The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb--Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.Comment: 55 pages, 82 figure

Front-end electronics for the ALICE TPC-detector

The Front-End electronics for the Time Projection Chamber (TPC) for the ALICE experiment consists of 5x105 channels. A single readout channel is comprised of three basic units: a charge sensitive amplifier/shaper with a fast tail cancellation; a 10 bit 10 Msamples/sec low power ADC; a digital ASIC which contains the zero suppression circuit and a multiple-event buffer. Data from a number of channels (4096) are multiplexed into an optical link (DDL) by means of a local custom bus which can support a data throughput of 2 Mbyte/event at a trigger rate of 50 Hz. The construction of a prototype of this electronics is presented in this paper

Conservation of Silk Genes in Trichoptera and Lepidoptera

Larvae of the sister orders Trichoptera and Lepidoptera are characterized by silk secretion from a pair of labial glands. In both orders the silk filament consists of heavy (H)- and light (L)-chain fibroins and in Lepidoptera it also includes a P25 glycoprotein. The L-fibroin and H-fibroin genes of Rhyacophila obliterata and Hydropsyche angustipennis caddisflies have exon/intron structuring (seven exons in L-fibroin and two in H-fibroin) similar to that in their counterparts in Lepidoptera. Fibroin cDNAs are also known in Limnephilus decipiens, representing the third caddisfly suborder. Amino acid sequences of deduced L-fibroin proteins and of the terminal H-fibroin regions are about 50% identical among the three caddisfly species but their similarity to lepidopteran fibroins is <25%. Positions of some residues are conserved, including cysteines that were shown to link the L-fibroin and H-fibroin by a disulfide bridge in Lepidoptera. The long internal part of H-fibroins is composed of short motifs arranged in species-specific repeats. They are extremely uniform in R. obliterata. Motifs (SX)n, GGX, and GPGXX occur in both Trichoptera and Lepidoptera. The trichopteran H-fibroins further contain charged amphiphilic motifs but lack the strings of alanines or alanine-glycine dipeptides that are typical lepidopteran motifs. On the other hand, sequences composed of a motif similar to ERIVAPTVITR surrounded by the (SX)4-6 strings and modifications of the GRRGWGRRG motif occur in Trichoptera and not in Lepidoptera

Linking formal child care characteristics to children's socioemotional well-being: A comparative perspective

Most research on formal child care and children’s outcomes has focused on single countries. We, however, contend that policy context may moderate the association between formal child care characteristics and children’s socioemotional well-being. We examined this by comparing the Netherlands, Finland and the UK; three countries that differ regarding family policies. Of these three countries, Finland was recently ranked highest (ranked 1st) with regards to quality of child care in a recent analysis by the Economist ,followed by the UK (ranked 3rd) and then the Netherlands (ranked 7th) .We hypothesized that children who attend child - care settings in countries with higher- uality formal child- are provision would generally show better socioemotional outcomes. Data from the comparative ‘F amilies 24/7’ survey were used, including 990 parents with children aged 0–12. We distinguished between two age groups in our analysis. Results indicated that, compared to the UK, longer hours in formal care were less beneficial in the Netherlands. Furthermore, spen ding time in formal care during nonstandard hours was more harmful for children in Finland compared to the UK. Lastly, receiving care from multiple caregivers was more disruptive for British children than for Dutch children. No differences were found between Finland and the Netherlands

The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb–Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.publishedVersio

The NOMAD Experiment at the CERN SPS

The NOMAD experiment is a short base-line search for ν&lt;sub&gt;μ&lt;/sub&gt; − ν&lt;sub&gt;τ&lt;/sub&gt; oscillations in the CERN neutrino beam. The ν&lt;sub&gt;τ&lt;/sub&gt;'s are searched for through their charged current interactions followed by the observation of the resulting τ− through its electronic, muonic or hadronic decays. These decays are recognized using kinematical criteria necessitating the use of a light target which enables the reconstruction of individual particles produced in the neutrino interactions. This paper describes the various components of the NOMAD detector: the target and muon drift chambers, the electromagnetic and hadronic calorimeters, the preshower and transition radiation detectors and the veto and trigger scintillation counters. The beam and data acquisition system are also described. The quality of the reconstruction and individual particles is demonstrated through the ability of NOMAD to observe K&lt;sub&gt;s&lt;/sub&gt;&lt;sup&gt;0&lt;/sup&gt;'s, Λ&lt;sup&gt;0&lt;/sup&gt;'s and π&lt;sup&gt;0&lt;/sup&gt;'s. Finally, the observation of τ− through its electronic decay being one of the most promising channels in the search, the identification of electrons in NOMAD is discussed

The NOMAD experiment at the CERN SPS

The NOMAD experiment is a short base-line search for $\nu_{\mu}\rightarrow \nu_{\tau}$ oscillations in the CERN neutrino beam. The $\nu_{\tau}$'s are searched for through their charged-current interactions followed by the observation of the resulting $\tau^{-}$ through its electronic, muonic or hadronic decays. These decays are recognized using kinematical criteria necessitating the use of a light target which enables the reconstruction of individual particles produced in the neutrino interactions. This paper describes the various components of the NOMAD detector: the target and muon drift chambers, the electromagnetic and hadronic calorimeters, the preshower and transition radiation detectors, and the veto and trigger scintillation counters. The beam and data acquisition system are also described. The quality of the reconstruction of individual particles is demonstrated through the ability of NOMAD to observe K$^0_{\rm s}$'s, $\Lambda^0$'s and $\pi^0$'s. Finally, the observation of $\tau^{-}$ through its electronic decay being one of the most promising channels in the search, the identification of electrons in NOMAD is discussed

The CPLEAR detector at CERN

The CPLEAR collaboration has constructed a detector at CERN for an extensive programme of CP-, T- and CPT-symmetry studies using ${\rm K}^0$ and $\bar{\rm K}^0$ produced by the annihilation of $\bar{\rm p}$'s in a hydrogen gas target. The ${\rm K}^0$ and $\bar{\rm K}^0$ are identified by their companion products of the annihilation ${\rm K}^{\pm} \pi^{\mp}$ which are tracked with multiwire proportional chambers, drift chambers and streamer tubes. Particle identification is carried out with a liquid Cherenkov detector for fast separation of pions and kaons and with scintillators which allow the measurement of time of flight and energy loss. Photons are measured with a lead/gas sampling electromagnetic calorimeter. The required antiproton annihilation modes are selected by fast online processors using the tracking chamber and particle identification information. All the detectors are mounted in a 0.44 T uniform field of an axial solenoid of diameter 2 m and length 3.6 m to form a magnetic spectrometer capable of full on-line reconstruction and selection of events. The design, operating parameters and performance of the sub-detectors are described.