Search

Abstract: The Alpha Magnetic Spectrometer (AMS-02) experiment will be mounted on the International Space Station (ISS) for 3 years to perform precision cosmic particle spectroscopy in space. The search for dark matter candidates requires precise -spectroscopy in the energy range from 10GeV up to 300GeV. Therefore, the dominating p-background has to be reduced by a factor of . This will be achieved with the AMS-02 electromagnetic calorimeter delivering 3–4 orders of magnitude and the transition radiation detector with proton rejection between 100 and 1000. The AMS-02 TRD consists of 20 layers of 6mm diameter straw modules alternating with 20mm layers of polyethylene/polypropylene fleece radiator. The straws are filled with a 80:20 gas mixture at 1.0bar absolute from a recirculating gas system designed to operate years. The straw modules will be operated in proportional mode at a gas gain of 3000. For the readout a dedicated low-power data-acquisition system based on VA analog multiplexers has been developed. The completed construction and assembly of the detector is presented with special emphasis on space qualification, long flight duration aspects and calibration of the AMS-02 TRD. This project is funded by the German Space Agency DLR (contract 50OO0501), the US Department of Energy DOE and NASA. [Copyright &y& Elsevier]

Abstract: Transition Radiation Detectors (TRDs) have been used to study highly relativistic cosmic rays in the last three decades. In recent and in future balloon or space experiments TRDs will be used as energy measuring or threshold devices with large acceptances and long flight durations. Energy measuring TRDs will be required to study the origin of high-energy particles in the cosmic rays at energies near . Threshold TRDs will be used for particle identification which is a key issue for dark matter and SUSY searches relying on positron spectroscopy up to 300GeV. This requires a proton rejection above from the TRDs. A review will be given of the different requirements and experimental solutions for threshold TRDs and the astrophysical significance of their measurements. Special emphasis will be dedicated to the space qualification and long flight duration aspects of the AMS-02 TRD. [Copyright &y& Elsevier]

Abstract: The Alpha Magnetic Spectrometer AMS02 will be equipped with a large transition radiation detector (TRD) to achieve a proton background suppression necessary for dark matter searches. The AMS02 TRD consists of 20 layers of fleece radiator each with proportional wire straw tubes read out by a dedicated low-power data-acquisition system. A space-qualified TRD design will be presented. The performance of a 20-layer prototype was tested at CERN with electron, myon and pion beams up to 100GeV and with protons up to 250GeV. The beam-test results will be compared to Geant3 MC predictions. The detector is under construction at RWTH Aachen; the gas system will be built at MIT, slow-control at MIT and INFN Rome and DAQ at TH Karlsruhe. This project is funded by the German Space Agency DLR, the US Department of Energy DOE and NASA. [Copyright &y& Elsevier]

The AMS02 experiment will be installed on the International Space Station for a data taking period of 3 years. The TRD consists of 20 layers of straw modules and fleece radiator with a total of 328 modules (16 straws each). The housing consists of a conically shaped octagon structure made out of CFC-Al-honeycomb material and is closed by a lower and upper honeycomb plate. The gas is a 80:20 Xe/CO2 mixture. The straw modules will be operated in proportional mode at a gasgain of 3000. The signals are readout by VA chips. The detector is under construction at RWTH Aachen, the gas system will be built at MIT, slow-control at INFN Rome and DAQ at TH Karlsruhe. In the presentation special emphasis will be dedicated to the space qualification aspects and the status of the straw module production. [Copyright &y& Elsevier]

Abstract: For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector (TRD) to improve particle identification. 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 built from final design components has achieved proton rejections from 100 to 2000 at 90% electron efficiency for proton beam energies up to 250GeV with cluster counting, likelihood and neural net selection algorithms. [Copyright &y& Elsevier]