Delivering the world's most intense muon beam
Delivering the world's most intense muon beam
复制标题
DOI：
10.1103/physrevaccelbeams.20.030101
复制
发表时间：
2017-03-15
影响因子：
1.7
通讯作者：
Yoshida, M.
中科院分区：
文献类型：
--
作者：
Cook, S.;D'Arcy, R.;Yoshida, M.
在日本大坂大坂大学核物理研究中心建立了一条新的μ子束线，即μ子科学创新通道，使用392 MeV质子束撞击靶。强μ子束的产生依赖于使用新型超导螺线管磁体系统有效捕获π介子，π介子随后衰变为μ子。在π介子捕获螺线管之后，第一个36度的弯曲μ介子传输线被调试，μ介子通量被测量。为了探测μ子，放置了铜或镁的靶，以阻止μ子束线末端的μ子。位于μ子靶上游和下游的两个塑料衰减器站被用来重建μ子的衰变谱。在检测带负电荷的μ子的补充方法中，在锗检测器中测量靶中μ子原子产生的X射线光谱。在6 pA的质子束流下进行的测量产生了（10.4 +/- 2.7）x 10（5）μ子/瓦特的质子束功率（μ（+）和μ（-）），远远超过了其他设施。在全光束功率（400 W）下，这意味着μ子的速率为（4.2 +/- 1.1）x 10（8）μ子s（-1），是世界上最高的。测量到的μ（-）的数量大约低10倍，这也是迄今为止产生的最有效的μ子束。该装置是未来需要高强度μ子束的实验的原型，例如μ子对撞机或中微子工厂，或者寻找罕见的μ子衰变，这将是粒子物理学标准模型之外的现象的特征。这样的μ子束也可以用于物理学的其他分支，核和凝聚态物质，以及其他科学研究领域。
A new muon beam line, the muon science innovative channel, was set up at the Research Center for Nuclear Physics, Osaka University, in Osaka, Japan, using the 392 MeV proton beam impinging on a target. The production of an intense muon beam relies on the efficient capture of pions, which subsequently decay to muons, using a novel superconducting solenoid magnet system. After the pion-capture solenoid, the first 36 degrees of the curved muon transport line was commissioned and the muon flux was measured. In order to detect muons, a target of either copper or magnesium was placed to stop muons at the end of the muon beam line. Two stations of plastic scintillators located upstream and downstream from the muon target were used to reconstruct the decay spectrum of muons. In a complementary method to detect negatively charged muons, the x-ray spectrum yielded by muonic atoms in the target was measured in a germanium detector. Measurements, at a proton beam current of 6 pA, yielded (10.4 +/- 2.7) x 10(5) muons per watt of proton beam power (mu(+) and mu(-)), far in excess of other facilities. At full beam power (400 W), this implies a rate of muons of (4.2 +/- 1.1) x 10(8) muons s(-1), among the highest in the world. The number of mu(-)measured was about a factor of 10 lower, again by far the most efficient muon beam produced. The setup is a prototype for future experiments requiring a high-intensity muon beam, such as a muon collider or neutrino factory, or the search for rare muon decays which would be a signature for phenomena beyond the Standard Model of particle physics. Such a muon beam can also be used in other branches of physics, nuclear and condensed matter, as well as other areas of scientific research.