The ALICE Photon Spectrometer (PHOS)
PHOS (PHOton Spectrometer) is a high resolution electromagnetic calorimeter consisting of 17920 detection channels based on leadtungstate crystals (PWO).
WARNING The use of videos requires prior authorization from CERN.
Photo Credits: Antonio Saba
PHOS provides unique coverage of the following physics topics:
- study initial phase of the collision of heavy nuclei via direct single photons and diphotons,
- jet-quenching as a probe of deconfinement, studied via high pT_ and π0,
- signals of chiral-symmetry restoration.
Technical data:
- 17920 lead-tungstate crystals(PWO) .
- distance to IP 4400 mm
- coverage in pseudorapidity -0.12; +0.12
- coverage in azimuthal angle 100°
- crystal size 22 × 22 × 180 mm3
- depth in radiation length 20
- modularity 5 modules
- total area 8 m2
- total crystal weight 12.5 t
- operating temperature -25°C
- photoreadout APD