Corrections Tab. ORTEC A66-BW GammaVision

GammaVision

®

v7 (A66-BW) 783620H / 1013

! The Peak Cutoff is typically set to a high value (i.e., possibly 100 or higher) in order to preferentially find peaks using the normal peak search method rather than using Directed

Fit. This option is generally preferred when peak stripping is necessary because directed fit peaks are not considered in the peak stripping algorithms.

For more information, see the Directed Fit discussion in Section 6.3.2.2.

Corrections Tab

The Corrections tab is shown in Fig. 142.

Fig. 142. Corrections Tab.

The Peaked Background Correction (Section 6.10.4) can be turned On or off, and the correction file specified. The filename of the

.PBC

file to be used for the correction in the spectrum analysis can be the Internal (working) file or a File on disk. If the Internal box is not marked, a filename must be entered. The working file is the one most recently loaded with

Analyze/Settings/ Peak Background Correction/Select PBC... (which is discussed beginning on page 175).

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783620H / 1013 5. MENU COMMANDS

Adjust the Match Width as desired. For the Match Width By Energy option, when not using a library you may wish to use a greater PBC match width. It may be useful to perform test acquisitions based on your application.

! PBC subtraction is applied to ENV32 and GAM32 analyses only.

! If the By Energy checkbox is marked, PBC subtraction is also applied to the unknown peaks in the spectrum.

! For the peaks listed in the report’s Peaks in Range table, if By Energy is marked, PBC will be applied to applicable library and unknown peaks. If By Energy is not marked,

PBC will be applied to applicable library peak only.

The Geometry Correction (Section 6.10.5) can be turned On or off, and the correction (

.GEO

)

File can be specified. The filename of the

.GEO

file to be used for the correction in the spectrum analysis can be the Internal (working) file or a file on disk. If the Internal box is not checked, a filename must be entered. The working file is the file most recently loaded with Analyze/Set-

tings/Geometry Correction (see Section 5.5.1.4).

The Linear Attenuation can be turned On or off, Internal or External can be selected, and the source of the correction parameters (Internal or DataBase) can be specified. The correction function can be:

! The Internal (working) correction loaded in the Absorption Correction dialogs discussed in Section 5.5.1.3.

! A specific

.SOR

file calculated from two spectra.

! Selected from GammaVision’s built-in database of stored coefficients.

The filename of the

.SOR

file to be used for the correction in the spectrum analysis can be the internal (working) file or a file on disk. If the Internal box is checked, the internal file is used, otherwise a filename or database must be entered. The working correction is the correction most recently viewed or calculated per Section 5.5.1.3.

If Data Base is selected, the Material, Length, Configuration, and Internal or External type must also be selected. The material is selected from the list in the database. The Configuration is also selected from the database. The database values are based on an absorber Length of 1 cm.

For larger or smaller lengths (external) and thicker or thinner materials (internal), enter the actual length or thickness. Either Internal or External absorption can be selected. Internal absorption is for cases where the radioactive material is distributed throughout the absorber

(matrix) and External is where the absorber is between the radioactive material and the detector.

The attenuation correction is explained in detail in Section 6.10.6.

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