Dear Users:
1. Now MULT accepts keywords ANGLE, E1, E2, DROTATE to simulate a general combined function bending magnet. The multipoles in MULT with nonzero ANGLE are defined as
H = ... + As(x, y) ,
As(x, y) = Sum[ g_kn (Kn + I SKn)/(n + 1)! (rho + x)^(1/2 - k)
* (x + I y)^(n + k) / rho^(1/2),
{k, 0, Infinity}, {n, 0, nmax}]
with
g_kn = - (2k - 1)!! (2k - 3)!! (n + 1)! / (8^k (n + k + 1)! k!) ,
where rho = L/ANGLE . Actually the summation is truncated at n + k <= 21
in the current version. While this definition converges to the regular
one for multipoles when ANGLE -> 0, K0 and K1 of MUILT are
different from those of BEND.
The meaning of E1, E2, DROTATE, F1 are same as BEND's. The usage of FRINGE is
same as MULT's, i.e. FRINGE=3: ent and exit, 1: ent only, 2: exit only.
Remarks:
a) The fringe field of the multipoles are not involved at all.
b) The emittance calculation is not yet correct for the multipoles.
c) Since this code including the definition above are quite new, everything is subject to change.
Example:
MOMENTUM= 1 GEV; ON ECHO;OFF EMIT COD CTIME RAD RFSW RADCOD;
LINE AGCELL=( IP2 BF BD )
;
MULT BF = (L=1 ANGLE=30 DEG E1=0 E2=0 F1=0.1 FRINGE=3 K1=0.1
EPS=1E-4)
BD = (L=1 ANGLE=30 DEG E1=0 E2=0 F1=0.1 FRINGE=3 K1=-0.1
EPS=1E-4)
;
MARK IP2 =(BETAX = 0.703 BETAY = 0.703 EMIX = 4.0E-5
EMIY = 4.0E-5 DP = 0.01 SIGZ = 8E-4 )
;
FFS USE=AGCELL;
w=Window[];
c=Canvas[w,Width->600,Height->400];
Canvas$Widget=c;
dr:=(OpticsPlot[{{"BX","BY"},{"EX"},{"DX"}}];TkWait[]);
cell
fit nx .25 ny .25
free BF BD go
dr; !Press [ReturnToSAD] to proceed.
DP0=0.4;calc;dr; ! Off-momentum optics & orbit.
DP0=0.6;calc;dr;
end