Changeset 318b5bbb in sasview for sansmodels/src/sans/models/media/smear_computation.html
- Timestamp:
- Dec 18, 2012 10:55:24 AM (12 years ago)
- Branches:
- master, ESS_GUI, ESS_GUI_Docs, ESS_GUI_batch_fitting, ESS_GUI_bumps_abstraction, ESS_GUI_iss1116, ESS_GUI_iss879, ESS_GUI_iss959, ESS_GUI_opencl, ESS_GUI_ordering, ESS_GUI_sync_sascalc, costrafo411, magnetic_scatt, release-4.1.1, release-4.1.2, release-4.2.2, release_4.0.1, ticket-1009, ticket-1094-headless, ticket-1242-2d-resolution, ticket-1243, ticket-1249, ticket885, unittest-saveload
- Children:
- 6550b64
- Parents:
- 0203ade
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- 1 edited
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sansmodels/src/sans/models/media/smear_computation.html
r17574ae r318b5bbb 1 <html>2 1 3 2 <head> … … 30 29 smeared scattering intensity for SANS is defined by</span></p> 31 30 32 <p class=MsoNormal><img width=349 height=4931 <p class=MsoNormal><img 33 32 src="./img/sm_image002.gif" align=left hspace=12></p> 34 33 35 34 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'> 36 1)</span><br clear=all>35 ---- 1)</span><br clear=all> 37 36 <span style='font-family:"Times New Roman","serif"'>where Norm = <span 38 style='position:relative;top:15.0pt'><img width=137 height=4937 style='position:relative;top:15.0pt'><img 39 38 src="./img/sm_image003.gif"></span>.</span></p> 40 39 <br> 41 40 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>The 42 functions <span style='position:relative;top:6.0pt'><img width=43 height=2543 src="./img/sm_image004.gif"></span> and <span style='position:44 relative;top:6.0pt'><img width=43 height=2545 src="./img/sm_image005.gif"></span> refer to the slit width weighting41 functions <span style='position:relative;top:6.0pt'><img 42 src="./img/sm_image004.gif"></span> and <span style='position: 43 relative;top:6.0pt'><img 44 src="./img/sm_image005.gif"></span> refer to the slit width weighting 46 45 function and the slit height weighting determined at the q point, respectively. 47 46 Here, we assumes that the weighting function is described by a rectangular 48 47 function, i.e.,</span></p> 49 48 50 <p class=MsoNormal><span style='position:relative;top:7.0pt'><img width=13451 height=26src="./img/sm_image006.gif">49 <p class=MsoNormal><span style='position:relative;top:7.0pt'><img 50 src="./img/sm_image006.gif"> 52 51 </span><span style='font-family:"Times New Roman","serif";position:relative; 53 top:7.0pt'> 2)</span></p>52 top:7.0pt'> ---- 2)</span></p> 54 53 55 54 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>and </span></p> 56 55 57 <p class=MsoNormal><span style='position:relative;top:7.0pt'><img width=136 58 height=26 src="./img/sm_image007.gif"></span>, 59 <span style='font-family:"Times New Roman","serif"'>3)</span></p> 60 61 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>so that </span><span 62 style='position:relative;top:6.0pt'><img width=58 height=23 63 src="./img/sm_image008.gif"></span> <span style='position:relative; 64 top:16.0pt'><img width=76 height=51 src="./img/sm_image009.gif"></span> <span 65 style='font-family:"Times New Roman","serif"'>for</span> <span 66 style='position:relative;top:3.0pt'><img width=40 height=15 67 src="./img/sm_image010.gif"></span> <span style='font-family: 68 "Times New Roman","serif"'>and <i>u</i>. The </span><span style='position:relative; 69 top:6.0pt'><img width=28 height=24 src="./img/sm_image011.gif"></span> <span 70 style='font-family:"Times New Roman","serif"'>and </span><span 71 style='position:relative;top:6.0pt'><img width=28 height=24 72 src="./img/sm_image012.gif"> </span><span style='font-family: 73 "Times New Roman","serif"'>stand for the slit height (FWHM/2) and the slit 56 <p class=MsoNormal><span style='position:relative;top:7.0pt'><img 57 src="./img/sm_image007.gif"></span>, 58 <span style='font-family:"Times New Roman","serif"'> ---- 3)</span></p> 59 60 <p>so that <img 61 src="./img/sm_image008.gif"> <img src="./img/sm_image009.gif"> for <img 62 src="./img/sm_image010.gif"> and <i>u</i>. The <img src="./img/sm_image011.gif"> 63 and <img src="./img/sm_image012.gif"> stand for the slit height (FWHM/2) and the slit 74 64 width (FWHM/2) in the q space. Now the integral of Eq. (1) is simplified to</span></p> 75 65 76 <p class=MsoNormal><img width=283 height=5266 <p class=MsoNormal><img 77 67 src="./img/sm_image013.gif" align=left hspace=12><span 78 68 style='font-family:"Times New Roman","serif"'> 79 4)</span></p>69 ---- 4)</span></p> 80 70 81 71 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"; … … 89 79 style='font-family:"Times New Roman","serif"'>1)<span style='font:7.0pt "Times New Roman"'> 90 80 </span></span><span style='font-family:"Times New Roman","serif"'>For </span><span 91 style='position:relative;top:6.0pt'><img width=28 height=2492 src="./img/sm_image01 4.gif"></span>= 0 <span style='font-family:81 style='position:relative;top:6.0pt'><img 82 src="./img/sm_image012.gif"></span>= 0 <span style='font-family: 93 83 "Times New Roman","serif"'>and </span><span style='position:relative; 94 top:6.0pt'><img width=28 height=24 src="./img/sm_image015.gif"></span> =84 top:6.0pt'><img src="./img/sm_image011.gif"></span> = 95 85 <span style='font-family:"Times New Roman","serif"'>constant:</span></p> 96 86 97 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'>87 <p> 98 88 <img src="./img/sm_image016.gif"></p> 99 89 100 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'><span 101 style='font-family:"Times New Roman","serif"'>For discrete q values, at the q 90 <p> For discrete q values, at the q 102 91 values from the data points and at the q values extended up to q<sub>N</sub>= 103 q<sub>i</sub> + </span><span style='position:relative;top:6.0pt'><img width=28 104 height=24 src="./img/sm_image011.gif"></span><span 105 style='font-family:"Times New Roman","serif"'>, the smeared intensity can be 106 calculated approximately,</span></p> 107 108 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'><img 92 q<sub>i</sub> + <img src="./img/sm_image011.gif"> , the smeared intensity can be 93 calculated approximately, </p> 94 95 <p><img 109 96 src="./img/sm_image017.gif">. 110 <span style='font-family:"Times New Roman","serif"'>5)</span></p>111 112 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'><span 113 style='position:relative;top:7.0pt'><img width=23 height=2597 ---- 5)</p> 98 99 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'><span 100 style='position:relative;top:7.0pt'><img 114 101 src="./img/sm_image018.gif"></span> <span style='font-family: 115 102 "Times New Roman","serif"'>= 0 for <i>I<sub>s</sub></i> in</span> <i><span … … 123 110 style='font-family:"Times New Roman","serif"'>2)<span style='font:7.0pt "Times New Roman"'> 124 111 </span></span><span style='font-family:"Times New Roman","serif"'>For </span><span 125 style='position:relative;top:6.0pt'><img width=28 height=24126 src="./img/sm_image01 4.gif"></span>= <span style='font-family:112 style='position:relative;top:6.0pt'><img 113 src="./img/sm_image012.gif"></span>= <span style='font-family: 127 114 "Times New Roman","serif"'>constant </span> <span style='font-family:"Times New Roman","serif"'>and 128 </span><span style='position:relative;top:6.0pt'><img width=28 height=24129 src="./img/sm_image01 5.gif"></span> = <span style='font-family:115 </span><span style='position:relative;top:6.0pt'><img 116 src="./img/sm_image011.gif"></span> = <span style='font-family: 130 117 "Times New Roman","serif"'>0:</span></p> 131 118 … … 135 122 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'> 136 123 <img src="./img/sm_image019.gif"> 137 <span style='font-family:"Times New Roman","serif"'> 6)</span></p>124 <span style='font-family:"Times New Roman","serif"'> ---- 6)</span></p> 138 125 139 126 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'><span 140 127 style='font-family:"Times New Roman","serif"'>for q<sub>p</sub> = q<sub>i</sub> 141 - </span><span style='position:relative;top:6.0pt'><img width=28 height=24128 - </span><span style='position:relative;top:6.0pt'><img 142 129 