CERN Accelerating science

Cross section of the PANDA target spectrometer with the Barrel DIRC marked in blue.

Simulated phase space distribution of kaons from eight benchmark physics channels at $p_{\bar{p}}$~=~7~GeV/$c$. The Barrel DIRC coverage is marked with the dashed rectangle.

Left: Schematic of the PANDA Barrel DIRC baseline design. Right: Mechanical design of the PANDA Barrel DIRC in half-section views, highlighting the modular approach.

Geant simulation of the PANDA Barrel DIRC baseline design. The path of the Cherenkov photons is shown as orange lines. The colored histogram shows the accumulated hit pattern from 1000~$\pi^+$ at 3.5~GeV/c and $25^\circ$ polar angle.

$\pi$/$K$ separation power as a function of particle momentum and polar angle in Geant simulation, determined by the time-based imaging method for the baseline design. The area below the black line corresponds to the final-state phase space for charged kaons from various benchmark channels.

Left: Schematic of the prototype used at CERN in 2015, with 1: flat mirror, 2: quartz bar, 3: spherical lens, 4: quartz prism, 5: array of 5$\times$3 MCP-PMTs, 6: readout unit, and 7: TRB stack. Right: Photograph of the 2015 prototype in the CERN T9 beam line (top), close-up of the 3-layer spherical lens between the narrow bar and the prism (bottom).

Performance of the PANDA Barrel DIRC prototype with a narrow bar and a 3-layer spherical lens at the CERN PS in 2015. Left: Photon yield (top) and single photon Cherenkov angle resolution (SPR) (bottom) as a function of the track polar angle for tagged protons with a momentum of 7~GeV/$c$. The error bars correspond to the RMS of the distribution in each bin. Right: Proton-pion log-likelihood difference distributions for proton-tagged (red) and pion-tagged (blue) beam events as result of the time-based imaging reconstruction for a beam with 7~GeV/$c$ momentum and $25^{\circ}$ polar angle. The $\pi/p$ separation power from the Gaussian fits is 3.6 standard deviations.