43889438
Performance of fast high-resolution Muon drift tube chambers for LHC upgrades
Monitored drift tube chambers are used as precision tracking detectors in the muon spectrometer of the ATLAS experiment at the LHC at CERN. These chambers provide a spatial resolution of 35 mm and a tracking efficiency of close to 100 % up to background rates of 0.5 kHz/cm2, the former being limited at higher rates mainly due to space charge effects and the latter due to the maximum drift time of 700 ns. For LHC upgrades, a faster drift tube chamber has been developed, using drift tubes with a diameter of 15mm instead of 30 mm. The increased channel density and shorter drift time of about 200 ns raise the rate capability to about 10 kHz/cm2, while retaining the spatial resolution. A prototype chamber with trapezoidal shape consisting of 2×8 layers of 15mm diameter drift tubes with an active surface of 0.8 m2 has been constructed. This chamber has been tested at CERN with a 180 GeV muon beam (H8) and with cosmic ray muons at the Gamma Irradiation Facility (GIF) at high g radiation rates.
126243744
Measurement of the reaction π−p→π+π−n on a transversely polarized target at 17.2 GeV
Preliminary results from a high statistics measurement (1 M events) of the reaction π−p→π+π−n on strong polarization effects which must be attributed to amplitudes corresponding to ’’A1’’ exchange.
108271361
Concepts for the readout of time projection chambers
While the use of CCD’s for the readout of TPC’s offers a reliable and ever more of the digitization concept. The problem of precision of currently available FADC’s is discussed together with two proposals for a solution.
120421514
GAS SYSTEM FOR ALEPH TPC
Abstract Operation of the time projection chamber of the ALEPH experiment at LEP requires a high-purity argon/methane gas mixture supplied to the detector under stable conditions to ensure minimum signal attenuation throughout the 43 m 3 detector volume (max. 2.2 m drift length) and maintain near-constant electron drift velocity in the gas over extended periods of time. Design considerations for a gas system to fulfil these conditions are presented and details given of the construction, operational aspects and of the achieved performance.
120324718
Integration, commissioning and installation of monitored drift tube chambers for the ATLAS barrel muon spectrometer
The ATLAS experiment at the Large Hadron Collider (LHC) at CERN is currently being assembled to be ready to take data in 2007. Its muon spectrometer is designed to achieve a momentum resolution better than 10% at 1 TeV. In the barrel part, a toroidal air-core magnet is instrumented with three layers of Monitored Drift Tube (MDT) chambers for precision tracking. The Max-Planck-Institut fur Physik and the Ludwig-Maximilians-University in Munich have built 88 MDT chambers for the outermost barrel layer. We report on our experience with the tests of the MDT chambers, their integration with the Resistive Plate trigger chambers and the installation of the muon stations in the experiment. First results of their commissioning in the ATLAS detector will be presented.
122359864
Large-scale production of Monitored Drift Tube chambers for the ATLAS muon spectrometer
Abstract Precision drift tube chambers with a sense wire positioning accuracy of better than 20 μm are under construction for the ATLAS muon spectrometer. 70% of the 88 large chambers for the outermost layer of the central part of the spectrometer have been assembled. Measurements during chamber construction of the positions of the sense wires and of the sensors for the optical alignment monitoring system demonstrate that the requirements for the mechanical precision of the chambers are fulfilled.
67778447
A fast readout using switched current techniques for a DEPFET-pixel vertex detector at TESLA
Abstract A fully depleted silicon detector with a first amplifying transistor integrated in every pixel (DEPFET) is a promising proposal for the pixel-based vertex detector at TESLA. The DEPFET offers good spatial resolution, an excellent signal-to-noise ratio and low power consumption in a row-wise operation mode. A readout concept for a DEPFET pixel array matching the requirements at TESLA is described. In order to meet the operation specifications at TESLA ( 50 MHz row rate), a readout architecture based on current mode techniques (Switched Current) is presented. It contains stand alone zero suppression offering a triggerless operation. The core of the readout chip, a fast operating current memory cell, is discussed in detail. The results of a first prototype chip, CURO I (CUrrent ReadOut), show that the requirements for TESLA are achievable.
110855495
Performance of novel silicon n-in-p planar pixel sensors
Abstract The performance of novel n-in-p planar pixel detectors designed for future upgrades of the ATLAS Pixel system is presented. The n-in-p silicon sensors technology is a promising candidate for the pixel upgrade thanks to its radiation hardness and cost effectiveness that allow for enlarging the area instrumented with pixel detectors. The n-in-p modules presented here are composed of pixel sensors produced by CiS connected by bump-bonding to the ATLAS read-out chip FE-I3. The characterization of these devices has been performed before and after irradiation up to a fluence of 5×10 15 1 MeV n eq cm −2 . Charge collection measurements carried out with radioactive sources have proven the functioning of this technology up to these particle fluences. First results from beam test data with a 120 GeV/ c pion beam at the CERN-SPS are also discussed, demonstrating a high tracking efficiency of (98.6±0.3)% and a high collected charge of about 10 ke for a device irradiated at the maximum fluence and biased at 1 kV.
