Author: Tong, X.
Paper Title Page
MOPRB026 High-Quality Muon Beam Production Based on Superconducting Solenoids 630
 
  • Y. Bao, X. Li, Y. Li, Y.P. Song, X. Tong
    IHEP, Beijing, People’s Republic of China
 
  Funding: This work is supported by the Science Foundation of The Chinese Academy of Sciences and National Natural Science Foundation of China (No. 11875281)
In labs, muon beams are produced by protons hitting targets. The initial phase space of the muon beam is extremely large. In general, two types of muon collection methods have been used in the world. One is to put the muon production target in a superconducting solenoid, and low-energy muons are collected from the back of the target, then transported through a bent solenoid. In this way, a high-intensity muon beam can be collected, but the energy spread is wide and the beam polarization is low. For most muSR applications a surface muon beam with narrow energy bite and high polarization is required. Most muSR facilities are built with collecting magnets by the side of the target, in this way only a small fraction of muons with low emittance are collected and transported downstream. In this work we outline a muon collection method based on superconducting solenoid. Instead of using bent solenoids, a matching section with a dipole magnet is used to select muons with a certain momentum and match to downstream beamliines. A high-quality muon beam can be achieved with a high intensity and polarization. Such a method can be adapted to the MUSIC, Mu2e, and COMET muon beamlines after their dedicate experiments and convert the beamlines into a high quality muSR facility.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB026  
About • paper received ※ 30 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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THPGW039 Moderation of Positive Muons by Helium Gas 3667
 
  • Y. Li, Y. Bao, R. Fan, X. Li, X. Tong
    IHEP, Beijing, People’s Republic of China
  • C.J. Ning, P.C. Wang
    IHEP CSNS, Guangdong Province, People’s Republic of China
 
  Funding: This work is supported by CAS, National Natural Science Foundation of China (Grant No. 11875281), and China Postdoctoral Science Foundation (Grant No. 2019M650845)
Efficiently creating beams of spin-polarized positive muons with energies between eV and keV (so-called slow muon beams) is important for further development and application of muon spin rotation, relaxation, and resonance techniques. One existing moderation method involves the use of wide-band-gap materials as moderators such as rare gas solids and solid nitrogen thin films (band-gap energy between 11 eV and 22 eV). Based on this moderation method, we have studied the use of helium gas as a moderator, with the goal of producing the slow muon beam more efficiently. Because of helium’s high (24.6 eV) ionization energy and because the cross section for muonium formation is suppressed in helium gas, we expect the production of slow muons using helium gas to be highly efficient.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW039  
About • paper received ※ 01 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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