A negative muonium ion (${\mathrm{Mu}}^{-}$) source using an aluminum foil target (Al target) was developed as a low-energy muon source. ${\mathrm{Mu}}^{-}$ ions are produced by irradiating the Al target with a 3-MeV positive muon (${\mu }^{+}$) beam and observed using a microchannel plate. An experiment to produce ${\mathrm{Mu}}^{-}$ ions was conducted to evaluate the performance of this ${\mathrm{Mu}}^{-}$ ion source. The measured event rate of ${\mathrm{Mu}}^{-}$ ions was $(1.7\pm 0.3)\times {10}^{-3}{\mathrm{Mu}}^{-}/\mathrm{s}$ when the event rate of the incident ${\mu }^{+}$ beam was $1.3\times {10}^6/\mathrm{s}$. The experiment was conducted at the Muon Science Establishment, D-line in the Materials and Life Science Experimental Facility within the Japan Proton Accelerator Research Complex. The formation probability, defined as the ratio of the ${\mathrm{Mu}}^{-}$ ions to the incident muons on the Al target, was $(1.1\pm 0.2(\mathrm{stat}{)}_{+0.1}^{-0.0}(\mathrm{syst}))\times {10}^{-6}$. This ${\mathrm{Mu}}^{-}$ ion source was first adopted in the commissioning of the muon accelerator at the D-line, and the event rate of the accelerated ${\mathrm{Mu}}^{-}$ ions was consistent with the expectation. This ${\mathrm{Mu}}^{-}$ ion source boosted the development of the muon accelerator, and the practicality of this low-energy muon source obtained using a relatively simple apparatus was demonstrated.

中文翻译：

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用于加速介子的负acceleration离子源的开发

负mu离子（${亩}^{-}$）开发了使用铝箔靶材（Al靶材）的低能μon光源。 ${亩}^{-}$ 离子是通过用3-MeV正介子辐照铝靶产生的（${\mu }^{+}$）光束，并使用微通道板进行观察。产生实验${亩}^{-}$ 进行离子测试以评估其性能 ${亩}^{-}$离子源。测得的事件发生率${亩}^{-}$ 离子原为 $（1.7\pm 0.3）\times {10}^{-3}{亩}^{-}/\mathrm{s}$ 当事件的事件发生率 ${\mu }^{+}$ 梁是 $1.3\times {10}^6/\mathrm{s}$。该实验是在日本质子加速器研究中心材料与生命科学实验设施的Muon科学机构D-line进行的。形成概率，定义为${亩}^{-}$ 离子对铝靶上的入射μ子， $（1.1\pm 0.2（\mathrm{统计}{）}_{+0.1}^{-0.0}（\mathrm{系统}））\times {10}^{-6}$。这个 ${亩}^{-}$ 离子源首先用于在D线的μon加速器的调试中，并且加速的事件发生率 ${亩}^{-}$离子与预期一致。这个${亩}^{-}$ 离子源促进了μon加速器的发展，并证明了使用相对简单的设备获得的这种低能耗μon离子源的实用性。