The Small Angle photon and charged particle Vetos consists of two detectors, which are based on similar technologies:
- The IRC covering the region around the inner radius of the Liquid Krypton Calorimeter.
- The SAC situated behind the experimental cavern in the prolongation of the beam axis covering the angular region down to 0 degrees.
Schematic of downstream region of NA62. The IRC detector on the left and the SAC on the right (blue).
IRC(Intermediate Ring Calorimeter):
The IRC is a calorimeter made of alternating layers of lead and scintillators (shashlik). It is situated at the entrance of the LKr calorimeter.
- Radial coverage: 7 cm < R < 14 cm
- Shashlyk calorimeter with ~ 100 wavelength shifting fibers (~1/cm2)
- Photo detectors: PMTs or APDs, (between 12 and 24 channels)
- Weight ~100 kg
Cross section of the IRC detector
A dipole magnet situated at ~248m (from the target) deviates the beam particles into the beam dump which is situated off axis. Neutral particles and photons escaping through the beam pipe can be detected in the SAC located in the prolongation of the initial beam axis.
- Detector size: 24 x 24 cm
- Shashlyk calorimeter with wavelength shifting fibers (same as IRC)
- 70 Layers of (1.5mm lead + 1.5mm scintillators)
- ~480 wavelength shifting fibers
- Photo detectors: 4 PMTs