K. Reeves

The HERA-B RICH uses a radiation path length of 2.8 m in C_4F_10 gas and a large 24 square meters spherical mirror for imaging Cherenkov rings. The photon detector consists of 2240 Hamamatsu multi-anode photomultipliers with about 27000 channels. A 2:1 reducing two-lens telescope in front of each PMT increases the sensitive area at the expense of increased pixel size, resulting in a contribution to the resolution which roughly matches that of dispersion. The counter was completed in January of 1999, and its performance has been steady and reliable over the years it has been in operation. The design performance of the RICH was fully reached: the average number of detected photons in the RICH for a beta=1 particle was found to be 33 with a single hit resolution of 0.7 mrad and 1 mrad in the fine and coarse granularity regions, respectively.

Mutating replication-dependent (RD) histone genes is an important tool for understanding chromatin-based epigenetic regulation. Deploying this tool in metazoan models is particularly challenging because RD histones in these organisms are typically encoded by many genes, often located at multiple loci. Such RD histone gene arrangements make the ability to generate homogenous histone mutant genotypes by site-specific gene editing quite difficult. Drosophila melanogaster provides a solution to this problem because the RD histone genes are organized into a single large tandem array that can be deleted and replaced with transgenes containing mutant histone genes. In the last ~15 years several different RD histone gene replacement platforms have been developed using this simple strategy. However, each platform contains weaknesses that preclude full use of the powerful developmental genetic capabilities available to Drosophila researchers. Here we describe the development of a newly engineered platform that rectifies many of these weaknesses. We used CRISPR to precisely delete the RD histone gene array (HisC), replacing it with a multifunctional cassette that permits site-specific insertion of either one or two synthetic gene arrays using selectable markers. We designed this cassette with the ability to selectively delete each of the integrated gene arrays in specific tissues using site-specific recombinases. We also present a method for rapidly synthesizing histone gene arrays of any genotype using Golden Gate cloning technologies. These improvements facilitate generation of histone mutant cells in various tissues at different stages of Drosophila development and provide an opportunity to apply forward genetic strategies to interrogate chromatin structure and gene regulation.

Abstract The design issues and tests carried out with the ring imaging Cherenkov detector for the HERA-B experiment are reviewed. Results of on-the-bench tests of the employed photomultiplier tubes are reported together with the early commissioning measurements with the HERA proton beam.

In the High Energy Physics Comunity Grid (HEPCG) of Germany’s D-Grid initiative, a suite of tools supporting the user in monitoring his jobs was developed. In the HEP community many users submit large numbers of jobs. A considerable fraction of these jobs fail for various reasons. Until now, it has been hard or even impossible for the user to find the reason for the job failure. The AMon tool supports the user with a graphical web-based overview on status and resource usage of his jobs. The script wrapper JEM (Job Execution Monitor) monitors a job’s environment giving detailed information about the job execution. Finally, once the job itself is running, a computational steering tool allows the user to interact with his job at runtime, to visualize intermediate results, and to modify job parameters.

A small set of final prototypes of the ATLAS Inner Detector silicon tracking system (Pixel Detector and SemiConductor Tracker), were used to take data during the 2004 Combined Test Beam. Data were collected from runs with beams of different flavour (electrons, pions, muons and photons) with a momentum range of 2 to 180 GeV/c. Four independent methods were used to align the silicon modules. The corrections obtained were validated using the known momenta of the beam particles and were shown to yield consistent results among the different alignment approaches. From the residual distributions, it is concluded that the precision attained in the alignment of the silicon modules is of the order of 5 μm in their most precise coordinate.

We report on aging measurements of a photon detector candidate, based on proportional wire chambers operating in TMAE, for the HERA-B RICH. The detector consisted of 64 cells, each 100 mm long and 8×8 mm2 in area, constructed with brass cathode and 45 μm gold plated tungsten anode wire and was operated at room temperature with 50% TMAE saturated methane. To age the chamber it was exposed for several weeks to UV light from a deuterium lamp at 3 MHz/cm2 counting rate, the expected maximum rate in the HERA-B RICH. The detection efficiency of the chamber for Cherenkov photons, generated in 5 m of argon by a 3 GeV electron testbeam at DESY, was recorded at regular intervals during the aging process. The pulse-height distribution of the chamber was continuously monitored. We found significant chamber gain loss after an exposure equivalent to about one month of running at HERA-B. Based on our results HERA-B decided to employ a multi-anode PMT system as photon detector in the RICH.

The innermost part of the ATLAS experiment at the LHC, CERN, will be a pixel detector, which is presently under construction. The command messages and the readout data of the detector are transmitted over an optical data path. The readout chain consists of many components which are produced at several locations around the world, and must work together in the pixel detector. To verify that these parts are working together as expected a system test has been built up. It consists of detector modules, optoboards, optical fibres, Back of Crate cards, Readout Drivers, and control computers. In this paper, the system test setup and the operation of the readout chain are described. Also, some results of tests using the final pixel detector readout chain are given.

The ATLAS pixel detector is built from 1744 modules which are organized in three barrel layers and three disk layers in forward direction. The modules consist of an oxygen-enriched silicon sensor with an active area of 60.8×16.4mm2. Its 46 080 pixels are read out by 16 frontend chips, bump bonded to the sensor using a state-of-the-art hybridization technique. After extensive characterization of the single modules they are mounted on support structures, made from a carbon–carbon composite material, which make up the barrel or the disc layers. The first of these assemblies are used to study the behavior of the modules outside the lab environment.

The performance of the ring imaging Cherenkov counter (RICH) for the HERA-B experiment has been evaluated. The measured values of the basic parameters such as the number of detected photons per ring and Cherenkov angle resolution are found to agree with a priori estimates. Also at higher track densities, the detector is capable of identifying individual rings. Particle identification has been achieved by determining the momentum from tracks in the vertex detector and main tracking system, hits in the electromagnetic calorimeter and track directions as measured by the RICH.

