Low-level DAQ Data Structure

DAQ data is represented by a table, each row represents a DAQ event on a single (physical or logical) input channel. Event building will happen at a higher data level. The detailed structure of DAQ data will depend on the DAQ system and experimental setup.

Waveform vectors

Waveform vectors are regular Tables with three columns (table{t0,dt,values}):

• t0: the waveform time offsets (ralative to a certain global reference), optionally with units
• dt: the waveform sampling periods, optionally with units
• values: the waveform values. May be Array of equal-sized arrays, Vector of vectors, etc. t0 and dt must have one dimension (the last) less than values.

Example:

GROUP "waveform" {
    ATTRIBUTE "datatype" = "table{t0,dt,values}"
    DATASET "dt" {
        ATTRIBUTE "datatype" = "array<1>{real}"
        ATTRIBUTE "units" = "ns"
        DATA = [10, 10, 10, ...]
    }
    DATASET "t0" {
        ATTRIBUTE "datatype"= "array<1>{real}"
        ATTRIBUTE "units" = "ns"
        DATA = [76420, 76420, 76420, ...]
    }
    GROUP "values" {
        ATTRIBUTE "datatype"= "array<1>{array<1>{real}}"
        DATASET "cumulative_length" {
            ATTRIBUTE "datatype" = "array<1>{real}"
            DATA = [1000, 2000, 3000, 4000, ...]
        }
        DATASET "flattened_data" {
            ATTRIBUTE "datatype" = "array<1>{real}"
            DATA = [14440, 14442, 14441, 14434, ...]
        }
    }
}

Generic DAQ data example

A table daqdata with columns for channel number, unix-time, event type, veto and waveform will be written to an HDF5 file like this:

GROUP "daqdata" {
    ATTRIBUTE "datatype" = "table{ch,unixtime,evttype,veto,waveform}"
    DATASET "ch" {
        ATTRIBUTE "datatype" = "array<1>{real}"
        DATA = [1, 3, 2, 4, ...]
    }
    DATASET "unixtime" {
        ATTRIBUTE "datatype" = "array<1>{real}"
        DATA = [1.44061e+09, 1.44061e+09, ...]
    }
    DATASET "evttype" {
        ATTRIBUTE "datatype" = "array<1>{enum{evt_undef=0,evt_real=1,evt_pulser=2,evt_mc=3,evt_baseline=4}}"
        DATA = [1, 2, 1, 1, ...]
    }
    DATASET "veto" {
        DATA = [1, 1, 0, 0, ...]
        ATTRIBUTE "datatype" = "array<1>{bool}"
        DATA = [1, 1, 0, 0, ...]
    }
    GROUP "waveform" {
        ATTRIBUTE "datatype" = "table{t0,dt,values}"
        DATASET "dt" {
            ATTRIBUTE "datatype"= "array<1>{real}"
            ATTRIBUTE "units"= "ns"
            DATA = [10, 10, 10, ...]
        }
        DATASET "t0" {
            ATTRIBUTE "datatype"= "array<1>{real}"
            ATTRIBUTE "units"= "ns"
            DATA = [76420, 76420, 76420, ...]
        }
        GROUP "values" {
            ATTRIBUTE "datatype"= "array<1>{array<1>{real}}"
            DATASET "cumulative_length" {
                ATTRIBUTE "datatype" = "array<1>{real}"
                DATA = [1000, 2000, 3000, 4000, ...]
            }
            DATASET "flattened_data" {
                ATTRIBUTE "datatype" = "array<1>{real}"
                DATA = [14440, 14442, 14441, 14434, ...]
            }
        }
    }
}

The actual numeric types of the datasets will be application-dependent.

LEGEND FlashCam DAQ data read out by Orca

Full format specification of the raw tier data.

Coming Soon...