TITLE: GCN CIRCULAR NUMBER: 23491 SUBJECT: GRB 181201A: Insight-HXMT/HE detection DATE: 18/12/03 01:41:51 GMT FROM: Ce Cai at IHEP C. Cai, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2018-12-01T02:39:53.000 (T0), the Insight-HXMT/HE detected GRB 181201A (trigger ID: HEB181201111) in a routine search of the data, which was also triggered by INTEGRAL (S. Mereghetti et al.,GCN 23469); Fermi/LAT (M. Arimoto et al., GCN23480). The Insight-HXMT/HE light curve mainly consists of Single pulse with a duration (T90) of 15.18 s measured from T0+1.56 s. The 1-s peak rate, measured from T0+5.28 s, is 13844.5 cnts/s. The total counts from this burst is 88444.0 counts. URL_LC: http://www.hxmt.org/images/GRB/HEB181201111_lc.jpg All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (record energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was fundedjointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org.