TIPP 2011 - 2nd International Conference on Technology and Instrumentation in Particle Physics

Verification of focusing system for Time Of Propagation counter

Not scheduled

1m

Sheraton Hotel (Chicago)

Poster Presentation Particle Identification

Speaker

Mr Yoshinori Arita (Nagoya-Univ)

Description

We present the results of verifing focusing system for Time Of Propagation(TOP) counter. The TOP counter is a new detector of particle identification(PID) for burrel region of BelleII. TOP counter is a kind of Ring Imaging Cherenkov counter(RICH) which detect internally reflected Cherenkov light like DIRC. MCP-PMTs, which are compornent of TOP counter, detect ~20 Cherenkov photons per charged tra'ck , and we can reconstract a ring image from propagation time of detected photon.TOP counter are working as Time Of Flight (TOF) because it has very good time resolution less than 100ps per single photon. Performance of TOP counter is propotional to the time resolution.Propagated Cherenkov photons have group velocity related to wavelength.It generates fractuation of propagation time approximately 53ps/m.Chromatic dispersion provides serious deterioration of time resolution. Against this problem, we plan to introduce focusing mirror.Focusing mirror is set at forward part of TOP counter.It focuses Cherenkov light to different channels of MCP-PMT by different wavelength, and so that the deterioration of time resolution is suppressed. We verified focusing mechanism using 120GeV/c pion beam at CERN.We used prototype of TOP counter which have focusing mirror, and so we could confirm a proof of focusing mechanism. Time resolutoin improved 147ps to 95ps by using focusing mirror.