The FINUDA Online Monitor Task



The FINUDA Online Monitoring

and Event Display System

Design

The RDT event, from the DAQ system, is stored in the Global Event Builder (GEB) memory as an array of unsigned integers, and then written to file and, eventually, sent to the Online Monitoring System through a UDP socket.

The Online Monitor is organized into two separate and sequential stages:

and

The geb2hdt process runs in batch mode and takes care of the event pre-analysis: it connects to the Database (mSQL) and stores into a TFndFeeMap object all the information needed to map the electronic channel numbers of ADC and TDC modules into a meaningful set of parameters, uniquely identifying the physical channels (slabs, strips, wires, tubes).

It may get an input from two different sources, selected by a flag given as an argument when the program is started:

Once the input source and the database information are defined, geb2hdt starts a loop on events, which is infinite in online mode and defined by the number of events in the file in offline mode.

As a first step, the Raw Event is organized into a structure described by the TFndRdt class and stored into a Raw ROOT tree with many branches, containing different kinds of information, but still in encoded format:

  • Header ("hdr"): Run and Event number, date, etc.;
  • Trigger ("gts"): modules configuration and parameters;
  • Time of flight - inner and outer layer ("tof"): equipment contents;
  • Silicon Inner layer ("ism"): CRAMs contents;
  • Silicon Outer layer ("osm"): CRAMs contents;
  • Drift Chambers ("lmd"): equipment contents;
  • Straw Tubes ("stb"): equipment contents;

Then, the event is transformed into a structure described by the TFndHdt class, containing:

  • Header ("hdr"): Run and Event number, date, etc.;
  • Trigger ("gts"): Pattern Unit, I/O register, Corbo Module contents;
  • Time of flight - inner and outer layer ("tof"): list of hits, with Slab Number, Front & Rear ADC & TDC Contents, Space Coordinates in the detector reference frame;
  • Silicon Inner layer ("ism"): list of hits, with Module & Strip Number, ADC Content, Space Coordinates in the detector reference frame;
  • Silicon Outer layer ("osm"): same as ism;
  • Drift Chambers ("lmd"): list of hits, with Drift Chamber & Wire Number, Front & Rear ADC & TDC Contents, Space Coordinates in the detector reference frame;
  • Straw Tubes ("stb"): list of hits, with Crown & Tube Number, TDC Content, Space Coordinates in the detector reference frame;

The events in TFndHdt (Hit Data Tape) format are stored on file as a ROOT tree, accessible for local or (via the Web) remote detector control by the froot consumers.

At the same time, geb2hdt stores a set of histograms into the following set of shared memories, which are periodically updated and accessible at any time.

  • gts.map (Trigger histograms);

  • tof.map (Time of flight hit patterns & ADC/TDC correlations);
  • tof_adc.map (Time of flight ADC histograms);
  • tof_tdc.map (Time of flight TDC histograms);

  • sil.map (Microstrips patters);
  • sil_ism.map (Microstrip Inner layer),
  • sil_osm.map (Microstrip Outer layer);

  • lmd.map (Drift Chambers hit patterns & ADC/TDC correlations);
  • lmd_inner_adc.map, lmd_outer_adc.map (Drift Chambers ADC histograms for inner and outer layer);
  • lmd_inner_tdc.map, lmd_outer_tdc.map (Drift Chambers TDC histograms for inner and outer layer);

  • stb.map (Straw Tubes hit patterns);
  • stb_tdc_#N.map (Straw Tubes TDC histograms for crown #N = 1 ... 6);


The froot(s) consumer session(s) run(s) interactively an extended ROOT executable, which includes the FINUDA Classes, and can access:

  • the shared memories, for a real time monitoring;
  • the Hdt Tree stored on file, for an online data analysis.
The design was kept as user friendly as possible, in order to simplify the operator task during the data taking. Nevertheless, the HDT contains the whole event information: all the variables can be correlated to each other, in case of need, to investigate unexpected troubles.

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PC (update 27 Jan 99)