The attached figure shows the configuration used to test the synchronization of the DAQ systems using a
correlation scalar counted from a common clock signal (DAQcorrelation_diagram.pdf). 

The chosen solution was to use a 25 MHz clock generated by the MACB modules of AIDA, which was distributed to
the other two systems by a SIS36/38xx module in the BRIKEN VME crate. 

The correlation can be monitored online using the MIDAS DataXfer and DataSpy libraries 
(http://npg.dl.ac.uk/MIDAS/DataAcq/Data.html). Each system operates a
DataRelay program that sends a data stream consisting only of IDs and time-stamps to a common DataSink (this
requires a DataRelay code that does some filtering of the raw data for each system). The scheme is shown in
attached diagram (DAQsoftware.pdf).

The DataPeek_Merge and SyncCheck codes use C++11 for parallelization of tasks, which is a helpful feature to
improve the efficiency of finding coincidences between the correlation pulses. Thus, the code will not run in
PCs with any Linux version. For example, it requires version 7 of ScientificLinux, which installed in the PC 
being used for BRIKEN DAQ control that will stay at RIBF for the time being.


++ SYNCHRONIZATION RESULTS ++

The figure correlation_25Hz.png shows a correlation plot for the BRIKEN+RIBF+AIDA running with correlations done
by a pulser at 25 Hz. A large fraction of the pulsers appear in the double-coincidence plots (top row; same plots,
except the 'Partial' one is automatically cleared every ~10seconds).

The bottom plots show the pair-wise correlations between BRIKEN and RIBF or AIDA. BRIKEN was defined as the
'master' in this test, but current version of the program is flexible to select any stream as the master one.

The second figure (correlation_random.png) shows the same test, but using a non-periodic pulser to trigger the
correlation scalar. We observed the same level of synchronization (peaks look brader just because of the zoom level).