When planning an intervention on a complex experiment like ATLAS, the detailed knowledge of the system under intervention and of the interconnection with all the other systems is mandatory. In order to improve the understanding of the parties involved in an intervention, a rule-based expert system has been developed. On the one hand this helps to recognise dependencies that are not always evident and on the other hand it facilitates communication between experts with different backgrounds by translating between vocabularies of specific domains. To simulate an event this tool combines information from different areas such as detector control (DCS) and safety (DSS) systems, gas, cooling, ventilation, and electricity distribution. The inference engine provides a list of the systems impacted by an intervention even if they are connected at a very low level and belong to different domains. It also predicts the probability of failure for each of the components affected by an intervention. Risk assessment models considered are fault tree analysis and principal component analysis. The user interface is a web-based application that uses graphics and text to provide different views of the detector system adapted to the different user needs and to interpret the data

The HERA-B Vertex Detector System (VDS) is a Roman Pot system integrated into the proton ring of the HERA accelerator at DESY and serves as an independent part of the tracking system of the HERA-B forward spectrometer. The performance of the VDS meets the design specification. It is based on double-sided silicon micro-strip detectors which are operated as close as 1cm to the beam and are thus exposed to extremely high and inhomogeneous radiation levels. At the design luminosity the peak irradiation is around 3×1014 minimum ionizing particles per cm2 per year. Test measurements have shown adequate radiation tolerance on the required time scale of 1 year. New long-term studies presented here indicate that on periods longer than 1 year charge collection efficiencies might drop.

As with all detector systems at the Large Hadron Collider (LHC), the assignment of data to the correct bunch crossing, where bunch crossings will be separated in time by 25 ns, is one of the challenges for the ATLAS pixel detector. This document explains how the detector system will accomplish this by describing the general strategy, its implementation, the optimisation of the parameters, and the results obtained during a combined testbeam of all ATLAS subdetectors.

The ATLAS pixel detector consists of 1744 identical silicon pixel modules arranged in three barrel layers providing coverage for the central region, and three disk layers on either side of the primary interaction point providing coverage of the forward regions. Once deployed into the experiment, the detector will employ optical data transfer, with the requisite powering being provided by a complex system of commercial and custom-made power supplies. However, during normal performance and production tests in the laboratory, only single modules are operated and electrical readout is used. In addition, standard laboratory power supplies are used. In contrast to these normal tests, the data discussed here were obtained from a multi-module assembly which was powered and read out using production items: the optical data path, the final design power supply system using close to final services, and the Detector Control System (DCS).

The aging properties of a wire chamber, operating in a methane/TMAE gas mixture, were studied in a beam test. We emphasize here the precautions taken to minimize aging due to materials used in the chamber, and the redundancy in the design of the test. We compare our aging results to those recorded in the literature and find good agreement in the overall aging properties as a function of dose. We also report the results of increasing the high voltage of the aged chamber to restore the gain.

The physics potential of the RICH counter of the HERA-B experiment is illustrated in several MC simulated examples. In particular, we discuss its performance as an auxiliary tracking device.

The status of the RICH counter currently under construction for the HERA-B experiment is reviewed. Results of tests of various detector components in particular tests of the photon detector, the light collection system and the read-out chain are presented.

The innermost part of the ATLAS (A Toroidal LHC ApparatuS) experiment at the LHC (Large Hadron Collider) will be a pixel detector, which is presently under construction. Once installed into the experimental area, access will be extremely limited. To ensure that the integrated detector assembly operates as expected, a fraction of the detector which includes the power supplies and monitoring system, the optical readout, and the pixel modules themselves, has been assembled and operated in a laboratory setting for what we refer to as system tests. Results from these tests are presented.

The innermost part of the ATLAS (A Toroidal LHC ApparatuS)[1] experiment at the LHC (Large Hadron Collider) will be a pixel detector, which is presently under construction. Once installed into the experimental area, access will be extremely limited. To ensure that the integrated detector assembly operates as expected, a fraction of the detector which includes the power supplies and monitoring system, the optical readout, and the pixel modules themselves, has been assembled and operated in a laboratory setting for what we refer to as system tests. Results from these tests are presented.

The operational experience of the RICH detector for the first year at HERA-B is described. The design criteria, detector components, and reconstruction software are reviewed. The results show that the main design goals have been achieved.

Y~ , 'P -~upL2~~~~, l-LL ?m The operational expcrience of the RICH detector Tor the first year at HERA-B is descrihcd. The design criteria, detcc- tor coinponcnts, and reconstruction software are reviewed. The results show that the main dcsign goals have been achieved. is a fine-grained forward spec- most of the timc according to the standard b trOmcter constructed around the beam-pipe to meaSl,re the fi- resulting in a kaon. Thc charge of the kaon in the decay of (he nal states of interest. Thc geometric acceptance of the detector covers about 90% of the solid angle in the CMS frame. A schcmatic of the detector is shown in Figure 1. The protons, entering from the right, interact with 8 wire targets positioned inside the heam-pipe. The particles produced in an interaction are first tracked by 8 layers of silicon strip detector, deployed within 1 cm of the beam during data-taking, with high spatial A D~~~~~ criteria

The HEM-B RICH detector was installed in spring 1998, and has been in stable operation over the last two years. The design criteria, detector components and event analysis tools are reviewed, and the observed particle identification capabilities are presented. The performance was found to meet design expectations

This paper overviews the implementation of an automatic and portable electronic olfactory sensor unit suitable for remote operation. This unit is capable of complex odor identification.