Polarisation and Polarimetry at HERA
  Longitudinal polarisation of the lepton beam is a key ingredient to the success of the world's unique e\pmp ring collider HERA. This article aims at providing a brief introduction to the physics motivation for deep-inelastic scattering of polarised electrons or positrons off protons, the basic mechanisms to establish lepton polarisation in the high-energy storage ring and to describe briefly the three different polarimeters, which measured both the transverse and the longitudinal polarisation. 
Blanka Sobloher
physics.ins-det hep-ex physics.acc-ph