From MariachiWiki
Labview software is being developed to handle the data aquisition from the scintillation counters. This page is designed to give some background information about what this software is doing and some instructions on how to use it.
Programming the FPGA chip
A first labview module is used to program the FPGA chip. This program loads the VHDL code onto the chip through the USB port.
On the left, the current version of this interface is displayed. Use the "browse" button to locate the desired version of the VHDL code. Select the device shown and then hit "program." A green LED will light on the FPGA chip if it has been programmed. Any time the coincidence board loses power or the USB connection to the PC is lost the chip will need to be reprogrammed.
The VHDL code defines different "events" of interest that include signals from single detectors and coincidences between signals from different detectors. Counters are created in the VHDL code that store the number of events registered in the memory of the FPGA. The memory of the FPGA is read by a different Labview program.
Taking Data and Measuring Efficiency
The following image is a recent version of the interface used to take data.
Users can define how long to take data for with the "Auto Stop Time" field. The fields under "Read Counter" show the raw values on the counters while on the right hand side these are converted into rates. "Singles Rate" shows the rate of signals from each detector as a running average over the current duration of data collection. This is updated from the FPGA's memory once per second. "Coincidence Rate" displays the rate of simulataneous detection in the different combinations of detectors shown.
To the right of this field, "fraction" is the efficiency. In order for this field to have significance, counters should be stacked vertically with 1 and 2 on the top and bottom. The efficiency of any counters inbetween can then be measured.
In Development: Plotting and GPS coordination
Currently we are developing some plotting utilities in Labview to help visualize the rates of signals.
Here is an example of our current plotting program. The "Open Singles" and "Open Coincidence" controls on the main interface will open window that plot the singles or coincidence rates, respectively. The "bin size" option controls the bin size of the X(time) axis. The "plot history" field controls how far back in time from the current moment data will be plotted. Buttons displayed on the plot window allow the user to control which singles or coincidence rates will be displayed. These can be changed while the program runs.
