The ALICE Central Trigger Processor (CTP) at the CERN LHC has been upgraded for LHC Run 2, to improve the Transition Radiation Detector (TRD) data-taking efficiency and to improve the physics ...performance of ALICE. There is a new additional CTP interaction record sent using a new second Detector Data Link (DDL), a 2 GB DDR3 memory and an extension of functionality for classes. The CTP switch has been incorporated directly onto the new LM0 board. A design proposal for an ALICE CTP upgrade for LHC Run 3 is also presented. Part of the development is a low latency high bandwidth interface whose purpose is to minimize an overall trigger latency.
The integration of the ALICE trigger system with sub-detectors Krivda, M.; Barnby, L.; Bombara, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
The ALICE Trigger electronics (TRG) has been installed in the experimental cavern and tested with each of the detectors, both individually (‘standalone’ mode) and in ‘global’ runs, i.e. those ...involving other detectors. Global runs were performed with cosmic ray triggers, and also during the LHC startup period in September 2008. In this paper the status of the trigger system will be reviewed, in particular describing recent extensions to the system.
The ALICE trigger system installed in the experimental cavern processes information from triggering detectors at 3 hardware levels, and is used in p-p and Pb-Pb collisions. Many automatic functions ...have been developed to facilitate work in the control room. The hardware is permanently monitored, and around 1200 counters, with considerable built-in redundancy, are read at regular intervals (at least once per minute). This provides relevant physics information and also verifies the consistency of the hardware operation. In order to compensate for seasonal drift, the CORDE module has been installed, which allows the LHC clock to be delayed in steps of 10 ps. This paper describes the current status of the ALICE trigger system after experience with p-p and Pb-Pb runs, the new firmware developments and the appropriate software for this electronics.
We report the main results from experiment WA97 on the production of strange and multistrange hadrons at midrapidity in Pb+Pb, p+Pb and p+Be collisions at 158
A GeV/
c. A comparison with some of the ...available models is presented.
We propose a simple Glauber-type mechanism for the suppression of jet production up to transverse momenta of about 10 \(\mathrm {GeV}/c\) at RHIC. For processes in this kinematic region, the ...formation time is smaller than the interval between two successive hard partonic collisions and the subsequent collision influences the jet production. The number of jets then roughly scales with the number of participants. Proportionality to the number of binary collisions is recovered for very high transverse momenta. The model predicts suppression of jet production in \(d + {\mathrm {Au}}\) collisions at RHIC.
In the ALICE experiment, the Low-Voltage Differential Signalling (LVDS) format is used for the transmission of trigger inputs from the detectors to the Central Trigger Processor (CTP), the L0 trigger ...outputs from Local Trigger Units (LTU) boards back to the detectors and the BUSY inputs from the sub-detectors to the CTP. ALICE has designed a set-up, called the LVDS transmission tester, that aims to measure various transmission quality parameters and the bit-error rate (BER) for long period runs in an automatic way. In this paper, this method is described and the conclusions from these tests for the ALICE LVDS cables are discussed.
Results are presented on the production of K0S, hyperons and antihyperons in Pb--Pb and p--Be interactions at 40 GeV/c per nucleon. The enhancement pattern follows the same hierarchy as seen in the ...higher energy data--the enhancement increases with the strangeness content of the hyperons and with the centrality of collision. The centrality dependence of the Pb--Pb yields and enhancements is steeper at 40 than at 158 A GeV/c. The energy dependence of strangeness enhancements at mid-rapidity is discussed.
The WA97 experiment has measured the transverse mass (
m
T) spectra for negative hadrons (h
−) and strange particles produced at mid-rapidity in Pb−Pb collisions. The increased statistics of analysed ...data samples allowed us to perform a study of the spectra of K
0
S, Λ, Ξ, Ω and h
− as a function of the centrality of the collisions. The data, which correspond to the most central 40% of the total inelastic cross section, have been divided into four centrality classes according to the estimated number of nucleons taking part in the collision. The
m
T spectra, analysed separately for each centrality bin, exhibit only weak (≤ 15%) centrality dependence. The deviation of the Ω inverse slope from the linear dependence on the particle mass is confirmed even for the most central Pb−Pb collisions.
A study of the strangeness enhancement in Lead-Lead collisions with respect to proton-induced reactions is being carried out at the CERN SPS by the WA97 experiment: up to now, data from proton-Lead ...collisions have been used as a reference sample. In this paper we report on a study of particle production in proton-Beryllium collisions. These collisions are expected to constitute a better reference sample than p-Pb, because of the lighter target. The analysis of hyperon and negative particle production is presented and the results are compared with those previously obtained from Pb-Pb and p-Pb collisions.
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