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适用范围：<p>Adjustment methods provide a means for combining the results of neutron transport calculations with neutron dosimetry measurements (see Test Method E 1005<astmref rid="a00021"> and NUREG/CR-5049) in order to obtain optimal estimates for neutron damage exposure parameters with assigned uncertainties. The inclusion of measurements reduces the uncertainties for these parameter values and provides a test for the consistency between measurements and calculations and between different measurements (see 3.3.3). This does not, however, imply that the standards for measurements and calculations of the input data can be lowered; the results of any adjustment procedure can be only as reliable as are the input data.</p> <p><span class="italic"><span class="italic">Input Data and Definitions</span>: </span> <p>The symbols introduced in this section will be used throughout the guide.</p> <p>Dosimetry measurements are given as a set of reaction rates (or equivalent) denoted by the following symbols: <br><a id="num00001"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_1.gif"><br></p><p>These data are, at present, obtained primarily from radiometric dosimeters, but other types of sensors may be included (see 4.1).</p> <p>The neutron spectrum (see Terminology E 170<astmref rid="a00001">) at the dosimeter location, fluence or fluence rate <span class=''unicode''>x03A6;</span>(<span class="italic">E</span>) as a function of neutron energy <span class="italic">E</span>, is obtained by appropriate neutronics calculations (neutron transport using the methods of discrete ordinates or Monte Carlo, see Guide E 482<astmref rid="a00010">). The results of the calculation are customarily given in the form of <span class="italic">k</span> group fluences or fluence rates. <br><a id="num00002"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_2.gif"><br></p><p>where:<br> <span class="italic">E</span>_{<span class="italic">j</span>} and <span class="italic">E</span>_{<span class="italic">j</span>}₊₁ are the lower and upper bounds for the <span class="italic">j</span>-th energy group, respectively.</p> <p>The reaction cross sections of the dosimetry sensors are obtained from an evaluated cross section file. The cross section for the <span class="italic">i</span>-th reaction as a function of energy <span class="italic">E</span> will be denoted by the following: <br><a id="num00003"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_3.gif"><br></p><p>Used in connection with the group fluences, Eq 2, are the calculated group-averaged cross sections <span class=''unicode''>x03C3;</span>_{<span class="italic">ij</span>}. These values are defined through the following equation: <br><a id="num00004"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_4.gif"><br><br><a id="nonum00001"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_5.gif"><br><br><a id="nonum00002"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_6.gif"><br></p> <p>Uncertainty information in the form of variances and covariances must be provided for all input data. Appropriate corrections must be made if the uncertainties are due to bias producing effects (for example, effects of photo reactions).</p> <p><span class="italic"><span class="italic">Summary of the Procedures</span>: </span> <p>An adjustment algorithm modifies the set of input data as defined in 3.2 in the following manner (adjusted quantities are indicated by a tilde, for example, <span class="italic"><span class=''unicode''>?/span>_i</span>):<br> <br><a id="num00005"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_7.gif"><br><br><a id="num00006"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_8.gif"><br></p><p>or for group fluence rates<br> <br><a id="num00007"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_9.gif"><br><br><a id="num00008"></a><img src="http://www.astm.org/HTTP/IMAGES/E0944-08_10.gif"><br><br> </........