Dual Readout With PWO Crystals and LuAG Crystal Scintillating Fibers

One of the main challenges for detectors at future high-energy collider experiments is high-precision measurement of hadrons and jet energy and momentum. Such measurement can be provided by the particle flow approach (PFA) that requires a complex highly segmented calorimeter system to identify and to track all particles in a jet. An alternative so-called dual-readout approach consists of simultaneously recording, in an active medium, scintillation light that is proportional to total energy deposit and Cerenkov light that is proportional to the electromagnetic part only, thus allowing extracting the electromagnetic fraction of the total shower energy on an event-by-event basis. The dual-readout method approach can be implemented using several techniques. The first method proposed uses a copper absorber structure containing two types of fibers: quartz fibers that produce Cerenkov light and plastic scintillating fibers that produce scintillation light. A second method proposed is based on the separation of scintillation and Cerenkov signal produced in homogeneous detector blocks made of scintillating crystals such as bismuth germanate (BGO), lead tungstate (PWO), or others. More recently, a third method has been proposed by our group that uses so-called "meta-crystals" consisting of both Ce-doped and undoped heavy crystal fibers of identical material. The undoped fibers behave as Cerenkov radiator, while Ce-doped fibers behave as scintillators. In this paper, we discuss advantages and inconveniences of all methods and present first results on methods 2 and 3.