Time calibration for the end cap TOF system of BESIII

Abstract

The time calibration for end cap TOF system of BESIII is studied in this paper. It has achieved about 110 ps time resolution for muons in dimu events. The pulse height correction using electronic scan curve and the predicted time calculated using Kalman filter method are introduced. This paper also describes the study of using electrons and muons as calibration samples.

Simulation of the BESIII endcap time of flight upgrade

“…It is composed of a two-layer-structure of 2300 mm long BC-408 plastic scintillators in the barrel region (| cos θ < 0.82|, with θ being the polar angle) and of a onelayer-structure made of trapezoidal shaped BC-404 scintillators with a height of 480 mm in the endcap regions (0.84 < | cos θ| < 0.95). The time resolution σ for Bhabha scattering events was measured to be 78 ps in the barrel region, but only about 150 ps in the endcap region [11]. The worse resolution in the endcaps is mainly caused by multiple scattering interactions in the endcap plate of the MDC and material located between MDC and endcap ToF systems, such as electronics and cables [12].…”

“…The worse resolution in the endcaps is mainly caused by multiple scattering interactions in the endcap plate of the MDC and material located between MDC and endcap ToF systems, such as electronics and cables [12]. The resolution for pions and kaons in the endcaps is about 135 ps and thus allowing for a pion/kaon separation up to momenta of about 1 GeV/c [11].…”

The cosmic ray test of MRPCs for the BESIII ETOF upgrade

“…In high energy collision experiments particle identification (PID) play a crucial role, especially for hadrons analysis in τ-charm physics. Currently at BESIII the PID detector are dominated by time-of-fight(TOF) detector which consists of barrel TOF(BTOF) [6] and Endcap TOF(ETOF) [7] that is at the region 0.83<cosθ <0.90 ( θ is the polar angle as shown in Fig. 1).…”

“…The current ETOF consists of fast scintillators (BC204) and fine-mesh photomultiplier tubes (Hamamatsu R5924) [8]. The time resolution measured by ETOF detector is 138ps for π(1GeV/c) and the momentum range of K/π separation (2σ) is limited to 1.1GeV/c [6,7], which cannot satisfy the higher precision requirement of physics analysis. One of the reasons worsening ETOF resolution is scattering particle.…”

Test of high time resolution MRPC with different readout modes for the BESIII upgrade

“…The momentum range for K/π separation (greater than 2σ) is limited to 1.1 GeV/c [4]. A GEANT4 simulation has been carried out [5] to study the cause of the degradation of time resolution for electrons.…”