Simulation and calibration of deterctors for the 4n and 7H experiment at SAMURAI, RIKEN

In the light of the apparent binding effect of neutrons in the extremely neutron-rich light nuclei 5,6H and 6,7,8He and of the surprising long life-time of 8He (t=119ms), the SAMURAI 34 experiment aimed at definitively proving the existence of both 7H and 4n by making use of the same reaction 8He(p, 2p)7H through the knock-out technique. We describe the experimental setup used, focusing on DALI, 36 NaI crystals, and MINOS, a vertex tracker coupled to a thick liquid-hydrogen target. The beginning of the data analysis for the two detectors is exposed, and new simulation tools are developed in order to facilitate the calibration procedure. The kinematics of the calibration reaction is given, evaluating its relativistic nature. The problems encountered in the MINOS calibration are described and the possible causes explained. Different procedures were adopted finding conflicting results regarding the quality of the obtained results. Finally, the next steps for the data analysis are given, considering the perspectives on the possibility of obtaining results after the verified issues.