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

Abstract

The response of n⁺p silicon strip sensors to electrons from a ⁹⁰Sr 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 on 200 μm thick float-zone and magnetic-Czochralski silicon. Their pitch was 80 μm, and both p-stop and p-spray isolation of the n⁺ strips were studied. The electrons from the ⁹⁰Sr 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 SiO₂ at the maximum was about 50 Gy(SiO₂)/d. 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 °C and annealing times of 18 h showed that the changes can only be partially annealed. The observations can be qualitatively explained by the increase of the positive oxide-charge density due to the ionization of the SiO₂ by the radiation from the β source. TCAD simulations of the electric field in the sensor for different oxide-charge densities and different boundary conditions at the sensor surface supportmore » this explanation. As a result, the relevance of the measurements for the design of n⁺p strip sensors is discussed.« less

Authors:

Adam, W. ^[1]

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+ Show Author Affiliations

1. Institut fur Hochenergiephysik der Osterreichischen Akademie der Wissenschaften (HEPHY), Vienna (Austria). et al.

Publication Date:

Fri Aug 28 00:00:00 EDT 2015

Research Org.:

Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP)

Contributing Org.:

CMS Collaboration

OSTI Identifier:

1248040

Report Number(s):

FERMILAB-PUB-15-612-CMS
Journal ID: ISSN 0168-9002; 1396014

Grant/Contract Number:  

AC02-07CH11359

Resource Type:

Accepted Manuscript

Journal Name:

Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

Additional Journal Information:

Journal Volume: 803; Journal Issue: C; Journal ID: ISSN 0168-9002

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; silicon strip sensors; charge collection; radiation damage; surface damage