Radiation hardness and lifetime studies of LEDs and VCSELs for the opticalreadout of the ATLAS SCT

Citation
J. Beringer et al., Radiation hardness and lifetime studies of LEDs and VCSELs for the opticalreadout of the ATLAS SCT, NUCL INST A, 435(3), 1999, pp. 375-392
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences","Instrumentation & Measurement
Journal title
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
ISSN journal
0168-9002 → ACNP
Volume
435
Issue
3
Year of publication
1999
Pages
375 - 392
Database
ISI
SICI code
0168-9002(19991011)435:3<375:RHALSO>2.0.ZU;2-2
Abstract
We study the radiation hardness and the lifetime of Light Emitting Diodes ( LEDs) and Vertical Cavity Surface Emitting Laser diodes (VCSELs) in the con text of the development of the optical readout for the ATLAS SemiConductor Tracker (SCT) at LHC. About 170 LEDs from two different manufacturers and a bout 130 VCSELs were irradiated with neutron and proton fluences equivalent to (and in some cases more than twice as high as) the combined neutral and charged particle fluence of about 5 x 10(14) n (1 MeV eq. in GaAs)/cm(2) e xpected in the ATLAS inner detector. We report on the radiation damage and the conditions required for its partial annealing under forward bias, we ca lculate radiation damage constants, and we present post-irradiation failure rates for LEDs and VCSELs. The lifetime after irradiation was investigated by operating the diodes at an elevated temperature of 50 degrees C for sev eral months, resulting in operating times corresponding to up to 70 years o f operation in the ATLAS SCT. From our results we estimate the signal-to-no ise ratio and the failure rate of optical links using LEDs developed specif ically for application at LHC. (C) 1999 Elsevier Science B.V. All rights re served.