ZGOUBI USERS' GUIDE - HEP

4.4 Optical Elements and related numerical procedures 71BREVOL: 1-D uniform mesh magnetic field mapBREVOL reads a 1-D axial field map from a storage data file, whose content must fit the following FORTRAN readingsequenceOPEN (UNIT = NL, FILE = FNAME, STATUS = ‘OLD’ [,FORM=’UNFORMATTED’])DO 1 I = 1, IXIF (BINARY) THENREAD(NL) X(I), BX(I)ELSEREAD(NL,*) X(I), BX(I)ENDIF1 CONTINUE¤§ where is the number of nodes along the § (symmetry) § ¤ -axis, their coordinates, and § ¤ the values of the¡component of the field. ¡ § is normalized with BNORM factor prior to ray-tracing, as well X is normalized with a§XNORM coefficient (usefull to convert to centimeters, the working units in zgoubi ). For binary files, FNAME mustbegin with ‘B ’ or ‘b ’, a flag ‘BINARY’ will thus be set to ‘.TRUE.’.along a particle trajectory are calculated by means of a 5-point polynomial fit followed by second order off-axis Taylorseries extrapolation (see sections 1.3.1, 1.4.1).§ -cylindrical symmetry is assumed, resulting in ¡ and ¡ taken to be zero on axis.§#"$Œ"[ and its derivatives¡Entrance and/or exit integration boundaries may be defined in the same way as in CARTEMES by means of the flag ¤ Oand coefficients ´ , ¡ , ² , etc.