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Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors

The response of $n^+p$ silicon strip sensors to electrons from a $^{90}$Sr source was measured using a multi-channel read-out system with 25\,ns sampling time. The measurements were performed over a period of several weeks, during which the operating conditions were varied. The sensors were fabrica...

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Autor principal: The CMS Tracker Collaboration
Lenguaje:eng
Publicado: 2014
Materias:
Acceso en línea:http://cds.cern.ch/record/2026427
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author The CMS Tracker Collaboration
author_facet The CMS Tracker Collaboration
author_sort The CMS Tracker Collaboration
collection CERN
description The response of $n^+p$ silicon strip sensors to electrons from a $^{90}$Sr source was measured using a multi-channel read-out system with 25\,ns sampling time. The measurements were performed over a period of several weeks, during which the operating conditions were varied. The sensors were fabricated by Hamamatsu Photonics\,K.\,K. on 200\,$\mu $m thick float-zone and magnetic-Czochralski silicon. Their pitch was 80\,$\mu $m, and both $p$-stop and $p$-spray isolation of the $n^+$\,strips were studied. The electrons from the $^{90}$Sr source were collimated to a spot with a full-width-at-half-maximum of 2\,mm at the sensor surface, and the dose rate in the SiO$_2$ at the maximum was about 50\,Gy/d. % The measurements were performed over periods between 5 and 10 days. After only a few hours of making measurements, significant changes in charge collection and charge sharing were observed. Annealing studies, with temperatures up to $80^\circ $C and annealing times of 18\,hours, showed that the changes can only be partially annealed. % The observations are qualitatively explained with the help of TCAD simulations in which the effects of radiation damage in SiO$_2$ have been included. The observations can be qualitatively explained by the increase of the positive oxide-charge density due to the ionization of the SiO$_2$ by the radiation from the $\beta $\,source. TCAD simulations of the electric field in the sensor for different oxide-charge densities and different boundary conditions at the sensor surface support this explanation. % Results of TCAD simulations with different oxide-charge densities and different boundary conditions at the sensor surface are presented. The relevance of the measurements for the design of $p^+n$ strip sensors is discussed.
id cern-2026427
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2014
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spelling cern-20264272019-09-30T06:29:59Zhttp://cds.cern.ch/record/2026427engThe CMS Tracker CollaborationImpact of low-dose electron irradiation on $n^+p$ silicon strip sensorsDetectors and Experimental TechniquesThe response of $n^+p$ silicon strip sensors to electrons from a $^{90}$Sr source was measured using a multi-channel read-out system with 25\,ns sampling time. The measurements were performed over a period of several weeks, during which the operating conditions were varied. The sensors were fabricated by Hamamatsu Photonics\,K.\,K. on 200\,$\mu $m thick float-zone and magnetic-Czochralski silicon. Their pitch was 80\,$\mu $m, and both $p$-stop and $p$-spray isolation of the $n^+$\,strips were studied. The electrons from the $^{90}$Sr source were collimated to a spot with a full-width-at-half-maximum of 2\,mm at the sensor surface, and the dose rate in the SiO$_2$ at the maximum was about 50\,Gy/d. % The measurements were performed over periods between 5 and 10 days. After only a few hours of making measurements, significant changes in charge collection and charge sharing were observed. Annealing studies, with temperatures up to $80^\circ $C and annealing times of 18\,hours, showed that the changes can only be partially annealed. % The observations are qualitatively explained with the help of TCAD simulations in which the effects of radiation damage in SiO$_2$ have been included. The observations can be qualitatively explained by the increase of the positive oxide-charge density due to the ionization of the SiO$_2$ by the radiation from the $\beta $\,source. TCAD simulations of the electric field in the sensor for different oxide-charge densities and different boundary conditions at the sensor surface support this explanation. % Results of TCAD simulations with different oxide-charge densities and different boundary conditions at the sensor surface are presented. The relevance of the measurements for the design of $p^+n$ strip sensors is discussed.CMS-NOTE-2015-003CERN-CMS-NOTE-2015-003oai:cds.cern.ch:20264272014-07-25
spellingShingle Detectors and Experimental Techniques
The CMS Tracker Collaboration
Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
title Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
title_full Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
title_fullStr Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
title_full_unstemmed Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
title_short Impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
title_sort impact of low-dose electron irradiation on $n^+p$ silicon strip sensors
topic Detectors and Experimental Techniques
url http://cds.cern.ch/record/2026427
work_keys_str_mv AT thecmstrackercollaboration impactoflowdoseelectronirradiationonnpsiliconstripsensors