The southern side of BaBar - notice the beam injecting in the center.
... and the view just inside the PEP tunnel.
Southward down the PEP tunnel away from IR-2.
Firstoff, it might be a good idea to take a look at the PEP-II regions. I started my stroll in interaction region 2 (IR-2).
... and the view just inside the PEP tunnel.
Southward down the PEP tunnel away from IR-2.
A dipole. Notice the beampipe passing through the center.
A quadrapole.
This one was made in China.
Another quadrapole.
A bigger dipole.
Another view further down the tunnel.
There are two separate beams which collide in IR-2, a high energy electron one and a low energy positron one. The low energy ring (LER) is at 3.1 GeV whereas the high energy one (HER) is at 9 GeV. The LER is located above the HER in the PEP tunnel as shown in this photograph.
Being higher in energy, the HER beam needs somewhat larger dipoles like this one to steer it.
A sextapole.
A view back toward IR-2. For some reason there is alwayss drippy water in HEP facilities.
A dipole, sextapole, quadrapole and dipole aligned in tandem to steer the beam.
Survey markers were placed periodically in the floor of the PEP tunnel.
IR-4 is a smaller scale replica of IR-2, but without the detector. Had the government deigned to fund them, several experimental detectors could have taken data on collisions at various points around the ring simultaneously. The LEP ring at CERN operated this way in the 90's and the LHC (built in the old LEP ring) will also run several detectors at once.
Note that the HER and LER rings pass in IR-4 at slightly different radii soas to facilite steering them into collision had a detector been built here. Also the concrete curtain wall remains in place to left.
Apparently there was some rare zealousness to prevent graffiti in this region.
An RF power device for creating the electomagnetic wave the electrons surf on. (The one for the positrons is identical).
Run 5b ended due to a fire which I think was either here
or here (but I'm not really sure).
Several places along the tunnel are exits like this one off to the left.
Shafts allow airflow from the surface, and radiation shielding protects some exits in sensitive areas.
A view down the tunnel into IR-6.
Inside IR-6.
Another kind of sextapole, but still no sign of the elusive octopole.
Posters on the wall in the PEP tunnel. (One day I need to learn not to be such a retard with the flash).
IR-8
The concrete wall in the center shields large spare pieces of beampipe which are stored just inside the curtain wall.
Still further down the tunnel to go...
The LER beamdump ... I didn't linger.
Looking down from the end of the LINAC toward the LER and HER in the PEP ring. The beampipe in the foreground is the LER injector. Positrons are accelerated down the LINAC and the injected into the LER until it is full. When the LER and HER are full, then the magnets near IR-2 are tuned so that collisions take place inside BaBar.
More ring to go until one reaches the HER injector.
A spring in the wall.
The HER injector.
I decided to leave my own little bit of graffiti in the tunnel as well.
Almost back to IR-2 I finally encountered one of the elusive octopoles.
IR-2 is up ahead.
Tools for surgery on PEP-II.
Ah, the welcome sight of the DIRC on the north side of BaBar means I've completed all ? miles of the ring!
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