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faq.md

@@ -112,7 +112,16 @@ The fibber delay tempco is at the order of 50ps/Km/C. The fibbers in
 Gran Sasso are buried deep underground where temperature changes below
 1C are expected. This represents a maximun change inferiour to 1ns
 thourghout the year in the OPERA fibber. At CERN we have ~2Km of fibber
-between the CERN's Control Room (CCR) and HCA442,
+between the CERN's Control Room (CCR) and HCA442. This fibber is not
+buried as deeply as the one used in LNGS. If we take that the fibber is
+buried at 1m ,the temperature change could be of ~15C. This implies a
+possible change on the fibber delay of 1.5ns.
+
+Additionally the electronics could be affected by temperature changes.
+We have tested in the lab that after heating with a hot gun the CTRI
+(~80C), the reception delay increases by ~2ns. Notice that this is well
+beyond the electronics working environment. We can expect seasonal delay
+changes smaller than 2ns peak to peak.
 
 ## Beam Current Transformer cable calibration