src="./img/sm_image012.gif"></span><span style='font-family: 143 130 "Times New Roman","serif"'> and</span> <span style='font-family:"Times New Roman","serif"'>q<sub>N</sub> 144 131 = q<sub>i</sub> + </span><span style='position:relative;top:6.0pt'><img 145 width=28 height=24src="./img/sm_image012.gif"></span>. <span146 style='position:relative;top:7.0pt'><img width=23 height=25132 src="./img/sm_image012.gif"></span>. <span 133 style='position:relative;top:7.0pt'><img 147 134 src="./img/sm_image018.gif"></span> <span style='font-family: 148 135 "Times New Roman","serif"'>= 0 for <i>I<sub>s</sub></i> in</span> <i><span … … 155 142 style='font-family:"Times New Roman","serif"'>3)<span style='font:7.0pt "Times New Roman"'> 156 143 </span></span><span style='font-family:"Times New Roman","serif"'>For </span><span 157 style='position:relative;top:6.0pt'><img width=28 height=24158 src="./img/sm_image01 4.gif"></span>= <span style='font-family:144 style='position:relative;top:6.0pt'><img 145 src="./img/sm_image011.gif"></span>= <span style='font-family: 159 146 "Times New Roman","serif"'>constant </span> <span style='font-family:"Times New Roman","serif"'>and 160 </span><span style='position:relative;top:6.0pt'><img width=28 height=24161 src="./img/sm_image01 5.gif"></span> = <span style='font-family:147 </span><span style='position:relative;top:6.0pt'><img 148 src="./img/sm_image011.gif"></span> = <span style='font-family: 162 149 "Times New Roman","serif"'>constant:</span></p> 163 150 … … 177 164 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'> 178 165 <img src="./img/sm_image020.gif"> <span style='font-family: 179 "Times New Roman","serif"'> (7)</span></p>166 "Times New Roman","serif"'> ---- (7)</span></p> 180 167 181 168 <p class=MsoListParagraphCxSpMiddle style='margin-left:.25in'><span 182 169 style='font-family:"Times New Roman","serif"'>for q<sub>p</sub> = q<sub>i</sub> 183 - </span><span style='position:relative;top:6.0pt'><img width=28 height=24170 - </span><span style='position:relative;top:6.0pt'><img 184 171 src="./img/sm_image012.gif"></span><span style='font-family: 185 172 "Times New Roman","serif"'> and</span> <span style='font-family:"Times New Roman","serif"'>q<sub>N</sub> 186 173 = q<sub>i</sub> + </span><span style='position:relative;top:6.0pt'><img 187 width=28 height=24src="./img/sm_image012.gif"></span>. <span188 style='position:relative;top:7.0pt'><img width=23 height=25174 src="./img/sm_image012.gif"></span>. <span 175 style='position:relative;top:7.0pt'><img 189 176 src="./img/sm_image018.gif"></span> <span style='font-family: 190 177 "Times New Roman","serif"'>= 0 for <i>I<sub>s</sub></i> in</span> <i><span … … 207 194 208 195 <p class=MsoNormal><img src="./img/sm_image021.gif"><span 209 style='font-family:"Times New Roman","serif"'> 196 style='font-family:"Times New Roman","serif"'> ---- (8)</span></p> 210 197 211 198 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>For all … … 228 215 229 216 <p class=MsoNormal><img src="./img/sm_image022.gif"><span 230 style='font-family:"Times New Roman","serif"'> 217 style='font-family:"Times New Roman","serif"'> ---- (9)</span></p> 231 218 232 219 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>In Eq 233 (9), x<sub>0</sub> = qcos</span><span style='font-family:Symbol'>(theta)</span><span 234 style='font-family:"Times New Roman","serif"'> and y<sub>0</sub>=qsin</span><span 235 style='font-family:Symbol'>(theta)</span><span style='font-family:"Times New Roman","serif"'> 236 , and the primed axes are in the coordinate rotated by an angle </span><span 237 style='font-family:Symbol'>theta</span><span style='font-family:"Times New Roman","serif"'> 238 around z-axis (below) so that x<sub>0</sub> = x<sub>0</sub>cos</span><span 239 style='font-family:Symbol'>(theta) + </span><span style='font-family:"Times New Roman","serif"'>y<sub>0</sub> 240 sin</span><span style='font-family:Symbol'>(theta) </span><span style='font-family: 241 "Times New Roman","serif"'>and y<sub>0</sub> = -x<sub>0</sub>sin</span><span 242 style='font-family:Symbol'>(theta) + </span><span style='font-family:"Times New Roman","serif"'>y<sub>0</sub> 243 cos</span><span style='font-family:Symbol'>(theta) .