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

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: 1.the edge parameters of the entrance of the original dipole are copied to the edge parameters of the entrance of the first thick slice. 2.the edge parameters of the exit of the original dipole are copied to the edge parameters of the exit of the last thick slice. 3.All the other edge parameters are zeroed.

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;

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.

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[ ].b[12]. Proposal: Define in the sequence definition the reference node and offset data each element whose aperture needs to be displaced and the aperture offsets. Define in seqedit the commands to change this data.