Simulation studies of a high-repetition-rate electron-driven surface muon beamline at SHINE

A high-repetition-rate pulsed muon source operating at approximately 50 kHz holds the potential to improve the sensitivity of various particle physics and materials science experiments involving muons. In this article, we propose utilizing the high-repetition-rate pulsed electron beam at the SHINE facility to generate a surface muon beam. Our simulation studies indicate that an 8 GeV, 100 pC charge pulsed electron beam impinging on a copper target can produce up to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mn>2</a:mn><a:mo>×</a:mo><a:msup><a:mn>10</a:mn><a:mn>3</a:mn></a:msup></a:math> muons per pulse. Beamline optimization results demonstrate that approximately 60 surface muons per electron bunch can be efficiently transported to the end of the beamline. This translates to a surface muon rate of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mn>3</c:mn><c:mo>×</c:mo><c:msup><c:mrow><c:mn>10</c:mn></c:mrow><c:mrow><c:mn>6</c:mn></c:mrow></c:msup><c:mtext> </c:mtext><c:mtext> </c:mtext><c:msup><c:mrow><c:mi mathvariant="normal">μ</c:mi></c:mrow><c:mrow><c:mo>+</c:mo></c:mrow></c:msup><c:mo>/</c:mo><c:mi mathvariant="normal">s</c:mi></c:mrow></c:math> when the pulsed electron beam is operated at 50 kHz, which is comparable to existing muon facilities. This high-repetition-rate pulsed muon beam, with its ideal time structure, represents a unique and pioneering effort once constructed. It serves as a model for building cost-effective muon sources at existing electron machines with GeV electron energies. In addition to the typical challenges encountered in conventional muon beamlines, such as the installation and construction of the target station and beamline, the removal of substantial quantities of positrons is also a major challenge. A potential solution to this issue is also discussed.