</span><span style='font-family: 220 (9), x<sub>0</sub> = qcosθ</span><span 221 style='font-family:"Times New Roman","serif"'> and y<sub>0</sub> = qsinθ</span><span style='font-family:"Times New Roman","serif"'> 222 , and the primed axes are in the coordinate rotated by an angle θ</span><span style='font-family:"Times New Roman","serif"'> 223 around z-axis (below) so that x<sub>0</sub> = x<sub>0</sub>cosθ + </span><span style='font-family:"Times New Roman","serif"'>y<sub>0</sub> 224 sinθ </span><span style='font-family: 225 "Times New Roman","serif"'>and y<sub>0</sub> = -x<sub>0</sub>sinθ + </span><span style='font-family:"Times New Roman","serif"'>y<sub>0</sub> 226 cosθ.</span><span style='font-family: 244 227 "Times New Roman","serif"'> Note that the rotation angle is zero for x-y 245 symmetric elliptical Gaussian distribution</span> <span style='font-family:Symbol'>.246 < /span><span style='font-family:"Times New Roman","serif"'>The A is a228 symmetric elliptical Gaussian distribution</span>. 229 <span style='font-family:"Times New Roman","serif"'>The A is a 247 230 normalization factor.</span></p> 248 231 249 232 <p class=MsoNormal align=center style='text-align:center'><span 250 style='font-family:"Times New Roman","serif"'><img width=439 height=376233 style='font-family:"Times New Roman","serif"'><img 251 234 id="Object 1" src="./img/sm_image023.gif"></span></p> 252 235 … … 254 237 255 238 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Now we 256 consider a numerical integration where each bins in </span><span 257 style='font-family:Symbol'>THETA</span><span style='font-family:"Times New Roman","serif"'> 239 consider a numerical integration where each bins in </span> Θ </span><span style='font-family:"Times New Roman","serif"'> 258 240 and R are <b>evenly </b>(this is to simplify the equation below) distributed by 259 </span> <span style='font-family:Symbol'>Delta_THETA</span><span style='font-family:260 "Times New Roman","serif"'>and </span> <span style='font-family:Symbol'>Delta</span><span241 </span>ΔΘ </span><span style='font-family: 242 "Times New Roman","serif"'>and </span> Δ</span><span 261 243 style='font-family:"Times New Roman","serif"'>R, respectively, and it is 262 244 assumed that I(x, y) is constant within the bins which in turn becomes</span></p> … … 265 247 266 248 <p class=MsoNormal> <span 267 style='font-family:"Times New Roman","serif"'> (10)</span></p>249 style='font-family:"Times New Roman","serif"'> ---- (10)</span></p> 268 250 269 251 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>Since we 270 252 have found the weighting factor on each bin points, it is convenient to 271 transform x-y back to x-y coordinate (rotating it by -</span><span 272 style='font-family:Symbol'>(theta)</span><span style='font-family:"Times New Roman","serif"'> 253 transform x-y back to x-y coordinate (rotating it by -θ</span><span style='font-family:"Times New Roman","serif"'> 273 254 around z axis). Then, for the polar symmetric smear,</span></p> 274 255 275 256 <p class=MsoNormal><img src="./img/sm_image025.gif"><span 276 style='position:relative;top:35.0pt'> </span>(11)</p>257 style='position:relative;top:35.0pt'> </span> ---- (11)</p> 277 258 278 259 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>where,</span></p> 279 260 280 <p class=MsoNormal><img src="./img/sm_image026.gif"> </p>261 <p class=MsoNormal><img src="./img/sm_image026.gif">,</p> 281 262 282 263 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>while … … 284 265 285 266 <p class=MsoNormal><img src="./img/sm_image027.gif"><span 286 style='font-family:"Times New Roman","serif"'> 267 style='font-family:"Times New Roman","serif"'> ---- (12)</span></p> 287 268 288 269 <p class=MsoNormal><span style='font-family:"Times New Roman","serif"'>where,</span></p> … … 301 282 </body> 302 283 303 </html>
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