Direct diode detection tune measurement in the BESSY II booster

The Direct Diode Detection (3D) method for transverse tune measurement, which was developed at CERN, has been implemented in numerous hadron machines and has recently been tested in electron machines. This method can provide orders of magnitude greater sensitivity to betatron oscillations than conventional beam position measurement approaches, which is particularly useful in fast-ramping synchrotrons such as the Booster of the BESSY~II light source. Typical systems used for tune measurement in an electron storage ring, which rely on the beam being in a relatively steady state, are not well-suited for fast-ramping machines; in order to measure the tune throughout the full acceleration ramp using conventional beam position approaches in the BESSY~II Booster, it is necessary to use large external excitation which disturbs injection into the storage ring. Here we describe tune measurement in the BESSY~II Booster using diode detectors, which allows for tune measurements during the full acceleration ramp with little to no external excitation and therefore no disturbance to user operation.