fold -- Apply a gamma gate as a fold


fold -apply ggate-name spectrum1 ?spectrum2 ...?

fold -list ?pattern?

fold -remove spectrum


Folds are a simple mechanism to unravel complex gamma spectra into coincident sets of peaks. Whenver a fold is applied to a gamma spectrum, if the gate on that spectrum allows the gamma spetrum to be incremented, the fold controls the way in which the gamma specrum is incremented.

Without a fold, a gamma 1d spectrum is incremented once for each parameter in the spectrum. A gamma 2d spectrum is incremented once for each parameter pair in the spectrum. This provides a means to aggregate all of the gamma ray detectors in an experiment into a single spectrum.

With a fold, each parameter (for a gamma slice) or parameter pair (for a gamma band or contour) is checked against the gate. Whenever a parameter or pair of parameters satisfies the gate, the spectrum is incremented for all other parameters (1D) or parameter pairs (2D) that make up the spectrum. The effect is to remove the peak around which the gate was drawn and leave only the peaks that occur in coincidence with that peak (note that a bump in a 2-d spectrum already represents a gamma-gamma coincidence allowing 4-fold coincidence spectra to be produced by looking for bumps in a 2-d spectrum on which a gamma contour e.g. has been applied).


fold -apply ggate-name spectrum1 ?spectrum2 ...?

Applies the fold ggate-name to the spectra that follow. ggate-name must be a gamma gate and the spectra named must be gamma spectra.

Once applied, the gamma spectrum will only be incremented if the parameter(s) don't satisfy the gate, effectively removing the region described by the fold but requiring a coincidence with a gamma in the region described by the fold.

fold -list ?pattern?

Lists the set of spectra with folds that match the optional pattern. If the pattern is not supplied, it is taken to be * which matchs all spectra. The result of the fold -list command is a list of spectra with folds. Each list element is, itself a two element list consisting of, in order, the spectrum name and the name of the gate that is used to produce the folded spectrum.

fold -remove spectrum

Removes any fold that is applied to spectrum