GREAT Data Acquisition

On-line Analysis

The various components of the data acquisition system (Data Collector, Data Processor, Tape Server and On-line Data Analysis) are interconnected via a private data broadcast network using Fast Ethernet (100 MHz; 10Mbytes/sec) or Gigabyte Ethernet (1000MHz; 100Mbytes/sec). The main requirement of the data network is to transfer formatted raw data blocks between the Data Collector and the Data Processor or Tape Server and formatted event data blocks between the Event Collector and the Tape Server. However using the broadcast nature of networks such as Fast Ethernet it is possible in total safety and at no additional cost to the Data Acquisition system for the formatted data to be made available to any number of data analysis workstations/PCs. This technique has been used in systems such as those built for Eurogam and Euroball and proved to be very valuable.

Event blocks sent via the data network from the Data Collector or Data Processor to the Tape Server are available in "spy" mode to any number of workstations.

 "Spy" on the on-line data -- non intrusive -- cannot effect main task of getting data to tape".

 "User" programs running in standard workstations.

 Multiple concurrent data analyses are possible.

 Procedure library allows histograms to be created for viewing using the MIDAS Spectrum Viewer.

A "standard" supported on-line sort package will be available (Liverpool University) which is fully integrated with the MIDAS GUI. This can be used both on-line (in "spy" mode) and off-line. Allows Doppler correction and gain correction if not already performed in-line.