Development of the ftof detector for future tau-charm factories

 

 V.  A. Yeroshenko¹, S. Barsuk², O. A. Bezshyyko¹, L. Burmistrov², V. Chaumat², L.O. Golinka‑Bezshyyko¹, V. Puill², A. Stocchi²

 

¹ Taras Shevchenko National University of Kyiv, Kyiv, Ukraine

² Laboratoire de L'accélérateurLinéaire, Orsay, France

 

The FTOF detector is proposed to use for the particle identification (PID) in forward region for the HIEPA project, China, and is applicable for other tau-charm factories. The goal of PID in this experiment is to perform 4σ pion/kaon separation up to 2 GeV/c momentum. Also due to the good time resolution this detector can be used for bunch crossing time stamp.

The DIRC-like TOF detector for the SuperB experiment was taken as a base for the FTOF development. The ring of 12 wide trapezoidal sectors was replaced with 100 narrow sectors to improve time measurements. The complete research of Cherenkov light in detector was performed to determine factors that degrade time resolution. Geometry with two layers with sectors shifted by the half of width was proposed as a solution to increase resolution and to cover dead spaces between sectors where the optical insulation is placed. The tilted geometry of sectors with some angle was proposed to collect light with less reflections which causes less time of light propagation and delta electron Cherenkov light suppression. Results show that it provides better timing up to dozen picoseconds with idealistic photodetector. In this framework a threshold counter approach was proposed assuming that all sides absorb all the light. This approach is based on tuning the angle to collect a light from particles with a narrow range of velocity. It allows to separate particles with different masses by a fact of light presence or absence. Placing few layers with different angles can make possible to cover whole range of momentum. Both analytical solution and Geant4 simulations are taken into account in the future development of final geometry.

Newest achievements in silicon photomultipliers (SiPM) photon detection efficiency (PDE) and single-photon time resolution (SPTR) made possible to replace microchannel plate photomultipliers (MCP PMT) in the region with strong magnetic field. Geant4 simulations including PDE of few different SiPM and MCP PMT models showed that this factor is very decisive in our approach. Also the use of SiPM is more scalable solution on the big sensitive surface because of simplicity of making custom sized matrix and sufficiently low cost compared with MCP PMT.

Research was conducted in the scope of the IDEATE International Associated Laboratory (LIA).