Data Acquistion System

Each of the 64 stations contains 4 seperate Proportional Wire Chambers. within each chamber there are 2 planes of x-y wires. The Data Acquisition System (DAS) room receives a timing signal from each detector when a hit is registered. Then the DAS coincidence circuit is triggered by hits in 3 detectors within a very small time frame.

A coincidence causes a train of clock pulses to be sent to all the detectors. This shifts the data serially from their shift register memory to the trailer in 70 microseconds. The time of the trigger, accurate to 1 millisecond, is recorded along with the rest of the trigger's data. Single track muon data are stored at a average rate of 2400 muons per second. The bulk of the data stored is of this form. The data is stored on a large external disk which holds several months of data.

The data coming from each hut is fed into a MVME 5100 computer which does basic processing of the data and stores it on a hard drive that is connected to PC1, a linux based server computer which also processes the data and is stored on a hotswappable hard drive which can swapped out for a new one without stopping data collection.

Clock Synchronization

Time synchronization is provided by a Network Time Protocol, NTP.

Oscilloscopes

There are two oscilloscopes in the DAS room: an analog Tektronix 2230 and a digital Fluke PM3394A. We usually use the analog Tektronix for its accuracy and it suits our needs fine, but the digital Fluke has advantages of its own such as having multiple inputs which lets us analyze multiple huts at the same time. The oscilloscopes can be used to analyze a specific hut in realtime to help diagnose any problems because the diagnostics page on the web server only updates about once every 2 hours.

Rack

The Rack is the center of the experiment. It holds the 5100 and the coincidence board, it takes in information, and it distributes clock and high voltage to all of the quad boxes.

Coincidence Board

Data coming from the huts connects to a coincidence board which basically detects if multiple adjacent huts received hits at about the same time to aid in the detection of muon showers.

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