mTOF performance during the first main commissioning beam time at mCBM

Abstract

The future Facility for Anti-proton and Ion Research (FAIR), currently in construction in Darmstadt, Germany, is one of the largest research projects worldwide. The Compressed Baryonic Matter (CBM) experiment is one of the main pillars at FAIR, studying the quantum chromodynamics (QCD) phase diagram at high baryon densities with unprecedented interaction rate in heavy ion collisions up to 10 MHz. This requires new data-driven readout chain, new data analysis methods and high-rate capable detector systems. The task of the CBM Time of Flight wall (CBM-TOF) is the charged particle identification. Multi-gap Resistive Plate Chambers (MRPCs) with different rate capabilities will be used at CBM-TOF corresponding regions. To reduce the commissioning time for CBM, a CBM full system test-setup called mini-CBM (mCBM) had been installed and tested with beams at GSI SIS18 facility in 2019. The high-rate MRPC prototypes developed at Tsinghua University, called MRPC2, were selected to be implemented in mTOF modules for mCBM. Additional thin float glass MRPCs from USTC called MRPC3, foreseen for the CBM lower rate region, were also tested in the mCBM experiment. Performance results of the two kinds of MRPCs analyzed by the so called tracking method will be shown.

The Compressed Baryonic Matter (CBM) Experiment at FAIR – Physics, Status and Prospects

“…A conceptual verification of the triggerless-streaming readout and data transport was demonstrated by observing the time and spatial correlations between the synchronized data streams of the detector subsystems (see figure 14). Further details about the mCBMʼs first commissioning phase and performance of detector sub-systems are mentioned in [102][103][104][105].…”

The FAIR Phase 0 program of the CBM TOF

“…The triple stack, centered at 25 • in respect to the beam, allows to form triple hit tracklets, which can be used by the other subsystem as a reference. However, with three staggered modules the performance of each module can be elaborated by using the other two as a reference (see contribution [8] this proceeding). The double stack, located closer to the beam (at a polar angle of about 12 • ), faces a higher particle flux and offers a reference system to additional CBM TOF MRPC prototypes, which were tested during the beam time campaigns.…”

“…More information about the MRPC2/3 prototypes is given in table 1. With the tracking method described in [8] the efficiency of counter 901 was evaluated for a run where the incident particle flux was about 600 Hz/cm 2 . Figure 2 upper left shows the number of found hits (blue) and the number of missed hits (red) as function of time in spill (bin size 0.1 s).…”