A harp system is being developed for monitoring proton beam profile direct upstream of the proton beam window at the Second Target Station of the Spallation Neutron Source, Oak Ridge National Laboratory. It consists of two sensor planes which have arrays of thin conducting wires aligned vertically and horizontally, respectively. It monitors beam profiles in two transverse directions to the beam axis by measuring the net-charge depositions in the sensor wires, which are caused by ejection of secondary electrons and delta rays driven by electromagnetic interactions with high-energy protons. The net charge deposition in a sensing wire linearly correlates with the number of incident protons on it. This correlation is perturbed when the wire interacts with secondary electrons and delta rays originating from beam-matter interactions in neighboring wires, PBW and residual gases. In this paper, we analyze the physical phenomena that affects the measurement uncertainties of the harp using particle transport simulations.

A unique opportunity exists to investigate alternative radionuclide production technologies utilizing the high-energy proton beams available at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The Second Target Station (STS) is being built to address emerging science challenges in energy, security, and transportation. The STS will complement the capabilities of the First Target Station (FTS) and High Flux Isotope Reactor (HFIR) by filling gaps in materials research that require the combined use of intense, long-wavelength (cold) neutrons, and instruments that are optimized for exploration of complex materials. The construction of the STS beamline to the target also presents an opportunity to capitalize on additional applications, such as the production of high-demand radioisotopes for medical applications. Work began in 2024 to investigate the possibility of Radioisotope Production at SNS (RIPS) through four main goals: (1) identification of isotopes of interest through the modeling and simulation of prospective irradiation parameters and target compositions, (2) development of a target design concept that can receive high energy beam pulses from the SNS accelerator, (3) identification of enhanced isotope separation methods for SNS produced radionuclides, and (4) a design concept for an experimental/demonstration facility. An overview of the project and progress towards achieving these goals will be presented.

Completion of the Proton Power Upgrade Project for the Spallation Neutron Source (SNS) accelerator at Oak Ridge National Laboratory opens an opportunity to utilize reserve beam power of more than 100 kW for applications beyond neutron production. One of these applications is the production of critical radionuclides. To demonstrate the feasibility of using the reserve beam power to produce radioisotope at SNS, a design concept of a small-scale experimental target station in the Linac Dump area has been developed. This experimental facility will provide isotope yield benchmarking data using protons in the GeV range. It will also enable additional research and development in isotope handling and radiochemical separation. The target station consists of a target module enclosed in a vessel and concrete shielding. Particle transport calculations and thermo-mechanical simulations are used to determine beam parameters, decay time, isotope yield, shielding dimensions, and target design parameters. Calculations verified that the irradiated capsule can be handled manually using hands-off tools and transported to a hot cell in a shielded container for post-irradiation characterizations.

Upon completion of the Second Target Station (STS) Project in the mid 2030s, the Spallation Neutron Source accelerator at Oak Ridge National Laboratory will deliver a 2.7 MW proton beam to the neutron production targets. In the post-STS phase, the accelerator will have a reserve beam power capacity of at least 100 kW beyond what the two neutron production targets will receive, which could potentially be ramped up to 300 kW. In this paper, a design concept for a radioisotope production target that could utilize 250 kW of the reserve beam power capacity is presented. The target consists of thorium discs encapsulated in 316L austenitic steel shells that are cooled by water. The estimated post-irradiation activity of Ac-225 and Ra-225, critical medical radioisotopes used in targeted alpha therapy cancer treatment, is calculated at the end of bombardment after a 14 day long irradiation time. Thermal and structural analyses are performed on the basis of calculated nuclear heating data. The technical feasibility of a high-power target under a 250-kW beam load with an extremely low duty factor of $3.5\cdot 10^{-6}$ is presented from thermal, structural and fatigue lifetime perspectives.