Pareto Optimization and Tuning of a Laser Wakefield Accelerator.

Optimization of accelerator performance parameters is limited by numerous trade-offs, and finding the appropriate balance between optimization goals for an unknown system is challenging to achieve. Here, we show that multiobjective Bayesian optimization can map the solution space of a laser wakefield accelerator (LWFA) in a very sample-efficient way. We observe that there exists a wide range of Pareto-optimal solutions that trade beam energy versus charge at similar laser-to-beam efficiency.

Laser-accelerated electron beams at 1 GeV using optically-induced shock injection.

In recent years, significant progress has been made in laser wakefield acceleration (LWFA), both regarding the increase in electron energy, charge and stability as well as the reduction of bandwidth of electron bunches. Simultaneous optimization of these parameters is, however, still the subject of an ongoing effort in the community to reach sufficient beam quality for next generation's compact accelerators. In this report, we show the design of slit-shaped gas nozzles providing centimeter-long supersonic gas jets that can be used as targets for the acceleration of electrons to the GeV regime.

Measuring spatio-temporal couplings using modal spatio-spectral wavefront retrieval.

Knowledge of spatio-temporal couplings such as pulse-front tilt or curvature is important to determine the focused intensity of high-power lasers. Common techniques to diagnose these couplings are either qualitative or require hundreds of measurements. Here we present both a new algorithm for retrieving spatio-temporal couplings, as well as novel experimental implementations.

Radiation Exposure in the Acute Phase after Aneurysmal Subarachnoid Hemorrhage in the Era of CT Perfusion.

Purpose: Aneurysmal subarachnoid hemorrhage (aSAH) is associated with a high risk of developing multiple complications requiring further diagnostics including imaging associated with radiation exposure (RE). Since aSAH often affects younger patients, the obtained cumulative RE may have serious long-term health consequences. The aim of this study was to calculate the cumulative RE in the acute phase after aSAH and to identify contributors to RE.

On which evidence can we rely when prescribing off-label methotrexate in dermatological practice? - a systematic review with GRADE approach.

If an authorized drug is prescribed for a use that is not described in the Summary of Product Characteristics, this is defined as 'off-label use.' Methotrexate is often used off-label for dermatological indications. Off-label use is permitted if physicians can justify the treatment based on scientific evidence available to them.