W. Karpinski

Hadron calorimetry in the L3 detector

Abstract The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e + e − collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granulatiry of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted.

A transition radiation detector for AMS

Abstract For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector to improve proton background supression up to 300 GeV. The TRD has 20 layers of fleece radiator with Xe/CO2 proportional-mode straw-tube chambers. They are supported in a conically shaped octagon structure made of CFC-Al-honeycomb. For low power consumption VA analog multiplexers are used as front-end readout. A 20 layer prototype has achieved proton rejections above 100 at 90% electron efficiency for beam energies up to 250 GeV. The detector is under construction at RWTH Aachen, the gas system will be built at MIT, slow-control and DAQ at TH Karlsruhe.

A high-resolution scintillating fiber tracker with silicon photomultiplier array readout

We present prototype modules for a tracking detector consisting of multiple layers of 0.25 mm diameter scintillating fibers that are read out by linear arrays of silicon photomultipliers. The module production process is described and measurements of the key properties for both the fibers and the readout devices are shown. Five modules have been subjected to a 12 GeV/c proton/pion testbeam at CERN. A spatial resolution of 50 mu m and light yields exceeding 20 detected photons per minimum ionizing particle have been achieved, at a tracking efficiency of more than 98.5%. Possible techniques for further improvement of the spatial resolution are discussed

Radiation and cryogenic test results with a monolithic GaAs preamplifier in C-HFET technology

Abstract We report test results with a monolithic GaAs preamplifier fabricated in industrial C-HFET technology irradiated with a total dose of 10 14 neutrons/cm 2 and 100 Mrad γ radiation and operated under cryogenic conditions. The measured gate current of the input transistor of a few nA increases by

The AMS-02 Anticoincidence Counter

The AMS-02 detector will measure cosmic rays on the International Space Station. This contribution will cover production, testing, space qualification and integration of the AMS-02 anticoincidence counter. The anticoincidence counter is needed to to assure a clean track reconstruction for the charge determination and to reduce the trigger rate during periods of high flux.

Radiation tests on GaAs particle detectors

Abstract 24 GaAs surface barrier diodes of 0.64 cm2 active surface have been fabricated and tested as particle detectors. Several diodes have been subjected to an irradiation test with 100 Mrad of 3 MeV electrons and 50 Mrad of 60Co gammas.

Experimental Studies Towards a DC-DC Conversion Powering Scheme for the CMS Silicon Strip Tracker at SLHC

The upgrade of the CMS silicon tracker for the Super-LHC presents many challenges. The distribution of power to the tracker is considered particularly difficult, as the tracker power consumption is expected to be similar to or higher than today, while the operating voltage will decrease and power cables cannot be exchanged or added. The CMS tracker has adopted parallel powering with DC-DC conversion as the baseline solution to the powering problem. In this paper, experimental studies of such a DC-DC conversion powering scheme are presented, including system test measurements with custom DC-DC converters and current strip tracker structures, studies of the detector susceptibility to conductive noise, and simulations of the effect of novel powering schemes on the strip tracker material budget.

A wiring system for mass production of drift and proportional chambers

Abstract We describe the equipment and procedures developed and employed for the wiring in mass production of the forward/backward muon drift chambers of the L3 experiment. A computer-controlled machine is used to stretch simultaneously all wires of one drift cell to the required tension. After manual insertion of the wire group into the chamber, another computer-controlled device is used to measure the tension of each wire, thus providing an immediate quality check.

DC-DC buck converters for the CMS Tracker upgrade at SLHC

The CMS experiment at the Large Hadron Collider (LHC) at CERN, Geneva, is planning major upgrades of its current pixel and strip detectors for the LHC luminosity upgrade, known as the SLHC. Due to the larger channel count and — in case of the strip tracker — increased functionality, the powering scheme adopted today, namely parallel powering of several detector modules, has to be abandoned. Instead, a powering scheme based on the DC-DC conversion technique is foreseen, which would lead to lower power losses in the supply cables, and would allow to reduce the material budget of cables and associated electronic boards in the sensitive detector volume. This paper deals with the development, characterisation and optimisation of DC-DC buck converter prototypes for the upgrades of the CMS pixel and strip detectors at the SLHC.

System Tests with DC-DC Converters for the CMS Silicon Strip Tracker at SLHC

The delivery of power is considered to be one of the major challenges for the upgrade of the CMS silicon strip tracker for SLHC. The inevitable increase in granularity and complexity of the device is expected to result in a power consumption comparable or even higher than the power consumption of todays’ strip tracker. However, the space available for cables will remain the same. In addition, a further increase of the tracker material budget due to cables and cooling is considered inacceptable, as the performance of the CMS detector must not be compromised for the upgrade. Novel powering schemes such as serial powering or usage of DC-DC converters have been proposed to solve the problem. To test the second option, substructures of the current CMS silicon strip tracker have been operated for the first time with off-the-shelf DC-DC buck converters as well as with first prototypes of custom-designed DC-DC converters. The tests are described and the results are discussed.