MadX proposals

1. MadX proposals R. De Maria, 29/8/2014

2. Makethin and thick dipoles Issues: • Dipole edge elements cannot be used together thick dipole elements unless one implements a body only flag (takes time, many line of code to change) • Thick slicing of dipoles does not propagate correctly the edge parameters. Proposal: • When slicing a thick dipole: • the edge parameters of the entrance of the original dipole are copied to the edge parameters of the entrance of the first thick slice. • the edge parameters of the exit of the original dipole are copied to the edge parameters of the exit of the last thick slice. • All the other edge parameters are zeroed.

3. Example s1: SBEND, l=1, angle=1e-3; s2: SBEND, l=2, angle=2e-3; s3: SBEND, l=3, angle=3e-3; m: marker; beam; seq1: sequence,l=4; s1,at=.5; dddd:m ,at=1; s2,at=2; m1: m ,at=3; endsequence; seq2: sequence,l=4; s3,at=1.5; m2: m,at=3; endsequence; s1,fint=0,hgap=0.0,e1= 0.0,e2=0.0; s2,fint=0,hgap=0.0,e1=-0.0,e2=0.0; s3,fint=0,hgap=0.0,e1= 0.0,e2=0.0; select,flag=sectormap,pattern=m.*; use,sequence=seq1; twiss,betx=1,bety=1,SECTORMAP,sectorfile=sec10; t133_10=table(sectortable,m1,t133); use,sequence=seq2; twiss,betx=1,bety=1,SECTORMAP,sectorfile=sec20; t133_20=table(sectortable,m2,t133); s1,fint=1,hgap=0.0,e1= 0.1,e2=0.1; s2,fint=1,hgap=0.0,e1=-0.1,e2=0.1; s3,fint=1,hgap=0.0,e1= 0.1,e2=0.1; select,flag=sectormap,pattern=m.*; use,sequence=seq1; twiss,betx=1,bety=1,SECTORMAP,sectorfile=sec11; t133_11=table(sectortable,m1,t133); use,sequence=seq2; twiss,betx=1,bety=1,SECTORMAP,sectorfile=sec21; t133_21=table(sectortable,m2,t133); s1,fint=1,hgap=0.2,e1= 0.1,e2=0.1; s2,fint=1,hgap=0.2,e1=-0.1,e2=0.1; s3,fint=1,hgap=0.2,e1= 0.1,e2=0.1; select,flag=sectormap,pattern=m.*; use,sequence=seq1; twiss,betx=1,bety=1,SECTORMAP,sectorfile=sec12; t133_12=table(sectortable,m1,t133); use,sequence=seq2; twiss,betx=1,bety=1,SECTORMAP,sectorfile=sec22; t133_22=table(sectortable,m2,t133); set,format="40.16g"; value,t133_10,t133_20; value,t133_11,t133_21; value,t133_12,t133_22;

4. Adding thin elements inside the thick elements Issues: • Installing a thin element inside a thick element generates negative drifts, although is physically justified. • The vacuum aperture layout is not compatible with thick opitcs. Proposals: • Adding a thin element inside an already existing thick element, slice automatically the thick element. • Adding a thick element on an already thin element, slice automatically the thick element. • Adding a thick element on an already thick element generate a negative drift.

5. Aperture offset Aperture not centered on the reference trajectory can be displaced by a file called offset that contains one reference node that defines the reference frame of the displacement vector. Displaced element has a x,x’,x’’,y,y’,y’’ parameters that are components of the vector that displace the center of the aperture as a function of s in the reference frame of the reference node. Issues: • The offset files are not generated by the layout database. The offset data cannot be in the sequence file. Offset data cannot be parametric. • Offset data depends on the sequence in which common elements are installed (it is not a simple property, but a sequence dependent property.) • For offsets in the arc (e.g 11T dipoles) is not practical have a reference node in the straight section, but it practical that the offset itself is defined in the reference frame of the center of the element. • For elements in the straight section is not practical to have in the center of the element itself, but from the IP or as of now from the s.ds.l[12345678].b[12]. Proposal: • Define in the sequence definition the reference node and offset data each element whose aperture needs to be displacedand the aperture offsets. • Define in seqeditthe commands to change this data.