A new Compton longitudinal polarimeter currently under construction for HERA is presented. The key component of the polarimeter is a Fabry-Perot cavity located around the electron beam pipe. With such an optical cavity, a continuous laser power equivalent to 5 kW, much higher than those commercially available, can be achieved, leading to one backscattered photon per bunch crossing. This ``few-photon mode'' will allow a very precise determination of the calorimeter response with little systematic uncertainty. The electron polarization measurement at the per mill level is expected.
@article{arxiv.hep-ex/0201033,
title = {Electron polarization measurement using a Fabry-Perot cavity at HERA},
author = {Zhiqing Zhang},
journal= {arXiv preprint arXiv:hep-ex/0201033},
year = {2007}
}
Comments
Talk given at the International Europhysics Conference on High Energy Physics, Budapest (Hungary), July 12-18, 2001. On behalf of E. Barrelet, V. Brisson, M. Jacquet-Lemire, A. Reboux, C. Pascaud, F. Zomer and the HERA POL2000 group