G Data for absorption and extinction corrections

(The G stands for ``Gaussian integration") A G card starts with G then a CCSL-word which determines what else is on the card. There is no predetermined sequence for G cards. It would be usual, but not essential, to type all G cards starting with the same CCSL-word consecutively.

DATA FOLLOWING ALLOWED CCSL WORDS:

FACE
Data

The coefficents $a, b, c,$ and $d$ in the equation for one of the plane faces of the crystal:

$$ax + by +cz \ge d$$

where $x$, $y$, and $z$ are CCSL orthogonal axes defined near the start of this chapter and $d$ is positive.

Example

G FACE 0.312 0.534 0 0.86

MU
Data

The absorption or depolarisation coefficient, which should be in the same type of units as $d$ in the G FACE cards above (e.g. in inverse mm if $d$ is in mm).

MODE
Data

the integer NINT indicating which kind of integral is required:

NINT = 1

Transmission factor integral: $exp(-\mu(\tau_{in}+\tau_{out}))$

NINT = 2

Depolarisation integral: $exp(-\mu\tau_{in})$

NINT = 3

Derivative integral for extinction:
$(\tau_{in}+\tau_{out}) exp(-\mu(\tau_{in}+\tau_{out}))$

NINT = 4

Means do 1 and 2

NINT = 5

Means do 1 and 3

NINT = 6

Means do 2 and 3

NINT = 7

Means do all three

PNTS
Data

The number of points for integration in the $x$, $y$, and $z$ directions respectively. The maximum for each is 10.

CARDS DEMANDED:

As many FACE cards as the crystal has faces

ASSUMPTIONS MADE:

For both MODE and MU , if no G card is given, the values of NINT and/or the absorption coefficient are expected to be set up in COMMON /ABSDAT by the calling program. If no G PNTS card is given, 5 points are set up as default in each direction.

TELESCOPING OF SIMPLE CARDS:

The MU and MODE information may occur on the same card.

ROUTINES WHICH READ THE CARDS:

Routine SETGAU calls INPUTG to read and interpret the G cards. Routines SETABS and SETPOL call SETGAU.