72 lines
3.1 KiB
HTML
72 lines
3.1 KiB
HTML
<HTML>
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<HEAD>
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<TITLE>4 Circle Diffractometer Setting Calculation</TITLE>
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</HEAD>
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<BODY>
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<H1>4 Circle Diffractometer Setting Calculation</H1>
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<P>
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An essential part of operating a 4 circle diffractometer is the calculation
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of the setting angles for the diffractometer for a given reciprocal lattice
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point from the UB matrix and the wavelength. SICS does this through the hkl
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object. The hkl object can calculate the required settings both for normal 4
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circle configuration and normal beam configuration. It is possible to
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specify if low chi or high chi values are preferred. The wavelength can be
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dealt with in two ways: it can be set manually. Or a variable controlling
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the wavelength can be specified. The hkl object will then be updated
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automatically with the newest value for the wavelength whenever the
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wavelength changes.
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</P>
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<p>
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The hkl object understands the following commands:
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<DL>
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<DT>hkl list
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<DD>Prints a listing of all relevant settings calculation parameters.
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<DT>hkl current
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<DD>Prints the value of the last calculated reflection.
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<DT>hkl lambda val
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<DD>Manually sets the wavelength to val. No automatic updates of the
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wavelength will be performed.
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<DT>hkl lambdavar val
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<DD>Sets the name of the variable controlling the wavelength. The wavelength
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in the hkl object will be automatically updated whenever the wavelength is
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modified by driving variable val. This is a user command because the TRICS
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spectrometer has more then one monochromator.
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<DT>hkl setub a11 a12 a13 a21 a22 a23 a31 a 32 a33
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<DD>SetUB sets the UB matrix to the nine values given.
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<DT>hkl nb val
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<DD>Switches the mode for normal beam calculation. If val is 1 a normal beam
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calculation is performed, else normal four circle calculations are done.
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<DT>hkl quadrant val
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<DD>Defines the chi quadrant to prefer. The parameter val can be 0 for low
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chi and 1 for high chi.
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<DT>hkl calc h1 h2 h3 psi hamil
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<DD>Calculates and prints the setting angles for the reflection (h1,h2,h3).
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Optionally a psi value and a hamilton position can be specified.
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<DT>hkl run h1 h2 h3 psi hamil
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<DD>Calculates the setting angles for the reflection (h1,h2,h3) and starts
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the motors to run to that position. This command will return immediately and
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will not wait for the diffractometer to arrive at the setting angles
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requested.
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Optionally a psi value and a hamilton position can be specified.
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<DT>hkl drive h1 h2 h3 psi hamil
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<DD>Calculates the setting angles for the reflection (h1,h2,h3) and starts
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the motors to drive to that position. This command will wait for the
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diffractometer to arrive at the setting angles requested.
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Optionally a psi value and a hamilton position can be specified.
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<dt>hkl hm
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<dd>Retrieves the value of the histogram memory flag.
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<dt>hkl hm val
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<dd>Sets the histogram memory flag to val. This is a special for
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TRICS. TRICS has three detectors at 0, 45, 90 degree offset to two
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theta. If this flag is greater 0, hkl checks if the reflection to be
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calculated is on any of the three detectors and calculates two theta
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accordingly.
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<dt>hkl fromangles two-theta om chi phi
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<dd>Calculates hkl from the angles given on the command line using the
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current UB matrix and wavelength.
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</DL>
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</p>
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</BODY>
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</HTML>
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