APV25 Irradiation (December 2000)

In December 2000, APV25S1 chips were placed in an intense particle beam at PSI [65] to study the effects of radiation. A total dose of $1.87 \cdot 10^{14}\,\rm\pi^+\,cm^{-2}$ was achieved with positive pions at a momentum of $300\,\rm MeV/c$. This dose slightly exceeds the total expected hadron fluence in the innermost layer of the CMS Silicon Strip Tracker over 10 years. The flux achieved in the PSI test was approximately $10^9\,\rm\pi^+\,cm^{-2}\,s^{-1}$ and thus about 1000 times higher than during CMS operation. The nuclear interaction cross-section of positive pions on protons peaks at $300\,\rm MeV/c$, which makes them ideal for such a test.

Of the radiation effects described in section , p. , a large number of single event upsets (SEUs) was measured, but also an effect which might come from oxide charging. No single event latchup or gate ruptures were observed. The digital SEU rates will be compared to the results of a similar test with heavy ions, concluded with a prediction for the rates in the CMS tracker.

Additional information on the SEU test can be obtained at [12].