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Contents → FOUR-CIRCLE REFERENCE → Zone Macros

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Zone mode is controlled with the cz (calculate zone), sz (set zone) and mz (move zone) macros. Given two Bragg reflections, cz will calculate and display the values of χ and φ necessary to put both of these reflections in the scattering plane. To find the angles needed to put (0,0,2) and (0,2,2) in the scattering plane, type

1.FOURC> cz 0 0 2 0 2 2
Chi = 45  Phi = 90

2.FOURC> 

Once appropriate values of χ and φ have been calculated, the scattering plane can be set using the pl (plane) macro, which moves the 2θ and θ motors together,

1.FOURC> pl 45 90

2.FOURC> 

Alternatively, you can use the mz macro, which calculates the necessary χ and φ, moves there, sets zone mode, if not already in it, and saves the values of the zone vectors in the G[] geometry parameter array.

1.FOURC> mz 0 0 2 0 2 2

2.FOURC> p A[chi], A[phi]
45 90

3.FOURC> 

The sz macro calculates and displays the χ and φ values, sets zone mode, if not already in it, saves the values of the zone vectors, sets the frozen values of zone -mode χ and φ, but does not move the diffractometer.

The cz, sz and mz macros make use of the Z[] array variables to pass the zone vectors to the geometry code.

1.FOURC> prdef cz
def cz '
      if ($# != 6) {
              eprint "Usage:  cz h0 k0 l0 h1 k1 l1"
              exit
      }
      Z[0]=$1; Z[1]=$2; Z[2]=$3; Z[3]=$4; Z[4]=$5; Z[5]=$6
      calcZ
      printf("Chi = %g  Phi = %g\n", A[chi], A[phi])
      waitmove; get_angles; calcHKL
'

2.FOURC> 

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