Patrick Hurh

Beryllium is widely used as a beam-window material in particle accelerators because its low atomic number and high specific stiffness minimize beam scattering while maintaining good thermal resistance. However, energetic proton irradiation alters its microstructure and degrades its mechanical performance. Temperature-resolved static mechanical data for proton-irradiated beryllium remain limited. Here, we report the behavior of PF-60 and S-65F, two widely used beryllium grades, using quasi-static uniaxial tensile and four-point bend testing at room temperature and elevated temperatures up to 400 °C. The materials were irradiated with 168 MeV protons at the Brookhaven Linac Isotope Producer (BLIP) facility to simulate service conditions relevant to high-energy accelerator environments. Mechanical properties including yield strength, ultimate tensile strength, elongation, and flexural response were evaluated to quantify the effects of irradiation and test temperature. Tensile results show pronounced irradiation hardening and embrittlement in both grades, with substantial reductions in elongation and ductility. Four-point bending complements tension by revealing temperature-dependent transitions from micro-crack initiation to macro-fracture and by providing flexural strength under a constant-moment stress field, thereby exposing failure features not evident from tensile data alone. Fractography of fractured tensile specimens correlates the observed property changes with irradiation-induced changes in fracture morphology. In parallel, ultrasonic measurements on a dose-graded specimen were used to assess the sensitivity of elastic modulus to radiation dose. Together, these results provide a temperature-resolved, application-relevant property dataset for irradiated beryllium and directly relate fracture morphology to mechanical behavior, supporting beam-window material selection and qualification under high-energy proton exposure.

A good knowledge of nuclear fragmentation cross sections is important to interpret the fluxes of secondary cosmic rays from the Galaxy. Here we report new measurements of nuclear fragmentation with the NA61/SHINE experiment at the CERN SPS. The specific focus is on cross sections important for the production of boron in the Galaxy from the interactions of C 12 nuclei with hydrogen in the interstellar medium, including the contribution from the decay of the short-lived C 11 fragments. The data were taken with the secondary C 12 beam at beam momentum of 13.5 GeV / c per nucleon and two fixed targets, polyethylene ( CH 2 ) and graphite (C), from which we derive the cross sections of carbon on hydrogen. We present the measurement of the fragmentation cross sections of C 11 , B 11 , and B 10 as well as the mass- and charge-changing cross sections. Published by the American Physical Society 2025

The U.S. Department of Energy's Office of Scientific and Technical Information

Superconducting Radio‐Frequency (SRF) cavities containing cryogens under pressure pose a potential rupture hazard to equipment and personnel. Generally, pressure vessels fall within the scope of the ASME Boiler and Pressure Vessel Code however, the use of niobium as a material for the SRF cavities is beyond the applicability of the Code. Fermilab developed a guideline to ensure sound engineering practices governing the design, fabrication, testing, installation and operation of SRF cavities. The objective of the guideline is to reduce hazards and to achieve an equivalent level of safety afforded by the ASME Code. The guideline addresses concerns specific to SRF cavities in the areas of materials, design and analysis, welding and brazing, pressure relieving requirements, pressure testing and quality control.