Design studies for a compact tungsten scintillator electromagnetic calorimeter

Several designs are currently being investigated for a new type of compact electromagnetic calorimeter that should improve the performance and reduce the cost of electromagnetic calorimeters that are used in high multiplicity environments such as heavy ion collisions at RHIC or LHC. One is a so-called “optical accordion”, which is based on the design of the liquid argon accordion calorimeter that has been used by ATLAS, but employs either scintillating fibers or scintillating plates with wavelength shifting fibers as the active medium, and accordion shaped tungsten plates as the absorber medium. The tungsten can be either a composite or sintered material that allows the formation of accordion shaped plates and has a density nearly that of pure tungsten. Another design is a projective “shashlik” which has a tower structure with alternating layers of tungsten absorber and scintillator plates read out with wavelength shifting fibers. Both designs can utilize a silicon photomultiplier or APD readout that would allow it to be used inside a magnetic field. Results are presented on the light output of various configurations of the optical accordion and projective shashlik, as well as from a Monte Carlo study of the expected performance of the design.