Time resolved studies of Single Event Upset in optical data receiver for the ATLAS pixel detector

Abstract

A multichannel optical transceiver (optoboard) housing a PiN array coupled to a BPM signal decoding ASIC, was exposed to a proton beam of 24 GeV/c momentum. The 40 MHz clock and 40 Mbit/s data supplied to the optoboard were restored directly on the board and then in addition transmitted back to the counting room for online checking of consistency. In the case of a data bit error or a missing clock transition, indicating an occurrence of a SEU, a sequence of time aligned data bits along with the corresponding clock states were recorded for offline analyses. A compact DAQ system based on a FPGA processor was customdeveloped for this task. Measurements were performed for input signals covering a certain range of optical power. We present results obtained from the August 2009 run at the CERN irradiation facility, including the SEU occurrence rate and crosssection, both as a function of the input optical amplitude, along with the timeresolved structure of the SEU incidents. 9th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor

Time-Resolved Studies of Single-Event-Upset effects in Optical Data Receiver for the First LHC Upgrade Phase of the ATLAS Pixel Detector.

“…It is evident from the decomposition of the total SEU rate into D, C and B contributions ( Table 1, Figure 2), that the type-D events clearly dominate the SEU rate for all optical power settings with 79% probability of occurrence, whereas for type-C and -B events a relative contribution of nearly 10% each was observed. This is almost the same result we obtained from 2009 measurement [2], which was limited by 110 μA maximum input photocurrent. The newly measured SEU cross-section is presented in Figure 3.…”

“…A scaling factor of 8, derived in section 6.5, has been applied. A comparison with our earlier SEU cross-section measurements reveals good agreement at 300 µA [3], at 100 µA [2] the present result is lower by a factor 3 and at 500 µA [3] higher by a factor 5.…”

“…The observed SEU rate decreases by a factor 3 in response to the increase of input photocurrent from 100 to 400 µA. In comparison, nearly the same factor of 3 was measured earlier for input photocurrent raise from 50 to 100 μA [2]. Hence, the effectiveness of SEU rate mitigation by boosting light signal amplitude becomes limited with increasing input photocurrent.…”

“…In parallel to irradiation tests addressing optoboard performance as a function of accumulated irradiation dosage, the optical receiver part of the opto-board was studied in August 2010, regarding instantaneous effects of Single-EventUpset (SEU) on the integrity of the clock and data output signals. The study we report has been performed in a similar way to our previous SEU test conducted one year earlier [2] on an assembly consisting of the first generation DORIC chip in 0.25 μm CMOS technology [3], connected to a fast PiN-photodiode array [4] and subjected to newly developed approach of time-resolved SEU analyses. A similar time-resolved error-logging approach was adopted earlier for a set of comprehensive SEU studies at Multi-Gbps data transmission rates [5].…”

“…A similar time-resolved error-logging approach was adopted earlier for a set of comprehensive SEU studies at Multi-Gbps data transmission rates [5]. In [2] we have discussed the SEU rate prediction in the ATLAS pixel detector, resulting in one biterror in 20 minutes per transmission channel and reaching one bit-error in 80 seconds at the end of the detector life time. It is well known from earlier radiation-induced SEU studies [6]- [8], that the optical PiN-photodiode receiver itself is the device most vulnerable to the instantaneous impact of radiation on transmitted signals due to its comparatively large SEU sensitive area.…”