Ionoacoustics for three-dimensional particle bunch monitoring

Ionoacoustics refers to the measurement of acoustic waves excited by ions as they slow down in matter. One particularly interesting application is the monitoring of individual laser-accelerated ion bunches, which challenges many established online detection systems. The ionoacoustic approach offers advantages in this context. It is resistant to the strong electromagnetic pulse emitted during the laser-plasma interaction, and it does not exhibit saturation even at very high particle fluxes. Recovering the Ion-Bunch Energy distribution from a recorded Acoustic Trace (I-BEAT) has conceptually been proven. This work introduces two new detector designs, the I-BEAT 3D and the TI-BEAT detector, and develops a fast analysis routine based on an analytical model. The result is a novel and versatile online detector for short and intense ion bunches that enables immediate feedback. Describing the dose deposition of protons in matter, particularly in the entrance window and the water reservoir of the detector, connects the most important proton bunch parameters to the resulting ionoacoustic signals and hence serves for the development of a simple and fast data analysis method for particle bunches with Gaussian energy spectra and lateral distributions. This is key to the analysis and interpretation of the acoustic traces obtained with the detector designs. The I-BEAT 3D detector uses four transducers and is studied in experiments at two laser-driven proton beamlines located at CALA and the HZDR. Via the new analytical model, it provides the mean bunch energy, energy spread and lateral bunch position of individual bunches in less than one second. Additionally, the detector allows the monitoring of relative changes in lateral bunch size. Experiments with proton bunches at kinetic energies between 10 MeV and 30 MeV reveal sub-MeV and sub-mm resolution. Cross-calibration using radiochromic films proves that the new methodology can determine the absolute number of particles contained in a single bunch with uncertainties of only 10%. The TI-BEAT detector uses a short water reservoir to allow ions with sufficient energy to pass through. It is developed to prove that ionoacoustics can also function as transmission monitor for particle bunches. The detector concept is evaluated at the GSI’s SIS-18 synchrotron with xenon ions at kinetic energies of 385 MeV/u. The precision of determining the absolute lateral position and relative changes in the lateral size of ion bunches is 0.15 mm and less than 0.1 mm, respectively. The particle number is extracted with a precision between 4% and 8%. The new detector designs and the data evaluation method provide a fast, compact, cost-effective and electromagnetic pulse-resistant online tool for monitoring important ion bunch parameters at application sites. This provides the foundation for irradiation studies and can serve as feedback for automated optimization of laser-driven proton sources

Beam characterization and feasibility study for a small animal irradiation platform at clinical proton therapy facilities

A deeper understanding of biological mechanisms to promote more efficient treatment strategies in proton therapy demands advances in preclinical radiation research. However this is often limited by insufficient availability of adequate infrastructures for precision image guided small animal proton irradiation. The project SIRMIO aims at filling this gap by developing a portable image-guided research platform for small animal irradiation, to be used at clinical facilities and allowing for a precision similar to a clinical treatment, when scaled down to the small animal size. This work investigates the achievable dosimetric properties of different lowest energy clinical proton therapy beams, manipulated by a dedicated portable beamline including active focusing after initial beam energy degradation and collimation. By measuring the lateral beam size in air close to the beam nozzle exit and the laterally integrated depth dose in water, an analytical beam model based on the beam parameters of the clinical beam at the Rinecker Proton Therapy Center was created for the lowest available clinical beam energy. The same approach was then applied to estimate the lowest energy beam model of different proton therapy facilities, Paul Scherrer Institute, Centre Antoine Lacassagne, Trento Proton Therapy Centre and the Danish Centre for Particle Therapy, based on their available beam commissioning data. This comparison indicated similar beam properties for all investigated sites, with emittance values of a few tens of mm·mrad. Finally, starting from these beam models, we simulated propagation through a novel beamline designed to manipulate the beam energy and size for precise small animal irradiation, and evaluated the resulting dosimetric properties in water. For all investigated initial clinical beams, similar dosimetric results suitable for small animal irradiation were found. This work supports the feasibility of the proposed SIRMIO beamline, promising suitable beam characteristics to allow for precise preclinical irradiation at clinical treatment facilities

Bewertung von Vogelarten bei der Zulassung von Pestiziden in Europa

Es wird eine Übersicht zur Vorgehensweise der Risikobewertung von Vögeln zu potentiell durch Pflanzenschutzmittel auftretenden akuten und reproduktiven Effekten gegeben. Grundlage einer solchen Risikobewertung ist die aktuelle Richtlinie (EFSA 2009) der europäischen Behörde für Lebensmittelsicherheit, EFSA. Nach kurzer Einleitung über die Veränderungen der Zulassungsbestimmungen für Vögel der Agrarlandschaft und Erläutern des grundsätzlichen Prozedere, wird an einem Beispiel eines fiktiven Fungizids eine Risikobewertung exemplarisch aufgezeigt. Grundlagen der derzeitigen Risikobewertung und deren Bewertung durch die Richtlinie werden kurz diskutiert.Stichwörter: Risikobewertung, Pflanzenschutzmittel, VögelAssessing bird species in the registration process of pesticides in EuropeAbstractWe provide an overview and discussion of the methodology currently used to assess the acute and chronic (i.e. reproductive) risk posed by plant protection products to birds. The methodology follows guidance published by the European Food Safety Authority, EFSA (EFSA, 2009). Our overview begins with a short introduction including a brief discussion of recent changes to the regulations on which the EFSA Guidance is based. The standard risk assessment procedure is then explained using the example of a hypothetical fungicide. This is followed by a discussion of the basis, weighting and evaluation of the current risk assessment methodology for birds.Keywords: risk assessment, plant protection products, bird

Tango Controls and data pipeline for petawatt laser experiments

The Centre for Advanced Laser Applications in Garching, Germany, is home to the ATLAS-3000 multi-petawatt laser, dedicated to research on laser particle acceleration and its applications. A control system based on Tango Controls is implemented for both the laser and four experimental areas. The device server approach features high modularity, which, in addition to the hardware control, enables a quick extension of the system and allows for automated data acquisition of the laser parameters and experimental data for each laser shot. In this paper we present an overview of our implementation of the control system, as well as our advances in terms of experimental operation, online supervision and data processing. We also give an outlook on advanced experimental supervision and online data evaluation – where the data can be processed in a pipeline – which is being developed on the basis of this infrastructure