The demand for muon facilities has been continuously increasing since surface muons play a significant role in particle and solid-state physics. The installation of a refurbished muon target station and two new High-Intensity Muon Beam lines (HIMB) in the framework of the Isotope and Muon Production using Advanced Cyclotron and Target technology project (IMPACT) at PSI will pave the way to unprecedented muon intensities allowing, among others, next generation lepton flavor violation experiments. In this context, a new collimation system composed of three collimators made of oxygen free copper has been designed in order to reduce the divergence of the proton beam due to multiple scattering in the new target. The thermomechanical integrity of each collimator has to be investigated also in the prospect of an increased proton beam current up to 3 mA. The cooling of the collimator system is provided by water flowing in a system of eight helicoidal stainless steel pipes brazed to the main copper bodies. Steady-state computational fluid dynamics simulations and tailored semi-analytical models in the ANSYS software package have been used to provide the optimal design of the collimator system.

The Isotope and Muon Production using Advanced Cyclotron and Target technology (IMPACT) project at the Paul Scherrer Institut aims to produce and fully exploit unprecedented quantities of muons and radionuclides for further progress in particle physics, material science and life science. The proposed Targeted Alpha Tumor Therapy and Other Oncological Solutions (TATTOOS) facility will provide, for research purposes, medically relevant radionuclides, especially α-emitters, via proton-induced spallation. This new 100 μA / 590 MeV proton beamline will deliver up to 40 kW to an oxygen-free copper beam dump. A hybrid analytical / numerical cooling model was developed to reduce the simulation time and the total amount of CFD simulations. This model consists of analytical surface temperatures applied as boundary conditions to an ANSYS thermal model. It was validated using CFD simulations and then used in the design process of the beam dump. Since the copper blocks are brazed together at temperatures beyond the recrystallization point, a temperature dependent multilinear isotropic hardening model was used to simulate the behavior of soft-ductile annealed copper. Irradiation induced hardening was also taken into account to ensure that no exhaustion of ductility would occur in the beam dump.

The proposed Targeted Alpha Tumor Therapy and Other Oncological Solutions (TATTOOS) facility at the Paul Scherrer Institute aims to produce radionuclides, especially alpha-emitters, via proton-induced spallation for potential clinical studies of advanced cancer treatments. This new 100 microA / 590 MeV proton beamline delivers in the best-case scenario 26 kW to the target. In this study, a numerical CFD model for the TATTOOS target was developed. The boundary condition to this model is the energy deposition calculated with the particle transport Monte Carlo method. Since the operation temperature of the target is up to 2900 degree Celsius, close to the melting point of Ta, to enable the diffusion of the radionuclides, the temperature distribution of the target has to be well predicted. As it is not possible to cool the target directly, the main cooling is by radiation. For this reason, it is important to optimize the geometry of the target by maximizing the surface area. The incoming Gaussian beam will induce an inhomogeneous temperature distribution on the spallation target, consisting of stacked discs. To ensure that the temperature of the target is within the acceptable limits, a twofold optimization strategy was selected. Firstly, the inner geometry of the target was optimized using a genetic algorithm, to ensure uniform power deposition. Secondly, a more spread “wobbled” beam and a large outer surface area will be used.