BEAM DIAGNOSTICS WITH IR LIGHT EMITTED BY POSITRON AT DAΦNE

摘要

Real-time beam diagnostics is a key issue of accelerator operations and is certainly one of the most demanding aspects of modern storage rings and 4th generation radiation sources such as FEL's. Compact and vacuum compatible mid-IR fast uncooled photo-detectors have been tested at DAΦNE to monitor single e-bunches with a FWHM of 150-300 ps separated by 2.7 ns. These detectors appear suitable to set up a compact and low cost bunch-by-bunch longitudinal diagnostic device useful to improve the DAΦNE diagnostic. To this purpose a bending magnet synchrotron radiation (SR) front end on the e+ ring has been set-up with a HV chamber, a goldcoated plane mirror and an IR window. The system will allow collection of the SR light for tests of IR detectors and diagnostic of e~+ bunches using a compact optical system installed in air after the IR window. Here we will present the DAΦNE source characteristics, the optical setup and the detector acquisition system that may allow to monitor, identify and characterize bunch instabilities and/or increase the DAΦNE current in the e~+ ring.