Log entry time 13:18:40 on February21,2010

Entry number 309520

the quadruplets at 120Hz help cancel 60 Hz noise.  The figures shows a few 
events from run 1231. ( the vqwk integration time was using only about half the 
windows, but nevermind that).  In black, one sees the deviation of the points 
from the RAW tree from their mean.  60 Hz noise is plainly evident in the 
up/down pattern.

Forming pairs (shown in red) enhances this pattern of noise, with the sign 
flipping depending on the helicity-ordering of the pair.  

The multiplets differences (shown in blue) cancel this noise to a large degree.