BOE1 (4), Trigger type (4), LV1_id (24), BX_id (12), Source_id(12), FOV (4), Hx(2), $$(2)
Trigger number (32), Orbit number (32)
Trigger type (4), BX_id (12), DAQ partition number (4) , L1A per partition (4), connected subdetector partitions (5), GTFOV (4), free (31)
GPS time 64 bits
Algo bits_0: Trigger algorithm bits 0-63 (64)
Algo bits_1: Trigger algorithm bits 64-127 (64)
Technical trigger bits (64)
Muon 1 (32), Muon 2 (32)
Muon 3 (32), Muon 4 (32)
Isolated electron 1 (16), isolated electron 2 (16), isolated electron 3 (16), isolated electron 4 (16)
Non-isol. electron 1 (16), non-isol. electron 2 (16), non-isol. electron 3 (16), non-isol. electron 4 (16)
Central jet 1 (16), central jet 2 (16), central jet 3 (16), central jet 4 (16)
Forward jet 1 (16), forward jet 2 (16), forward jet 3 (16), forward jet 4 (16)
Tau-jet 1 (16), tau-jet 2 (16), tau-jet 3 (16), tau-jet 4 (16)
Total ET (13), HT(13), Etmiss (13), phi of ETmiss (6), free (19)
Jet count 1 (5), jet count 2 (5), ..., jet count 12 (5), free (4)
Input for technical triggers (64) - to be defined later
EOE (4), xxxx (4), Evt_lgth (24), BX_id (12), CRC(16), xxxx (4), Evt_stat(8), xx$$(4)
Record size (excluding header and trailer): 1024 bits or 16 64-bit words (without reserve,
see notes).
Similar records may be read out for events before and after the triggered bunch crossing.
Explanations
BOE1: Bits to identify beginning of event record (header)
Trigger type : 4 bits, e.g. to distinguish calibration from physics events, final definition still to be made.
LV1_id: event number since beginning of run. 24 bits may not be enough since 8h at 100 kHz need 32 bits....
BX_id: bunch crossing number, goes from 0 to 3563
Source_id: Global Trigger has at most 4 single data sources (including GMT) - identifiers to be defined (10 bits + 2 internal)
FOV: Defined by DAQ or GT event record format version? To be defined. If not defined by GT need format version in GT record.
Hx: header word. It is 0 for the last header word, otherwise 1.
$$: used by S-LINK64 hardware
Trigger number: event number since beginning of run
Orbit number: since last ,Reset Orbit Counter'; (29 bits=13.5h): 32 bits
DAQ partition number: presently only 3 bits needed (8 partitions)
L1A per partition: Level-1 accept signal sent to DAQ partition
GTFOV: GT format version.
Algo bits_0: Algorithm bits from algo chip 0
Algo bits_1: Algorithm bits from algo chip 1 (if more algorithms available they can be added here, but need different GT format version)
Technical trigger bits: also used for external test trigger signals
EOE: Bits to identify end of event record (trailer)
Evt_lgth: Event length expressed in number of 64 bit words
CRC: Cyclic Redundancy Code
Evt_stat: Event status. To be defined.
Notes
Header and trailer will be removed by DAQ before final event storage.
Order of words not guaranteed.
Items in red still under discussion.
Extra algorithm and technical trigger bits should be possible for upgrades - foresee 3 additional
64-bit words.