Event Conversion Program

There exist as many event formats as acquisition systems.
For our analysis we have adopted a special event format to which all externally taken data are converted.

EVC is an X window based application to the event format conversion for data taken at WNSL (Yale University), HRIBF (Oak Ridge National Lab) and LBL(88 Inch Cyclotron), where the Rutgers Nuclear Physics Group has measured magnetic moments of short lived excited nuclear states.

The experiments make use of 4 Clover detectors and involves the measurement of one or more gammas in coincidence with particles up to 33 parameters per event. The analysis requires gain matched gamma energies for each clover segment. This gain matching is built into the event conversion.

The user interface is simple and intuitive. The final parameter ranges can be specified in the "setup" menu. Gain match information has to be provided or is automatically obtained for a given set of peak positions.

File

• Open Data File: event data file
• Reopen: resets the read pointer to the begin of a event data file.
  Does not work for ORNL files !
• Read Peak File:
  This file contains all gain match information. The format is fixed (sample .pks file). The gain match factors are calculated and displayed in the text window. Useful for gain matching of already converted event files.
• Peak position Information:
  The input requests are energies for two peaks, a center for the aligned tac spectra and a file containing the approximate peak positions for each detector including limits for the tac center search (conveniently created as .win file in xsa). The automatic gain matching procedure makes gamma energy and tac histograms for all gamma detectors Then find the peak centroids for the given peak positions (±4 channels), searches for the maxima of the tac spectra in the given range. In a second run though the event file the actual gain matching is performed. This procedure is repeated for each event-file, small drifts are automatically adjusted.
• Exp_Setup file.
  The actual experimental setup, total gain settings, which adc or tdc has which input is contained in a configuration file. This file may have to be updated (edited) to refect the current experiment.

Options

• Convert: Conversion including gain matching when enabled. If no peak positions or gain match factors are input, the conversion proceeds without gain matching.
• gain match: Only gain match for already converted data
• show event: for diagnostic purposes (converted data only)

Setup

• Experiment setup:can be modified and saved. The tac spectra can be shifted in addition to being compressed.
  (/2 500 divide each channel by 2 and shift 500 channels left).