• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name R. Michaels

    Log entry time 13:35:56 on January 9,2003

    Entry number 91208

    keyword=scaler cabling change (DATA FORMAT CHANGE)

    We plugged in the helicity into the 32nd scaler channel of the normalization scaler
    on each spectrometer. This signal comes from the helicity by way of a V-to-F
    converter which is either 197 kHz for one helicity or zero for the other.

    I modified the scaler readout to add this channel to the ring buffer. So, the ring
    buffer now contains 6 words, and the 6th one is helicity. This is documented on
    my DAQ web page.

    NOTE: THIS MEANS THE DATA FORMAT HAS CHANGED for the ring
    buffer data of 30 Hz deadtime free scalers.

    Interestingly, the first look at data shows that the data words are out of phase
    by one 30 Hz cycle compared to the helicity and QRT bits. This confirms the
    empirically determined delay-by-9 problem, though I still don't understand
    why the scaler works that way. But it will be recoverable.