RESIDUAL GAS IONIZATION BEAM PROFILE MONITORS FOR THE HERA PROTON MACHINES

Gescribed are beam profile monitors designed for the proton accelerators of the HERA project, namely, the 7 GeV DESY III, the 40 GeV PETRA II and the 820 GeV HERA P machines. Utilizing residual gas ionization (as has been used in many proton accelerators [l-7]), all profile monitors are of a similar basic design offering three main features: 1) "separated function " design, 2) optical sensing of the proton beam image, and 3) selectable modes of operation. The "separated function " feature allows the most critical components to be outside the vacuum. Optical sensing provides a wide field of view with good spatial resolution and allows multiple, simultaneousl but independent readout systems, such as a television camera, a linear array of photodiodes and an image dissector. Remotely selectable modes of use allow the beam profile to be derived from ionized electrons, ions, or both. The proton beam imaging component may be optionally operated with a magnetic field to increase the resolution. Sensitivity of the system can be increased by the use of an external image intensifier or by increasing the internal partial pressure of the monitor by a remotely controlled leak valve