# Sample data for Laue_Spot_Identify
#
# Based on measurements from a real Laue image (Example_W001_45kV_18mA_30mm.jpg)
#    from University of Toronto Engineering Physics student Hollis Milroy for a
#    Tungsten single crystal with nominal (but not precise) 001 orientation. The
#    image was taken with the University of Toronto Advanced Undergraduate
#    Physics Lab Laue X-ray machine with Tungsten X-ray target, 18±0.5 mA
#    current, 45 KV electron potential, for 22±1 minutes exposure.
#    This can be viewed in QLaue by opening Example_W001_45kV_18mA_30mm.xtl, but
#    you may want to tweak the QLaue settings.

# Lattice constant in Angstroms (Set to 1 if unknown)
a_c = 3.1652   # for Tungsten

# Distance (in mm) between crystal and Laue film plane
d_film = 29.5

# Horizontal, Vertical position (in mm) of X-ray beam on film.
#    This was hard to identify and these are uncalibrated values, so they
#    could be off by several mm.
beam_yz =[2.0, 0.0]

# Horizontal (+ve to the left), Vertical (+ve up) position (in mm) of
#     diffraction spots on Laue film. (We use "Horizontal" and "Vertical"
#     instead of "x" or "y" or "z" because of differing and confusing
#     axis naming conventions.
#
spots = [
[  4.52, 15.81],
[-11.22, 12.33],
[-23.60, -0.03],
[-21.00, -18.26],
[ -7.03, -32.33],
[ 12.00, -26.19],
[ 22.84, -11.02],
[ 29.19, 12.47],
[ 17.07, 5.75]
]

# Uncertainty (in mm) of crystal-film distance and Laue spot measurements.
#     With these values, you will get many possible sets of planes, but
#     one set has much smaller deviation from the measured spots, and hence
#     is most likely the correct identification. You can try reducing these
#     uncertainties which may be slightly overestimated, but note that if you
#     halve the uncertainties, no set of planes will match the data.
dx = 1.5   # film-crystal distance uncertainty
dy = 1.0   # horizontal spot position uncertainty
dz = 1.0   # vertical spot position uncertainty

# Maximum plane index to be considered.
#     The number of planes to be considered increases as the
#     cube (maximum_plane_index**3), so a too large value may
#     dramatically increase the CPU time needed. With maximum_plane_index =7,
#     it may take several minutes to for Laue_Spot_Identify to finish.
maximum_plane_index = 5


# Measured and calculated distances are said to agree if they are within
#    this many uncertainty units of each other.  Can be increased if no
#    solutions found.
nsigma = 2