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project - SpecTcl Command

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project [-[no]snapshot] sourcespec newspec x|y [contourname]



Creates projections of 2d and gamma 2d spectra..


Detailed Description


Projections create new 1-d or 1-d gamma spectra (called the target spectrum) from existing 2-d or 2-d gamma spectrum (called the source spectrum) by taking a projection (possibily limited by a region of interest specified by a contour or gamma contour) in either the X or Y direction. There are two specific cases to consider.

Projections of ordinary 2-d spectra

The result of projecting an ordinary 2-d spectrum is an ordinary 1-d spectrum. If the -snapshot switch is supplied, this spectrum will be frozen.

The target spectrum may automatically have gates applied to it. Gates will only be applied to targets that are not snapshot spectra. The intent of these gates is to ensure that the target spectrum increments in such a way that it remains a faithful projection of the source spectrum.

Automatic gating is as follows:

Suppose, for example, we have a spectrum named pid_gamma which is gated on a gamma slice named 511kev, and that the X axis of this spectrum is an energy, while the Y is e.g. a de. Suppose this spectrum has a contour drawn on it (not applied to it) named 6Li. The command:

   project pid_gamma 6Li511kev x 6Li
Produces a new spectrum named 6Li511kev which is gated on the and of 6Li and 511Kev. The spectrum is initially filled with the projection of pid_gamma in the x direction within the region of interest defined by the contour 6Li. The and gate created is named __PROJECTION_6Li__AND__511Kev__

Projections of gamma 2-d spectra

The target spectrum of a projection of a 2d gamma spectrum is a 1d gamma spectrum. If the -snapshot switch is supplied, the target is frozen.

The target spectrum may have gates and folds automatically applied to it. These gates and folds, in general, will not result in a continued faithful projection as the target spectrum increments, as the increments of gamma spectra are correlated within the sets of parameters gates and folds.

If the source spectrrum has a fold applied to it, the same fold will be applied to the target spectrum. Gates are applied to the target spectrum in the same way they are applied to ordinary 2-d projection targets.

Last Modified: May 27, 2005 by: fox@nscl.msu.edu
Copyright NSCL 2005, All rights reserved