Design of a high power production target for the beam dump facility at CERN

Abstract

The Beam Dump Facility (BDF) project is a proposed general-purpose facility at CERN, dedicated to beam dump and fixed target experiments. In its initial phase, the facility is foreseen to be exploited by the Search for Hidden Particles (SHiP) experiment. Physics requirements call for a pulsed 400 GeV/c proton beam as well as the highest possible number of protons on target (POT) each year of operation (4.0 · 10 13 /year), in order to search for feebly interacting particles. The target/dump assembly lies at the heart of the facility, with the aim of safely absorbing the full high intensity Super Proton Synchrotron (SPS) beam, while maximizing the production of charmed and beauty mesons. High-Z materials are required for the target/dump, in order to have the shortest possible absorber and reduce muon background for the downstream experiment. The design of the production target is one of the most challenging aspects of the facility design, due to the high energy and power density deposition that are reached during operation, and the resulting thermomechanical loads. The nature of the beam pulse induces very high temperature excursions between pulses (up to 100 • C), leading to considerable thermally-induced stresses and long-term fatigue considerations. The high average power deposited on target (305 kW) creates a challenge for heat removal. During the BDF facility Comprehensive Design Study (CDS), launched by CERN in 2016, extensive studies have been carried out in order to define and assess the target assembly design. These studies are described in the present contribution, which details the proposed design of the BDF production target, as well as the material selection process and the optimization of the target configuration and beam dilution. One of the specific challenges and novelty of this work is the need to consider new target materials, such as a molybdenum alloy (TZM) as core absorbing material and Ta2.5W as cladding. Thermo-structural and fluid dynamics calculations have been performed to evaluate the reliability of the target and its cooling system under beam operation. In the framework of the target comprehensive design, a preliminary mechanical design of the full target assembly has also been carried out, assessing the feasibility of the whole target system.

Tau neutrinos in the next decade: from GeV to EeV

“…The setup consists of a high-density proton target located in a target bunker [319][320][321], followed by a hadron stopper and a muon shield [322]. The target is made of blocks of a titanium-zirconium doped molybdenum alloy, followed by blocks of pure tungsten.…”

Study of alternative locations for the SPS Beam Dump Facility

“…The beam is dumped on a 12λ target/dump composed of disks of molybdenum alloy and tungsten, cladded with a diffusion bonded tantalum alloy [26,27]. The disks are separated by thin gaps for active water cooling within a closed pressurised vessel.…”

Monte Carlo simulation of proton- and neutron-induced radiation damage in a tantalum target irradiated by 70 MeV protons

“…However, as it is frequently used as spallation material and also regarded as a plasma-facing material [60] and solid target for neutrino production [61], a few data do exist. In addition, tungsten ( Z = 74 ) behaves in a similar way to tantalum and is often alloyed or coated with tantalum (solid solution) to reduce corrosion-erosion effects [62][63][64]. Investigations of such Ta-clad W targets may at least partly reflect the radiation damage behavior of tantalum.…”