Design Studies of the Calorimeter Systems for the sPHENIX Experiment at RHIC and Future Upgrade Plans

Abstract

The PHENIX Experiment at RHIC is planning a series of major upgrades that will enable a comprehensive measurement of jets in relativistic heavy ion collisions, provide enhanced physics capabilities for studying nucleon-nucleus and polarized proton collisions, and allow a detailed study of electron-nucleus collisions at the Electron Ion Collider at Brookhaven (eRHIC). The first of these upgrades, sPHENIX, will be based on the former BaBar magnet and will include a hadronic calorimeter and new electromagnetic calorimeter that will cover ±1.1 units in pseudorapidity and 2π in azimuth in the central region, resulting in a factor of 6 increase in acceptance over the present PHENIX detector. The electromagnetic calorimeter will be a tungsten scintillating fiber design with a radiation length ~ 7 mm and a Moliere radius ~ 2 cm. It will have a total depth of ~ 18 radiation lengths and an energy resolution ~ 15%/√E. The hadronic calorimeter will consist of steel plates with scintillating tiles in between that are read out with wavelength shifting fibers, It will have a total depth of ~ 5 interaction lengths and an energy resolution 100%/√E. Both calorimeters will use silicon photomultipliers as the readout sensor. Detailed design studies and Monte Carlo simulations for both calorimeters have been carried out and prototype detectors have been constructed and tested in a test beam at Fermilab in February 2014. This contribution describes these design studies for the sPHENIX experiment and its future upgrade plans at RHIC.