BaBar Interaction Region and Backgrounds


[ Beampipe Package | Machine Backgrounds | IR Commissioning ]
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BBSIM Beampipe Package

The gnbpip package of BBSIM describes the PEP-II IR geometry and materials and provides support for simulating some machine-related background processes within the framework of GEANT.

The primary archive for the gnbpip package is a CVS repository (click here to review the log of recent changes). Stable debugged versions are also available through the BaBar Software Release Tools (SRT) and become included in coordinated releases of the entire BaBar software base (click here to browse the contents of recent versions of the gnbpip package available through SRT). If you really want the latest features and bugs directly from CVS you can use the SRT addpkg command with the -h flag.

The following material describes aspects of the BBSIM beampipe package in more detail:

Machine Backgrounds

The unique design of PEP-II required to achieve high luminosity and assymetric energies results in high levels of machine-related backgrounds near the IR. These backgrounds can lead to high detector occupancy and radiation exposure and are an important consideration in the designs of both PEP-II and BaBar. The expected sources of detector backgrounds are:

The most comprehensive review of detector backgrounds can be found in Chapter 12 of the BaBar Technical Design Report. The results of more recent calculations of expected backgrounds are described in the following material:

IR Commissioning

PEP-II will begin commissioning of the high-energy ring in the spring of 1997, and of the low-energy ring about one year later. We plan to instrument the IR during commissioning with simple detectors optimized for studying machine-related backgrounds.

Other web sites with material relevant to commissioning:


Go to the BaBar Home Page or the PEP-II Near-IR Home Page

This page is maintained by David Kirkby