Tile and crystal calorimeters for the KLOE 2 experiment

Abstract

The upgrade of the DA$\Phi$NE machine layout requires a modification of the size and position of the inner focusing quadrupoles of KLOE$^2$ thus asking for the realization of two new calorimeters covering the quadrupoles area. To improve the reconstruction of $K_L\to 2\pi^0$ events with photons hitting the quadrupoles, a tile calorimeter, QCALT, with high efficiency to low energy photons (20-300 MeV), time resolution of less than 1 ns and space resolution of few cm, is needed. We propose a tile calorimeter with a high granularity readout corresponding to about 2500 silicon photomultipliers (SiPM) of $1\times 1$ mm$^2$ area. Moreover, the low polar angle regions need the realization of a dense crystal calorimeter with very high time resolution performances to extend the acceptance for multiphotons events. Best candidates for this calorimeter are LYSO crystals with APD readout or PbWO$_4$ crystals with large area SIPM readout.