ZGOUBI USERS' GUIDE - HEP

90 4 DESCRIPTION OF THE AVAILABLE PROCEDURES¢b‰g‰j ¢b g ^>îREBMULT: Electro-magnetic multipoleEBMULT simulates an electro-magnetic multipole, by addition of electric¢ and magnetic¡ multipole components(dipole to 20-pole).and its derivatives) are derived from the general expression ofj^ ^( ªšðaœ§ the multipole scalar potential (eq. 1.3.5), ç^followed by arotation ( pole order), as described in section X 1.5.4 (seealso ELMULT). and its derivatives are derived from the same general potential, as described in section 1.3.6 (see ž alsoMULTIPOL).The entrance and exit fringe ¡ fields of the and components are treated separately, in the same way as described underELMULT and MULTIPOL, for each one of these two fields. Wedge angle correction is applied in sharp edge field ¢ ¡ modelif is non zero, as in MULTIPOL. Any of the or multipole field component can be rotated independently of theqothers.Use PARTICUL prior to EBMULT, for the definition of particle mass and ¡ ¢ charge.¡Figure 23: An example of ¢ , ¡ multipole: the achromatic quadrupole(known for its allowing null second order chromatic aberrations [19]).