First operational experience from the LHCb Silicon Tracker Gallas, A.; Bay, A.; Blanc, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2011, Letnik:
636, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The LHCb Silicon Tracker is a silicon micro-strip detector covering a sensitive area of 12
m
2 with a total of 272k readout channels. The installation of the detector is complete and commissioning is ...making excellent progress. The detector has recorded first beam-induced events during LHC synchronization tests in August 2008 and in June 2009. These events have allowed the performance to be studied, and adjustments to the operational parameters to be made. In this contribution, we will draw first lessons from the in situ commissioning of the Silicon Tracker, and present results from the reconstruction of data collected during the LHC synchronization tests.
Installation and operation of the LHCb Silicon Tracker detector Esperante, D.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The LHCb experiment is designed to perform high-precision measurements of CP violation and rare decays of B hadrons. The construction and installation of the Silicon Tracker (ST) was completed by ...early summer 2008. The Silicon Tracker covers a sensitive area of about 12m2 using silicon micro-strip technology and must withstand a radiation dose of 5×10131MeVn/cm2 equivalent after 10 years of operation. In these proceedings the preparation of the detectors for the first LHC beams is reported. Selected results from the detector commissioning in LHCb are shown, including the first beam-related events accumulated during the LHC injection and synchronization tests in September 2008. Lessons are drawn from the experience gathered during the installation and commissioning.
Although glutamine status in the critically ill patient can be improved by nutritional means, the most effective way of effecting such supplementation has received little attention. We evaluated two ...different ways of supplementing clinical nutrition products with glutamine, either with free glutamine or by providing a glutamine-rich protein source, in acute glucocorticoid-treated (intraperitoneal dexamethasone, 120 mg/kg) rats. During the recovery period, the animals received isonitrogenous and isoenergetic diets containing either casein, mixed whey proteins with or without glutamine, or carob protein plus essential amino acids. Plasma and tissue amino acids and glutathione as well as tissue protein synthesis were measured. Dexamethasone treatment lowered weight gain, muscle glutamine, and muscle and jejunal protein synthetic rate. Muscle protein synthesis was increased (from 15.9% to 24.2%/d) only when glutamine was included in the diet as a free amino acid. This increase paralleled a rise in plasma glutamine. We speculate that glutamine provided in dietary protein is extensively metabolized by the splanchnic tissues and does not influence peripheral glutamine status to the same extent as glutamine provided in a free amino acid form. However, both forms of glutamine supplementation were equally effective in increasing protein synthesis in the jejunum (by 25%). This is likely the main benefit of glutamine supplementation of enteral nutrition formulas.
We give here a short review of the LHCb Silicon Tracker, the main points of the module production and quality control, followed by the commissioning of the detector. Problems that were found during ...production or commissioning are described and the first performance assessment of the installed detector with “beam data” is given.
First experience and results with the LHCb Silicon Tracker Fave, V.; Bay, A.; Blanc, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
The LHCb experiment is designed to perform high-precision measurements of CP violation and rare decays of b hadrons. The construction and installation of the Silicon Tracker (ST) was completed by the ...summer of 2008. Here, we report on first results obtained using the data taken during injection tests (‘TED’ run) in August and September 2008.
LHCb Silicon Tracker DAQ and ECS Online Systems Esperante, Daniel; Rodriguez, P; Buchler, A ...
IEEE transactions on nuclear science,
2010-April, 2010-04-00, 20100401, Letnik:
57, Številka:
2
Journal Article
Recenzirano
The LHCb experiment at CERN is designed to perform precision measurements of b quark decays. The Silicon Tracker plays a crucial role in reconstructing particle trajectories and consists of two ...silicon micro-strip detectors, the Tracker Turicensis and the Inner Tracker. The radiation environment and the magnetic field represent new challenges for the implementation of the Experiment Control System (ECS) and the data acquisition (DAQ). The DAQ has to deal with ~272 000 analog read-out channels and real-time DAQ at a rate of ~ 1.1 MHz with data processing at the Trigger Electronics and L1 (TELL1) board level. The TELL1 real-time algorithms for clustering thresholds and other computations run on dedicated FPGAs. After data processing the total throughput amounts to about 6.4 GB from an input data rate of ~ 337 GB per second. The ECS is based on the hierarchical finite state machine paradigm and allows distributed control access and multi-platform use. The ECS is able to control and monitor the detector hardware infrastructure (power supplies, DAQ electronics ...) as well as monitor the environmental parameters. It can also take automated actions on warnings or alarms. Finally a completely independent, hardware based safety system ensures the detector safe operation.
Conjugated linoleic acid (CLA) has been reported to decrease fat deposition, and increase lean body mass. This has been broadly inferred to mean that CLA alters protein turnover. However, data to ...test the effects of CLA on protein turnover are lacking. An enhancement in immune responses by CLA has also been demonstrated.
The objective of this study was to determine the potential for dietary CLA and protein intervention to improve nutritional and functional recovery in an animal model of catabolic stress and immunodepletion.
Diets varying in their protein levels in the presence or absence of CLA were tested for their effects on the recovery of glucocorticoid (intraperitoneal injection of dexamethasone, 120 mg/kg) treated rats. Following steroid injection, rats were fed 4 dietary treatments for 4 d. The diets contained 10 or 20 g/100 g protein with or without 0.5 g/100 g CLA.
Dexamethasone treatment resulted in a decreased food intake and loss of weight, independent of dietary treatment. A higher number of blood monocytes occurred in rats fed the high CLA diets. The protein fractional synthesis rate in spleens of rats fed the diets containing either high proteins or CLA were higher compared to those fed diets with low protein content or without CLA, respectively. CLA, consumed post-dexamethasone treatment, did not improve protein turnover in the other tissues studied, including gut mucosa, liver, muscle and thymus.
The present study was performed to determine the effect of CLA in acute conditions, as opposed to a preventive approach, on the recovery from a catabolic stress with immunodepletion. Overall, no effect of short-term feeding CLA on the recovery from dexamethasone-mediated immunodepletion was observed.
The LHCb experiment at the Large Hadron Collider (LHC) at CERN in Geneva (Switzerland) is designed to perform precision measurements of b quark decays. The Silicon Tracker (ST) plays a crucial role ...in reconstructing particle trajectories and consists of two silicon micro-strip detectors, the Tracker Turicensis upstream of the LHCb magnet and the Inner Tracker downstream. The radiation environment and the magnetic field represent new challenges for the implementation of a Detector Control System (DCS) and the data acquisition (DAQ).The DAQ has to deal with ~272 K analog read-out channels, 2 K read-out chips and real time DAQ at a rate of 1.1 MHz with data processing at TELL1 level. The TELL1 real time algorithms for clustering thresholds and other computations run on dedicated FPGAs that implement 13 K configurable parameters per board, in total 1.17 M parameters for the ST. After data processing the total throughput amounts to about 6.4 GB from an input data rate of ~337 GB per second. A finite state machine based hierarchical control system is the fundamental of the DCS and allows distributed control access and multi-platform use. The implementation of the DCS system for two sub-detectors requires a design which can be used for TT and IT which have a different hardware mapping. With the DCS an operator is able to control the power supplies, to program the read-out chips and to monitor online the state of all the hardware in the read-out chain. It features as well a monitoring of temperature and humidity readings and can take automated actions on warnings or alarms. To guarantee safe operation a completely independent, hardware-based system is used for the 'vital' alarms to ensure redundancy.
PDF
