<p>We present the results of an experiment conducted to measure cosmic-ray muons and muon-induced fluxes at the China Jinping Underground Laboratory. Utilizing a 28-L 0.5% gadolinium-doped liquid scintillator detector, which operated stably for 412 days in a 1-m-thick polyethylene shielding, we reconstructed saturated signal pulses and pulse shape discrimination to facilitate measurements across a range starting from 0.2 MeV. The event rates incorporating the mountain geometry effects for cosmic rays and their induced particles were derived. The experimental results show that the cosmic ray muon flux is (3.64 ± <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$0.69_{\textrm{stat}.}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>0</mn> <mo>.</mo> <msub> <mn>69</mn> <mrow> <mtext>stat</mtext> <mo>.</mo> </mrow> </msub> </mrow> </math></EquationSource> </InlineEquation> ±<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$0.25_{\textrm{syst}.}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>0</mn> <mo>.</mo> <msub> <mn>25</mn> <mrow> <mtext>syst</mtext> <mo>.</mo> </mrow> </msub> </mrow> </math></EquationSource> </InlineEquation>) <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\times$</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> 10<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$^{-10}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>10</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation> cm<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$^{-2}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>2</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation> s<InlineEquation ID="IEq6"> <EquationSource Format="TEX">$^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>, muon-induced electron flux is (5.59 ± <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$1.06_{\textrm{stat}.}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>1</mn> <mo>.</mo> <msub> <mn>06</mn> <mrow> <mtext>stat</mtext> <mo>.</mo> </mrow> </msub> </mrow> </math></EquationSource> </InlineEquation> ± <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$0.40_{\textrm{syst}.}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>0</mn> <mo>.</mo> <msub> <mn>40</mn> <mrow> <mtext>syst</mtext> <mo>.</mo> </mrow> </msub> </mrow> </math></EquationSource> </InlineEquation>) <InlineEquation ID="IEq9"> <EquationSource Format="TEX">$\times$</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq10"> <EquationSource Format="TEX">$10^{-10}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mn>10</mn> <mrow> <mo>-</mo> <mn>10</mn> </mrow> </msup> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq11"> <EquationSource Format="TEX">$\hbox {cm}^{-2}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mtext>cm</mtext> <mrow> <mo>-</mo> <mn>2</mn> </mrow> </msup> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq12"> <EquationSource Format="TEX">$\hbox {s}^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mtext>s</mtext> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </math></EquationSource> </InlineEquation>, and the upper limit of the muon-induced neutron flux was 3.52 <InlineEquation ID="IEq13"> <EquationSource Format="TEX">$\times$</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq14"> <EquationSource Format="TEX">$\hbox {10}^{-9}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mtext>10</mtext> <mrow> <mo>-</mo> <mn>9</mn> </mrow> </msup> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq15"> <EquationSource Format="TEX">$\hbox {cm}^{-2}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mtext>cm</mtext> <mrow> <mo>-</mo> <mn>2</mn> </mrow> </msup> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq16"> <EquationSource Format="TEX">$\hbox {s}^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mtext>s</mtext> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </math></EquationSource> </InlineEquation>. They indicated that no significant excess was observed at a 90% confidence level, and no muon-induced neutrons above 10 MeVee were detected.</p>

Measurements of muon and muon-induced fluxes using gadolinium-doped liquid scintillator at the China Jinping Underground Laboratory

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发表日期：

2026年4月11日

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Xiao-Yu Peng,
Chang-Hao Fang,
Shin-Ted Lin,
Shu-Kui Liu,
Han-Yu Li,
Qian-Yun Li,
Ren-Ming-Jie Li,
Yu Liu,
Hao-Yu Shi,
Qin Wang,
Hao-Yang Xing,
Yu-Lu Yan,
Li-Tao Yang,
Qian Yue,
Jing-Jun Zhu

摘要

We present the results of an experiment conducted to measure cosmic-ray muons and muon-induced fluxes at the China Jinping Underground Laboratory. Utilizing a 28-L 0.5% gadolinium-doped liquid scintillator detector, which operated stably for 412 days in a 1-m-thick polyethylene shielding, we reconstructed saturated signal pulses and pulse shape discrimination to facilitate measurements across a range starting from 0.2 MeV. The event rates incorporating the mountain geometry effects for cosmic rays and their induced particles were derived. The experimental results show that the cosmic ray muon flux is (3.64 ± $0.69_{\textrm{stat}.}$ $0 . 69_{stat .}$ ± $0.25_{\textrm{syst}.}$ $0 . 25_{syst .}$ ) $\times$ $\times$ 10 $^{-10}$ $^{- 10}$ cm $^{-2}$ $^{- 2}$ s $^{-1}$ $^{- 1}$ , muon-induced electron flux is (5.59 ± $1.06_{\textrm{stat}.}$ $1 . 06_{stat .}$ ± $0.40_{\textrm{syst}.}$ $0 . 40_{syst .}$ ) $\times$ $\times$ $10^{-10}$ $10^{- 10}$ $\hbox {cm}^{-2}$ ${cm}^{- 2}$ $\hbox {s}^{-1}$ $s^{- 1}$ , and the upper limit of the muon-induced neutron flux was 3.52 $\times$ $\times$ $\hbox {10}^{-9}$ $10^{- 9}$ $\hbox {cm}^{-2}$ ${cm}^{- 2}$ $\hbox {s}^{-1}$ $s^{- 1}$ . They indicated that no significant excess was observed at a 90% confidence level, and no muon-induced neutrons above 10 MeVee were detected.