195 research outputs found
Comparative study of < 111 > and < 100 > crystals and capacitance measurements on Si strip detectors in CMS
No full textFor the construction of the silicon microstrip detectors for the Tracker of the CMS experiment, two different substrate choices were investigated. A high-resistivity (6 k Omega cm) substrate with (111) crystal orientation and a low-resistivity (2 k Omega cm) one with (100) crystal orientation. The interstrip and backplane capacitances mere measured before and after the exposure to radiation in a range of strip pitches from 60 mu m to 240 mu m and for values of the width-over-pitch ratio between 0.1 and 0.5
Comparative study of (111) and (100) crystals and capacitance measurements on Si strip detectors in CMS
No full textFor the construction of the silicon microstrip detectors for the tracker of the CMS experiment, two different substrate choices were investigated: A high-resistivity (6 k Omega cm) substrate with crystal orientation and a low-resistivity (2 k Omega cm) one with crystal orientation. The interstrip and backplane capacitances were measured before and after the exposure to radiation in a range of strip pitches from 60 mu m to 240 mu m and for values of the width-over-pitch ratio between 0.1 and 0.5. (3 refs)
Comparative study of < 111 > and < 100 > crystals and capacitance measurements on Si strip detectors in CMS
No full textFor the construction of the silicon microstrip detectors for the Tracker of the CMS experiment, two different substrate choices were investigated. A high-resistivity (6 k Omega cm) substrate with (111) crystal orientation and a low-resistivity (2 k Omega cm) one with (100) crystal orientation. The interstrip and backplane capacitances mere measured before and after the exposure to radiation in a range of strip pitches from 60 mu m to 240 mu m and for values of the width-over-pitch ratio between 0.1 and 0.5
Test results of heavily irradiated Si detectors
No full textA large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300 mu m thick, p(+) on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2 x 10(14) n/cm(2). The detector performances do not significantly change if the detectors are biased well above the depletion voltage. S/N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500 V). (C) 1999 Published by Elsevier Science B.V. All rights reserved
New results on silicon microstrip detectors of CMS tracker
No full textInterstrip and backplane capacitances on silicon microstrip detectors with pf strip on n substrate of 320 mu m thickness were measured for pitches between 60 and 240 mu m and width over pitch ratios between 0.13 and 0.5. Parametrisations of capacitance w.r.t. pitch and width were compared with data. The detectors were measured before and after being irradiated to a fluence of 4*10/sup 14/ protons/cm/sup 2/ of 24 GeV/e momentum. The effect of the crystal orientation of the silicon has been found to have a relevant influence on the surface radiation damage, favouring the choice of a (100) substrate. Working at high bias (up to 500 V in CMS) might be critical for the stability of detector, for a small width over pitch ratio. The influence of having a metal strip larger than the p/sup +/ implant has been studied and found to enhance the stability. (7 refs)
R & D for the CMS silicon tracker
No full textThe CMS silicon tracker, consisting of about 70 m/sup 2/ of silicon microstrip devices, has to be operated for at least 10 years in a harsh radiation environment. The main implications of this environment on the detector design are summarized and an overview of the expected performance is given. (2 refs)
CMS silicon tracker developments
No full textThe CMS Silicon tracker consists of 70 m/sup 2/ of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors. (9 refs)
The silicon microstrip tracker for CMS
No full textThe CMS silicon strip tracker involves about 70 m/sup 2/ of instrumented silicon, with approximately 18500 microstrip detectors read out by 5*10/sup 6/ electronics channels. It has to satisfy a set of stringent requirements imposed by the environment and by the physics expected at the LHC: low cell occupancy and good resolution, radiation hardness aided by adequate cooling, low mass combined with high stability. These conditions have been incorporated in a highly modular design of the detector modules and their support structures, chosen to facilitate construction and to allow for easy assembly and maintenance. (3 refs)
The CMS silicon microstrip detectors: Research and development
No full textA large quantity of silicon microstrip detectors is foreseen to be used as part of the CMS tracker. A specific research and development program has been carried out with the aim of defining layouts and technological solutions suitable for the use of silicon detectors in high radiation environment. Results presented here summarise this work on many research areas such as techniques for device manufacturing, pre- and post-irradiation electrical characterization, silicon bulk defects analysis and simulations, system performance analytical calculations and simulations and test beam analysis. As a result of this work we have chosen to use single-sided, AC-coupled, poly silicon biased, 300 mu m thick, p(+) on n substrate detectors. We feel confident that these devices will match the required performances for the CMS tracker provided they can be operated at bias voltages as high as 500 V. Such high-voltage devices have been succesfully manufactured and we are now concentrating our efforts in enhancing yield and reliability. (C) 1999 Elsevier Science B.V. All rights reserved
Upgrade of the Alpha Magnetic Spectrometer (AMS-02) for long term operation on the International Space Station (ISS)
No full textFollowing the decision to maintain the International Space Station (ISS) on orbit until at least 2020 (possibly until 2028) the AMS collaboration decided to correspondingly extend the lifetime of the experiment. Since the limited amount of helium used to cool the superconducting magnet allowed for only a limited run time of the experiment, a change from the superconducting magnet to the permanent magnet used in AMS-01 became necessary. Due to the lower magnetic field, to maintain the resolution the silicon tracker also had to be reconfigured with the installation of a silicon plane on the top of the experiment and a new plane above the electromagnetic calorimeter
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