Ultra-high dose rate dosimetry for pre-clinical experiments with mm-small proton fields.

PURPOSE To characterize an experimental setup for ultra-high dose rate (UHDR) proton irradiations, and to address the challenges of dosimetry in millimetre-small pencil proton beams. METHODS At the PSI Gantry 1, high-energy transmission pencil beams can be delivered to biological samples and detectors up to a maximum local dose rate of ∼9000 Gy/s. In the presented setup, a Faraday cup is used to measure the delivered number of protons up to ultra-high dose rates. The response of transmission ion-chambers, as well as of different field detectors, was characterized over a wide range of dose rates using the Faraday cup as reference. RESULTS The reproducibility of the delivered proton charge was better than 1 % in the proposed experimental setup. EBT3 films, Al2O3:C optically stimulated luminescence detectors and a PTW microDiamond were used to validate the predicted dose. Transmission ionization chambers showed significant volume ion-recombination (>30 % in the tested conditions) which can be parametrized as a function of the maximum proton current density. Over the considered range, EBT3 films, inorganic scintillator-based screens and the PTW microDiamond were demonstrated to be dose rate independent within ±3 %, ±1.8 % and ±1 %, respectively. CONCLUSIONS Faraday cups are versatile dosimetry instruments that can be used for dose estimation, field detector characterization and on-line dose verification for pre-clinical experiments in UHDR proton pencil beams. Among the tested detectors, the commercial PTW microDiamond was found to be a suitable option to measure real time the dosimetric properties of narrow pencil proton beams for dose rates up to 2.2 kGy/s

The Ganymede Laser Altimeter (GALA) for the Jupiter Icy Moons Explorer (JUICE): Mission, science, and instrumentation of its receiver modules

The Jupiter Icy Moons Explorer (JUICE) is a science mission led by the European Space Agency, being developed for launch in 2023. The Ganymede Laser Altimeter (GALA) is an instrument onboard JUICE, whose main scientific goals are to understand ice tectonics based on topographic data, the subsurface structure by measuring tidal response, and small-scale roughness and albedo of the surface. In addition, from the perspective of astrobiology, it is imperative to study the subsurface ocean scientifically. The development of GALA has proceeded through an international collaboration between Germany (the lead), Japan, Switzerland, and Spain. Within this framework, the Japanese team (GALA-J) is responsible for developing three receiver modules: the Backend Optics (BEO), the Focal Plane Assembly (FPA), and the Analog Electronics Module (AEM). Like the German team, GALA-J also developed software to simulate the performance of the entire GALA system (performance model). In July 2020, the Proto-Flight Models of BEO, FPA, and AEM were delivered from Japan to Germany. This paper presents an overview of JUICE/GALA and its scientific objectives and describes the instrumentation, mainly focusing on Japan’s contribution

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule

A Novel Spectral and Radiometric Calibration Target for the TIR Imager and the MARA Instrument on the Hayabusa2 Mission

At DLR we have developed a spectral and radiometric calibration target that will allow a cross calibration of the MARA and the TIR instrument. We use a serpentinite rock sample, which in the thermal infrared shows a strong spectral slope as well as well defined spectral feature. Obtaining measurements of this target with both instruments will greatly facilitate the correlation of orbital measurements obtained by the TIR with in-situ measurements by MARA. The calibration target is portable and highly adaptable, which will allow use for future mission

Commissioning of a clinical pencil beam scanning proton therapy unit for ultra‐high dose rates (FLASH)

Purpose: The purpose of this work was to provide a flexible platform for FLASH research with protons by adapting a former clinical pencil beam scanning gantry to irradiations with ultrahigh dose rates. Methods: PSI Gantry 1 treated patients until December 2018. We optimized the beamline parameters to transport the 250 MeV beam extracted from the PSI COMET accelerator to the treatment room, maximizing the transmission of beam intensity to the sample. We characterized a dose monitor on the gantry to ensure good control of the dose, delivered in spot-scanning mode. We characterized the beam for different dose rates and field sizes for transmission irradiations. We explored scanning possibilities in order to enable conformal irradiations or transmission irradiations of large targets (with transverse scanning). Results: We achieved a transmission of 86 % from the cyclotron to the treatment room. We reached a peak dose rate of 9000 Gy/s at 3 mm water equivalent depth, along the central axis of a single pencil beam. Field sizes of up to 5x5 mm$^{2}$ were achieved for single spot FLASH irradiations. Fast transverse scanning allowed to cover a field of 16x1.2 cm$^{2}$. With the use of a nozzle-mounted range shifter we are able to span depths in water ranging from 19.6 to 37.9 cm. Various dose levels were delivered with a precision within less than 1 %. Conclusions: We have realized a proton FLASH irradiation setup able to investigate continuously a wide dose rate spectrum, from 1 to 9000 Gy/s in a single spot irradiation as well as in the pencil beam scanning mode. As such, we have developed a versatile test bench for FLASH research.Comment: Submitted to Medical Physic

Faraday cup for commissioning and quality assurance for proton pencil beam scanning beams at conventional and ultra-high dose rates.

