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User name Adaq
Log entry time 07:59:41 on February 5,2000
Entry number 32643
keyword=otr cabling
MCC called. Early in our shift Sandy Kaufmann called to alert us that we needed to insert filters to get useful otr measurements (at 100 mikes we saturated the digitizer). Hall C (or Liping Gan) has set an operational number of <150 for the max pixel displayed on the rhs of MaxVideo.
When inserted, the average xwidth and ywidth were again less than the 0.2 that Arun suggested as meaning good beam quality. But there were fluctuations as big as a factor of two in this width. However this morning when the MCC dayshift crew chief arrived, he noticed an unterminated extra cable hanging from the rack. This had the effect of reflecting a signal, as well as changing the impedance.
He removed it, the singal stablized (narrower) but had a max pixel slightly greater than 150. Another optical filter was added. The cable was probably there for a few days (possibly this entire run period?). The beam was then of slightly better quality than our otr would have suggested, since it was "polluted" or noisy.