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.
The meta-crystals concept is an approach that consists of using both undoped and properly doped heavy crystal fibers of identical material as the active medium of a calorimeter. The undoped fibers ...behave as Cherenkov radiators while the doped ones behave as scintillators. A dual readout calorimeter can be built with its sensitive volume composed of a mixture of both types of crystals. In addition if the calorimeter is adequately finely segmented it can also functionas a particle flow calorimeter at the same time. In this way one could possibly combine the advantages of both the particle flow concept and the dual readout scheme. We discuss the approach of dual readout calorimetry with meta-crystals made of Lutetium Aluminium Garnet (LuAG). We briefly present studies on the material development and first testbeam activities and then focus on performance expectation studies based on simulation. We discuss in more detail the results from generic systematic scannings of the design parameters of a dual readout calorimeter. The parameters under study include the transverse and longitudinal granularity, the sampling frequency and readout fraction of the scintillation and the Cherenkov signals, the total calorimeter length, the mixture of homogeneous and sampling dual readout components, their corresponding composition etc. We close with a brief outlook on open issues and further R&D needed to proceed from an ideal conceptual case to the design of a realistic detector.
A detailed study of correlated scalars, produced in collisions of nuclei and associated with the
σ-field fluctuations,
(
δ
σ
)
2
=
〈
σ
2
〉
, at the QCD critical point (critical fluctuations), is ...performed on the basis of a critical event generator (critical Monte Carlo) developed in our previous work. The aim of this analysis is to reveal suitable observables of critical QCD in the multiparticle environment of simulated events and select appropriate signatures of the critical point, associated with new and strong effects in nuclear collisions.
The calibration procedure of a finely granulated digital hadron calorimeter with Resistive Plate Chambers as the active elements is described. Results obtained with a stack of nine layers exposed to ...muons from the Fermilab test beam are presented.
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