physics models Comparative study of alternative Geant4 hadronic ion inelastic physics models for prediction of positron-emitting radionuclide production in carbon and oxygen for prediction of positron-emitting radionuclide production in carbon and oxygen ion therapy ion therapy

A local charged particle source in Jupiter’s inner radiation belts generates oxygen ions of cosmic ray energies.

The magnetosphere of Jupiter harbors the most extreme fluxes of MeV electrons in the solar system and therefore provides a testbed of choice to understand the origin, transport, acceleration, and loss of energetic electrons in planetary magnetospheres. Along this objective, the Pitch Angle Distribution (PAD) of energetic electrons may reveal signatures of the dominant physical processes. Here, we analyze for the first time the PAD of MeV electrons observed by the Galileo‐Energetic Particle Detector (EPD) experiment in orbit around Jupiter from 1995 to 2003. We find that the MeV electron PADs observed by the integral channels of EPD appear relatively isotropic with a flux anisotropy lower than a factor of 3. Due to the relatively large angular apertures of the EPD telescopes, the actual anisotropy may be larger than the observed one. The fine anisotropy observed by Galileo‐EPD reveals persistent pancake distributions at the M‐shell of M = 9. Outward of this distance, at M = 15 and M = 20–60, MeV electron distributions have pancake, isotropic, and scattered beam field‐aligned distributions. The scattered beam distributions can either be evidence of outward adiabatic transport or may suggest that high‐latitude auroral acceleration can transiently supply as much trapped MeV electrons to the middle magnetosphere as the inward adiabatic transport of electrons from an outer equatorial reservoir.