Beam Loss Monitors for Energy Measurements in Diamond Light Source

Abstract

Resonant Spin Depolarization is a high precision technique for beam energy measurement employed in the Diamond Light Source storage ring. The relation between spin tune and beam energy can be used to determine the energy of a transversely polarized beam. Vertical oscillations excite the beam at frequencies that match the fractional part of the spin tune and the beam loss rate is used to monitor the beam depolarization. However, the standard procedure of these measurements is intrusive and not compatible with user operation of a light source. The Advanced Resonant Spin Depolarization (AdReSD) project aims to extend and improve the method with the goal of making the measurements compatible with the user operation, for instance by acting only on a small fraction of the stored beam. As a first step, we are investigating the beam loss monitors that will be used to detect beam depolarization. The material, location and optimal geometry of the detector to capture the largest fraction of the radiation footprint resulting from beam losses are studied. Results and designs are presented and future work is discussed.