CERN PS Booster Transverse Damper: 10 kHz - 200 MHz Radiation Tolerant Amplifier for Capacitive PU Signal Conditioning

After connection to the LINAC4, the beam intensity in the PSBooster is expected to double and thus, an upgrade of the head electronics of the transverse feedback BPM is necessary. In order to cover the beam spectrum for an effective transverse damping, the pickup (PU) signal should have a large bandwidth on both the low and high frequency sides. Furthermore, in order to extend the natural low frequency cut-off from 6MHz (50' load) down to the required 10kHz, with no modification of the existing PUs, a high impedance signal treatment is required. The electronic parts should withstand the radiation dose received during at least a year of service. This constraint implies the installation of the amplifier at a remote location. A solution was found inspired by the technique of oscilloscopes' high impedance probes that mitigates the effect of transmission line mismatch using a lossy coaxial cable with an appropriate passive circuitry. A new large bandwidth, radiation tolerant amplifier has been designed. The system requirements, the analysis, the measurements with the present PUs, the design of the amplifier and the experimental results are described in this contribution.