32 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
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)
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)
65 Comparing Radiation Time in Radiology Technologist-Controlled Versus Endoscopist-Controlled Fluoroscopy During Endoscopic Retrograde Cholangiopancreatography
No full textThe CMS silicon tracker at LHC
No full textThe paper describes the Silicon Tracking System of the Compact Muon Solenoid (CMS) experiment that is foreseen to collect events from p-p collision at the E-cm = 14 TeV at the CERN future Large Hadron Collider (LHC). The proposed system consists of four layers of silicon microstrip detectors placed between the two inner layers of the pixel detector and the outer microstrip gas chamber system. The barrel part covers the eta region up to 1.8, instrumenting the central radial region between 20 and 50 cm. The forward-backward disks extend the coverage up to eta = 2.6. This paper will review the main characteristics and performances of the system, the actual status of the R&D activities that we are carrying on, and the status of the milestones we have to fulfill in view of the Technical Design Report expected at the end of the year. (C) 1998 Elsevier Science B.V. All rights reserved
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
Investigation of design parameters for radiation hard silicon microstrip detectors
No full textIn the context of the development of radiation hard silicon microstrip detectors for the CMS Tracker, we have investigated the dependence of interstrip and backplane capacitance as well as depletion and breakdown voltage on the design parameters and substrate characteristics of the devices. Measurements have been made for strip pitches between 60 and 240 mu m and various strip implants and metal widths, using multi-geometry devices, fabricated on wafers of either or crystal orientation, of resistivities between 1 and 6 k Omega cm and of thicknesses between 300 and 410 mu m. The effect of irradiation on properties of devices has been studied with 24 GeV/c protons up to a fluence of 4.3*10/sup 14/ cm /sup -2/. (15 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
Test results on heavily irradiated silicon detectors for the CMS experiment at LHC
No full textWe report selected results of laboratory measurements and beam tests of heavily irradiated microstrip silicon detectors. The detectors were single-sided devices, produced by different manufacturers and irradiated with different sources, for several total ionizing doses and fluences up to 4 x 10(14) 1-MeV-equivalent neutrons per cm(2). Strip resistance and capacitance, detector leakage currents and breakdown performance were measured before and after irradiations. Signal-to-noise ratio and detector efficiency were studied in beam tests, for different values of the detector temperature and of the read-out pitch, as a function of the detector bias voltage. The goal of these test is to optimise the design of the final prototypes for the Silicon Strip Tracker of the CMS experiment at the CERN LHC collider
The R & D program for silicon detectors in CMS
No full textThis paper describes the main achievements in the development of radiation resistant silicon detectors to be used in the CMS tracker. After a general description of the basic requirements for the operation of large semiconductor systems in the LHC environment, the issue of radiation resistance is discussed in detail. Advantages and disadvantages of the different technological options are presented for comparison. Laboratory measurements and test beam data are used to check the performance of several series of prototypes fabricated by different companies. The expected performance of the final detector modules are presented together with preliminary test beam results on system prototypes. (C) 1999 Elsevier Science B.V. All rights reserved
