120394706
Construction and test of a full prototype drift-tube chamber for the upgrade of the ATLAS muon spectrometer at high LHC luminosities
Abstract For the planned high-luminosity upgrades of the Large Hadron Collider (LHC) background rates of neutrons and gamma rays of up to 14 kHz / cm 2 are expected which exceed the rate capability of the current ATLAS precision muon tracking detectors, the Monitored Drift Tube (MDT) chambers, with a drift tube diameter of 30 mm. Smaller diameter drift tube (sMDT) chambers with 15 mm tube diameter have been developed for upgrades of the ATLAS muon spectrometer. A full sMDT prototype chamber has been constructed and tested in a muon beam at CERN and with cosmic muons at high background irradiation rates of up to 95 kHz / cm 2 and 1400 kHz/tube. The test results demonstrate the required track reconstruction efficiency and spatial resolution of the sMDT chambers at background rates well beyond the maximum expected values at high-luminosity LHC. The sense wire locations in the prototype chamber have been measured with few microns precision with cosmic rays using precise reference chambers confirming the required wire positioning accuracy of better than the 20 μ m .
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.
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.
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.
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.
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.
19809846
Development of Fast High-Resolution Muon Drift-Tube Detectors for High Counting Rates
Abstract Pressurized drift-tube chambers are efficient detectors for high-precision tracking over large areas. The Monitored Drift-Tube (MDT) chambers of the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) reach a spatial resolution of 35 μ m and almost 100% tracking efficiency with 6 layers of 30 mm diameter drift tubes operated with an Ar:CO 2 (93:7) gas mixture at 3 bar and a gas gain of 20 000. The ATLAS MDT chambers are designed to cope with background counting rates due to neutrons and γ rays of up to about 300 kHz per tube which will be exceeded for LHC luminosities larger than the design value of 10 34  cm −1  s −1 . Decreasing the drift-tube diameter to 15 mm while keeping the other parameters, including the gas gain, unchanged reduces the maximum drift time from about 700 to 200 ns and the drift-tube occupancy by a factor of 7. New drift-tube chambers for the endcap regions of the ATLAS muon spectrometer have been designed. A prototype chamber consisting of 12 times 8 layers of 15 mm diameter drift tubes of 1 m length has been constructed with a sense wire positioning accuracy of 20 μ m . The 15 mm diameter drift-tubes have been tested with cosmic rays in the Gamma Irradiation Facility at CERN at γ counting rates of up to 1.85 MHz.
118634238
Development of muon drift-tube detectors for high-luminosity upgrades of the Large Hadron Collider
Abstract The muon detectors of the experiments at the Large Hadron Collider (LHC) have to cope with unprecedentedly high neutron and gamma ray background rates. In the forward regions of the muon spectrometer of the ATLAS detector, for instance, counting rates of 1.7 kHz / cm 2 are reached at the LHC design luminosity. For high-luminosity upgrades of the LHC, up to 10 times higher background rates are expected which require replacement of the muon chambers in the critical detector regions. Tests at the CERN Gamma Irradiation Facility showed that drift-tube detectors with 15 mm diameter aluminum tubes operated with Ar : CO 2 ( 93 : 7 ) gas at 3 bar and a maximum drift time of about 200 ns provide efficient and high-resolution muon tracking up to the highest expected rates. For 15 mm tube diameter, space charge effects deteriorating the spatial resolution at high rates are strongly suppressed. The sense wires have to be positioned in the chamber with an accuracy of better than 50 μ m in order to achieve the desired spatial resolution of a chamber of 50 μ m up to the highest rates. We report about the design, construction and test of prototype detectors which fulfill these requirements.
120274396
Timing properties of an avalanche diode for single photon counting
A new concept for a silicon single photon counter has been developed at the Semiconductor Laboratory of the Max-Planck-Institute for Physics. The concept combines the principles of a drift diode and an avalanche diode. The electron which is generated by an incoming photon has to drift to the small avalanche region and avalanche breakdown will take place. The detector is operated in Geiger mode. In order to provide high efficiency and good timing properties, the electrons have to be focussed properly with short time jitter. Therefore, drift and timing properties have been investigated using simulations.
122734759
Measurement and Optimization of the Emittance of a 300-ns 250-A 3.4-MeV Electron Beam
Author(s): Allison, R.W.; Beal, J.W.; Everett, W.L.; Guggemos, J.R.; Lamb, W.A.S.; Richter, R.M.; Sherwood, W.A.; Spoerlein, R.L.; Tanabe, J.; Wright, R.E.; Zajec, E.
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.