The OPAL Discussion Forum

[Andreas Adelmann <andreas.adelmann AT psi.ch>]

Hi Andy here a translation between OPAL, MADX and TRANSPORT

for the quadrupole. I will update the manual asap.

Bfieldf   =  0.593;                // B-field in T

Bfieldd  = -0.702;

apperture  =  0.125                 // m

OPAL

QP1: Quadrupole, L= 0.644, ELEMEDGE= ...., K1= Bfieldf / apperture;

QP2: Quadrupole, L= 0.644, ELEMEDGE= ...., K1= Bfieldd / apperture;

QP3: Quadrupole, L= 0.644, ELEMEDGE= .., K1= Bfieldf / apperture;

MADX

brho = GAMMA*BETA*(PMASS)*1E9/CLIGHT;

kf  = Bfieldf / length;          // focusing strength [T/m]

kd = Bfieldd / length;          // focusing strength [T/m]      

vk1   := kf/brho;                       // focusing strength 1

vk2   := kd/brho;                       // focusing strength 2  

qf: quadrupole, k1:=vk1, l:=0.644;    // Quadrupole 1

qd: quadrupole, k1:=vk2, l:=0.644;    // Quadrupole 2 

TRANSPORT

5. 0.644 5.93 125.0 /QG21/ ;

5. 0.644 -7.02 125.0 /QG22/ ;

5. 0.644 5.93 125.0 /QG23/ ;

Andreas 

On Jun 13, 2013, at 5:31 PM, Andrii Rusanov wrote:

For some reason, some browsers do not show Unicode characters from my
post... Here is the TeX version of my question on K1.

Quadrupole chapter of the manual says: K1 is the normal quadrupole
component K1 = \frac{\partial B_y}{\partial B_x}.
Dipole chapter says: K1 defines the field gradient index of the magnet
K1 = (\frac{1}{\Beta\rho})\frac{\partial B_y}{\partial B_x}...

I suppose for the quadrupole, K1 should be also  K1 =
(\frac{1}{\Beta\rho})\frac{\partial B_y}{\partial B_x}. And if
OPAL follows MAD9 conventions,a positive K1 implies horizontal
focusing of positively charged particles. Am I right?

Any your comments are very appreciated. Thank you!
Andy Rusanov
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