Extraction Scenarios of CIS

extraction section Spetum Extracted beam Traveling wave kicker

Traveling wave kicker for extraction

• In order to perform the single turn extraction, it is required that the rising and falling time of extraction pulse must be within the electron cycling time 60 ns (at energy 25 MeV). Thus, one suitable choice is using the traveling wave kicker for extraction and thus we can get the rising time for 10ns.



k



E c

 

L B

   1   1   Spetum metal thickness : 5 mm with gap width : 40mm.

for extraction , close orbit bump is 25 mm at septum.

Extraction :  k  19

mrad



E

 23 .

0 [

kV

/

cm

]

Kickers’ Strength

Vertical Lambertson extraction magnet

The vertical Lambertson septum is used for both injection and extraction.

Injection Extraction

Septum

0.81m

35  35  35 

1.15m

1.15m

0.2m

We put the septum in the middle of the drift space for both injection and extraction design convenienc e.



z

'  B  

B x B



l

we choose 

z

'  35  deflected by the septum to avoid the next element.

0.0834[Tm] , then we get septum field strength Β x  0 .

25[T] needed to deflect beam by 35  .

Practical consideration to cancel the horizontal small angle of extracted beam The beam kicked to the septum have a small horizontal eliminate this horizontal angle: 1) rotate the septum; 2) rotate the extraction dipole (vertical bending). However, because we plan to use the septum for both injection and extraction, and consider the fact that Px is very small, we choose to rotate the vertical bending dipole slightly to eliminate the horizontal angle of beam.

Using vertical bending dipole to eliminite the horizontal small angle 35  35 

Ideal orbit

If we rotate the extraction to  x'  B

B

z 

l



B d l

sin

B

 

r

dipole by  r , according ,  z'  B

B

x 

l



B d l

cos 

r B

 where

l

 0 .

1

m

, we get  x  r  2 0  m at the extraction  0 .

05  , very small.

B d  0 .

51 [

T

] as the strength dipole.

needed to flat the beam.