ZGOUBI USERS' GUIDE - HEP

92 4 DESCRIPTION OF THE AVAILABLE PROCEDURESw@˜22Mf@w©2@w©§@©w¢ww¢¢ELMIR: Electrostatic N-electrode mirror/lens, straight slitsThe device works as mirror or lens, horizontal or vertical. It is made of £2-plate electrodes and has mid-plane symmetry.Electrode lengths ¨ q are ¨ ,(after Ref. [22, p.412]), ..., ¨¦£ . O is the mirror/lens gap. The model for the -independent electrostatic potential is1(*)'é-1 ¨O ˜å˜}&` §#§#"[ ¡¨è f¡ )bEc >êO where ˜- are the potential at the £electrodes (and normally ˜ q_\refers to the incident beam energy), §„ are thelocations of the § slits,second electrodes). ˜ Fromin section 1.5.4 (page 26).The total X-extent of the mirror/lens is ¨ ` MbEc 7In the mirror mode (i.e., option flagstarts at § wis the distance from the origin taken at the first slit §ºq\(located at between the first andthe field ¢ §#"kS"e and derivatives are deduced following the procedure described §#"e. ¨for vertical mid-plane or qqqfor horizontal mid-plane) stepwise integrationelectrode). In the latter case particles are stopped with their ¤ indexhave negligible effectsection 4.6.8 on page 135). Normally § q should exceed U O (possibly sensibly, so that ˜q (entrance of the first electrode) and terminates either when back to § ww Ç ¨q or when ¨ reachingset to (see” w §in terms of trajectory behavior).In the lens mode (i.e., option flag§ ï § qq for vertical mid-plane or @@ for horizontal mid-plane) stepwise integration§ ¨¨ q (end of the £starts at § wto w U .electrode) or when the particle deflection exceeds ©. In the latter case the particle is stopped with their index ¤¨ q (entrance of the first electrode) and terminates either when reaching § ¨¨ q (end of the £§ setw ÇUse PARTICUL prior to ELMIR, for the definition of particle mass and charge.YYYCEXALE