Development of Central Time-of-Flight System for CLAS12@JLAB Detector at KNU

Description
The new research program at HALLB@JLAB aims at 3D imaging of the nucleon by means of Deeply Virtual Compton Scattering and Deeply Virtual Meson Production. The realization of this program requires the upgrade to 12 GeV of Continuous Electron Beam Accelerator Facility (CEBAF) and the upgrade of existing detectors. One major new component of the future CLAS12 Detector will the Central Time-of-Flight System (CTOF). It will be a barrel made of 50 scintillator bars that will surround a target at a distance of 26 cm. The system will be located inside a solenoidal magnet that will generate magnetic field up to 5 Tesla for the momentum analysis. The design goal is to achieve the time-of-flight resolution of about 50 ps. One CTOF solution is being developed at Kyungpook National University (Daegu, South Korea). It is based on magnetic-resistant fine-mesh photomultipliers (PMs) which view scintillator bars through relatively short light guides. The light guides deliver scintillation light to the regions where the magnetic field drops down to about 1 Tesla. The design of prototype counters and the results of test measurements will be presented together with the new method to measure time-of-flight resolution using low-energy protons. The method was implemented at the MC-50 Cyclotron of Korea Institute for Radiological and Medical Sciences.
Organised by Vincenzo Bellini