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At least 523 records · Page 29

rf chopper for prebunched radioactive ion beams

An rf chopper system is being designed for the ReAccelerator (ReA) linac at the Facility for Rare Isotope Beams at Michigan State University. The 80.5 MHz ReA radio-frequency quadrupole accelerates prebunched 16.1 MHz beams, producing four satellite bunches for every main bunch. The chopper system includes an rf deflector that kicks every bunch vertically to spatially separate main and satellite bunches. A constant magnetic field superimposed with the chopper electric field biases the beam trajectory to ensure the high-intensity bunches do not experience a net deflection and are injected straight to the ReA6 cryomodule or sent for experiments. The kicked bunches are low in intensity and will be sent to a beam dump, resulting in a clean 16.1 MHz beam structure, which allows for a reliable time-of-flight separation of the isotopes. Published by the American Physical Society 2024

Physics↗

Comparison of Feschenko BSM and Fast Faraday Cup with Low Energy Ion Beams

A comparison between Fast Faraday Cup and Feschenko longitudinal bunch shape detectors was recently performed at HELIAC Advanced Demonstrator beamline at GSI. Feschenko bunch shape monitor (BSM) uses the time to space conversion by means of secondary electrons emitted from a wire correlated to a rf deflector, while the fast Faraday cup (FFC) measures the deposited charge in a cup geometry matched to 50 Ohm. The FFC design aims to minimize the bunch shape dilution due to field polarization and secondary electrons produced on irradiation. An He¹⁺ with 100 µA average current and 1.4 MeV/u kinetic energy is utilized for this comparison. A buncher upstream of the detectors was operated to focus the beam longitudinally. The results are discussed in this contribution.

43 PARTICLE ACCELERATORS↗

Volume 9: Critical Facility with Add-On Ion Beam

Completion of the originally planned critical facility has been considered as part of the High Flux Isotope Reactor (HFIR) Sustaining and Enhancing Neutron Science Initiative at Oak Ridge National Laboratory (ORNL). A working group of ORNL staff members was formed to develop the idea and to recommend one or more configurations to best support future HFIR operations and scientific capacities. HFIR was designed with a critical pool in the reactor bay that was projected to be outfitted as a critical facility. The primary purpose of the planned critical facility was to measure the subcritical worth of fresh fuel elements to support startup requirements. However, the Y-12 National Security Complex already housed a critical facility that was used for this purpose. This report presents the working group’s efforts, including determination of the proposed critical facility’s high-impact benefits. A generic low-power critical facility would be employed for reactor physics measurements, code and data validation, reactor operator and staff training, and education. This facility would be instrumental in supporting current HFIR operations, conversion of HFIR to low-enriched uranium, existing light water reactor operations, and advanced reactor development and deployment.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