25787680
Spectroscopic performance of the DePMOS detector/amplifier device with respect to different filtering techniques and operating conditions
A DePMOS structure provides detection and amplification jointly, and it is free of interconnection stray capacitance. To fully exploit the intrinsic low noise of the device an electrical model has been developed. The most relevant parameters have been measured in order to choose an adequate readout electronics. DePMOS can operate in continuous mode, i.e., without applying any clear pulse during the signal processing, and can be read out by a time-continuous shaper amplifier. An unequalled noise of 2.2 electrons rms at room temperature has been measured. In this mode DePMOS can be used, for example, as the readout device for silicon drift detectors. Anyway , DePMOS was developed to be the basic element of an active pixel sensor suitable to cope with the requirements of the XEUS Wide Field Imager. In a matrix arrangement, each pixel must be read out by a time-variant filter. A multichannel integrated shaping amplifier, based on multicorrelated double sampling, has been designed. Spectroscopic resolution obtained filtering the pixel matrix with this readout chip is in agreement with measurements in continuous mode and matches the predictions of the model presented. It has also been experimentally proved that the clear procedure does not introduce additional noise contribution, even in the very low noise range achieved. This qualifies DePMOS as a "reset-noise-free" device
118357728
Thin n-in-p pixel sensors and the SLID-ICV vertical integration technology for the ATLAS upgrade at the HL-LHC
Abstract This R&D activity is focused on the development of new modules for the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The performance after irradiation of n-in-p pixel sensors of different active thicknesses is studied, together with an investigation of a novel interconnection technique offered by the Fraunhofer Institute EMFT in Munich, the Solid–Liquid-InterDiffusion (SLID), which is an alternative to the standard solder bump-bonding. The pixel modules are based on thin n-in-p sensors, with an active thickness of 75 μ m or 150 μ m , produced at the MPI Semiconductor Laboratory (MPI HLL) and on 100 μ m thick sensors with active edges, fabricated at VTT, Finland. Hit efficiencies are derived from beam test data for thin devices irradiated up to a fluence of 4 × 10 15 n eq / cm 2 . For the active edge devices, the charge collection properties of the edge pixels before irradiation are discussed in detail, with respect to the inner ones, using measurements with radioactive sources. Beyond the active edge sensors, an additional ingredient needed to design four side buttable modules is the possibility of moving the wire bonding area from the chip surface facing the sensor to the backside, avoiding the implementation of the cantilever extruding beyond the sensor area. The feasibility of this process is under investigation with the FE-I3 SLID modules, where Inter Chip Vias are etched, employing an EMFT technology, with a cross section of 3 μ m × 10 μ m , at the positions of the original wire bonding pads.
34283775
Tracking and level-1 triggering in the forward region of the ATLAS muon spectrometer at sLHC
In the endcap region of the ATLAS Muon Spectrometer (η  >  1) precision tracking and Level-1 triggering are performed by different types of chambers. Monitored Drift Tube chambers (MDT) and Cathode Strip Chambers (CSC) are used for precision tracking, while Thin Gap Chambers (TGC) form the Level-1 muon trigger, selecting muons with high transverse momentum (pT). When by 2018 the LHC peak luminosity of 1034 cm−2s−1 will be increased by a factor of ~ 2 and by another factor of ~ 2–2.5 in about a decade from now (``SLHC''), an improvement of both systems, precision tracking and Level-1 triggering, will become mandatory in order to cope with the high rate of uncorrelated background hits (``cavern background'') and to stay below the maximum trigger rate for the muon system, which is in the range of 10–20 % of the 100 kHz rate, allowed for ATLAS. For the Level-1 trigger of the ATLAS Muon Spectrometer this means a stronger suppression of sub-threshold muons in the high-pT trigger as well as a better rejection of tracks not coming from the primary interaction point. Both requirements, however, can only be fulfilled if spatial resolution and angular pointing accuracy of the trigger chambers, in particular of those in the Inner Station of the endcap, are improved by a large factor. This calls for a complete replacement of the currrently used TGC chambers by a new type of trigger chambers with better performance. In parallel, the precision tracking chambers must be replaced by chambers with higher rate capability to be able to cope with the intense cavern background. In this article we present concepts to decisively improve the Level-1 trigger with newly developed trigger chambers, being characterized by excellent spatial resolution, good time resolution and sufficiently short latency. We also present new types of precision chambers, designed to maintain excellent tracking efficiency and spatial resolution in the presence of high levels of uncorrelated background hits, as generated by γ and neutron conversions.