New Method for Measuring Pulsed Muon Beam Intensity Using Silver Activation
A study published on arXiv reports a new method for measuring the absolute intensity of pulsed muon beams using nuclear activation reactions in copper, zinc, and silver targets. Accurately counting negative muons in high-intensity pulsed beams has long been a challenge at particle accelerator facilities. The identification of the natAg(μ⁻, νμx)¹⁰⁷ᵐPd reaction as a reliable calibration reference could improve precision in a range of muon-based physics experiments.
Researchers have measured production branching ratios for muon nuclear capture reactions in natural-abundance copper, zinc, and silver, aiming to expand the toolkit for calibrating pulsed muon beam intensities at accelerator facilities. The in-beam activation method works by detecting beta-delayed gamma rays emitted by residual nuclei following muon capture, with short-lived isotopes enabling rapid intensity measurements during beam operation. Previously, only a limited number of isotopes had well-characterized branching ratios, constraining the method's applicability. After evaluating candidates on the basis of branching ratio strength, muon capture probability, detector efficiency, and the rarity of the target material in surrounding structures, the team identified the reaction of natural silver producing metastable palladium-107 (¹⁰⁷ᵐPd) as the most suitable new reference. This finding is expected to enhance the accuracy and flexibility of absolute muon number determinations in high-intensity pulsed beam environments. The work, submitted to arXiv on June 7, 2026, covers nine pages and includes three figures.
What's missing
The study's own scope is limited to a small set of target materials (Cu, Zn, and Ag), and the authors acknowledge that only a limited number of isotopes currently have reliable branching ratio data, leaving open the question of how broadly the method can be extended.
What different sources said
- arXiv physicsCenter
Absolute intensity measurement of pulsed muon beams using in-beam activation
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