Project

General

Profile

Running modes

"Triggered"

500 V/cm: ZSrf =20 => max rate 15 Hz
ZSrf =10 => max rate 7.5 Hz
250 V/cm: ZSrf =20 => max rate 10 Hz
ZSrf =10 => max rate 5 Hz
max rate limited by 50 MBytes/s disk write bottleneck

Possible Trigger sources:

  • Horizontal counters - 2 Hz measured
  • Telescope counters (above cryostat for muons entering the TPC from the top) - 60 Hz measured
  • PDS (internal photon detector system) - 1 kHz guesstimated

Preferred mode:

  • Nominal trigger 5Hz - Horiz(2Hz)+Vert (prescaled to 2Hz)+PDS (prescaled to 1Hz)
  • PDS Readout "external+internal trig" mode, 5 us readout window
  • 1 microslice = 1000 ticks. Trigger activates 3+1+6=10 microslices at 500 V/cm, 5+1+9=15 at 250 V/cm

Data volume estimates: (assume that zero suppression reduces data volume a factor of ZSrf=20)
500 V/cm - total 3 MB/trigger = 15 MBytes/sec

  • TPC: 2048*10000*2*(1/20)=2.1 MBytes/trigger
  • PDS: 625*71*2 = 0.090 MBytes/flash, (0.35+0.20) MBytes/trigger. 0.20 from radiologicals, can be weeded?
  • PTB: 1 MByte/s = 0+0.2 MB/trigger (0.5 kB/trigger + cont readout)

"Untriggered"

Data Volume:

  • PDreadout in header only mode
  • data volume flow (MBytes/sec) = 200 Hz*2048*10000*2*(1/ZSrf)
  • example: ZSrf=100 => 80 Mbytes/s (write 2 disks in parallel)

Note that ZSrf=100 will be extremely difficult if noise remains at rms=6 counts for signals with pulse heights of 40 counts (second lowest gain setting)

"Triggered-long events"

  • Nominal trigger from pulser?
  • PDS Readout header only
  • 1 microslice = 1000 ticks.
  • EXAMPLE: Trigger at 5 Hz activates 100 microslices (25% live time). ZSrf=25 and final data rate is 40 Bytes/s

The ZS reduction factor determines the effective rate possible. See table in "Triggered" description.