Within the context of a design study of a LINAC for ionization cooling, this paper presents the result of incorporating a scattering model in RF-Track (v2.1) for charged particles heavier than electrons. This inclusion enables simulations for applications like ionization cooling channels for muon colliders. Within RF-Track, a novel semi-Gaussian mixture model has been introduced to describe the deflection of charged particles in material. This innovative model comprises a Gaussian core and a non-Gaussian tail function to account for the effects of single hard scattering. To validate the accuracy of our results, we conducted a benchmarking comparison against other particle tracking codes, with the outcomes demonstrating a high level of agreement.

Ionization cooling stands as the only cooling technique capable of efficiently reducing the phase space of a muon beam within a short time frame. The optimal cooling parameters of a muon collider aim to minimize transverse emittance while simultaneously limiting longitudinal emittance growth, resulting in optimal luminosities within the collider ring. This study shows that achieving efficient cooling performance requires selecting the best initial muon beam parameters. Because for every transvere emittance there exist an optimal beam energy for ionization cooling. We present a technique that enables the determination of these optimal initial parameters through simulations and compare them with an improved analytical scattering model.

Dielectric laser acceleration (DLA) is a promising approach to accelerate single electrons at a high repetition rate to GeV energies, for indirect dark matter searches. Relevant concepts include the integration of the dielectric structure inside the laser oscillator. To efficiently use muons for high energy physics applications, they need to be accelerated rapidly, before they decay. Plasma acceleration achieves GV/m accelerating fields and could be ideal for accelerating to muon-collider energies. Single muons could also be accelerated in DLAs for dark matter searches. They could be injected from existing low-intensity muon sources, such as the one at PSI. A workshop organized in the frame of the EU project “Innovation Fostering in Accelerator Science and Technology” (I.FAST) focused on GHz Rate & Rapid Muon Acceleration for Particle Physics to address these topics. We report highlights and future research directions.

Circular muon colliders provide the potential to explore center-of-mass energies at the multi-TeV scale within a relatively compact footprint. Because of the short muon lifetime, only a small fraction of stored beam particles will contribute to the physics output, while most of the muons will decay in the collider ring. The resulting power carried by decay electrons and positrons can amount to hundreds of Watt per meter. Dedicated shielding configurations are needed for protecting the superconducting magnets against the decay-induced heat and radiation damage. In this paper, we present generic shielding studies for two different collider options (3 TeV and 10 TeV), which are presently being explored by the International Muon Collider Collaboration. We show that the key parameter for the shielding design is the heat deposition in the magnet cold mass, which will be an important cost factor for facility operation due to the associated power consumption.

Muon production in the multi-TeV muon collider studied by the International Muon Collider Collaboration is planned to be performed with a high-power proton beam interacting with a fixed target. The design of the target area comes with a set of challenges related to the radiation load to front-end equipment. The confinement of the emerging pions and muons requires very strong magnetic fields achievable only by superconducting solenoids, which are sensitive to heat load and long-term radiation damage. The latter concerns the ionizing dose in insulation, as well as the displacement damage in the superconductor. The magnet shielding design has to limit the heat deposition and ensure that the induced radiation damage is compatible with the operational lifetime of the muon production complex. Finally, the fraction of the primary beam passing through the target unimpeded poses a need for an extraction channel. In this study, we use the FLUKA Monte Carlo code to assess the radiation load to the solenoids, and we explore the possible spent proton beam extraction scenarios taking into account the constraints stemming from the beam characteristics and the required magnetic field strength.

Ionization cooling stands as the only cooling technique capable of efficiently reducing the phase space of a muon beam within a short time frame. The optimal cooling parameters of a muon collider aim to minimize transverse emittance while simultaneously limiting longitudinal emittance growth, resulting in optimal luminosities within the collider ring. This study shows that achieving efficient cooling performance requires selecting the best initial muon beam parameters. Because for every transvere emittance there exist an optimal beam energy for ionization cooling. We present a technique that enables the determination of these optimal initial parameters through simulations and compare them with an improved analytical scattering model.

Within the context of a design study of a LINAC for ionization cooling, this paper presents the result of incorporating a scattering model in RF-Track (v2.1) for charged particles heavier than electrons. This inclusion enables simulations for applications like ionization cooling channels for muon colliders. Within RF-Track, a novel semi-Gaussian mixture model has been introduced to describe the deflection of charged particles in material. This innovative model comprises a Gaussian core and a non-Gaussian tail function to account for the effects of single hard scattering. To validate the accuracy of our results, we conducted a benchmarking comparison against other particle tracking codes, with the outcomes demonstrating a high level of agreement.