1. The IR beam pipe M. Sullivan For
M. Boscolo, K. Bertsche, E. Paoloni, S. Bettoni,
P. Raimondi, et al.
SuperB General Meeting
Perugia, Italy
June 15-20, 2009

2. Some thoughts concerning the IR beam pipe
As thin a Be wall as possible
PEP-II beam pipe
Double Be wall 800 um inner and 400 um outer
1.4 mm water channel
4 um Au
What can we do with a new design?
500 um inner wall?
At least 4 um Au inner layer
Water cool ends only?
Needs engineering study (maybe done?)

3. Some drawings
Plan view
Side view

4. The “Magic” Flange
Several IRs have been designed with flanges inside of the two cryostats
KEKB
BEPCII
CESR
However, as far as I can tell, these magic flanges can be accessed only after a cryostat is removed
All of these machines have a single shared beam pipe inside the cryostat

5. Magic flange (cont.) We can not do this for at least two reasons
Our beams go into separate beam pipes before we get to the cryostats
We don’t have enough space inside the cryostat to have two separate walls
This has implications as to how we put the IR components together and how we get them into the detector

6. So what are these things?
Not sure at this time, but we do need strain relief for the Be chamber so we need some form of bellows
This could still be some form of vacuum disconnect
Place holder for now – position not fixed but it must be inside of the chamber split

7. How do we put this together?
This is starting to look like the PEP-II design with large stiff cryostats (permanent magnets for PEP-II) on either side of a small fragile beampipe surrounded by a big fragile SVT
If we have to put this together outside of the detector, then how do we get it into the detector?
We assume no support tube. Perhaps a removable trough with temporary stiffeners between cryostats? Rolled in on small rollers? How close does the DCH have to be to the SVT?

8. Summary We need to try to minimize the material for the Be beam pipe
We need to decouple the Be pipe from the cryostats
If we can not do a magic flange then we have to put everything together outside of the detector
This will have implications for space between the SVT and the DCH