Recently, proton therapy treatments delivered with ultra-high dose rates have been of high scientific interest, and the Faraday cup (FC) is a promising dosimetry tool for such experiments. Different institutes use different FC designs, and either a high voltage guard ring, or the combination of an electric and a magnetic field is employed to minimize the effect of secondary electrons. The authors first investigate these different approaches for beam energies of 70, 150, 230 and 250 MeV, magnetic fields between 0 and 24 mT and voltages between -1000 and 1000 V. When applying a magnetic field, the measured signal is independent of the guard ring voltage, indicating that this setting minimizes the effect of secondary electrons on the reading of the FC. Without magnetic field, applying the negative voltage however decreases the signal by an energy dependent factor up to 1.3% for the lowest energy tested and 0.4% for the highest energy, showing an energy dependent response. Next, the study demonstrates the application of the FC up to ultra-high dose rates. FC measurements with cyclotron currents up to 800 nA (dose rates of up to approximately 1000 Gy s-1) show that the FC is indeed dose rate independent. Then, the FC is applied to commission the primary gantry monitor for high dose rates. Finally, short-term reproducibility of the monitor calibration is quantified within single days, showing a standard deviation of 0.1% (one sigma). In conclusion, the FC is a promising, dose rate independent tool for dosimetry up to ultra-high dose rates. Caution is however necessary when using a FC without magnetic field, as a guard ring with high voltage alone can introduce an energy dependent signal offset

First collection of landrace vegetable crops cultivated in Valle Fértil, Argentina

La riqueza cultural de las comunidades andinas de la Argentina está integrada por la diversidad de sus recursos genéticos, el desarrollo de un sistema agrícola sostenible y por el mantenimiento de sus semillas. La agricultura local es una actividad económica familiar, donde las variedades tradicionales de hortalizas son muy apreciadas por su sabor, color y aroma. Sin embargo, distintos factores sociales, económicos y ambientales afectan la diversidad de tales cultivos. Los objetivos de este trabajo fueron recuperar y conservar una muestra representativa de los recursos genéticos vegetales tradicionales aún presentes en el departamento de Valle Fértil, provincia de San Juan, Argentina, y documentar las experiencias y usos de ellos por parte de los productores. Se entrevistaron 50 familias de las cuales 26 donaron un total de 49 muestras pertenecientes a ocho especies. Las variedades criollas recolectadas mostraron una distribución geométrica típica en comunidades con pocasespecies, y un patrón de dominancia donde algunas especies están presentes en casi todas las huertas mientras que especies poco representadas se encuentran en ambientes específicos. La recuperación del germoplasma local puede prevenir la erosión genética, de modo que tanto los mejoradores como los productores puedan aprovechar la diversidad de esta colección.The richness of the cultural values found in the Argentinean Andean communities is integrated by a varied diversity of genetic resources, the development of a sustainable agriculture, and the conservation of the producer’s own seeds. Local agriculture is a family economic activity, in which traditional varieties of vegetable landraces are highly appreciated for their flavour, colour and aromas. However; social, economic and environmental factors have an effect on crop diversity conservation. The main aim of this work was to retrieve and maintain a representative collection of traditional crop genetic resources still cultivated in the District of Valle Fértil, San Juan Province, Argentina, and to document the farmers’ crop experiences and uses. Fifty families were interviewed; 26 of these donated a total of 49 samples belonging to eight species. The landraces collected showed a geometric distribution, typical of communities with low number of species; and a pattern of dominance. A few species are present in almost all farms while rare species are found in specific environments. Local germplasm recovery can prevent genetic erosion, so that both the formal breeding sector and the farmers can make use of the diversity of this collection.Fil: Asprelli, Pablo Diego. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lorello, Inés María. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Occhiuto, Patricia Noemí. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Togno, M. A.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Makuch, M. A.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Garcia Lampasona, Sandra Claudia. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Peralta, Iris Edith. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin

Commissioning of a clinical pencil beam scanning proton therapy unit for ultra-high dose rates (FLASH).

PURPOSE The purpose of this work was to provide a flexible platform for FLASH research with protons by adapting a former clinical pencil beam scanning gantry to irradiations with ultra-high dose rates. METHODS PSI Gantry 1 treated patients until December 2018. We optimized the beamline parameters to transport the 250 MeV beam extracted from the PSI COMET accelerator to the treatment room, maximizing the transmission of beam intensity to the sample. We characterized a dose monitor on the gantry to ensure good control of the dose, delivered in spot-scanning mode. We characterized the beam for different dose rates and field sizes for transmission irradiations. We explored scanning possibilities in order to enable conformal irradiations or transmission irradiations of large targets (with transverse scanning). RESULTS We achieved a transmission of 86 % from the cyclotron to the treatment room. We reached a peak dose rate of 9000 Gy/s at 3 mm water equivalent depth, along the central axis of a single pencil beam. Field sizes of up to 5x5 mm2 were achieved for single spot FLASH irradiations. Fast transverse scanning allowed to cover a field of 16x1.2 cm2 . With the use of a nozzle-mounted range shifter, we are able to span depths in water ranging from 19.6 to 37.9 cm. Various dose levels were delivered with precision within less than 1 %. CONCLUSIONS We have realized a proton FLASH irradiation setup able to investigate continuously a wide dose rate spectrum, from 1 to 9000 Gy/s in single spot irradiation as well as in the pencil beam scanning mode. As such, we have developed a versatile test bench for FLASH research

Comparing radiolytic production of H₂O₂ and development of Zebrafish embryos after ultra high dose rate exposure with electron and transmission proton beams.

The physico-chemical and biological response to conventional and UHDR electron and proton beams was investigated, along with conventional photons. The temporal structure and nature of the beam affected both, with electron beam at ≥1400 Gy/s and proton beam at 0.1 and 1260 Gy/s found to be isoefficient at sparing zebrafish embryos