55270733
Using XDAQ in Application Scenarios of the CMS Experiment
XDAQ is a generic data acquisition software environment that emerged from a rich set of use-cases encountered in the CMS experiment. They cover not the deployment for multiple sub-detectors and the operation of different processing and networking equipment as well as a distributed collaboration of users with different needs. The use of the software in various application scenarios demonstrated the viability of the approach. We discuss two applications, the tracker local DAQ system for front-end commissioning and the muon chamber validation system. The description is completed by a brief overview of XDAQ.
115001576
Single event effect measurements on the resistive plate chambers front-end chips for the CMS experiment
120049072
The resistive plate chambers for CMS and their simulation
In this paper some results obtained by the CMS Resistive Plate Chamber collaboration during its five years long period of research and development are reported. The importance of the simulation in the design of the Resistive Plate Chambers for CMS is stressed.
56416813
Aging study for Resistive Plate Chambers of the CMS Muon Trigger Detector
A long-term aging test of a Resistive Plate Chamber (RPC) was carried out with an intense gamma source. The detector was operated in avalanche mode and had the bakelite surface treated with linseed oil. After the irradiation the estimated dose, charge and fluence were approximately equal to the expected values after 10 years of operation in the CMS barrel region. During and after the irradiation, the RPC performance was monitored with cosmic muons and showed no relevant aging effects. Moreover, no variation of the bakelite resistance was observed.
123170336
NEUTRON-INDUCED SINGLE EVENT UPSET ON THE RPC FRONT-END CHIPS FOR THE CMS EXPERIMENT
Neutrons from a reactor and from a cyclotron have been used to characterise the CMS Resistive Plate Chambers (RPCs) front-end chip to neutron-induced damaging events. Single Event Upset (SEU) cross-sections have been measured up to for different chip thresholds. Tests at a reactor were done with an integrated fast () neutron fluence of and a thermal neutron fluence of . High-energy neutrons from a cyclotron were used up to a fluence of . Data indicate the existence of a chip SEU sensitivity already at thermal energy and a saturated SEU cross-section from 3 to . Values of the SEU cross-sections from the thermal run well agree with those obtained by another CMS group that uses the same technology ( BiCMOS) though with different architecture. Cross-sections obtained with fast neutrons (from to about ) are consistently higher by one order of magnitude compared to the thermal one. The average time between consecutive SEU events in each chip of the CMS barrel RPCs can be estimated to be 1 h.
15045293
The bakelite for the RPCs of the experiment CMS
Results from aging tests on the bakelite used for the CMS RPCs are presented. Samples of melaminic bakelite were exposed to a heavy gamma and neutron radiation. Data on the bulk resistivity were collected while accumulating gamma and neutron doses and particles fluence up to values well beyond those expected in 10 years of RPCs operation in the barrel region of CMS. The test with gamma radiation was performed at the CERN Gamma Irradiation Facility (GIF) with a 20 Ci 137Cs source. A total absorbed dose of 5 Gy was accumulated during an irradiation period of about one month. The test with both neutron and gamma radiation was held at the Triga Mark II 250 kW reactor located in Pavia. A total of 80 h of exposure were accumulated integrating a neutron and gamma dose of about 80 Gy and a fast neutron fluence of some . Experimental data on dose rate in both the test facilities have been compared to simulation output and show a good agreement.
116993540
Latest results from the NA57 experiment
The NA57 experiment at the CERN SPS has measured the production of strange and multi‐strange particles in Pb‐Pb (and p‐Be) collisions at mid‐rapidity. The collective dynamics of the collision is studied in the transverse and longitudinal directions as a function of centrality and beam momentum and analysed on the basis of hydrodynamical models. Central‐to‐peripheral nuclear modification factors at 158 A GeV/c are presented and compared with other measurements and theory.
119200364
NA57 main results
The CERN NA57 experiment was designed to study the production of strange and multi-strange particles in heavy-ion collisions at SPS energies; its physics programme is essentially completed. A review of the main results is presented.
15830879
Centrality dependence of the expansion dynamics in Pb Pb collisions at 158-A-GeV/c
Two-particle correlation functions of negatively charged hadrons from Pb-Pb collisions at 158?GeV?c-1/nucleon have been measured by the WA97 experiment at the CERN SPS. A Coulomb correction procedure that assumes an expanding source has been implemented. Within the framework of an expanding thermalized source model the size and dynamical state of the collision fireball at freeze-out have been reconstructed as a function of the centrality of the collision. Less central collisions exhibit a different dynamics than central ones: both transverse and longitudinal expansion velocities are slower, the expansion duration is shorter and the system freezes out, showing smaller dimensions and higher temperature.
7281568
New results from the NA57 experiment
The production of hyperons in Pb–Pb and p–Be interaction at 40 A GeV/c beam momentum has been measured by the NA57 experiment. Strange particle enhancements at 40 A GeV/c are presented for the first time and compared to those measured at 158 A GeV/c. The transverse mass spectra of high statistics, high purity samples of K0S, Λ, Ξ and Ω particles produced in Pb–Pb collisions at 158 A GeV/c have been studied in the framework of the blast-wave model. The dependence of the freeze-out parameters on particle species and event centrality is discussed.
119419969
Transverse mass distributions of strange particles produced in Pb-Pb collisions at 158 A GeV/c
Experiment NA57 has collected high statistics, high purity samples of $K^0_s$, $\Lambda$, $\Xi$ and $\Omega$ produced in Pb-Pb collisions at 158 $A$ GeV/$c$. In this paper we present a study of the transverse mass spectra of these particles for a sample of events corresponding to about the most central 55% of the inelastic Pb-Pb cross section. We analyse the transverse mass distributions in the framework of the blast-wave model for the full sample under consideration and, for the first time at the SPS, as a function of the event centrality.