Changeset 5ed76f8 in sasview for src/sas/sasgui/perspectives/calculator/media/resolution_calculator_help.rst
- Timestamp:
- Apr 7, 2017 1:11:41 AM (7 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, magnetic_scatt, release-4.2.2, ticket-1009, ticket-1094-headless, ticket-1242-2d-resolution, ticket-1243, ticket-1249, ticket885, unittest-saveload
- Children:
- fca1f50
- Parents:
- 727c05f
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- 1 edited
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src/sas/sasgui/perspectives/calculator/media/resolution_calculator_help.rst
r6aad2e8 r5ed76f8 10 10 ----------- 11 11 12 This tool is approximately estimates the resolution of Q from SAS instrumental13 parameter values assuming that the detector is flat and normal to the 12 This tool is approximately estimates the resolution of $Q$ from SAS instrumental 13 parameter values assuming that the detector is flat and normal to the 14 14 incident beam. 15 15 … … 23 23 2) Select the source (Neutron or Photon) and source type (Monochromatic or TOF). 24 24 25 *NOTE! The computational difference between the sources is only the 25 *NOTE! The computational difference between the sources is only the 26 26 gravitational contribution due to the mass of the particles.* 27 27 28 3) Change the default values of the instrumental parameters as required. Be 28 3) Change the default values of the instrumental parameters as required. Be 29 29 careful to note that distances are specified in cm! 30 30 31 4) Enter values for the source wavelength(s), |lambda|\ , and its spread (= FWHM/|lambda|\).32 33 For monochromatic sources, the inputs are just one value. For TOF sources, 34 the minimum and maximum values should be separated by a '-' to specify a 31 4) Enter values for the source wavelength(s), $\lambda$, and its spread (= $\text{FWHM}/\lambda$). 32 33 For monochromatic sources, the inputs are just one value. For TOF sources, 34 the minimum and maximum values should be separated by a '-' to specify a 35 35 range. 36 37 Optionally, the wavelength (BUT NOT of the wavelength spread) can be extended 38 by adding '; nn' where the 'nn' specifies the number of the bins for the 39 numerical integration. The default value is nn = 10. The same number of bins 36 37 Optionally, the wavelength (BUT NOT of the wavelength spread) can be extended 38 by adding '; nn' where the 'nn' specifies the number of the bins for the 39 numerical integration. The default value is nn = 10. The same number of bins 40 40 will be used for the corresponding wavelength spread. 41 41 42 5) For TOF, the default wavelength spectrum is flat. A custom spectral 43 distribution file (2-column text: wavelength (|Ang|\) vs Intensity) can also 42 5) For TOF, the default wavelength spectrum is flat. A custom spectral 43 distribution file (2-column text: wavelength (|Ang|\) vs Intensity) can also 44 44 be loaded by selecting *Add new* in the combo box. 45 45 46 6) When ready, click the *Compute* button. Depending on the computation the 46 6) When ready, click the *Compute* button. Depending on the computation the 47 47 calculation time will vary. 48 48 49 7) 1D and 2D dQ values will be displayed at the bottom of the panel, and a 2D50 resolution weight distribution (a 2D elliptical Gaussian function) will also 51 be displayed in the plot panel even if the Q inputs are outside of the49 7) 1D and 2D $dQ$ values will be displayed at the bottom of the panel, and a 2D 50 resolution weight distribution (a 2D elliptical Gaussian function) will also 51 be displayed in the plot panel even if the $Q$ inputs are outside of the 52 52 detector limit (the red lines indicate the limits of the detector). 53 54 TOF only: green lines indicate the limits of the maximum Q range accessible53 54 TOF only: green lines indicate the limits of the maximum $Q$ range accessible 55 55 for the longest wavelength due to the size of the detector. 56 57 Note that the effect from the beam block/stop is ignored, so in the small Q58 region near the beam block/stop59 56 60 [ie., Q < 2. |pi|\ .(beam block diameter) / (sample-to-detector distance) / |lambda|\_min] 57 Note that the effect from the beam block/stop is ignored, so in the small $Q$ 58 region near the beam block/stop 59 60 [i.e., $Q < (2 \pi \cdot \text{beam block diameter}) / (\text{sample-to-detector distance} \cdot \lambda_\text{min})$] 61 61 62 62 the variance is slightly under estimated. 63 63 64 8) A summary of the calculation is written to the SasView *Console* at the 64 8) A summary of the calculation is written to the SasView *Console* at the 65 65 bottom of the main SasView window. 66 66 … … 76 76 .. image:: q.png 77 77 78 In the small-angle limit, the variance of Q is to a first-order78 In the small-angle limit, the variance of $Q$ is to a first-order 79 79 approximation 80 80 … … 85 85 .. image:: sigma_table.png 86 86 87 Finally, a Gaussian function is used to describe the 2D weighting distribution 88 of the uncertainty in Q.87 Finally, a Gaussian function is used to describe the 2D weighting distribution 88 of the uncertainty in $Q$. 89 89 90 90 .. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ … … 93 93 ---------- 94 94 95 D.F.R. Mildner and J.M. Carpenter 95 D.F.R. Mildner and J.M. Carpenter 96 96 *J. Appl. Cryst.* 17 (1984) 249-256 97 97 98 D.F.R. Mildner, J.M. Carpenter and D.L. Worcester 98 D.F.R. Mildner, J.M. Carpenter and D.L. Worcester 99 99 *J. Appl. Cryst.* 19 (1986) 311-319 100 100
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