一种远距离高分辨率检测光纤链路的方案

针对检测远距离光纤链路时光时域反射仪（OTDR）空间分辨率过低的问题，文章提出一种线性调频（LFM）-Golay OTDR方案。该方案通过生成周期LFM信号调制光信号，生成Golay序列信号调制周期LFM光信号来提高OTDR的动态范围和空间分辨率。实验结果表明，在长度为200 km的待测光纤链路中，LFM-Golay OTDR的空间分辨率可达到0.22 m，参数设置相同的情况下，比单脉冲OTDR动态范围提高了约15 dB，与Golay码OTDR和LFM OTDR相比动态范围提高了约6 dB

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^