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The name of the
.UFO
file corresponds to the spectrum file from which it derives. A user-written program can read the report filename from the command line, change the extension to
.UFO
, and read the analysis results from the
.UFO
file.
The Report Writer check box is only active if the GammaVision Report Writer (A44-BW) is installed. This option uses an Access database and SAP
®
BusinessObjects Crystal Reports™ to produce the desired report. Click Browse... to select the report template to be used (see the
GammaVision Report Writer’s user manual for a complete discussion of templates).
Analysis Tab
Use this screen (Fig. 141) to select the Analysis Method, Additional Error, Analysis, and
Peak Stripping options to be used. The actual analysis is done by a separate program referred to as an analysis engine.
Fig. 141. Analysis Tab.
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Analysis Method
The analysis engine for the normal analysis is named WAN32; GammaVision also offers the
ROI32, GAM32, NPP32, and ENV32 engines.
See Chapter 6 for more information on the analysis programs.
GammaVision also accommodates user-supplied analysis programs. The program must be able to read the spectrum name from the command line. There are no other restrictions, but if the program does not produce a results file in the
.UFO format, the display results functions and the
GammaVision Report Writer database will not work. All the analysis options can be taken from the
.SPC
file. The analysis program should also produce an ASCII report file so the report can be printed by the Windows print spooler.
Additional Error
The parameters in the Additional Error section are used in the calculation of the total uncertainty. Total uncertainty is composed of error estimates that follow a normal distribution and error estimates that follow a uniform distribution over a range. Most errors in gamma spectroscopy, whether systematic or random, follow a normal distribution. Error estimates are included for counting, random summing, absorption, nuclide uncertainty, efficiency, and geometry. Enter additional errors (%) related to the measurement that follow a normal distribution at the 1-sigma level. Enter uniform distribution errors (%) at the complete range of the uniform error limit. That is, if the likelihood of an uncertainty is uniform over 3% of the reported results, enter 3.0 in this field. The error estimates from all corrections are explained in Section 6.12.
Peak Stripping
When Peak Stripping is enabled, the analysis will perform the library-based peak deconvolution or “peak interference correction” described in Section 6.5.5. Briefly, this will separate peak areas that are too close together to be accurately separated by mathematical deconvolution. Gamma-
Vision supports two types of peak stripping: Library Based and Manual Based. In Library
Based peak stripping, the program automatically detects overlapped peaks and the associated peaks needed. The program then performs the peak stripping using these peaks. In Manual
Based peak stripping, you determine the overlapping peaks and the associated peaks. The associated peaks are given in the Second Library and the analysis peaks are given in the Third
Library.
The availability of peak-stripping options depends on the analysis engine you choose. See
Section 6.2 for a discussion of the analysis engines, a decision matrix, and selection guidelines.
WAN32 offers both the Library Based and Manual Based options, however, you can only choose one option at a time (or leave the boxes unmarked to perform no stripping).
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When GAM32 is selected, the Library Based Peak Stripping and Directed Fit methods are turned off and the selections disabled.
When NPP32 is selected, the automatic Library Based Peak Stripping is enabled. We strongly recommend that this option be left enabled. It can be turned off or Manual Based (manual, library-based) peak stripping can be enabled, but these selections will not allow NPP32 to function in its intended mode. If you wish to perform the analysis without any library-based peak stripping, you should use the GAM32 engine. For manual library-based peak stripping, use
WAN32.
When ENV32 is selected, the automatic Library Based Peak Stripping is enabled. We strongly recommend that this option be left enabled. It can be turned off or Manual Based peak stripping can be enabled, but these selections will not allow ENV32 to function in its intended mode. If you wish to perform the analysis without any library-based peak stripping, you should use the
GAM32 engine. For manual library-based peak stripping, use WAN32.
Analysis
For all but the NPP32 analysis engine, the Peak Cutoff limits the unknown peak list to peaks with 1-sigma uncertainty below this value. For the NPP32 engine, only the peaks that meet the
Peak Cutoff are printed. Library peaks with 1-sigma uncertainty are printed, but are not used in the activity calculation. Note that parameters in the b30winds.ini
file also determine which peaks are printed; see Section A.2.2.
Click True Coincidence Correction to enable TCC.
! If the Detector has not been calibrated for TCC, the correction is automatically turned off in the analysis.
! If preparing to analyze a saved spectrum, be sure it contains a TCC calibration; other-
wise the analysis results may be incorrect. To check a spectrum file for TCC calibration, recall it, step through the Calibration Wizard (Section 5.3.8), and on the final screen
(Fig. 126, page 142) confirm that the lower-right window says
TCC Calibrated
.
Click Directed Fit to allow for negative peak areas in low-level spectra. The following rules should normally be followed when using directed fit:
! Preferentially use the ENV32 analysis engine unless a feature of one of the other engines is required. ENV32 is required when analyzing complicated spectra with overlapping peaks or large libraries.
! Use NPP32 or WAN32 only for relatively simple spectra that contain only singlet peaks.
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