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At least 793 records · Page 44

Deuteron-induced reactions on natural Zr from threshold to 50 MeV: production of 86g Y

Two stacks of thin Zr foils were irradiated with 30 and 50 MeV deuterons, respectively, using the Lawrence Berkeley National Laboratory 88-Inch Cyclotron, and 19 excitation functions for nat Zr(d,x) reactions were measured over a beam energy range of 6.3–47.64 MeV, where the independent cross sections for nat Zr(d,x) 88 Nb and nat Zr(d,x) 86m,g Y were measured for the first time. The well-characterized nat Fe(d,x) 56 Co, nat Ni(d,x) 56 Co, nat Ni(d,x) 58 Co, nat Ni(d,x) 61 Cu, nat Ti(d,x) 46 Sc and nat Ti(d,x) 48 V monitor reactions were used to determine the deuteron beam current throughout the stacks. All cross sections were determined using High Purity Germanium (HPGe) detector γ-ray spectroscopy. A variance minimization technique was employed to simultaneously constrain the deuteron beam currents with multiple monitor reactions, thus reducing systematic uncertainties. An additional 16 channels are reported for reactions on the nickel, titanium, and iron monitor foils, leading to a total of 35 excitation functions, with seven reaction channels reported for the first time in this work. The measured excitation functions are compared to calculations provided by the reaction modeling codes TALYS – 2.0, ALICE – 2020, CoH – 3.5.3 and EMPIRE – 3.2.3, as well as the TENDL – 2023 data library. The degree of agreement between theory and experiments is discussed. The possible production of the important PET radionuclide 86g Y via the nat Zr(d,x) route was critically examined. The physical yields for nat Zr(d,x) 86 Y and other yttrium isotopes produced were calculated and compared to other production pathways. Due to high-level of associated radionuclide impurities, this route cannot deliver 86g Y suitable for medical applications.

86gY↗

Detection Thresholds and Sensitivities of Geophysical Techniques for CO2 Plume Monitoring

This report assesses capabilities and limitations of different geophysical techniques for monitoring geologic sequestration of CO 2 . Seismic, gravity, electrical, and electromagnetic (EM) techniques are considered. Monitoring approaches for site characterization prior to CO 2 injection are different from those used while injecting CO 2 , or those suitable for post-injection monitoring. The focus of this study is on the aspects relevant to long-term monitoring of large areas in the post-injection phase, and specifically on early detection of secondary CO 2 plumes.

54 ENVIRONMENTAL SCIENCES↗

Applications of seismic threshold monitoring at an Antarctic glacier [Slides]

Geophysical waveforms collected from Arctic regions provides data required for monitoring global security targets. Some seismic instruments deployed on Scandinavian and Greenlandic sites provide waveform data, but these installations include specific challenges: Sea ice and glacial ice generates waveform interference; Meltwater generates narrowband interference, resembling tonal noise.

58 GEOSCIENCES↗

Discriminator Threshold Study for Scint 1

During electronics testing at NSRL, the fluence/spill is recorded from the QC1 chamber. This chamber, which is a permanent fixture on the NSRL beamline, requires calibration from an external radiation detector that can measure ion flux directly. A 1.0 × 1.0 × 0.5 cm 3 scintillator is used at the testing location to calibrate all NSRL beams for electronic experiments. A calibration factor is derived by comparing the ions observed by the scintillator and QC1 during an exposure of at least 10 5 scintillator counts or total ions.

43 PARTICLE ACCELERATORS↗