# source:Tutorials/DeterminingWavelength/DeterminingWavelength.html@3544

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3<body class="c5"><div><p class="c1"><span class="c4 c7"></span></p></div><p class="c3">
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5Area Detector Calibration with Multiple Distances, part 1: Determine Wavelength
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8<B>A video version of this tutorial is available at
9<A href="https://anl.box.com/v/DeterminingWavelength" target="_blank">https://anl.box.com/v/DeterminingWavelength</A></B>
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12In this tutorial you will use a standard with a known lattice parameter (silicon) to determine the wavelength of the X-ray beam without precise knowledge of the sample-to-detector distance. This is done
13for APS beamline 17-BM-B by collecting diffraction data with multiple detector distances, where the
14relative placement of the detectors is known to some degree. Here 23 images with approximate placements ranging from 200 to 1300 mm from the sample. First the x-ray wavelength is determined and then in a subsequent
15tutorial that wavelength is used to calibrate the actual detector placements.
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17Note that menu entries are listed in bold face below as </span><span class="c0">Help/About GSAS-II</span><span class="c2">, which lists first the name of the menu (here </span><span class="c0">Help</span><span class="c2">) and second the name of the entry in the menu (here </span><span class="c0">About GSAS-II</span><span class="c4 c2">). Bold text is also used to highlight actions, such as
18clicking on a control in the GSAS-II graphical interface.
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21If you have not done so already, start GSAS-II or start a new project.</span></p>
22<h2 class="c3" id="h.e0ybb39ui38f"><span class="c4 c6">Step 1: Load data</span></h2><p class="c3"><span class="c2">First do </span><span class="c0">Import/Image/from TIF image file, </span><span class="c2">&nbsp;select all images; then press </span><span class="c0">Open</span><span class="c4 c2">&nbsp;to read all of them. The GSAS-II data tree window will show entries for 23 images and will expand the last one</span></p><p class="c3"><span style="overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 614.38px; height: 396.50px;"><img alt="" src="images/image9.png" style="width: 1050.34px; height: 592.22px; margin-left: -385.46px; margin-top: -74.24px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);" title=""></span></p>
23<h2 class="c3" id="h.e0ybb39ui38f"><span class="c4 c6">Step 2: Calibrating the Wavelength: First Image</span></h2>
24<p class="c3"><span class="c2">First select the </span><span class="c0">IMG Si_free_dc200_1-00000.tif</span><span class="c2">&nbsp;entry from the tree (the first in the tree) and expand it (press the </span><span class="c0">+</span><span class="c2">&nbsp;box); then select </span><span class="c0">Image controls</span><span class="c2">. The data window (</span><span class="c0">Image Controls</span><span class="c4 c2">) will show the default settings.</span></p><p class="c3"><span style="overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 624.00px; height: 435.00px;"><img alt="" src="images/image10.png" style="width: 858.00px; height: 481.66px; margin-left: -183.12px; margin-top: -6.86px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);" title=""></span></p><p class="c3"><span class="c2">Select the </span><span class="c0">Calibrant</span><span class="c2">&nbsp;(near bottom of window) as </span><span class="c0">Si SRM640c.</span><span class="c2">&nbsp;</span><span class="c0">Check</span><span class="c2">&nbsp;the box next to </span><span class="c0">Wavelength </span><span class="c2">and </span><span class="c0">uncheck</span><span class="c2">&nbsp;the box next to </span><span class="c0">Distance</span><span class="c2">. We are doing this because we will initially treat the reported
26<h2 class="c3" id="h.e0ybb39ui38f"><span class="c4 c6">Step 3: Calibrating all Images</span></h2>
27<p class="c3"><span class="c4 c2">Since the single-image calibration looks good, it is time to copy these parameters onto the rest of the images.</span></p><p class="c3"><span class="c2">Next select </span><span class="c0">Parms/Copy Selected</span><span class="c4 c2">. A text box like this will pop up:</span></p><p class="c3"><span style="overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 446.50px; height: 299.36px;"><img alt="" src="images/image7.png" style="width: 936.47px; height: 523.88px; margin-left: -321.16px; margin-top: -99.15px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);" title=""></span></p><p class="c3"><span class="c2">Click </span><span class="c0">Set All</span><span class="c2">&nbsp;on the bottom then go back and unselect both </span><span class="c0">distance (10)</span><span class="c2">&nbsp;and</span><span class="c0">&nbsp;setdist</span><span class="c2">&nbsp;</span><span class="c0">(25)</span><span class="c2">, as below, then press</span><span class="c0">&nbsp;OK</span><span class="c4 c2">. We want to copy all parameters except for the distances because they differ for each image. </span></p><p class="c3"><span style="overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 465.50px; height: 414.40px;"><img alt="" src="images/image16.png" style="width: 902.09px; height: 506.81px; margin-left: -284.79px; margin-top: -30.32px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);" title=""></span></p><p class="c3"><span class="c2">Another dialog box will appear for selection of the images to copy these parameters to, hit </span><span class="c0">Set All</span><span class="c2">&nbsp;and press </span><span class="c4 c0">OK</span></p><p class="c3"><span style="overflow: hidden; display: inline-block; margin: 0.00px 0.00px; border: 0.00px solid #000000; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px); width: 246.75px; height: 321.50px;"><img alt="" src="images/image23.png" style="width: 1015.29px; height: 565.44px; margin-left: -466.62px; margin-top: -106.06px; transform: rotate(0.00rad) translateZ(0px); -webkit-transform: rotate(0.00rad) translateZ(0px);" title=""></span></p><p class="c3"><span class="c2">Next select </span><span class="c0">C</span><span class="c0">alibration/Recalibrate all </span><span class="c2">to recalibrate all images with the new parameters.
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