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

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:
 [1]
  1. Institut fur Hochenergiephysik der Osterreichischen Akademie der Wissenschaften (HEPHY), Vienna (Austria). et al.
Publication Date:
OSTI Identifier:
1248040
Report Number(s):
FERMILAB-PUB--15-612-CMS
Journal ID: ISSN 0168-9002; 1396014
Grant/Contract Number:
AC02-07CH11359
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
Research Org:
Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Orgs:
CMS Collaboration
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