Network of the Day: Aggregating and Visualizing Entity Networks from Online Sources

This software demonstration paper presents a project on the interactive visualization of social media data. The data presentation fuses German Twitter data and a social relation network extracted from German online news. Such fusion allows for comparative analysis of the two types of media. Our system will additionally enable users to explore relationships between named entities, and to investigate events as they develop over time. Cooperative tagging of relationships is enabled through the active involvement of users. The system is available online for a broad user audience

The performance of irradiated CMS silicon mirco-strip detector modules

The central tracking system of the Compact Muon Solenoid (CMS) experiment will be entirely buil in silicon technology. The majority of the CMS tracker consists of silicon micro-strip detectors which have to be operated in the harsh environment of the Large Hadron Collider (LHC) over a period of ten years. The expected equivalent fluences range from a low of 0.7 x 10^14 n_1MeV/cm^2 at the outermost layers of the tracker, to a high of 1.6 x 10^14 n_1MeV/cm^2 at the layers closest to the interaction region. In this paper, results from studies of irradiatied CMS silicon detector modules are presented

Performance test of a micro-pattern stereo detector with two gas electron multipliers [online]

We report on the performance of a large micro-pattern detector with two gas electron multiplier foils (GEM) and a two-layer readout structure at ground potential. The two readout layers each have a 406 micro-m pitch and cross at an effective angle of 6.7 degrees. This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be 50 micro-m and 1 mm respectively (1 stand.dev.). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields

Construction and performance of a micro-pattern stereo detector with two gas electron multipliers [online]

The construction of a micro-pattern gas detector of dimensions 40 x 10 cm² is described. Two gas electron multiplier foils (GEM) provide the internal amplification stages. A two-layer readout structure was used, manufactured in the same technology as the GEM foils. The strips of each layer cross at an effective crossing angle of 6.7 degrees and have a 406 micro-m pitch. The performance of the detector has been evaluated in a muon beam at CERN using a silicon telescope as reference system. The position resolutions of two orthogonal coordinates are measured to be 50 micro-m and 1 mm, respectively. The muon detection efficiency for two-dimensional space points reaches 96%. Key words: detector, position sensitive, GEM, two-layer readou

Reception Test of Petals for the End Cap TEC+ of the CMS Silicon Strip Tracker

The silicon strip tracker of the CMS experiment has been completed and was inserted into the CMS detector in late 2007. The largest sub system of the tracker are its end caps, comprising two large end caps (TEC) each containing 3200 silicon strip modules. To ease construction, the end caps feature a modular design: groups of about 20 silicon modules are placed on sub-assemblies called petals and these self-contained elements are then mounted onto the TEC support structures. Each end cap consists of 144 such petals, which were built and fully qualified by several institutes across Europe. Fro

Integration of the End Cap TEC+ of the CMS Silicon Strip Tracker

The silicon strip tracker of the CMS experiment has been completed and inserted into the CMS detector in late 2007. The largest sub-system of the tracker is its end cap system, comprising two large end caps (TEC) each containing 3200 silicon strip modules. To ease construction, the end caps feature a modular design: groups of about 20 silicon modules are placed on sub-assemblies called petals and these self-contained elements are then mounted into the TEC support structures. Each end cap consists of 144 petals, and the insertion of these petals into the end cap structure is referred to as TEC integration. The two end caps were integrated independently in Aachen (TEC+) and at CERN (TEC--). This note deals with the integration of TEC+, describing procedures for end cap integration and for quality control during testing of integrated sections of the end cap and presenting results from the testing

Beam loss studies on silicon strip detector modules for the CMS experiment

The large beam energy of the LHC demands for a save beam abort system. Nevertheless, failures cannot be excluded with last assurance and are predicted to occur once per year. As the CMS experiment is placed in the neighboured LHC octant, it is affected by such events. The effect of an unsynchronized beam abort on the silicon strip modules of the CMS tracking detector has been investigated in this thesis by performing one accelerator and two lab experiments. The dynamical behaviour of operational parameters of modules and components has been recorded during simulated beam loss events to be able to disentangle the reasons of possible damages. The first study with high intensive proton bunches at the CERN PS ensured the robustness of the module design against beam losses. A further lab experiment with pulsed IR LEDs clarified the physical and electrical processes during such events. The silicon strip sensors on a module are protected against beam losses by a part of the module design that originally has not been intended for this. The third study with a pulsed and high intensive IR laser provided the damage threshold of the officially used module design and ensured and explained the sensor´s robustness against pulse energies far above the energy dissipated by the sensor during a beam loss

Study on 150 mu m thick n- and p-type epitaxial silicon sensors irradiated with 24-GeV/c protons and 1-MeV neutrons

A study on 150@mm epitaxial (EPI) n- and p-type silicon diodes irradiated with neutrons up to 8x10^1^5n/cm^2 and protons up to 1.7x10^1^5p/cm^2 has been performed by means of CV/IV, charge collection efficiency (CCE) and transient current techniqu e (TCT) measurements. It is found that the effective space charge density increases three times faster after proton than after neutron irradiation with a slightly higher effective space charge generation rate for n-type material compared to p-type materia l. A drop in charge collection efficiency already at fluences of 1x10^1^2n_e_q/cm^2 can be seen in n-type material, but is absent in p-type material. TCT measurements show space charge sign inversion from positive to negative charge in n-type material aft er neutron irradiation and from negative to positive space charge in p-type material after proton irradiation. No difference was found in the response of diodes manufactured by different producers out of the same wafer material

Characterization of proton and neutron irradiated low resistivity p-on-n magnetic Czochralski ministrip sensors and diodes

Transient Current Technique (TCT) and Charge Collection Efficiency (CCE) measurements were performed on low resistivity (280Ωcm) n-bulk, p-readout magnetic Czochralski ministrip sensors and diodes. The detectors were irradiated with neutrons and 24 GeV/c protons up to a total NIEL equivalent fluence of 8×10 15/ cm2. The study was addressed to assess the radiation tolerance of the detectors up to fluences expected in the next generations of High Energy Physics experiments. The charge collection efficiency after irradiation was found to be much higher than for standard FZ silicon p-in-n sensors. The underlying physics of this remarkable result was investigated by performing Edge-TCT measurements on one of the neutron irradiated ministrip sensors to extract detailed informations about the field and efficiency profiles of the detector. © 2011 Elsevier B.V