Status of the PANDA Barrel DIRC

G Kalicy ,B Lewandowski ,M Hoek ,R Höhler ,L Schmitt ,E Cowie ,D Lehmann ,G Rosner ,M Thiel ,L Gruber ,B Seitz ,W Eyrich ,R A Montgomery ,J Schwiening ,M Patsyuk ,K Föhl ,A Gerhardt ,A Britting ,F Uhlig ,B Kröck ,H Kumawat ,A Vodopianov ,Peter Koch ,T Keri ,G Schepers ,K Suzuki ,C Ugur ,M Zühlsdorf ,M Traxler ,A Lehmann ,M Düren ,O Merle ,C Sfienti ,A Hayrapetyan ,M Cardinali ,C Schwarz ,R Dzhygadlo ,V.kh Dodokhov ,P Achenbach ,J Márton ,K Peters ,P Bühler ,E Widmann

doi:10.1088/1748-0221/9/05/c05060

Abstract

The PANDA experiment at the future Facility for Antiproton andIon Research in Europe GmbH (FAIR) at GSI, Darmstadt will studyfundamental questions of hadron physics and QCD using high-intensitycooled antiproton beams with momenta between 1.5 and 15 GeV/c.Hadronic PID in the barrel region of the PANDA detector will beprovided by a DIRC (Detection of Internally Reflected Cherenkov light)counter. The design is based on the successful BABAR DIRC withseveral key improvements, such as fast photon timing and a compactimaging region. Detailed Monte Carlo simulation studies wereperformed for DIRC designs based on narrow bars or wide plates with avariety of focusing solutions. The performance of each design wascharacterized in terms of photon yield and single photon Cherenkovangle resolution and a maximum likelihood approach was used todetermine the π/K separation. Selected design options wereimplemented in prototypes and tested with hadronic particle beams atGSI and CERN. This article describes the status of the design andR&D for the PANDA Barrel DIRC detector, with a focus on theperformance of different DIRC designs in simulation and particlebeams.

Highlights

The PANDA experiment at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR) at GSI, Darmstadt will study fundamental questions of hadron physics and QCD using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c
Mirrors are attached to the forward end of the bars to reflect the Cherenkov photons towards the readout end where they exit through a focusing lens and a window into a 30 cm-deep tank that serves as expansion volume (EV)
The single photon Cherenkov angle resolution (SPR) σC,γ can be calculated as σC2,γ = σC2,det + σC2,bar + σC2,trans + σC2,chrom where σC,det is the contribution from the detector pixel size, σC,bar is the error due to optical aberration and imaging errors, σC,trans is the error due to bar imperfections, such as non-squareness, and σC,chrom is the uncertainty in the photon production angle due to the dispersion n(λ ) of the fused silica material

Summary

Barrel DIRC design

The PANDA Barrel DIRC design is inspired by the successful BABAR DIRC counter [3]. Some key improvements have been investigated to optimize the performance for PANDA. The single photon Cherenkov angle resolution (SPR) σC,γ can be calculated as σC2,γ = σC2,det + σC2,bar + σC2,trans + σC2,chrom where σC,det is the contribution from the detector pixel size, σC,bar is the error due to optical aberration and imaging errors, σC,trans is the error due to bar imperfections, such as non-squareness, and σC,chrom is the uncertainty in the photon production angle due to the dispersion n(λ ) of the fused silica material. This is a good match to the performance of a Barrel DIRC, which is best for steep forward and backward angles where the photon yield is highest

Design options

Simulation and reconstruction

Prototyping the PANDA Barrel DIRC

Component prototypes

Findings

Conclusions