The goal of the ALICE Time-of-Flight detector, based on MRPC technology, is to perform the charged-particle identification at midrapidity, in the region |
η|<0.9. This large area (∼150
m
2), finely ...segmented detector (∼157,000 channels), provides fast signals which will contribute to the Level 0 and Level 1 trigger decisions. We use the TOF detector information to perform an online estimate of the total track multiplicity and to identify simple and peculiar topologies, like those produced by minimum bias p–p, Ultra Peripheral ion–ion collisions and cosmic muons. The system architecture foresees a first layer of 72 VME boards interfacing the detector front-end to a second layer, which receives and processes all the information and takes trigger decisions.
The ALICE Time-of-Flight system will be a large area (150m2) detector made by Multigap RPC (MRPC). The time digitisation is based on the High Performance TDC chip (HPTDC). Tests carried out on board ...prototypes are discussed, emphasising the optimisation of the effective time resolution of the chip when working in its Very High Resolution Mode. Lab bench tests and test beam results show that a 20ps resolution has been achieved.
The MRPC (multi resistive plate chamber) strip is the basic element of the ALICE time-of-flight detector. A test of a large sample of MRPC-strip prototypes corresponding to 1.2% of the full detector ...was carried out during the autumn of 2002 at the CERN proton syncroton facility. This paper summarizes the main results obtained in terms of uniformity of response for all the tested channels.
In this work we explore the possibility to perform “effective energy” studies in very high energy collisions at the CERN large hadron collider (LHC). In particular, we focus on the possibility to ...measure in pp collisions the average charged multiplicity as a function of the effective energy with the ALICE experiment, using its capability to measure the energy of the leading baryons with the zero degree calorimeters. Analyses of this kind have been done at lower centre-of-mass energies and have shown that, once the appropriate kinematic variables are chosen, particle production is characterized by universal properties: no matter the nature of the interacting particles, the final states have identical features. Assuming that this universality picture can be extended to ion–ion collisions, as suggested by recent results from RHIC experiments, a novel approach based on the scaling hypothesis for limiting fragmentation has been used to derive the expected charged event multiplicity in AA interactions at LHC. This leads to scenarios where the multiplicity is significantly lower compared to most of the predictions from the models currently used to describe high energy AA collisions. A mean charged multiplicity of about 1000–2000 per rapidity unit (at η∼0) is expected for the most central Pb–Pb collisions at \(\sqrt{s_{{\text{NN}}} = 5.5\,\text{TeV}\).
.
This work reports a Monte Carlo study of Δ
++
resonance production and decay in p-p collisions at
= 10 TeV. For this study case, the ALICE detector at the LHC collider has been chosen. The Δ
++
→ π
...p
decay is studied using a simulation of the full ALICE detector response. Special care is taken to extract the signal using the event-mixing technique for background estimation. Results from a 4.8 million events sample are presented. This number of events corresponds to a few days data-taking at the nominal acquisition rate and luminosity.
Scintillation tiles with MRS APD light readout (START) are proposed to be used as basic triggering units of a cosmic muon facility intended for regular tests of all of the numerous ALICE TOF modules ...in the course of their mass production and exploitation. A prototype 32-channel array of STARTs has been assembled and tested with cosmic rays and beam. With the bias voltage at approximately 50
V, the system has shown operational consistency and homogeneity, almost 100% detection efficiency over the whole surface and intrinsic noise of
10
-
2
Hz
per detecting unit. If STARTs are to be mass-produced, the cost of a mosaic array is estimated at a moderate level of 3–
4
kUSD
/
m
2
.
The ϕ → K+K– decay channel in Pb-Pb collisions at LHC is studied through a full simulation of the ALICE detector. The study focuses on possible signatures in this channel of quark-gluon plasma (QGP) ...formation. On a basis of 106 collisions at high centrality some proposed QGP signatures are clearly visible both in K + K– invariant mass and transverse mass distributions. The high significance of this observation appears to reside heavily on the use of the TOF (Time Of Flight) system of ALICE in addition to its central tracking detectors.
AbstractA procedure developed to achieve particle identification in very high multiplicity conditions using a complex time-of-flight system is illustrated in detail by simulating and studying the ...performance of the ALICE TOF detector in a realistic scenario of Pb-Pb and p-p interactions at LHC.
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