SEU tests of an 80 Mbit/s optical receiver

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SEU tests of an 80 Mbit/s optical receiver

• F. Faccio, K. Gill, M. Huhtinen, A. Marchioro, P.
  Moreira, F. Vasey
• CERN, Geneva, Switzerland
• G. Berger
• UCL/CRC, Louvain-la-Neuve, Belgium

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Outline

• Introduction the optical receiver
• The experiment
• SEU results
• System implications
• Conclusions

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Introduction

• Optical receiver for the CMS tracker slow control
  gt data clock (_at_ 80 Mbit/s)
• Tracker radiation environment gt PIN diode
  ASIC have to be radiation tolerant
• Influence of radiation on the BER performance of
  the link?

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Optical receiver
Fermionics InGaAs/InP
ASIC

• ASIC designed in commercial 0.25 mm using
  radiation tolerant layout techniques
• Both photodiode and ASIC have been proven
  radiation hard

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Mounting with two photodiodes
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Experimental setup
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SEU measurements at CRC(Louvain-la-Neuve,
Belgium)

• 59MeV protons (1-4108 p/cm2s)
• lower energy with moderators
• 62MeV (106 p/cm2s) and 32MeV neutrons (5105
  p/cm2s), 50 of neutrons within 2MeV from the
  peak
• different angles to the beam
• shielding either receiver or PIN diode

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InGaAs PIN diode sensitive region
90 deg
45 deg
20 deg
Beam
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BER calibration
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Irradiation results (1)
Events in the PIN diode dominate the error rate!
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Irradiation results (2)
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Irradiation results (3)
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Summary
Direct ionization, angle 20-80deg
Direct ionization, angle ?90deg
Nuclear interaction
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System implications
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Conclusion

• BER performance of the receiver system is
  degraded!
• SEU observed under irradiation in the form of
  bit-errors
• Events in the PIN diode dominate the rate
• Errors due to both direct and secondary
  ionization, depending on Popt, angle of incidence
  and particle nature