Ring Branch

The figure below shows the 3rd-order ion optics as a “beam plot”. The Main Separator of the Super-FRS is shown, from FPF4 along the Ring Branch up to the focus at FRF3, where slits would be used to reject unwanted isotopes. The beam injection into the rings requires very short beam packets from the synchrotrons (SIS-18 and SIS-100). If a small beam spot of such a time-concentrated beam were put on the Super-FRS production target, it is likely it would be destroyed. To avoid this, we will use a relatively large beam spot at the target, especially in the vertical, non-dispersive dimension. The large emittance of the beam is reflected in the ion-optics shown, which is quite different to that of the other branches, particularly in the vertical (y) dimension.

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The table below gives the 1st-order transfer matrix elements at the focal planes in the Ring Branch of the Main-Separator. The linear dimensions x and y are in meters, the angles a and b in radians, and the momentum deviation d as a fraction of the nominal (reference) value. The “path length” is from the Super-FRS target. FRF3 is 3.5 m from the end of the last quadrupole, FRF3QT32.

1st-order transfer matrix elements at the focal planes in the Ring Branch.

Matrix element

FMF1

FMF2

FRF1

FRF2

FRF3

(x,x)

-4.18

1.84

-1.82

4.18

-2.00

(x,a)

         

(x,d)

6.35

-5.59

5.52

-6.35

 

(a,a)

-0.24

0.54

-0.55

0.24

-0.50

(a,d)

0.09

   

0.03

 

(y,y)

0.25

0.11

1.34

 

1.37

(y,b)

-0.61

0.63

-0.76

1.34

-0.10

(b,b)

-0.19

0.03

-0.25

-0.36

0.71

Path length (m)

98.08

123.86

150.46

176.24

203.32

 

After FRF3, there will be a coupling line (not shown)  to the Collector Ring. The Collector Ring is the first of a chain of storage rings in the FAIR facility, the next being the RESR and NESR where the EXL and ILIMA  experiments are planned. Additionally, an intersecting electron ion ring will allow the scattering of electrons on exotic nuclei ELISe.