Database quantities

mid_e_wc2v : Mid-spill Wire Chamber 2 Voltage (there should be one for each WC.)

end_g_e21snc : End-of-spill, time since TEV clock event. (Has to do
with spill timing.)

end_f_mc7sc1: Pions on target this spill

end_f_mc7u09: Fake cosmic coincidences during beam (very useful! One measure of halo.)
end_f_mc7u10: Hits on Halo paddle during beam (not very useful, Jason St. John suspects. Even good tertiary beam often sprays this paddle.)
end_f_mc7u11: TPC trigger signals sent this spill. (Might be less than MC7U12 if readout electronics vetoed trigger signals, as they do when they are busy with an earlier event)
end_f_mc7u12: Total trigger signals sent this spill. (In principle should match event count this spill, after raw2digit)

end_f_mc6ic: Another device in the secondary beam, upstream of MC7SC1. Might be greater than MC7SC1 if there are beam losses on the way from MC6IC to MC7SC1. Might be different for other reasons of efficiency or dead time.