//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22816 SUBJECT: GRB 180618B: CALET Gamma-Ray Burst Monitor detection DATE: 18/06/21 06:58:09 GMT FROM: Takanori Sakamoto at AGU K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, V. Pal'shin, Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU), S. Nakahira (RIKEN), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration: The long GRB 180618B (INTEGRAL SPI-ACS trigger #8079; Konus-Wind trigger time on 22:40:26.066) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 22:40:18.199 UTC on 18 June 2018. The burst signal was clearly seen by the SGM instrument. There is a hint of the emission seen by the HXM instrument. The burst light curve shows a single FRED-like pulse which starts at T-3.8 sec, peaks at T-1.5 sec and ends at T+15.4 sec. The T90 and the T50 durations measured by the SGM data are 17 +- 4 sec and 5.3 +- 0.5 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1213396756 The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.